18650 Rechargeable Lithium-Ion Battery 2 Pack. 18650 lithium battery pack

How to Calculate a Lithium-Ion Battery Pack‘s Capacity and Runtime

Capacity Varies With Load Current. Batteries have a nominal capacity, but their real capacity depends on the current being drawn from them.

Capacity is a function of the type of battery you are using, the load current, temperature and age of the cell. The capacity of lithium-ion batteries can be reduced by as much as 25% at high current (C rating) and operating temperature as compared to their published capacity. Manufacturers typically publish the the capacity when the load is C/5 or one fifth of the rated capacity. When you are trying to determine the capacity at your use conditions, a bit more engineering is required.

Batteries have internal impedance which reduces capacity and runtime at high load currents. Basic battery calculators don’t account for the reduction in capacity. The best solution is to generate empirical cycling data at the desired current or use an advanced battery calculator that accounts for the cell’s unique impedance profile.

Cell Capacity 101:

What is a Cell’s Rated Capacity? A Lithium Ion battery’s published rated capacity is the capacity of the cell when the load current is one fifth of the rated capacity (the C Rate). When the current varies from C/5, the capacity will change due to chemical reaction rates including a chemical effect called concentration polarization.

What Is the Capacity of a Cell When the Load Current Increases ? If the load current is greater than one fifth of rated capacity, the capacity and runtime decreases. The cell’s capacity will be less than the rated capacity.

What Is the Capacity of a Cell When the Load Current Decreases? If the load current is lower than the rated capacity, the capacity and runtime increases.The cell’s capacity will be grater than the rated capacity.

Method 1. Standard Battery Calculators

Standard online battery calculators us the formula

Benefits of Standard Battery Calculators. The calculator is very helpful because it provides a first order approximation for the runtime. You can experiment with our standard calculator here.

Limitations of Standard Battery Calculators. This formula is only an approximation because it uses the same rated capacity regardless of the load current. The actual capacity of a cell varies with the load current.

18650, rechargeable, lithium-ion, battery, pack

Method 2. Use a Cell Data Sheet Discharge Curve

Use a cell data sheet (like this one for the MoliCell ICP103450DA 2200 mAh Cell) for the specif cell you are assessing. Use the discharge curve to approximate the capacity at the desired load current then use the formula Runtime = Capacity at Load Current/Load Current

Advantages of Discharge Curves. When available, discharge curves provide a more precise calculation for runtime as they are based on empirical data.

Limitations of Discharge Curves. Even when vendors provide data sheets, they may not be the most helpful. For example, the LG INR 21700 M50LT and Samsung NR21700-50E are very popular Lithium-Ion 21700 cells with ~4900 mAh capacity. Their data sheets only contain the cell’s capacity at the standard discharge rate of one firth of the rated capacity (know as C/5). Further, Discharge curves only show a few different load profiles. For load profiles not displayed, the capacity can only be approximated. They only show the capacity of a fresh battery and don’t show how the capacity desegregates over time.

Method 3. Use an Advanced Lithium-Ion Battery Pack Calculator

Advanced battery pack runtime calculators account for internal impedance by utilizing empirical cell cycling data to provide a more accurate runtime calculation. Each cell has a unique chemical profile which gets captured through cell cycling and uploaded to a database. The advance calculator uses the cell’s impedance profile to calculate the capacity at the load current. You can try our Advanced 18650 Lithium-Ion Battery Pack Calculator.

Advantage of Advance Battery Pack Calculators. Advanced battery pack calculators are a great way to get a quick answer. You can experiment with what if scenarios and compare different cells at the same time.

Limitations of Advance Battery Pack Calculators. Advanced Battery Pack Calculators require a large database of cell cycling data. Often times, the cell you are considering may not be part of the dataset. The result is based on a mathematical model and therefore has some variance from the true capacity. Advanced battery pack calculators are therefore best used for engineers looking to understand how different batteries behave under varying load conditions.

Method 4. Use Empirical Cell Cycling Data

The most precise way to determine a cell’s runtime is to cycle multiple cells on a battery analyzer under the same conditions the cell will be used. Analyzers can be run with varying currents, constant current loads, constant power loads, and pulse currents. The resulting data will provide both the voltage curve across time and the variance from cells within a lot.

Advantages of Empirical Cell Cycling Data. Cycling data will provide the most accurate results. Cycling a battery hundreds of time can also provide data on how capacity desegregates with use. Using a thermal chamber, cycling studies can be performed at varying temperatures.

Limitations of Empirical Cell Cycling Data. The greatest limitation is time and cost. Cell cycling data, especially under low currents can take weeks or months to generate.

Rose offers lab testing services. We offer the first cycle for free! To find out more, contact us for lab testing services.

Example: MoliCell’s ICP103450DA 2200 mAh Cell

The MoliCell ICP103450DA is a very popular prismatic cell. It’s rated capacity is 2200 mAh. As we can see from the below discharge rate characteristics, this capacity is only at 0.44A, which is one fifth the rated capacity. At a load of 0.44A, the cell will have a capacity of 2200 mAh and a runtime of 5 hours (2200 mAh divided by 440 mA)

What if we increase the load current to 4A? What will happen to the runtime?

  • Method 1: Using a Standard Battery Calculator. If we use the standard battery calculator formula, we would use the rated capacity of 2200 mAh, calculate the runtime as 2200 mAh divided by 4000 mA and conclude the runtime is 0.55 hours or 33 minutes. This is only an approximation.
  • Method 2: Using Use a Cell Data Sheet Discharge Curve

As we can see from the chart and the datasheet, under a 4A load, the battery capacity decreases to ~1980 mAh. The runtime will therefore be 1980 mAh divided by 4000 mAh which is ~0.4950 hours or ~29.7 minutes. The capacity decreased because the high current increases the internal impedance.

