# Battery Charge Time Calculator. 18650 battery 5000mah

## Battery Charge Time Calculator

Use our battery charge time calculator to easily estimate how long it’ll take to fully charge your battery.

## Battery Charge Time Calculator

Tip: If you’re solar charging your battery, you can estimate its charge time much more accurately with our solar battery charge time calculator.

### How to Use This Calculator

Enter your battery capacity and select its units from the list. The unit options are milliamp hours (mAh), amp hours (Ah), watt hours (Wh), and kilowatt hours (kWh).

Enter your battery charger’s charge current and select its units from the list. The unit options are milliamps (mA), amps (A), and watts (W).

If the calculator asks for it, enter your battery voltage or charge voltage. Depending on the combination of units you selected for your battery capacity and charge current, the calculator may ask you to input a voltage.

Select your battery type from the list.

Optional: Enter your battery state of charge as a percentage. For instance, if your battery is 20% charged, you’d enter the number 20. If your battery is dead, you’d enter 0.

Click Calculate Charge Time to get your results.

## Battery Charging Time Calculation Formulas

For those interested in the underlying math, here are 3 formulas to for calculating battery charging time. I start with the simplest and least accurate formula and end with the most complex but most accurate.

### Formula 1

Formula: charge time = battery capacity ÷ charge current

Accuracy: Lowest

Complexity: Lowest

The easiest but least accurate way to estimate charge time is to divide battery capacity by charge current.

Most often, your battery’s capacity will be given in amp hours (Ah), and your charger’s charge current will be given in amps (A). So you’ll often see this formula written with these units:

charge time = battery capacity (Ah) ÷ charge current (A)

However, battery capacity can also be expressed in milliamp hours (mAh), watt hours (Wh) and kilowatt hours (kWh). And your battery charger may tell you its power output in milliamps (mA) or watts (W) rather than amps. So you may also see the formula written with different unit combinations.

charge time = battery capacity (mAh) ÷ charge current (mA) charge time = battery capacity (Wh) ÷ charge rate (W)

And sometimes, your units are mismatched. Your battery capacity may be given in watt hours and your charge rate in amps. Or they may be given in milliamp hours and watts.

In these cases, you need to convert the units until you have a ‘matching’ pair.- such as amp hours and amps, watt hours and watts, or milliamp hours and milliamps.

For reference, here are the formulas you need to convert between the most common units for battery capacity and charge rate. Most of them link to our relevant conversion calculator.

Battery capacity unit conversions:

• watt hours = amp hours × volts
• amp hours = watt hours ÷ volts
• milliamp hours = amp hours × 1000
• amp hours = milliamp hours ÷ 1000
• watt hours = milliamp hours × volts ÷ 1000
• milliamp hours = watt hours ÷ volts × 1000
• kilowatt hours = amp hours × volts ÷ 1000
• amp hours = kilowatt hours ÷ volts × 1000
• watt hours = kilowatt hours × 1000
• kilowatt hours = watt hours ÷ 1000

Charge rate unit conversions:

The formula itself is simple, but taking into account all the possible conversions can get a little overwhelming. So let’s run through a few examples.

### Example 1: Battery Capacity in Amp Hours, Charging Current in Amps

Let’s say you have the following setup:

• Battery capacity: 100 amp hours
• Charging current: 10 amps

To calculate charging time using this formula, you simply divide battery capacity by charging current.

In this scenario, your estimated charge time is 10 hours.

### Example 2: Battery Capacity in Watt Hours, Charging Rate in Watts

Let’s now consider this scenario:

Because your units are again ‘matching’, to calculate charging time you again simply divide battery capacity by charging rate.

In this scenario, your estimated charge time is 8 hours.

### Example 3: Battery Capacity in Milliamp Hours, Charging Rate in Watts

Let’s consider the following scenario where the units are mismatched.

First, you need to decide which set of matching units you want to convert to. You consider watt hours for battery capacity and watts for charge rate. But you’re unable to find the battery’s voltage, which you need to convert milliamp hours to watt hours.

You know the charger’s output voltage is 5 volts, so you settle on amp hours for battery capacity and amps for charge rate.

With that decided, you first divide watts by volts to get your charging current in amps.

Next, you convert battery capacity from milliamp hours to amp hours by dividing milliamp hours by 1000.

Now you have your battery capacity and charging current in ‘matching’ units. Finally, you divide battery capacity by charging current to get charge time.

In this example, your estimated battery charging time is 1.5 hours.

### Formula 2

Formula: charge time = battery capacity ÷ (charge current × charge efficiency)

Accuracy: Medium

Complexity: Medium

No battery charges and discharges with 100% efficiency. Some of the energy will be lost due to inefficiencies during the charging process.

This formula builds on the previous one by factoring in charge/discharge efficiency, which differs based on battery type.

Here are efficiency ranges of the main types of rechargeable batteries (source):

Note: Real-world charge efficiency is not fixed and varies throughout the charging process based on a number of factors, including charge rate and battery state of charge. The faster the charge, typically the less efficient it is.

### Example 1: Lead Acid Battery

Let’s assume you have the following setup:

To calculate charging time using Formula 2, first you must pick a charge efficiency value for your battery. Lead acid batteries typically have energy efficiencies of around 80-85%. You’re charging your battery at 0.1C rate, which isn’t that fast, so you assume the efficiency will be around 85%.

With an efficiency percentage picked, you just need to plug the values in to the formula.

100Ah ÷ (10A × 85%) = 100Ah ÷ 8.5A = 11.76 hrs

In this example, your estimated charge time is 11.76 hours.

Recall, that, using Formula 1, we estimated the charge time for this setup to be 10 hours. Just by taking into account charge efficiency our time estimate increased by nearly 2 hours.

### Example 2: LiFePO4 Battery

Let’s assume you again have the following setup:

Based on your battery being a lithium battery and the charge rate being relatively slow, you assume a charge efficiency of 95%. With that, you can plug your values into Formula 2.

1200Wh ÷ (150W × 95%) = 1200Wh ÷ 142.5W = 8.42 hrs

In this example, your estimated charge time is 8.42 hours.

Using Formula 1, we estimated this same setup to have a charge time of 8 hours. Because lithium batteries are more efficient, factoring in charge efficiency doesn’t affect our estimate as much as it did with a lead acid battery.

### Example 3: Lithium Ion Battery

Again, let’s revisit the same setup as before:

First, you need to assume a charge efficiency. Based on the battery being a lithium battery and the charge rate being relatively fast, you assume the charge efficiency is 90%.

As before, you need to ‘match’ units, so you first convert the charging current to amps.

Then you convert the battery’s capacity from milliamp hours to amp hours.

With similar units, you can now plug everything into the formula to calculate charge time.

3Ah ÷ (2A × 90%) = 3Ah ÷ 1.8A = 1.67 hours

In this example, your estimated charge time is 1.67 hours.

### Formula 3

Formula: charge time = (battery capacity × depth of discharge) ÷ (charge current × charge efficiency)

Accuracy: Highest

Complexity: Highest

The 2 formulas above assume that your battery is completely dead. In technical terms, this is expressed by saying the battery is at 100% depth of discharge (DoD). You can also describe it as 0% state of charge (SoC).

Formula 3 incorporates DoD to let you estimate charging time regardless of how charged your battery is.

### Example 1: 50% DoD

Let’s revisit this setup, but this time assume our lead acid battery has a 50% DoD. (Most lead acid batteries should only be discharged to 50% at most to preserve battery life.)

As before, let’s assume a charging efficiency of 85%.

We have all the info we need, so we just plug the numbers into Formula 3.

