4-Pack of ICR 18650 Blue Lithium-Ion Rechargeable Batteries 3.7V 2600mAh. Batterie 18650 Li-ion

Learn About 18650 Lithium-ion Batteries

As far as LED flashlights go, most users will tell you that a light which primarily runs on a 18650 battery is usually the preferred choice. Therefore, I predict this discussion on 18650 Lithium-ion batteries to be quite informative.

Where Did The Name Come From?

All lithium-ion batteries get their numeric identifiers from their size. In the case of a 18650, (for instance) it’s 18mm in diameter and 65mm long. The zero at the end simply means it’s cylindrical. Some 18650’s will differ in length…but only slightly. The difference is with those that are “protected”.

4-pack, 18650, blue, lithium-ion

What’s This “Protection” Stuff About?

This means that a protection circuit has been physically added to the cell. This is preferred since it gives the battery added protection from being accidentally over-charged or over-discharged. If you’re given a choice of protected or unprotected, think of the protected cell as being an insurance policy against possible charging failures. Nominal voltage on a 18650 is 3.7 and shouldn’t be discharged below 3.0 in most cases. The added circuit will make certain that while being discharged in a flashlight, the cell’s voltage doesn’t go below that threshold. On the high end, a freshly charged 18650 Lithium-ion battery will normally peak at 4.2 volts.

What Does mAh mean?

A 18650 battery is a very powerful choice when it comes to operating an LED flashlight. A Lithium-ion’s available power is measured in milliamp hours (mAh). The higher the mAh capacity, the better. This ensures longer lasting power from the battery. Cells are marketed with capacities anywhere from 2100 all the way up to 3400mAh. Do yourself a tremendous favor by reading this article on the dangers of buying 18650 cells that are marketed at capacities ABOVE 3400mAh.

Pricey Little Devils!

When shopping for a 18650 battery, you may be surprised at the price tag. But what you’re paying for is a very durable and powerful piece of technology. Many of the LED flashlights made today can crank out up to one thousand lumens of light. To drive a flashlight hard enough to produce this level of light, you NEED a powerful battery! And most 18650 lights will only take ONE cell.

Since these batteries are rechargeable, you’ll definitely get your money’s worth from them! Even though can easily reach up to 30, it’s worth it. You’re getting a quality made, dependable, long-lasting battery capable of hundreds of charging cycles.

I have many flashlights that operate on 18650 batteries and can tell you from personal experience that it’s a quality combination!

The photo is showing two different brands of 18650… EagleTac and Olight. As you can probably make out, the top one is 3.7 volts and the bottom battery is 3.6 volts. Operationally, there’s no difference between the two.

Please note that they’re often available in both button-top and flat-top versions. Protection circuits are included on both.

Flat-top cell on left; Button-top on right

Flat or Button Top?

In many situations, buying a button-top vs. a flat-top makes no difference. BUT, for some flashlights, depending on whether the battery tube features a spring, or a direct electronic connection to the head, it might be a tight fit. This is often due to the added protection circuit, not so much the style of battery. In other cases, the light in question might not work with a flat-top cell. I own a couple that won’t. Although this might be more of an exception, it’s often hit or miss when attempting to marry batteries and lights, and not finding out until the last second if they’re actually compatible!

Bottom line, when shopping for an LED light, pay close attention to the battery configurations recommended for that particular flashlight. Choosing one which accepts a 18650 Lithium battery will ensure many years of dependable service!

Looking to Buy?

It can be tricky shopping for 18650’s, and deciphering the GOOD ones from the BAD!

Therefore I’m suggesting you follow THIS LINK which will take you to an 18650 battery page at Banggood.com. There are many VERY GOOD QUALITY cells at that page!! It’s much SAFER than buying them from Amazon!

What’s your opinion of this article?

Do you have additional questions, or perhaps some personal experience with lithium-ion that you’d like to share?

Please let me know in the Комментарии и мнения владельцев

This is a money-saving 4-pack of high-capacity ICR 18650 3.7V 2600mAh rechargeable Lithium batteries.

These batteries are perfect for solar science fair projects involving solar cells and panels. Also great for building an off-grid solar power system for camping, RVs, household appliances, doorbell cameras, etc.

Multiples can be hooked together in series to get higher voltage or in parallel to achieve higher capacity.

Use it in any device that requires a standard 18650 Lithium battery cell.


  • 4 x ICR 18650 Lithium-ion batteries
  • Button Top
  • Voltage: 3.7V
  • Rechargeable
  • Capacity: 2600mAh (2.6Ah)
  • Power: 9.62 Wh
  • Material: Li-ion
  • Each battery size: 67 mm (2.63 inch) long, 18 mm (0.71 inch) diameter


At our online store, we prioritize providing our customers with brand new and high-quality rechargeable lithium batteries. Due to the nature of batteries, we do not accept returns on these batteries as we cannot verify their usage or condition after purchase. By only selling new batteries, we are able to offer competitive pricing and ensure that all of our customers receive only the best products. Thank you for choosing us for your rechargeable battery needs.