Method 1s answer was off by about 11%

Advance battery pack calculators use empirical data. Under lab conditions the the capacity may be closer to 1982 mAh. The runtime will therefore be 1982 mAh divided by 4000 mAh which is ~0.4955 hours or ~29.7 minutes. The capacity decreased because the high current increases the internal impedance.

Method 2 produces a similar result to method 3 because both use empirical data

Under lab conditions the the capacity may be closer to 1982 mAh. The runtime will therefore be 1982 mAh divided by 4000 mAh which is ~0.4955 hours or ~29.7 minutes. The capacity decreased because the high current increases the internal impedance.

Method 2, 3 and 4 will produce similar results because they use empirical data


A basic battery calculator is a great way to get a first pass approximate calculation for battery runtime. As the load current varies from one fifth of the rated capacity, the calculation becomes less accurate. The best way to calculate runtime is using empirical data that is unique to the cell, because each cell has a different non-linear impedance profile. Empirical data can be obtained using a data sheet, Advanced 18650 Battery Pack Calculators or cell cycling.

650 Rechargeable Lithium-Ion Battery 2 Pack

Solaray 18650 rechargeable lithium-ion batteries are ideal for use in medium and large flashlights as well as other devices.

The 18650 rechargeable lithium-ion battery is ideal for use in medium and large flashlights as well as other devices.

Features and Benefits

These batteries come with a Protection Circuit Board (PCB). This limits the amount of energy the battery can absorb and release. It also helps to prevent battery from being overcharged or short circuiting while in use.

It holds more energy yet weighs less compared to other batteries. This means that you can get more use out of a single charge cycle while not adding to the weight of your device.

Do not use together with e-cigarettes. An explosion or fire can occur as a result of overheating.

In addition, they should not be used as a replacement for other battery types. Please read the relevant documentation for your device prior to using them.

Battery Specifications:

18650, rechargeable, lithium-ion, battery, pack
  • It has a normal capacity of 3,000 mAh and a minimum capacity of 2,200 mAh.
  • The normal voltage is almost 3.7 volts with a cutoff voltage of 2.5 volts.
  • The internal impedance is less than or equal to 180 milli-Ohms.
  • It can hold almost 90% of its original charge after 400 cycles.
  • The total cycle life is almost 500 full recharge cycles.
  • It has a charge current of 0.5C (~1500mA) Voltage which equals 4.2 V End Current or 0.01 mA.
  • It has a discharge current of 0.5C (~1500mA) End Voltage or 3.0V.

2 x 18650 3,000mAh Rechargeable Lithium-ion Batteries.

So don’t delay. Click “Add to Cart” to buy today. Add a BC-1 Battery Charger to take advantage of our free shipping on orders 25 and more.

User Manual

Downloadable PDF File

EBL 18650 Lithium Rechargeable Batteries 3.7V 3000mAh for Vaping. Flat Top


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.

Thank you for your understanding.

International Shipping

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

And we can ship to other countries, but only for wholesale orders. Please contact us at support@eblofficial.com for more details.

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).

Please note

  • 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.


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

18650, rechargeable, lithium-ion, battery, pack

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.

Delivered but Not Received

If the tracking information shows that your package has been delivered, but you cannot find it, please wait two business days for it to arrive. In the meantime, we recommend that you check your home and ask your neighbors if they may have received it for you.2. If after that you still haven’t received it, please contact us via support@eblofficial.com and we will be happy to help you.

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.

If your product is defective during the warranty period, please contact us by mail or via live chat and let us know what we can do to help you.

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:

18650, rechargeable, lithium-ion, battery, pack
  • 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.

How to claim warranty?

To obtain warranty service, please contact our customer service team at support@eblofficial.com.


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.


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.

Late or Missing Refunds

If you haven’t received your refund, first check your bank account again. If payment was made by credit card, we will refund the money to your account once we receive the product. Please allow 10-15 business days for the credit to be applied to your credit card or original payment method.Then contact your credit card company, it may take some time for your refund to be officially posted. Next contact your bank. There is usually some processing time before the refund is credited. If you have done all of this and you still have not received your refund, please contact us at support@eblofficial.com.

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.

650 lithium battery pack

Lord Kelvin born (1824)


NewBeeDrone provides the best customer service in this industry.

If you have questions, please send an email to: support@newbeedrone.com

Let customers speak for us

Arrived quickly as expected, well packaged, easy to install and performed as expected.

I got a bunch of these for my source micro and baby ape long rangers. They work great on my sub 250 high flyers

Brought this antenna as a replacement for my tinywhoop, found out that when the antenna came off it also ripped the connector off the pad. I will still have use for them as a spare, looks to be good quality and a suitable replacement. Warning it is a little longer than a normal tinywhoop receiver antenna.

Would not buy any more. I have not got it to work i have not heard back from foxeer about it. Can not update it at all and it does not work out of the box i have tried 4 defferent cameras and cables that work on a true hdzero vtx.

While this tiny whoop may not be the lightest or have the most powerful video transmitter, it has been a blast learning the basics of flying and a few tricks as a beginner. With that being said, I’ve ran into a few problems. The strength of the solder joints on the motor wires is questionable, one came undone in a small crash. Another aggravating issue was that the battery leads on my quad were very short, they needed to be bent extremely bent in order to connect the battery. After a few short weeks the ground cable came completely disconnected at the connector head. These problems were fixed relatively easily but it’s something to keep in mind if you’re getting started in the hobby. I broke the canopy in one mounting place on the third day of owning the drone but it has been holding up and the frame seems very resilient to damage.

Leave a Comment