(100Ah × 50%) ÷ (10A × 85%) = 50Ah ÷ 8.5A = 5.88 hrs

In this example, your battery’s estimated charge time is 5.88 hours.

### Example 2: 80% DoD

For this example, imagine you have the following setup:

As before, we’ll assume that the charging efficiency is 95%.

With that in mind, here’s the calculation you’d do to calculate charge time.

(1200Wh × 80%) ÷ (150W × 95%) = 960Wh ÷ 142.5W = 6.74 hrs

In this example, it will take about 6.7 hours to fully charge your battery from 80% DoD.

### Example 3: 95% DoD

Let’s say your phone battery is at 5%, meaning it’s at a 95% depth of discharge. And your phone battery and charger have the following specs:

As before, we need to convert capacity and charge rate to similar units. Let’s first convert battery capacity to amp hours.

Next, let’s convert charge current to amps.

Because the charge C-rate is relatively high, we’ll again assume a charging efficiency of 90% and then plug everything into Formula 3.

(3Ah × 95%) ÷ (2A × 90%) = 2.85Ah ÷ 1.8A = 1.58 hrs

Your phone battery will take about 1.6 hours to charge from 5% to full.

### Why None of These Formulas Is Perfectly Accurate

None of these battery charge time formulas captures the real-life complexity of battery charging. Here are some more factors that affect charging time:

• Your battery may be powering something. If it is, some of the charge current will be siphoned off to continue powering that device. The more power the device is using, the longer it will take for your battery to charge fully.
• Battery chargers aren’t always outputting their max charge rate. Many battery chargers employ charging algorithms that adjust the charging current and voltage based on how charged the battery is. For example, some battery chargers slow the charge rate down drastically once the battery reaches around 70-80% charged. These charging algorithms vary based on charger and battery type.
• Batteries lose capacity as they age. An older battery will have less capacity than an identical new battery. Your 100Ah LiFePO4 battery may have only have around 85Ah capacity after 1000 cycles. And the rates at which batteries age depend on a number of factors.
• Lithium batteries have a Battery Management System (BMS). Besides consuming a modest amount of power, the BMS can adjust the charging current to protect the battery and optimize its lifespan. iPhones have a feature called Optimized Battery Charging that delays charging the phone’s battery past 80% until you need to use it.
• Lead acid battery chargers usually have a timed absorption stage. After being charged to around 70-80%, many lead acid battery chargers (and solar charge controllers) enter a timed absorption stage for the remainder of the charge cycle that is necessary for the health of the battery. It’s usually a fixed 2-3 hours, regardless of how big your battery is, or how fast your charger.

In short, batteries are wildly complex, and accurately calculating battery charge time is no easy task. It goes without saying that any charge time you calculate using the above formulas.- or our battery charge time calculator.- should be viewed as an estimate.

## EBL INR 26650 Li-ion Rechargeable Batteries 3.7V 5000mAh

### WHAT ARE EBL’S SHIPPING OPTIONS?

Each order from EBL is shipped from the United States and will be delivered by standard shipping with an estimated delivery time of 7-14 business days.

### When will my order be shipped?

We usually take 2 to 5 business days to schedule shipments, except for pre-sales items. A notification will be sent to the customer via email after shipment.

### Which countries do you ship to?

We can ship to the United States, Canada and Mexico.

### Do you ship internationally on your website? Can you ship to my country?

Our website is still testing shipping products worldwide. Therefore, the shipping cost charged at checkout is an estimate and will be based on the actual postage cost incurred when the product is sent by courier (generally based on the weight and volume of the products).Please Note: We will refund the excess if the postage charged is more than the actual shipping charge. Meanwhile, if the postage charged is less than the actual shipping cost, we will also charge the customer for the additional shipping cost.

### Domestic Shipping

Orders over 25

Orders under 25

Standard shipping charge of 5

Weight Between 1-4oz

Weight Between 5-15oz

Weight Between 16-25oz

Weight Between 26-49oz

Weight Between 50-80oz

Delivery areas within the U.S.

EBL official website supports delivery to most areas of the United States. We cannot deliver to the following areas:

• American Samoa
• Guam
• Marshall Islands
• Northern Mariana Islands
• Palau
• U.S. Virgin Islands
• Armed Forces Americas
• Armed Forces Europe
• Armed Forces Pacific

Please note: Power stations and solar panels cannot be shipped to Hawaii, Puerto Rico or Alaska.

### International Shipping

We also offer international shipping to the following countries: Canada and Mexico.

As we are still testing shipping of EBL products to all parts of the world. Therefore, the shipping charges charged at checkout are an estimate and the actual shipping charges will be based on the actual postage costs incurred when the product is sent by the courier (generally based on the weight and volume of the product).

• Batteries cannot be shipped to other countries.
• If the postage charged is more than the actual postage cost, we will refund the excess. Also, if the postage charged is less than the actual shipping cost, we will charge the customer for the additional shipping cost.

### Notes:

1) Standard Shipping is not available for P.O. Boxes and APO/FPO addresses.

2) After the order has been paid, the warehouse needs 2-5 business days to process your order. You will receive a notification once your order has been shipped.

3) If you place more than one order, you may get multiple deliveries. We’ll send you a shipping confirmation email for each order, so you’ll know exactly what to expect and when to expect it.

4) In most cases, the package will be delivered within the estimated time of arrival. However, the actual delivery date may be affected by weather conditions and other external factors. Please refer to the tracking information for the most accurate delivery date.

5) If there is any shipping issue with your package, you must contact Customer Support within 30 days of placing your order.

### How would EBL Official ship my order?

USPS and UPS are our logistics partners to ship out EBL products. we will choose the carrier that we think works best for our customers.

### How do I check the status of my order?

Once your order is picked up by the carrier at our warehouse, we will send you a shipment tracking update email with the estimated delivery date and tracking number. If you do not receive this email, please check your spam or junk mail folder or contact us by email at support@eblofficial.com.

### I ordered more than one item. Will they all be delivered at the same time?

We try to make sure all your items reach you at the same time. Sometimes our products are not always sent together since different shipping options can be used,depending on the product. Once an item has been shipped,you will receive a shipment notification email.

### Why is there no tracking update?

If your order is still under the estimated delivery time frame, kindly wait patiently. Once this process has been completed, you will see tracking updates.

If your order has not been updated for a long time and is overdue, you may contact the shipping courier or contact us for help.

### Can I change the delivery address of my package after it has been shipped out?

Unfortunately, we cannot change the shipping address once the product is in transit.

### What do I need to do when the product I received is different from the one I ordered?

Please provide some details about the issue and contact customer support at support@eblofficial.com.

Welcome to EBL’s Warranty and Refund Policy page, where you can email us directly if you encounter any quality-related problems after purchasing EBL products. We apologize in advance for any inconvenience your purchase of EBL products may cause.

We will take care of all quality-related issues and offer a REPLACEMENT or FULL REFUND, including the return shipping costs.

Please note that this page is for products purchased through eblofficial.com. For products purchased through the EBL store on sites such as eBay and Amazon or from EBL’s authorized distributors, please contact them directly.

## Warranty Period

All products purchased from EBL are guaranteed with a 12-month hassle-free warranty. In each case, the warranty period is measured starting on the date of purchase by the original consumer purchaser.

### Valid Proof of Purchase

A sales receipt from the consumer’s first purchase, or other reasonable proof, is required in order to confirm the start date of the warranty period. Please provide both of the following vouchers when processing warranty claims:

• Provided order number from eblofficial.com.
• The email or phone number or name used to place the order.

### Limited to Original Consumer Buyer

The warranty on EBL’s product is limited to the original consumer purchaser and is not transferable to any subsequent owner.

