5 Things to Know Before Buying custom lipo battery pack

31 Mar.,2025

 

15 things every LiPo battery user should know - The Drone Girl

LiPo batteries are generally safer and more environmentally friendly than other R/C batteries like NiCd and NiMH. LiPo batteries have become the most common high performance R/C battery and are used in R/C cars, boats, planes, helis, multirotors, and more. However, if charged, discharged, stored, maintained, or handled improperly, they can become extremely dangerous. This is a simple guide for safe LiPo battery ownership and use.

Click here to get more.

This guide applies to all R/C LiPo batteries including all the “smart” batteries made by DJI, like the Smart Batteries designed for Phantom drones, the Intelligent Flight Battery for the teeny Mavic Mini drones and the Intelligent Flight Batteries made for DJI’s racing drone, DJI FPV.

1. Never charge, discharge, use, or store a damaged or puffy LiPo battery.

Immediately follow proper disposal protocols.

2. Avoid purchasing used LiPo batteries.

While some items are smarter to buy used to save money and help the environment, LiPo batteries are not one of those things. You never know what the previous owner did with them and they could already be badly damaged. “LiPo Battery Like New, Used Once” is usually a scam and should be avoided.

3. Don’t leave your batteries fully charged — or fully dead for long periods.

Depending on how they are used, most LiPo batteries typically do not last longer than 300 charge cycles. But the way you treat your batteries can have an impact on whether they last longer or shorter than the average.

Leaving them around on a full or depleted charge all the time, running them completely dead, or exposing them to high temperatures will shorten this lifespan dramatically.

4. Always use a proper LiPo battery balance charger/discharger when charging and discharging your LiPos.

It is crucial that all cells in a LiPo battery maintain the same voltage across all cells at all times. If the voltages across the cells deviate too much from each other (5mV ~ 10Mv), the battery can become unstable and dangerous. (Unless it’s a single cell LiPo, in which case you do not need to worry about cell balance).

To make it easy to charge or discharge your battery to the perfect level, use a balance charger/discharger, which you can find for less than $50 (ensure the one you buy is compatible with your own set of batteries).

If you have a DJI drone, use DJI’s two-way charging hub (again, check to make sure the specific hub you buy is compatible with your DJI drone).

5. Never overcharge a LiPo battery.

Typically a full charge is 4.2v per cell. Never “trickle” charge a LiPo battery. Luckily, the aforementioned LiPo battery balance charger/discharger can help ensure you charge it to the perfect level.

6. Never discharge a LiPo battery below 3.0v per cell.

And in that same vein, letting the charge get too low can be bad, too, so keep that LiPo battery charger on hand even if your drone flights are on pause for an extended period of time.

Ideally you never want to go below 3.2v per cell to maintain a healthy battery. 2.9v per cell and lower is causing permanent damage.

7. Never leave your LiPo batteries sitting around on a full charge for more than 2-3 days.

If by the 3rd day you realize you are not going to use your battery today, you need to discharge your battery down to 3.6v-3.8v per cell for safe storage until you are ready to use the battery again.

8. Always use a fire proof LiPo safety bag, metal ammo box, or other fire proof container when you are charging, discharging, or storing your LiPo batteries.

While LiPo fires are rare, they can happen incredibly quickly and can do a lot of damage. All it takes is an internal short circuit to set the battery off. There is no way to predict when it will happen. It does tend to happen more often when batteries are fully charged, being overcharged, or while being discharged, but it can happen to any LiPo at any time. Never fill the container to capacity with your batteries, always follow manufacturer recommendations on LiPo bags for how many mAh’s it can safely contain. It’s ALWAYS worth investing in an (under $10) explosion-proof LiPo bag or ammo can.

9. Do not use your flight case/travel case for long term LiPo storage.

To really hammer the point home of ammo cans and other more serious storage protocols, realize that the foam and plastic in these cases can help spread a LiPo fire. Always use a fire proof container such as a metal ammo box or fire proof safe for storage.

10. Never leave your LiPo batteries charging while unattended.

If a battery starts to become puffy, smoke, or catches fire you need to be able to immediately handle the situation. Walking away for even just 5 minutes can spell disaster.

11. A LiPo fire is a chemical fire.

Always keep a Class D fire extinguisher nearby your battery charging/discharging and storage area. The battery charging/discharging and storage area should be free from any materials which can catch fire such as wood tables, carpet, or gasoline containers. The ideal surface for charging and storing LiPo batteries is concrete or ceramic.