NO RETURNS: Due to the nature of this product and to protect our staff and customers we do not accept returns on this product. You will not be allowed to return this product.

Customer Reviews

Reinhold Schlieper from Palm Coast, Florida Replaced the old battery and got several days more of light in the flashlight used every day for an hour while jogging. I’m impressed.

4-Pack of ICR 18650 Blue Lithium-Ion Rechargeable Batteries. 3.7V 2600mAh Michael from Canon City, Co. USA Excellent purchase. 2nd time I ordered these. Works great.

Delivered quickly Liz from Henderson Being used to Amazon, I was so pleased with how quickly these specialty batteries came.

Great batteries Amanda M Michael from Des moines I bought these for my night owl camera because nightowls only come in 2s. This is the best bang for your buck.

Jonny from Arizona Very good product for the money

They work perfectly! Meridith Lynne Croucher from USA, NY, Newark Came quickly. I had ordered them correctly and they keep our security system running fine!

Jonny from Arizona Great product

Debbie Morgan from Florida My husband was thrilled I found the batteries he needed!! They last an extra-long time and he doesn’t worry about replacing them during the day!! Excellent product!!

1.29 3 x 18650 Lithium Cell Battery Holder. 11.1V 4.99 ICR 18650 Blue Lithium-Ion Rechargeable Battery. 3.7V 2600mAh 4.95 ICR 18650 Green Flat-Top Lithium-Ion Cell Rechargeable Battery. 3.7V 2600mAh 2.59 3.7V Lithium Battery Indicator Tester 1.09 18650 Lithium Cell 3.7V Battery Holder with Leads

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Custom 18650 Battery Packs

Our Vision: Provide world-class Lithium battery pack for customers world-widely DNK Mission: to become an internationally renowned supplier of Rechargeable Lithium ion Battery. Company values: integrity and pragmatic, responsibility


DNK Power offers Custom 18650 Battery Pack Design Services for all of our customers without any charges, You can work closely with our Engineer from the beginning of your device.

ISO 9001 Certified

10 Years of experience and ISO 9001 Manufacturer ensure that All your 18650 battery packs are made right every time. What’s. we have all the certificates like UL, KC, PSE, IEC.


DNK Power has all the certificates of MSDS And UN 38.3 IEC 62133 for our 18650 batteries just ensure your fast Transport by Train, Sea Or Air, We will assist On transportation or even taxes

At DNK Power, we provide services for custom 18650 battery packs for all your industrial businesses and equipment applications, The equipment or system or let’s say our business includes the following batteries


A). Portable Equipment: Post machine, handset, portable printer, data terminal;

B). Medical Instruments: Ecg monitoring instrument, ultrasonic, breath machine, electrocardiograph,Ultrasound devices,Drug delivery systems,Patient monitors,Imaging systems: popular brands like Spectrum Imaging;ACD Systems;Orbital Atk;ECRM;Sirona;Nexus Publications,Ventilators,Defibrillators: Advanced Life Support (ALS), Automated External Defibrillators (AED), Implantable Cardioverter Defibrillators and Implantable Cardioverter Defibrillators (ICDs),Surgical tools: includes ENT Instruments Haemostatic Forceps Diagnostic Instruments Home Surgical Kit Anesthesia,Medical UPS Systems,Motorized wheelchairs

C). Industrial instrument and communication instrument: Flaw detector, fusion splicer, optical power meter, gas detector

D). Consumer Electronics: PDA, MID, PC, POS machine, electric tool, laptop. Ebike, emergency light power, data camera, DV, speaker, mp3, mp4 portable DVD and so on.

E). Portable Equipment: POS, Portable printer, handset. Electric toy: RC car/ boat/helicopter etc.

Our intensive and rigid material selection, production, and QC testing ensure that all of the 18650 battery pack are assembled to meet or exceed customer expectations.

Since medical equipment are used to save lives, maintain health, so they will need high performance of 18650 battery packs to ensure the medical devices are working properly, a small failure would end in disaster. Our rich experiences in cooperation with some of the best industrial equipment brands help us to serve better also for you.

Rechargeable 18650 Battery Cell

Introduction: How to Prolong the Life of an 18650 Battery

About: Battery Bro supplies lithium-ion 18650 batteries and packs to emerging technologies like drones, electric vehicles, robots, Smart appliances, vaporizers. We have cooperated with Hyperloop, Mars Rover, DARPA … About 18650 battery »

There are many important specifications for an 18650 battery, including:

  • Capacity (mAh)
  • Discharge Current (A)
  • Charge Current (A)
  • Maximum Cycle Life

In this Instructable, I want to talk about maximum cycle life, and how you can use this measure to prolong the life of your batteries.