### Warranty excludes :

• Products without sufficient proof of purchase.
• Damage caused by misuse the faulty parts.(including static discharge).
• Improper installation.
• Damaged by yourself.
• Purchase the product by mistake.
• Neglect, accident or modification, which have been soldered or altered during assembly.
• Complimentary products.

### Exchange

EBL will replace any EBL product that fails to operate within the applicable warranty period due to defect in workmanship or material. The replacement product assumes the remaining warranty period of the original product.

## Refund

We offer a 30 day hassle-free money back guarantee on items purchased directly from eblofficial.com. ( We only provide prepaid return label for quality problem products. Other than that, customers need to pay for the return shipping fee. ) If for any reason you are not satisfied and would like to return an item, please let us know within 30 days.

Refunds can only be issued to the original payment method and cannot be issued to other cards or bank accounts. Refunds will be processed within 3-5 business days, and refunds generally take 10-15 business days to be returned to the original payment method.

Note: Once the package is shipped, any shipping costs paid at the time of the order, if applicable, are non-refundable.

There are certain situations where only partial refunds are granted:

• Products with missing parts that do not affect normal use.
• Products that cannot be replaced and have quality problems in part.

Return shipping costs should be paid by the customer in the following situations:

• Purchase the product by mistake.
• Usage of product contrary to its stated instructions.
• Returning products without any proven defect.
• Removal of identification labels such as, but not limited to, the original label, patent, serial number, or trade dress.
• Damage caused by improper storage, abuse or user error.
• Neglect, accident or modification, which have been soldered or altered during assembly.

### How do I return an item?

• Get in touch with us and start the return process within 30 days of the original shipping date.
• Provide proof of purchase from eblofficial.com (either the email address, phone number used to register, or order number).
• The product should be returned in its original packaging, unused, and in the same condition as the item you received.
• Refunds will be processed within 3-5 business days after we confirm receipt of your returned items at our warehouse.

## ⚡ 26650 Rechargeable Battery ⚡

### 【26650 Battery Specifications】

Store humidity

≤70mQ2(AC Impedance, 1000 Hz)

26650 cell dimensions/26650 battery diameter

### 【 Ultra Long Lasting 】

EBL high-performance Li-ion 26650 batteries have been manufactured with premium raw materials and high-density cell technology, they will give your devices enough power and last longer, so you can rest assured to use your various devices.

### 【 High Quality Competitive price 】

100% Brand New and High quality. 3.7v 26650 With a high capacity of 5000mAh, it can last a long time. Superior performance under low-temperature conditions. EBL 26650 li-ion rechargeable batteries for high power LED flashlights, electronic devices and other equipment 26650 size(please carefully confirm whether your equipment needs 26650 size before your order)

### 【 Safety】

Quality Steel Shell, very sturdy and durable. Effectively prevent the 26650 rechargeable battery from leakage and short circuit.

### 【S torage 】

The rechargeale 26650 cells stored in the RT (room temperature), the 26650 battery’s cell should be charge once per 6 months to avoid the cell over-discharge. The customer should charge the cell for I hour by 0.5C for long-term storage.

The 26650 li-ion battery working principle is to release energy by electrochemistry to provide the power; actually, it is a chemistry product so that it should be re-charged to active the battery energy after a storage period because its performance will be attenuated after long term storage. If you cant to knwo more information about battery storage, related battery storage article here: Battery Storage Guidelines!

### 【 What You Get 】

2/4/8/16 Pack lithium rechargeable 26650 batteries 3.7V 5000mAh

All ebl 26650 batteries are protected by plastic battery case. Reliable Li-ion packing.(Provided with every pair of 26650 rechargeable batteries purchased )

We also sell 26650 rechargeable batteries with charger/ 26650 battery charger As reputable battery wholesaler, you can bulk buy batteries in our Eblofficial store at very affordable price, but high quality household batteries and rechargeable battery chargers.

【What is the size of 26650 battery?】

A 26650 battery is a type of cylindrical rechargeable lithium-ion battery, 26650 battery size: 26mm 65mm(DL). It is one of the larger rechargeable battery sizes and is commonly used in high-drain devices such as flashlights, power tools, and electric bicycles. The 26650 battery has a high capacity and can provide a substantial amount of power, making it a popular choice for high-powered devices that require long-lasting energy.

【Are 18650 and 26650 interchangeable?】

No, 18650 and 26650 batteries are not interchangeable because they have different battery sizes. Since the 26650 battery size.26mm 65mm(DL) has a substantially bigger diameter than the 18650 battery size.18mm 65mm(DL), it cannot be used in accessories made for that smaller battery.

## Everything You Need to Know About the 18650 Battery

This article tells you everything you need to know about 18650 batteries. We’ll talk about different types, features, charging, lifespans, and our recommendations for batteries and chargers.

• What is an 18650?
• Recommended 18650 Batteries
• Various Battery Sizes
• Comparing 18650s to Other Common Batteries
• 18650 Terminology
• Protected vs Unprotected 18650 Batteries?
• How much power does an 18650 have?
• How many times can you recharge an 18650 or other battery?
• How frequently should I recharge my 18650?
• How do I know my 18650 is Dying?
• How can I measure the quality of an 18650 if I am unsure of the age of a battery?
• 18650 Battery Chemistry
• What are 18650 batteries used for?
• What is the best travel 18650 battery?
• What 18650 Brands are Best?
• s

## What is an 18650?

An 18650 is a lithium ion rechargeable battery. Their proper name is “18650 cell”. The 18650 cell has voltage of 3.7v and has between 1800mAh and 3500mAh (mili-amp-hours).

18650s may have a voltage range between 2.5 volts and 4.2 volts, or a charging voltage of 4.2 volts, but the nominal voltage of a standard 18650 is 3.7 volts.

There are two types; protected and unprotected. We absolutely recommend protected cell 18650 batteries. Protected cells include a protection circuit that stops the cell from being overcharged.

Unprotected cells can be overcharged and burst and potentially cause a fire unless there are specific electronics to protect the battery. The popular LG HG2 and INR and Samsung 25r and 35e are UNPROTECTED batteries, only use them in a device designed to use unprotected 18650s.

We also recommend you stick with high quality brand name 18650s. Knock offs may lie about high mAh (capacity).

The average 18650 battery charge time is about 4 hours. Charge time can vary with amperage and voltage of the charger and the battery type.

### Recommended 18650 Batteries

 Battery Make and TypeAll are 3.7v Lithium Ion (Li-ion) Max Milliamp hours NotesShop around for best price Orbtronic 18650 Protected #ORB3500P 3500 mAh Only available direct from vendorgood price Olight ORB-186C35 Protected #ORB-186C35 3500 mAh Ok price Nitecore 18650 NL1835RProtected #NL1835R 3500 mAh Good for travel, expensive.Has micro-USB charger port so it can charge itself with a cable/USB port Panasonic NCR18650BD ButtonProtected#NCR18650-BD 3180mAh Less expensive PROTECTED and good for high drain devices. Panasonic NCR 18650 3400mAh NOT PROTECTED#NCR18650B-3400 3400 mAh Less expensive but is NOT PROTECTED. Use carefully. Panasonic NCR18650BE NOT PROTECTED#NCR18650BE-3200 3200 mAh Less expensive but isNOT PROTECTED. Use carefully.

### Various Battery Sizes

The following is a picture showing various battery sizes. The 18650 is 1170 cubic mm, the 14500 and AA are 700 cubic mm, the AAA is 467 cubic mm.

Note the 14500’s cannot be used in all AA devices unless they support both 3.7 and 1.5 volt batteries. The 21700 at 1550 cubic mm, is larger than the 18650 battery – the 21700 and 18650 is not interchangeable.