12. Care for your LiPo batteries properly.

Always store your LiPo batteries at room temperature. Do not store them in a hot garage, or in a cold refrigerator. Even though a cold battery has less chemical reaction taking place which can prolong its lifespan, taking a battery out from a cold fridge can cause condensation to occur on the inside of the battery, which can be very dangerous. The next two points go into greater detail on temperature:

13. Avoid letting LiPos get too hot.

Always remember that heat is the number one enemy of LiPo batteries. The hotter your batteries get, the shorter their lifespan will be. Never charge a battery that is still warm from usage, and never use a battery that is still warm from charging.

14. Avoid letting LiPos get too cold.

Sure, heat is the enemy, but the cold isn’t exactly friendly. LiPo batteries do not work well in cold weather.

The colder it is, the shorter your run times will be due to the slowing down of the chemical activity within the battery. If it is below 14F (-10C), LiPo usage is not recommended at all. Your battery could cause your R/C vehicle to suddenly fail without warning in these temperatures.

15. Always pack your LiPo batteries in your carry-on bag and never in your checked baggage when traveling on an airplane.

Not only is it the law, but it’s common sense. The Transportation Security Administration specifically states that drones are allowed through TSA checkpoints, meaning you can bring a drone in your carry-on bag. However, the TSA does have some rules around packing lithium ion drone batteries — which can restrict how you can travel with a drone.

All spare, or otherwise uninstalled lithium ion and lithium metal batteries, such as drone batteries are only allowed in carry-on baggage, according to the Federal Aviation Administration. Lithium ion drone batteries are not allowed in checked baggage. There are also limits on watt hours.

When flying with a drone, it’s recommend to pack your batteries (in your carry-on luggage, of course) in a fireproof battery pouch. For multiple drone batteries, there are full fireproof Lipo battery storage bags, and they typically won’t cost more than $20.

For more information, please visit JOINSUN.

-Written by Jessika Farrar

Jessika Farrar is the founder of ASG Aerial and specializes in aerial photography for personal and business use. Visit www.ASGaerial.com to learn more, or to book an appointment.

Jessika Farrar is also the Network Administrator for the S.W.A.R.M. Network where thousands of pilots from around the world volunteer their skills to help connect life saving drone technology with missing people. Go to www.SARdrones.org to learn more about how you can help.

Related posts:

  • Shop burns down after suspected LiPo fire: chat with Jim Bonnardel
  • LiPo battery may have caused the RC shop fire

Quick Facts About Lipo Battery Packs

Part 1. What is the lipo battery pack?

A lipo battery pack, or lithium polymer battery pack, is a type of rechargeable battery commonly used in various applications such as RC vehicles, drones, electric vehicles, and portable electronics. It’s part of the lithium-ion family but differs in its construction and performance characteristics, which make it ideal for devices that require high power output with minimal weight.

Key Characteristics of Lipo Batteries:

  • Lightweight: One of the most significant advantages of lipo batteries is their lightweight nature. The battery cells are housed in a flexible, pouch-like casing rather than a hard, cylindrical case, making them much lighter than traditional batteries.
  • High Energy Density: Lipo batteries offer a high energy density, meaning they can store a lot of energy relative to their size and weight. This makes them highly effective in applications where space and weight are critical, such as drones and RC cars.
  • Customizable Sizes: Lipo battery packs can be tailored to specific applications, allowing users to choose the voltage and capacity that suit their needs. This flexibility is a major reason why lipo batteries are so popular in hobbyist and DIY communities.
  • Higher Discharge Rates: Lipo batteries can provide higher discharge rates than their lithium-ion counterparts, making them perfect for high-performance devices that require a quick burst of energy.

Components of a Lipo Battery Pack:

A lipo battery pack is composed of several lipo cells connected together. These cells are usually made of lithium cobalt oxide or lithium iron phosphate materials, depending on the battery’s application. The cells are connected in series or parallel to create the desired voltage and capacity.

  • Series Connection: This connects the positive terminal of one cell to the negative terminal of the next. The voltage increases with each cell added in series, but the capacity remains the same.
  • Parallel Connection: This connects all the positive terminals together and all the negative terminals together. The voltage remains constant, but the capacity increases as more cells are added.

Additionally, most lipo battery packs contain a battery management system (BMS). The BMS protects the cells from overcharging, over-discharging, and ensures each cell is balanced, which is crucial for safe operation.

Part 2. Lipo cell vs. lipo battery pack

It’s important to understand the difference between a lipo cell and a lipo battery pack, as they’re often used interchangeably but serve different purposes. Here’s a more detailed comparison:

In essence, a lipo cell is a single battery unit with a defined voltage, while a lipo battery pack is a collection of cells that work together to provide the power necessary for more demanding applications.

Part 3. What do S and P on a lipo battery pack mean?

When looking at a lipo battery pack, you’ll often see numbers like 3S mAh or 6S mAh. These numbers might seem confusing at first, but they’re actually essential in understanding the pack’s configuration and performance.

