USE AND CARE OF LI-PO BATTERIES

Taking care of your drone and its batteries is crucial to keeping your equipment in perfect condition. In this article, we will focus on one of the most important aspects: how to care for your batteries. Here, you'll find basic guidelines, tips, and advice on what mistakes to avoid to ensure that your multicopter's Li-Po batteries last as long as possible, providing safe flights without unpleasant surprises.

1. What is a LiPo Battery?

LiPo batteries are a type of rechargeable battery, known for their high energy density. They typically consist of multiple cells, each with a nominal voltage of 3.7V up to a maximum of 4.2V.

These cells are already batteries themselves, but to achieve higher voltages or capacities, they are often connected to each other to create batteries with superior performance that meet the requirements of the circuit they will power.

2. Main Characteristics of a LiPo Battery

• Discharge Capacity: Indicated by a number followed by the letter C, it refers to how much current the battery can safely provide in relation to its total capacity (mAh).

• Charge Capacity: Like discharge capacity, it is indicated as C and corresponds to the maximum amperage the battery can handle during charging. This is important for generic batteries when using a charger that allows you to set this amperage. For most commercial models, this is not necessary since the manufacturer includes a charger designed with these limits in mind.

• Nominal Voltage: This value is given in volts. For standard LiPo batteries, it is 3.7V per cell. For example, if you have a 3-cell battery, your nominal voltage will be 11.1V.

• Maximum Voltage: This indicates when the battery is 100% charged. For standard LiPo batteries, it is 4.2V per cell, though some batteries, such as HV (High Voltage) types, may have slightly higher voltages. This will be indicated in the battery's specifications, usually on a sticker attached to it.

• Capacity: Measured in mAh, this refers to the amount of energy the battery can store.

• Number of Cells: This tells you how many elements make up the battery. These batteries typically group cells in series or parallel to achieve the appropriate voltage (series) or capacity (parallel) for the device you're using.

3. What is a Smart Battery?

Smart batteries have an integrated circuit connected to the cells that make up the battery. This circuit monitors the battery's charge status and balances the cells. They also include protection systems against possible short circuits, overcharging, or over-discharging.

Overall, they make the battery a much safer component and are typically used by manufacturers of ready-to-fly drones like DJI, Parrot, Fimi, etc.

4. How Should I Use My Batteries?

It's recommended to use batteries within the 30% to 100% range. Every time you go below 30%, you're putting stress on the battery. This doesn't mean you can't use the full capacity, but to get the most cycles as indicated by the manufacturer, it's better not to drop below 30%.

If you regularly use your batteries below this range, there's a greater risk that you'll accidentally over-discharge them, which can cause them to swell and, in severe cases, drop below the safe voltage, rendering them unusable.

5. How Should I Charge Them?

Always use a specific LiPo charger. Charging them any other way carries a high risk of damaging the battery or even causing it to catch fire.

Charging is the time when you should be most vigilant about the batteries, in case one is damaged (due to a bump, short circuit, poor connection, etc.) or the charger has a defect.

6. How Should I Discharge Them?

The easiest way to discharge the battery is by flying the drone until it reaches a charge of 30-50%. There are also specific chargers that offer a discharge option, leaving the battery at the optimal level for storage. These are usually intended for generic batteries and may require adapters for batteries like DJI, Parrot, Yuneec, etc. Some batteries, like DJI's, discharge automatically, but it's not advisable to rely too much on this feature, as it's easy to accidentally press the power button and reset the auto-discharge counter.

The best option for consumer drones is to discharge them yourself, either by flying the drone or leaving it on long enough.

Contrary to what many believe, these batteries do not have a memory effect, so it's fine if you don't discharge them completely. In fact, it's better not to. You also don't need to perform "deep" discharges periodically.

7. How Should I Store the Batteries?

If after three days of storage you realize you won't be using them, it's best to discharge them to 50% until you use them again. Storing them fully charged or deeply discharged will only accelerate the battery's degradation.

Always store your batteries between 5 and 25°C, and avoid exposing them to high temperatures.

Since lithium is a highly reactive material, it's important to store them in a fireproof area. Ideally, use a fireproof bag for batteries, but ceramic pots or metal containers can also work. Additionally, they should be kept away from flammable materials for obvious reasons.

8. How to Tell if My Battery is in Good Condition?

It should be in good exterior condition, without visible dents, dings, or deformations.

Also, ensure they are not swollen. This is due to some of the internal material in the cell degrading, with the swelling caused by an excess of oxygen.

This makes the battery very dangerous, and it would be advisable to dispose of it at a designated recycling center.

If everything else is in order, check the voltage as the next indicator of the battery's condition. In this case, the cells should have a maximum difference of 0.05V between them. Simple chargers often do not balance the cells well, so it might be worth investing in a high-quality charger.

In general, the charger provided by the manufacturer is adequate, and you won't have to worry about finding another one.

9. Why Are My Batteries Swelling?

The most common cause is storing them fully charged for extended periods. After 3-4 days of being fully charged, the batteries start to degrade. If you frequently leave them in this state, they will eventually swell.

Another reason is overcharging due to a faulty charger or using an inappropriate charger.

Finally, they can also swell from over-discharge or exposure to high temperatures during storage or very low temperatures during use.

If your batteries swell, never try to puncture them to release the "gas" as this will most likely cause them to catch fire and, in some cases, explode.

10. What to Do with a Defective Battery?

The best course of action is to stop using it, whether it's due to significant voltage differences between cells or because it's swollen. The only risk is that the battery might fail suddenly during use or become dangerous.

11. Where Can I Dispose of a Defective Battery?

At your nearest recycling center, where they know how to dispose of it properly.

12. How Does Cold Affect My Batteries?

Cold is a double-edged sword. When storing batteries, it can be beneficial (moderate, never below 5°C) because it slows down the chemical reactions inside, prolonging their lifespan.

However, during battery use, such as when flying a drone, cold has the opposite effect, reducing the battery's discharge capacity and, therefore, its runtime.

During charging, it's important to keep batteries at room temperature (20°C), as lower temperatures can damage the battery and reduce the number of cycles it can provide.

Once charged to 100%, it's not good for them to get too cold. If the environment is very cold, many people choose to store them in pockets or anywhere above 20°C.

In general, sudden temperature changes are what ultimately damage the batteries, so during these three stages—charging, discharging, and when fully charged—it's best to avoid extreme temperature shifts, except during storage.

13. Safety Summary

• Always recharge and store the battery in a protected area away from flammable materials.
• Store your batteries between 30% and 50% of their total capacity, in a dry place, at a temperature between 5°C and 20°C, and in a fireproof container.
• Never recharge a damaged or punctured battery. It's better to dispose of it.
• If you notice a battery swelling during charging, disconnect it and move it to a safe place outdoors or in a fireproof container. Be careful: it could cause a fire. Swollen batteries should be discarded as a precaution.
• If you charge a Li-Po battery, do not leave it unattended: there's a chance it could catch fire. However, we recommend this only as a precaution (this has never happened to us… fortunately!).
• If the battery overheats during charging, disconnect it immediately.
• Do not let your Li-Po batteries fully discharge; if you do, they may not recharge, drastically reducing their lifespan and risking damage.
• Do not leave a battery charging for longer than the time specified in the instructions. The charger will usually indicate full charge in some way, such as LEDs or a beep.
• Never try to modify, disassemble, or repair a Li-Po battery.
• Most importantly, read the user manuals for your charger and batteries.

Still have questions? Send us an email at droneflyspaincontact@gmail.com.

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