### 18650 Terminology

A battery might say protected mode 3.7v 18650 3000 mAh low self discharge for high drain devices. What does that all these features mean?

• “protected mode” means it has an overcharge and overdraw circuit protection built in (more info below).
• “3.7v” – is the optimal or peak voltage. It will drop as you use the battery.
• “3000 mAh” measures the amp hours the battery can provide. A higher number is better. The highest realistically available on an 18650 today is about 4000 mAh, anything higher than that is marketing hype.
• “Low self discharge” is a good thing. That means it will hold a charge in storage. The less it loses in storage the more charge will be left for you to run your flashlight or other device.
• “for high drain devices” – the battery is optimized for high drain devices. These are devices that use a lot of power very fast, such as RC toy car.

### Protected vs Unprotected 18650 Batteries?

Protected 18650 batteries have an electronic circuit. The circuit is embedded in the cell packaging (battery casing) that protects the cell from “over charge”, heat or “over discharge”, over current and short circuit. A 18650 protected battery is safer than an 18650 unprotected battery (less likely to overheat, burst or start on fire).

Unprotected 18650 batteries are cheaper, but we do not recommend their use. Unprotected batteries should only be used where the load/draw and charging is externally monitored and controlled. The protected batteries normally have a “button top”, but check the specifications to make sure. Generally 18650 flat top batteries do not include the protection circuit.

If any 18650 battery is damaged or looks corroded or appears to be leaking, get rid of it at a battery recycling center. Be safe.

### How much power does an 18650 have?

A 3.7v a 3400mAh 18650 stores about 2 aH to max of 3.5 aH. It can store about 10 to 13 watt hours. A small air conditioning unit that can cool about 9000 BTU uses about 1100 watts per hour. So it would take more than 110 of the 18650 batteries to run the air conditioner for 1 hour.

In comparison you would need three 12v 40 amp car batteries. But 110 18650s are smaller than three car batteries.

### How many times can you recharge an 18650 or other battery?

Recharge cycles vary and are limited. Think of it like a bucket. The trick is that the bucket also gets filled with a tiny bit of other junk over time, so there is less room. As the battery is reused (recharged), the battery degrades due to oxidation and electro-chemical degradation.

This happens to any rechargeable battery such as an 18650, 21700, 26650, 14500, AA, AAA or even a car battery. They can only be recharged a limited number of times.

You want to select rechargeable batteries that can be recharged many times. We specifically recommend 18650‘s because they have the ability to be recharged 300 to as many as 2000 times.

### How frequently should I recharge my 18650?

The way you recharge your battery impacts the life of the battery. If you can measure it, you want to deplete from 3.7v down it to about 3v before you recharge. If you are not sure, use the device until it indicates a battery needs to be replaced. For a flashlight, run it till the light is dim or goes out.

A good charger will tell you the voltage of the battery so you can eventually get a sense of the life of the battery in various devices. If you recharge too frequently you “use up” the life without a return.

Some people don’t let it dip below 3.3v (or even higher). Each brand and model of 18650 has different maximum cycles. So this is really a process of matching your device and usage to the life cycle of the battery.

Be aware that an 18650 battery that drops below 2.5v may “lock” the device so it can’t be used. The “lock” function happens in devices such as vaping devices.

### How do I know my 18650 is Dying?

Here is a list of 7 ways you can tell if you need to get rid of an 18650 (or other rechargeable battery). Look through these to determine if your 18560 is nearing the end of its life and needs to be retired:

• The battery will lose a charge on the shelf must faster than normal. It loses it’s charge after a couple of days or even worse overnight.
• The battery gets hot when charging or discharging, warmer than normal.
• You have used the battery frequently over 2 to 3 years.
• The battery can hold less than 80% of its original capacity.
• Recharge time gets abnormally long.
• If there is ANY cracking or deformation in the battery.

These are the 6 signs your 18650 is dead and it is time to get a new one. If you ignore these warning signs you risk fire or even having the battery explode while being recharged.

### How can I measure the quality of an 18650 if I am unsure of the age of a battery?

A trick is to buy one or two similar 18650s and mark them “new” with a Sharpe (or label them A, B, C, etc). Then use them and compare their voltage and discharge rates with the questionable 18650s.

Basically you are comparing good vs unknown this way.

You can also gauge temperature this way. Charge both the new and unknown one to see how hot the new one is compared to the one you are unsure of.

### 18650 Battery Chemistry

There are a number of different chemical combinations for 18650 batteries. We recommend that you FOCUS on protected mode, the chemistry can change and isn’t always reported. Many simply say Li-ION (meaning Lithium Ion).

There are actually a number of Li-Ion batteries. Here are some of the current “types”. Depending on your device type one might be better than the others.

• LiFePO4 which is Lithium iron phosphate
• also known as IFR or LFP or Li-phosphate
• LiMn2O4 which is Lithium manganese oxide
• also known as IMR or LMO or Li-manganese (high amp draw)
• LiNiMnCoO2 which is Lithium manganese nickel
• also known as INR or NMC (high amp draw)
• LiNiCoAlO2 which is Lithium nickel cobalt aluminum oxide
• also known as NCA or Li-aluminum
• LiNiCoO2 which is Lithium nickel cobalt oxide
• also known as NCO
• LiCoO2 which is Lithium cobalt oxide
• also known as ICR LCO Li-cobalt

### What are 18650 batteries used for?

Flashlights, electronics, laptops, vaping and even some electric vehicles use 18650s. The Tesla uses 7180 of these batteries. Many high lumen flashlights such as the Thrunite TC15 v3 (best buy) or Fenix PD36 TAC (mo43 durable) use the 18650 or the even larger 21700 flashlights like the Nitecore P20iX a 4000 lumen flashlight.

Laptops and other electronic devices use one or more 18650’s and have recharging electronics built in. 18650’s are also used in vaping (smoking) devices.

18650s are are generally Lithium Ion batteries. If you are familiar with electronics you can change out some battery packs manually, but be careful – using the wrong type of 18650 or using it incorrectly can cause a fire.

## Which is the Best 18650 Battery?

Overall best 18650 battery – The Orbtronic 18650 battery. This is an 18650 3.7v 3500mAh Protected cell. This is a high drain battery. We like it but it is expensive.

Best low cost 18650 battery – The Olight ORB-186P26 18650 2600mAh 3. The Panasonic 18650 is an 18650 3.7v 2600mAh Protected cell. This battery is less expensive and slightly lower amp hours than the Orbtronic. Also, this lower cost protected 18650 battery is still more expensive than the unprotected ones.

### What is the best travel 18650 battery?

Nitecore NL1834R (currently not available on Amazon but available directly from Nitecore). This is an 18650 3.7v 3400mAh protected cells with a built-in micro-USB charger. It is a few dollars more, but it allows you to charge it on the go and not have to carry a dedicated charger. The unit we have has slightly different packaging.

The cheapest decent one is the Titanium Innovations 18650 at 2600mAh. It won’t last as long as the 3400 mAh Nitecore but is 1/2 the price.

### What 18650 Brands are Best?

The Orbtronic, Olight, Samsung, LG, Panasonic, Surefire, ThruNite and Nitecore are good reliable 18650 rechargeable cells. Be sure to buy them from a reputable source such as BatteryJunction or direct from the manufacturer. Note: Amazon stopped selling 18650s.

We don’t use the lower voltage and amperage 18650s, because they have lower amp hours and low peak wattage and lower sustained wattage.

We are willing to pay a few more dollars for the longer life, higher capacity and better quality.

## 650 Battery Charger

18650 batteries are rechargeable, so you will need a good charger. We use two different 18650 chargers.