Step 1: Step 1: Learn About Cycle Life

What is a cycle?

When an 18650 battery is charged and discharged, this is counted as one cycle.

  • 18650 lithium-ion batteries are charged up to 4.2V and down to between 2V and 3V depending on the cell’s specification for cut-off voltage.
  • To be safe, never discharge lower than 3.0V unless you know your cell’s specification.

Discharging occurs anytime you use the battery for power. The electricity is drawn from your device, and the battery discharges current. You can also use battery testing equipment to discharge a battery.

How is cycle life calculated?

Cycle life is determined by the difference in capacity of your cell taken from its first-use rating to its present rating. For example, if your cell started at 3000mAh, but now only has 2900mAh. 2900 mAh is 96% of the original capacity.

When this percentage reaches 80%, we say the cycle life has ended (even though you may get a few thousand more cycles out of your battery).

So if we take a 3000mAh cell, when do we say its life has ended?

(80% of 3000 is 2400) so when the cell reaches a capacity of 2400 mAh we say its cycle life is over.

How many cycles does a typical 18650 battery have?

Most modern 18650 batteries have a typical cycle life of 300. 500 (charge, discharge cycles). When in high-amp or high-drain situations, this can decrease substantially to 200 cycles. If you go over the maximum discharge current limit (A) you can decrease the cycle life all the way down to 50 cycles.

In optimal conditions, your cells may achieve more than 500 cycles.

Some chemistries are able to cycle thousands of times before reaching 80% of their capacity.

Step 2: Optimize Temperature

18650 cells are rated normally at between 20 and 25 degrees Celcius.

Any deviation from this will create a slight loss in efficiency. A 10-degree deviation might account for a loss of 20, or 30mAh.

While the extremes, below zero, or above 70 degrees, will see much faster cell degradation.

Using a cell at suboptimal temperatures will decrease its cycle life.

  • Tip: Never charge your 18650 cell below freezing! Eg. in a garage in Winter as it will degrade particularly quick this way

While you are using your cell, if you notice it gets hot, let it rest. Under normaly use your cell should not get hot-to-touch, and should never exceed 60 degrees. If it is getting hot fast, you are over-stressing it.

Step 3: Don’t Overcharge (above 4.2V), Consider Undercharging (under 4.0V)

If you are totally concerned about cycle life and not capacity, then you might not even do a full charge.

Instead, you might do a partial charge. This is when you charge your battery only up to say, 3.8V instead of 4.2V.

You will see decreased capacity, but less stress on your cell and an increased cycle life.

Overcharging will see increased capacity but it’s dangerous and will reduce your cell’s life.

Step 4: Lower Your Charge Current (amps)

Many chargers have the ability to lower charge current. A fast charge may be 1 amp or higher. While this charges your cells faster, it will reduce their cycle life.

Notice this graph, the big difference in cycle life that charging affects.

Step 5: Lower Your Discharge Current (amps)

Remember what a discharge is? If not, I recommend going back to Step 1.

When you discharge a cell you can choose its cut-off voltage like we already discussed. But we can also choose the amperage with which we are drawing current. The higher the amperage, the less capacity we will ultimately see.

Higher amperage discharges (called high-drain) will also reduce the cycle life of your cells.

When possible, use less amperage. Official tests by LG, Samsung, Panasonic, Sony, and so forth usually do their discharge tests at just 0.5 or 0.8 amps.

Step 6: Increase Your Cut-off Voltage

On the flip side of a partial charge is a partial discharge.

Rather than a full cycle, this is known as a partial cycle. It has the benefit of reducing stress on your battery and increasing cycle life.

4-pack, 18650, blue, lithium-ion

So instead of discharging all the way down to 2.8V or however your battery is rated, you might only discharge to 3.2V.

4-pack, 18650, blue, lithium-ion

Step 7: Know Thy Cell Chemistry

Different cell chemistries perform differently.

Many 18650 batteries can reach 1000 cycles comfortable in the right conditions.

The lithium-ion 18650 cell chemistry with one of the highest cycle lives is the lithium iron phosphate (LiFePO4) battery.

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Комментарии и мнения владельцев

Great tips! I am assuming Celsius? 70C notation would be helpful to all the Imperials out here!

that would be 158 degrees, my top shut off is 40c which is 100 so 25c is probqbly what they mean 70f optimal but unlikely, also low temp cut off is 0 so i set mine for 2

I have very old 18650 cells and they charge and discharge at appx 2500mah. How do I tell if they have life left in them before they fail?