S (Series)

  • The S represents the number of cells connected in series. When you connect cells in series, you add up their voltages, but the capacity (measured in mAh or Ah) stays the same.
  • For example, a 3S pack contains 3 cells connected in series, which gives a total voltage of 11.1V (3 x 3.7V).
  • A 6S pack contains 6 cells, resulting in a voltage of 22.2V.

P (Parallel)

  • The P refers to the number of cells connected in parallel. When cells are connected in parallel, their capacity increases, but the voltage stays the same.
  • For example, a 2P pack would have two cells in parallel, doubling the total capacity (e.g., mAh becomes mAh).
  • A 1P pack means the cells are arranged one by one, with no increase in capacity.

Part 4. Lipo battery pack vs lithium-ion battery pack

While both lipo and lithium-ion battery packs belong to the same family of batteries, there are significant differences that affect their performance and suitability for specific applications. Here’s a more in-depth comparison:

Lipo battery packs are typically preferred for applications that need a lightweight, high-performance battery capable of delivering quick bursts of power. In contrast, lithium-ion packs are better for long-term power supply needs, as they offer better durability and safety features.

Part 5. How to DIY a lipo battery pack

Building your own lipo battery pack might seem daunting, but with the right tools and understanding, it can be a rewarding project. Here’s how you can make your own custom battery pack:

Step 1: Gather Your Materials

  • Lipo cells: Choose the cells based on your required voltage and capacity.
  • Battery connectors: To link the cells together.
  • Battery management system (BMS): A crucial component that ensures your cells are balanced and prevents overcharging or over-discharging.
  • Welding tools: For securely connecting the cells.
  • Protective casing: To keep the cells safe from physical damage.

Step 2: Connect the Cells

  • Series Connection: To increase voltage, connect the positive terminal of one cell to the negative terminal of the next. For example, for a 3S pack, connect 3 cells in series to achieve 11.1V.
  • Parallel Connection: To increase capacity, connect the positive terminals of all cells together and do the same for the negative terminals. This configuration keeps the voltage constant while increasing the mAh rating.

Step 3: Install the BMS

Connect the Battery Management System to ensure that each cell in the pack is balanced. This prevents issues like overcharging, which can lead to swelling or, in extreme cases, fires.

Step 4: Test the Battery Pack

Before using the pack, test it to ensure that all cells are functioning properly and that the BMS is managing the cells correctly.

Step 5: Enclose and Insulate

Once everything is connected and tested, insulate the battery pack to avoid short circuits and enclose it in a durable casing to protect it from external damage.

Part 6. Lipo battery pack charger

Charging a lipo battery pack requires a specific type of charger designed for lithium polymer batteries. Unlike regular chargers, a lipo charger includes features to balance the cells and prevent overcharging.

Key aspects of a lipo battery charger:

  • Balancing Capability: Ensures that all cells in the pack are charged evenly to avoid overcharging individual cells.
  • Charging Rate: Lipo chargers typically charge at a rate of 1C (where C represents the battery’s capacity), but you can charge at higher rates, like 2C, depending on the pack’s specifications.

Always use a charger that’s compatible with the voltage and capacity of your battery pack. Avoid using a charger designed for lithium-ion batteries, as it may not provide proper balancing.

Part 7. Why does lipo battery pack swell?

Swelling in lipo battery packs is a common issue and occurs when the battery undergoes internal damage or overcharging. It’s typically caused by the buildup of gas inside the battery due to chemical reactions during improper usage.

Common causes of swelling:

  • Overcharging: Charging the battery beyond its maximum voltage can cause the internal chemicals to break down and release gas.
  • Over-discharging: If the battery is discharged too far, it can lead to instability and swelling.
  • Physical Damage: Punctures or impacts can cause internal damage, leading to swelling or leakage.

Why Do Batterry Bulge and Solutions to Li-ion Battery Bulge

If your lipo battery pack swells, stop using it immediately. Dispose of it properly, as swollen lipo batteries can be dangerous. Never puncture or attempt to drain a swollen battery.

Part 8. Charging and maintenance Tips

Proper charging and maintenance are critical for extending the lifespan of your lipo battery pack. Here are a few essential tips:

If you want to learn more, please visit our website custom lipo battery pack.

  • Never overcharge: Always ensure the voltage per cell does not exceed 4.2V.
  • Use a compatible charger: Only use chargers designed specifically for lipo batteries with balancing functions.
  • Store correctly: When not in use, store your lipo pack at room temperature and avoid leaving it fully charged or completely discharged for long periods.
  • Avoid extreme temperatures: Charge and use the battery at room temperature. Charging in hot or cold conditions can damage the battery and reduce its lifespan.