The best 18650 battery charger is the Nitecore Ci4 because it can charge pretty much anything.

Specifically, it supports: lithium ion 26650, 22650, 21700, 18650, 17670, 18490, 17500, 18350, 16340 (the 16340 is also known as RCR123), 14500, 10440 and Ni-MH and Ni-Cd AA, AAA, AAAA, C rechargeable batteries. This is our favorite charger for the 18650s.

Our runner up and “best buy” is the XTAR X4 Charger. It is a USB powered 18650 charger. It charges the batteries with any USB power source. This unit is dependent on the power source, and is a bit more expensive.

It has an LCD display for charging status. A 2amp interface yields slower charge speeds. Even the 5amp is slow because it charges at.5 amps. We have used the XTAR and Nitecore with a Nektek solar panel that has a 2amp USB interface and it has consistently worked.

## 650 Flashlight

The best mid priced 18650 flashlight is the Thrunite TC15 2403 lumen flashlight. It is about 1/2 the price of the PD36 and but a bit less bright. It is a GREAT buy (we have the older TN12 in emergency kits). We suggest two of these instead of one of the Fenix.

It has the following modes: Strobe (975 lumens for 226 minutes), Turbo (975 lumens for 126 minutes), High (652 lumens for 199minutes), Medium (266 lumens for 9.7 hrs), Low (19 lumens/177 hrs) and Firefly(0.29 lumens for 62 days) and it can charge itself with a USB power source. It is waterproof (IPX8) and has a max throw of 223m (764ft).

The toughest 18650 flashlight is the Fenix PD36 TAC. It is not cheap but it is durable and very bright, and has a clip. The light level is 1000 lumens, and it is water resistant to IPX8. This is a “duty” quality flashlight.

The PD36 TAC offers five different brightness levels and strobe:

• Turbo: 3000 lumen – 1 hr 30 min
• High: 1000 lumen – 3 hr 15 min
• Medium: 350 Lumen (8hr 24min)
• Low 150 lumen – 18 hr 45 min
• Eco: 30 lumen – 160 hr
• STROBE (about 3hrs 2000 lumen)

It has a 300 yard or 274 meter throw.

Both the Fenix PD36 or TN15 are great LED Flashlights that use the powerful 18650 battery.

It makes a HUGE difference when you share our articles. Thank you so much!

## 1 Комментарии и мнения владельцев

August, can you kind of put this in ‘plain English’ for us less tech savvy folks? Are these better than say, nicad batteries? longer life usage wise as well as recharge times wise? Are they more cost effective than other rechargeables? I don’t mind a larger up front cost if it is going to save me more money in the long run. DH uses rechargeable batteries for his work equipment (cheaper stuff, but company reimburses him) and if we can find something more cost effective, that would be great.

Hi August, I enjoy your articles and the great information they contain very much and those of your wife also. I just have one small complaint. Your articles can be shared on social media everywhere for people all over the world but you don’t have a print function. Many times I want to print an article to reference later without trying to remember which website it was on. For everyday living commonsensehome would be one of the first places I would look, but for a certain battery I might have to check seventy different sites and no telling how many articles. Please think about adding the print button.

I totally understand your dilemma and we wanted to provide that feature. Laurie and I researched (and regularly check) for a printing plugin. None of the ones we found so far work on all platforms (Windows, unix, Android, iPhone, Apple mac etc). Here are a couple options: (1) In many browsers you can right click and select print (2) cut the entire post and paste it into your favorite editor and print (3) use the specific browser print function.

Hi August, thank you for putting this article together! I bit the bullet and bought a 2018 Lupine Blika headlamp to use on week long ski trips here in Alaska. Really only use the 3 watt output setting, the larger bulbs give an unnecessary amount of light and drain a battery VERY quickly. The battery pack that came with the head lamp is small and I need more capacity but the larger OEM battery packs are prohibitively expensive. Owner’s manual says the OEM battery packs have 18650 batteries in them so I figured I’d just buy 18650 batteries and make up my own battery packs. Discovered when I went shopping for batteries that there are apparently dozens of 18650 battery types/outputs and I have no idea which one to use. The battery voltage in the owner’s manual says 7.2 volts and it has a visual battery level meter built right into the the battery pack. I’m afraid of 2 things: I assume the OEM battery pack has circuitry to give a consistent power output so the light stays near the same brightness for the duration of the battery discharge cycle. If I make up my own battery pack, I’ll lose that circuitry and may toast my very expensive headlamp due to too high or too low power input. Is there a stand alone voltage, wattage unit I can buy to put in line to properly regulate my home made battery pack output? And, which 18650 battery will be the best for my usage? Because I’m carrying them, low weight and high capacity is necessary. Thank you for any answers you have for my above questions and thank you for putting out this great site! Matt Obermiller

Thanks for the positive feedback. In response to your comment, the output must match the unit you are using. The 1860 I note in the article is protected mode, so it will not burn up or draw outside spec (that is the battery side). The headlamp battery pack may have a voltage regulator built in. The only suggestion I have is to tinker; but only if you can afford frying one. A lot of the LED emitters circuits will take any 18650 – but some may damage the circuit without protection on the LED side OR they may accept any voltage and work fine. The little AA flashlight we reviewed, will use either an AA or 14500 which are dramatically different, so the only way to find out is test it. Watch out for overheating and be prepared to fry your electronics. If you succeed (or fail), would you mind writing a guest post on this? I am sure the community would appreciate the information. Regarding weight, all 18650s are all fairly heavy. I have not seen a LIPO 18650 yet, but they might be available somewhere. If you are going for lightweight the Energizer Ultimate Lithium AA are super light but one-time use. You would need an AA based headlamp such as the Fenix HP15 – and then you could pick AA rechargeables such as Eneloop Pro or Tenergy are both good depending on use profile – in your case I think the higher mAh would be better from the Eneloop Pro. It really depends on what you are doing. If you are out for long periods the solar panel and rechargeable AA or 18650 would potentially cut your load (and allow you to charge a cellphone or any other USB device) but only if you carried more batteries than the weight of the solar panel. The nektek is 1.3lbs though so unless you need to charge a lot of stuff and are out for a long time this probably isnt an option. (ounces are pounds) All the best.

This is the 1st time I’ve ever heard of these and boy am I confused! I’m guessing that you don’t replace your regular rechargeable AA or AAA batteries with these? I’m going to read up and educate myself. This must be something that preppers are into. Love the preppers but the “prepping” is too overwhelming for me being average 65 year old female. Just had to share. I love reading all of the interesting things that preppers are doing. Thanks for letting me share. Debbie

No worries, Debbie. If a device needs an 18650 battery, it’ll be labeled somewhere that it needs one. No swapping out your current batteries required. It’s just a way to cram more power in a relatively small package. Some preppers use them, I’m sure, but they’re mainly for electronic gadgets that suck a lot of power – like our small LED flashlight that’s bright enough to light up the back of the ten acres from the front of the 10 acres.

Hi August. My question is how do I know if my 18650 batteries are not discharging cocorrectly? I bought some Samsung 25R and was notified by the seller not to use them as they were from a bad batch that were not discharging correctly after I had already been using them. They seemed to be working just fine, but I stopped using them anyway. But I have a lot of other 18650 batteris that I use for vaping and would like to know what I need to be on the lookout for. Thanks for your time.