I use 18650 of 2600 maH in flashlight and usually recharge my battery when flash light gets 80% dimmer than it’s original capacity.

Is this right way of usage for maintaining good life cycle of my 18650?

I built a bluetooth speaker with 4ohm 6×9 rms 70w and a Bluetooth amp board which operates from 8v to 24v I am powering with 3s 12v. Can I come off BMS board to boost converter input at 12 and out 15v or your suggestion, or 12.5 to get the most out of battery pack I built once battery hits below 8v of course it shuts off with plenty battery left.

First thing you want to do is weigh each cell.,Discard all those that weigh less than 40 grams. There are a lot of fake cells on the market. if they claim over 4000mah and weigh less than 40 grams they are fake cells. They will work for a short time then fail. The jelly roll inside the can is able to expand out and destroy the cell because it is not restricted by the can sides as a good cell is.

You always want to use matched batteries in a pack, especially with lithium batteries. Lithium batteries do not peak charge like NiMH, so I hope you’re using a suitable charger designed for lithiums. In your battery pack with the 18650 batteries, I hope you installed a BMS (battery management system). The BMS will shut the entire pack down as soon as one battery discharges to the low voltage point. Lithium batteries do not, or should not, be discharged to 0 volts, ever. Charge each cell no more than 4.2 volts or less unless it’s a Lipo graphene designed for higher voltage, and I personally never discharged less than 3.4 volts. Remember, a battery pack is only as good as the weakest cell.

I have e-scooter and it’s charger’s output is 42V, 1.5A MAX. So does this mean that it is a very fast charger and will have a big toll on battery degradation over charge cycles?

It depends on the battery capacity not on the voltage.For example if you have 5000mah battery and you’re charging it at the rate of 4A to 5A then I would call it a fast charge. but if charge it at 0.5A to 2A then everything fine!!

How do you get these numbers if at Step 4 it is said: A fast charge may be 1 amp or higher. ?

The article refers to specific cells, that is 18650 cells. No consumer 18650 cell does have more than 3500mAh capacity. At this capacity, 1A charge is considered quick charge. Depending on what is your escooter’s battery capacity, 1.5A charge may be quick or slow. I would also ask what are the cells in the scooter’s battery? Yeah, because what you’ve got there is a battery of cells. Most probably. Overall: if you use manufacturer’s charger, it should be designed for this specific battery, and basing on this assumption, 1.5A should be safe 🙂

My security camera uses the 18650 cell as it is a wireless unit. When I charge the battery, I noticed that it cannot fully charge, and it only reaches about 60 percent of charge potential. I use my mobile phone USB charger which outputs 5V and 2A. The seller suggested that I should be using a different charger that outputs 10V. I really would like the device to be charged to its fullest so I don’t have to keep charging the unit. Can you confirm that a more powerful charge is the right thing to do. Thanks in advance.

Hi,What is the specification for a charger for 4 Li-ion batteries(18650 3.7V 3000mAh) in series?We need it to keep it in series for our project.Our aim is to get 12v supply.

Or you can use a BALANCE CHARGER instead of BMS and settings of balance charger is not at all difficult to remember. its more about usage. if you’re going to use lot of li-ion or any other batteries in future then you can use Balance charger. BMS is just like plug n play. like Smart phone. BMS is meant for one particular designed pack can’t be used for different configuration of series and parallel pack. for that you have to buy a new BMS. but balance charger you can just change the settings to charge any kind configuration of batteries.

In this case I would recommend to use a BMS for 4S (Google bms 4s Li-ion). You will set up the batteries in serial and the Battery Monitor System will monitor each individual cell for you in parallel. So all cells will be connected to the BMS. You can use the BMS to charge and discharge while it will monitor the calls at the same time.

How do you identify lithium ion battery capacity by it’s colour code?

Thanks for those information. i agree, 18650 is the modern gasoline of the modern world, we find them everywhere but we don’t even know.

I didn’t get the part step 5: lower your discharge. Could you explain me the two curves?

Also, How can you in reality use less amperage? Except choosing better devices which doesn’t drain a lot?

4-pack, 18650, blue, lithium-ion

You might, in some cases, not actually reduce the overall amperage. What you would do is add 1 or more batteries in parallel. Thus reducing the load on the batteries and not increasing the voltage. Hope that helped

tedlabete, You want to reduce the amperage drawn from each individual cell, not the total needed for any given device. If your device draws 2 amps, for instance, instead of using two cells which would both need to provide 1 amp, you might use three or four cells, instead. That way each only has to provide 0.60 or 0.5 amps.

Sir if i use 18650 with tp4056 charger to make a project that can forever charge the battery is it safe to work with?

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