Good question. A bad 18650 can burst or damage the electronics using it. Some electronics have overload protection which greatly reduce the likelihood of damage. Your device may have that protection so the battery is protected once by the in battery “protection” (which might be failing) and again by the device. Regardless, if the manufacturer/seller is recommending not using them, I would stick with that. A burst 18650 is a mess. Get them to give you replacements and move on.

im trying to change dead 18650 batteries in a triple drill battery pack they have the code SE US 18650VT but i cant work out which battery i need, i know they are only 1.5 a/hr…(can i upgrade to bigger) 12v drill the other line under that code is.T C112VSG19R. this is the line i cant interperit or find any info on.thanks for any feedback…cheers

It’s probably safest to contact the tool manufacturer directly. If it’s a battery pack (versus individual batteries), they probably have proprietary battery packs and using anything else is likely to void the warranty.

You’re welcome. Sorry I don’t have more specific info, but there are a LOT of different tools out there, and many companies are bundling the 18650s for specific applications, even solar electric systems. If you’re past your warranty period on the tool, are handy, and the company is no help, you could try swapping out the batteries in the pack with well rated 18650s. I just snagged August and he’s going to comment more on this option.

We cant recommend any tinkering… but we have done it successfully on a laptop and a simple battery pack (both out of warranty). The risk is that you will damage electronics or even start a fire. Many of the devices are built in a way that you cannot easily access the battery packs. Also some are be designed for a specific voltage and/or amperage. The fact that tons of devices use 18650’s in series or parallel make them a tempting self repair project. All we can say is stay safe and if you choose to tinker and are successful, please leave a comment so others will know too. There are YouTube DIY rebuild videos for various brands of battery packs. All the best.

I have seen 18650 battery’s advertised with capacities up to 9900 mAh. Are these real? Is that a maximum a 18650 can be in mAh?

The highest current stable 18650 battery is 3500 mAh. I fully expect the research to improve over time. 9900 is not real. Also watch out for batteries without overcharge protection. Check reviews carefully. Best of luck.

After quick research, I believe it is a different form factor of battery. Not an 18650. The “S1 S2 S3 S4 S5” battery, is a brick design for cellphones, specifically a code that matches the form factor for the specific Samsung model. In my mind those are not 18650’s even if they are described as one. They are square or rectangular and thin and unique to a specific device. They use similar technology to an 18650 and fit inside a cellphone, tablet or other thinner portable computing device.

1s, 2s, is gow many cells in series. series connection will increase voltage, parallel will increase capacity. 1s would be 1 cell @3.7v 2s would be 2 cells connected positive to negative (think old flashlight stacking batteries in handle) @ 7.4, 3 s being 3 cell- @ 12.1v and so forth.

hello, I am a dentist and use my led surgical light powered by battery pack of two pack 18650 2200mah, I just replaced my battery pack with a fresh battery pack. question: how can I make my battery pack last longer? use it till it drains and then recharge? or keep it connected to my charger intermittently through out the day as I use is daily. thanks Drlopez

Good question. We added a couple sections in the post to answer this. A quick answer is you want to balance recharges with “using up” the battery. Check your specific battery specifications for lifecycle and charging recommendations. In general though, if you recharge before the battery is at least partly depleted you “lose” a recharge – and batteries only have 300 to 2000 total recharges before they should be replaced. Generally you want the battery to drop from 3.7v to about 3v. In other words don’t top off a 3400mAh battery at 3300mAh instead charge it at 2500mAh or even 2000 (where you choose depends on the number of recharges you expect and the devices sensitivity to low voltage/amperage). I hope this helps.

Hi August. I do not agree with you regarding the charging of batteries. If you look at the datasheets of these batteries, you will see that the lesser the drain on the battery the longer the battery will last. It is the same with cellphone batteries, also Li-ion. My cellphone battery get charged every night. Mostly my battery still have 35% to 45% charge left. I have no problem getting 2-3 years life out of my cellphone battery. Years ago people was told to fully discharge the battery before charging. That might have been correct for old battery types like Nickel Metal Hydrate batteries, but Li-Ion batteries give you the best life performance if you can keep them between 40% to 80% charge. I viewed the datasheet of a 100Ah Li-FePo4 battery pack, used for solar systems, the other day. It is rated at 2000 charge cycles, but they gave a graph showing expected life time at different discharge depths between charges. If you don’t discharge it more than 50% you can get almost 20 years life out of the battery, based on every day recharging via solar.

You are correct. It is why I like larger packs where possible (higher wattage at same voltage to allow lower overall drain). And as you noted, this is recommended by the manufacturers and has to do with the design of the 18650 batteries. I don’t follow all the rules, I leave mine in flashlights and other devices until they don’t light up the way I want. So I am not staying in the 40% to 80% range. I don’t worry about the cycle rates because 2000 is awesome but 500 to 1000 is just great too and I don’t have to monitor them all in detail, but if you do you can drastically extend their life. Thanks for the feedback.

I’m trying to use 18650 in a trail camera as directed by the owners manual. The 18650 I bought are Nurie18650-1A. 3.6 v. 2600mAh, it call for 2 batteries in the camera. How do I know if these are the correct battery ? It mentions something about PR200 when discussing the battery ?

I believe you are asking about the PR200 Trail Camera – it looks like that model requires any two 18650s. Although the Nuon NURE18650 will work, it lists that it is a high self discharge battery (it loses charge just sitting around). Also, the Nuon is only 2600mAh. Instead I recommend a 3000mAh to 3400mAh protected mode low self discharge 18650, such as the: Samsung, Panasonic, Orbtronic, LG or Nitecore. Finally, you need to confirm with the camera manufacturer manual for exact information and battery types.

Hi. What a useful website! I am in the process of changing the Samsung 1500mAh18650 batteries on my AEG vacuum cleaner. it is 5 1/2 years old and they have gone already! (joke). Am I best to replace with the 18650 3500mAh units. Same physical size etc. Also, the manufacturer’s instructions are to leave the cleaner permanently on charge. Is that a good idea? Thanks

High mAh will in general be safe- it will just run longer (more capacity) – the wattage is 3.7v x 1500 = 5500m-watts vs the 3.7v x 3500 = 12,950 m-watts. The “charge all the time” part is more tricky. It depends on the device, electronics and charger. If you get lower self discharge batteries i suspect you would only want to charge it before use (or after its dead). You really need to confirm with the manufacturer to confirm – if they have another small battery in the electronics the trickle charge could be to keep the unit powered. I cant be sure, so use your best judgement.

Hi August, I am one of those species that are naturally inquisitive and will forever “tinker” with everything. the latest being replacing my NiCD batteries in my cordless drill with LI-ion batteries. I have matched the voltage and the drill 18V works fine. I have not yet recharged the batteries.,Can I use my NiCD charger to charge the replaced LI-ion batteries? A friend of mine bought me Rekieta 18650 12000ma/h3.7v batteries from a china shop which I have tried in a similar way on my 14.4v drill, also matching the voltage. Sadly the drill does not work although the voltage is correct. the lettering on these batteries are very foreign and I cannot determine whether they are indeed rechargeable or not. HELP.

August is up to his eyeballs in alligators at work at the moment, so not much time for the site. From what I was able to find online at this QA on Quora “Can I use a NiCad battery charger for lithium?“, the most likely answer seems to be “No. voltage profile, current profile, and current tapering profile are all different.” Batteries can explode or have a meltdown under conditions that they were not designed for, so be careful.

I just received a flashlight that uses a 18650 battery. The flashlight says “shustar”, “Albinaly”, and “CE RoHS” in different places. The battery says “shustar”. The wall charger has a light on the plug-in part that glows yellow when plugged in; don’t know if it changes color when the battery is fully charged because I just started charging the battery. Did I get anything worthwhile? I assume the battery is not a protected type.

The best I can say is track back the manufacturer and try to find the specifications and documentation. I do not know which make/model devices you are using. We recommend the better reviewed, name brand flashlights and chargers. The name brand are a few more dollars but you can call for support and they have wider reviews. Regarding the battery, we recommend that you use a protected mode 18650 regardless of the device unless it specifies an unprotected 18650.

The solar panel USB feed is a good idea. To confirm runtime etc I would need specs on the panel. Two 18650s provide up to 25ah where the two AA provide 9ah. So the panels (if they charge even with lower quality batteries should do far better than the internal AAs and last for years. Solar Panel. The wattage (output) of the solar panel and amount of sun it gets is key. If the panel can’t get enough sun the batteries will eventually die. Solar Panel 18650. Nearly all manufacturers use the cheapest battery that will perform in the device. Unprotected are cheaper so they build the “protection” into the electronics instead of the battery. If you replace the unprotected battery with a better protected battery it will likely give you better life but I cannot be sure. If the panel gets enough sun it is probably unnecessary to replace the batteries right away. One way to confirm them is remove them and put them in a protected charger to check their max wattage. Alternate solution. The 6 MinPak waterproof 6×18650 pack could use your old vaping batteries and still have more than 10x the watt hours. If it works, you could just change them out every 3 to 5 years, recharge and replace. This might be a better pick for wooded areas. As I don’t have specs, any “creative solutions” would need to be tested.

Hello August: I have a cordless vacuum (Type AE – 14.4V DC) hat uses 4 batteries LGDAHB31865. I searched and find that this refers to a 18650 BATTERY. I want to replace it for equal or ideally better ones. I live in Canada and I do not find the reference above mentioned anywhere other than China. Could you please help me with some brand name, reference o place where I could buy it. I’m older and the vacuum is like new and been working well for me (light and handy), but the batteries are almost dead after 2 years and the manufacturer offers no help even know it is a big Company. Thanks in advance Jaime R.

Yes the LGDAHB31865 is a High Discharge LG 18650. They appear to be available on eBay. I can’t suggest using any other battery. The risk is that the electronics might be tweaked to match that specific battery (charge/draw). First, idea is to charge the LGDAHB31865 batteries outside the unit to see if they truly are dead (if they dont charge then you know its not your unit). Second idea… I suspect you could use two 2 packs Orbtronic 18650 batteries (I have these). There is a risk that this could damage the vacuum or the new batteries. I suspect the Orbtronic might allow the unit to run longer also. Although I cannot recommend it, if you test it out please keep us posted. Best of Luck Jaime R, sorry I could not provide a definitive answer.

August, thank you for your prompt answer. I’ll check on eBay to see if they have it. The solution of the Orbtronic 18650 batteries, will be more expensive than buying a new vacuum. Nowadays, it is difficult to find and appliance that last more than 2 years.

Yup that is why they use cheap batteries, everything is about cutting unit costs. BatteryJunction.com might have cheaper one unprotected 18650s (which I suspect that your vacuum is using). We buy the expensive batteries and they last much longer. Again be careful, the electronics could smoke if they had a tight match to the battery specs (and remember unprotected 18650s can burst).

August, this is the type of batteries that this machine uses (http://www.cylxpower.com/previewimg.jsp?fileID=ABUIABACGAAgseS5xQUo7rLI8wYw6Ac46Ac); I guess they are unprotected. I did find on eBay from a Canadian seller this (https://www.ebay.ca/itm/2X-18650-9900mAh-Li-ion-Battery-3-7V-Rechargeable-Canadian-seller/333462620310). Do you think that will work? Thanks again for all your help.

Hi Jaime. August is having an extra crazy week at work (they dumped a big project that would normally take months in his lap and want it done this week), so I decided to chime in. For better or worse, the only way to know for sure it to try and see if it works. The odds look good, but you can’t tell for sure until you try.

Please let me be BLUNT! There is no such thing as an 18650 Cell that can deliver over 4000 MAH! NONE Any advert saying that their battery provides this is a Lie False Adverts! and from testing they are usually less than 2400 Mah. Additionally they have a high “internal” resistance, which means that there is a higher voltage drop at higher current levels. My personal guide line would be : Buy Japan or South Korea mfg 18650’s ALL China branded are inferior and/or falsely labeled. Many of the Adverts are just LIES! Amazon and Ebay should stop listing them.

Hi, I just recently started buying LED flashlights powered by 18650’s. I understand the higher mAh batteries give longer runtime, but now I just ordered a “high power” flashlight that says to use “high discharge” rate batteries of 10A or more, so my question is, can you tell if a 18650 cell is “high discharge” just from the numbers/ letters printed on the side of the battery? Thanks, Ed

Some battery types are designed for high discharge, some are “LSD” low self discharge. The high discharge ones generally don’t hold a charge in storage, but do a good job of providing power fast. The low self discharge ones don’t provide power fast but also don’t “leak” power over time. If you have an 18650 battery you will need to research the type of battery to find out if it is normal, low self discharge or high discharge.

Ok, August, so if I understand you correctly, most high discharge batteries will say on the casing “High discharge” or similar- These are the batteries I got; https://edisonbright.myshopify.com/collections/batteries/products/3-pack-edisonbright-ebr34-3400mah-18650-rechargeable-li-ion-protected-batteries. and I am ordering this flashlight; https://lumintoplighting.com/lumintop-gt-mini-pro-3500-lumens-xhp502-led-high-intensity-outdoor-flashlight-p0068.html. which is 3500 lumens- I don’t want to smoke the battery…. Seem like they might work? Thanks, Ed

Ed, It would be best to check with the people selling that specific flashlight. We haven’t used that particular product before, and they should know the items they’re selling.

There are far too many general statements here. The author states his opinion of the best batteries and flashlights. Some of my flashlights are definitely better to use unprotected cells for the same reason some of my vape devices do. The protection circuits are sometimes built into the lights now, and protected batteries will not allow the amp draw needed because they are capped at 10 to 12 amps. Also the best light is often based on the intended use…do you need a long throw, more flood, or combination. Some lights now even have proprietary batteries and chargers. That is the case with Olight Seeker 2, but you can actually use an externally charged 21700 orbtronics protected battery with the buttontop closest to the cap. You can’t however charge that battery in the light. The Olight special modified battery re-routs a negative contact to the positive side for the magnetic charging. The negative terminal on the light is at the head.

Hi August, Is it safe for 18650 batteries to be “plugged in” all the time, for example in applications like emergency back up lights, where they come on only during power outages? Regards, Paul

August is up to his eyeballs at work, so I’ll chime in. While it might not be ideal from a battery life perspective, if that’s what the device requires to function, that’s what it requires to function. It should not be safety concern (no risk of explosion, etc).

I’m buying a protected 18650 battery for a solar charging light in my garage. I only need one, but the SH is the same as the price of one battery. If I order 2 or 3 and don’t need them for 2-4 years, will they still be good or am I better off just buying the one now and deal with it.

After doing some digging, it looks like most people are not having any issues with 18650 batteries that have been stored a few years. The article “Proper 18650 Battery Storage” suggests a charge of roughly 40% for best storage life.

## How to Know a Fake 18650 Battery

About: Tech nerd like web technologies and gadgets. Kitesurf on weekends and recently got involved in 3D printing technology. About danleow »

An average genuine 18650 batteries will weigh about 45g and no nothing less than 42g. You can see I have a fake 18650 battery in the pic weigh 32g only and the genuine 18650 battery weight 45g. Some genuine 18650 battery can weigh more than 50g. Good brands will tell you the weight of the battery.

You can use a digital kitchen scale.

Why fake 18650 battery weigh less? That is because inside is a smaller battery with step up circuit which wrap in layers of paper and stuffed inside a 18650 battery size case then heat shrink in a tight plastic label sheet to make it look real.

Genuine sellers will specify battery weight in their product description/sheet.

Did you make this project? Share it with us!

## Комментарии и мнения владельцев

There is a lot of great info here both in the video and in Комментарии и мнения владельцев too. I am learning from everyone I can about using these 18650 batteries but I dont see much info about their C ratings only mAh’s/fake or not. I use them for very high discharge applications (custom r/c vehicles) and now using an awesome little spotwelder to help create them. No more trying to solder/fail batteries. If i can figure out how to create (instructables) i will. https://youtu.be/TJq31wVMOuw

Fake is the wrong word. A fake battery would be one that is not a battery at all. In fact, there are empty cells made that are not fake, they are simply sold as empty to fill a mechanical void for battery packs with odd numbers of cells, and are used to fill a space mechanically for the structure of tha pack, without unbalancing the individual strings of cells. This is common in higher density packs that have staggered string sizes, or a pack with a specific shape, but wanting to maintain the fullness of the pack within that shape.

There are a lot of different capacity cells sold, and each weigh a different amount. There are a lot of reasons for using smaller cell sizes, ranging from reducing the cost of the cell for marketing or cost reasons, to safety regulations for a particular regulated application. There are safety standards for appliances used in critical or hazardous environments that might limit how much lithium is present, or have containment requirements that reduce how much you can put in a cell and still meet the safety spec. A cell that is integrated as a backup of short duration might be made for one application, and find it’s way to the surplus market where it is sold on ebay. Nothing fake going on there, as long as no lies are being told.

If the battery has a rating that matches it’s actual capacity, any capacity or weight is valid. That is a big IF as exaggerations and rip-offs are common. Anyone can cut the shrink wrap off a cell, and replace it with a new wrap, with whatever markings they want. These repackaged cells can simply be remarketed cells, or actual forgeries of popular brands. Some flashlight makers rebrand all batteries they sell. Some are honest and some are not.

And besides capacity specifications, there are safety features, and the absence or presence of cell protection circuitry that has an impact as well.

When evaluating a cell from a new vendor, you should perform a capacity test where you drain a cell to the rated cutoff voltage, then test the charge cycle to see how much charge it takes, then perform a discharge at both slow and fast rates to see the results from thos tests. Discharge rates matter! The slower you discharge a storage cell, the more power in total you get from it. And that affects the cell rating for a given application. So the same cell can have a different capacity depending on what it is used for.

And a sand filled cell sounds fishy, and probably is. Unless there are weight requirements that need to be met coupled with a lower capacity requirement. The buyer of a manufacturer’s production run is responsible for the specifications of that run, and their reasons and final product markings could be honest or dishonest. While I would agree in principle that dishonestly market batteries are somewhat fake in nature, the word fake is not an accurate word in most cases. A buyer will always do capacity spot checks as part of the qa of the incoming parts, as most parts have a certain percentage of bad units, and for a product build there will need to be some way to accommodate for the occasional bad part, especially from a new manufacturer or from a surplus supplier. Even new chips might be remanufactured pulls from scrap electronics, so the incoming QA team is there to keep suppliers honest.

So you are right that there is more to a battery than the claims printed on the shrink wrap cover. But the QA process is so much more than just weighing the cell.

## UltraFire 5000mAH 18650 Review: A Case Against This Battery

Today we are going to be conducting an UltraFire 5000mAh 18650 Battery review. While it might be one of the most economical options for energizing a vape pen, the battery’s capacity is just not up to snuff compared to one of the best batteries.

The price point for UltraFire is perhaps what entices vapers the most. The batteries can be found on eBay for under two dollars. However, when tested, the TR 18650 UltraFire has a fraction of its advertised battery life.

Some UltraFire 18650 battery reviews have blamed the poor battery life on bad cells. But the majority of users suggest that these particular batteries are merely cheap and poorly manufactured.

The one benefit of purchasing on eBay is that most of the sellers will offer free returns if you are not satisfied with your batteries. Therefore, you can be guaranteed your money back if the battery does not perform as advertised.

## UltraFire 5000mAH 18650 Review

The TR 18650 batteries received this rating because, as the majority of users claim, the cell life just doesn’t meet the officially designated capacity.

In fact, the batteries only reach about 1000mAH on average. They also cannot reach high currents.

### Pros

In the course of conducting an UltraFire 5000mAH 18650 review, one of the central plus sides was that the batteries are extremely cheap and readily available. Some users also claim that their batteries functioned properly, and held their recharging capabilities.

There are reports of users recharging their UltraFire 5000mAH 18650 batteries for several months and not seeing any compromised battery power. This kind of feedback occurs for about every one out of fifteen users.

The upside here is that the batteries are so cheap you could very feasibly buy a set to try out and then return them if they don’t end up functioning properly. You’d have to do this on either eBay or Amazon, though. Otherwise you’d run the risk of not be guaranteed a full refund. There are so many available on both websites that you will have no trouble finding competitive pricing.

It is also widely known that mAH on almost all batteries are going to be overstated. So, some users consider the fact that, for the price, the TR 18650 batteries only reaching 1000mAH is not such a bad thing. Furthermore, during all my tests with the batteries, they charged up properly without becoming overheated.

### Cons

Unfortunately for these batteries, the downsides still outweigh any of the benefits. Being that the official specifications are way higher than the actual performance of the batteries, most users feel that they were duped into buying a cheap and falsely advertised product, rightfully so. The batteries claim to be capable of recharging up to 1000 cycles, when they barely held their charge after just two.

Most users share a similar experience. If you were going to be taking your vape on a trip for business or a long car ride, these batteries will most likely leave you high and dry.

I read that one user made sure the batteries were fully charged, put one in and couldn’t even get his vape to turn on. The UltraFire TR 18650 5000mAH is also an unprotected battery, even though it is advertised as being protected on the cell itself.

The small electronic protection circuit protects against common hazards like overcharging, short-circuiting, high temperatures, and over-discharging. In addition to being a much safer bet all around, the protected cells are also generally last much longer than unprotected, and hold their recharge life much better. Most users like to spring for the protected options as it provides them a little more peace of mind; I know I’m one of them.

UltraFire battery reviews also seem to make a note that the batteries were constructed in China, and vapers are weary of Chinese mAH ratings being way off. Unless of course it is a more trusted brand. In almost all the tests that we performed for the UltraFire battery review, the levels were dramatically below the official specifications.

The discharge begins to lose capacity around 2 amps. Discharge time slowly diminishes down to under an hour after a few charges. Maximum discharge power and energy output also beings to crash at around thirty minutes once the batteries have been taken off the charger. Not to mention the button on the top is missing those critically important vent holes to avoid eventual overheating.

## Other Services

The UltraFire brand does offer some other useful products and services. Perhaps not too much for vapers, though. One of the great advantages for buying products on the official UltraFire website is that they offer a 180-day warranty. (Unfortunately, the UltraFire TR 18650 5000mAH are not sold on the website.)

The shop also has a number of competitively priced recharging stations and quick-charge stations for reusable batteries. But the most innovative and useful tool on the UltraFire docket is their portable solar panel with its own USB output, priced at thirty-five dollars.

### Conclusion

As you can probably tell by the UltraFire review above, I am not the biggest fan of this product. I’m perfectly ok with spending a little extra to make sure that the quality of the battery I’m receiving will be dependable, safe, and, perhaps most importantly, not compromise my vape.

However, there are plenty of options available to show those in doubt about the superior rechargeable battery for vape pens. The Sony VTC 4 18650 is popularly considered to be the most powerful and longest lasting rechargeable battery, and great for vape pens.

There is also the LG HG2 3000mAh and Samsung 25R 2500mAh which are industry favorites and have accurate mAH ratings that you can depend on.

This video compares a few different batteries: