Caring for your drone’s batteries
February 28, 2017
Bryan Verpoort | 28 February 2017
Your drone’s LiPo batteries are amazing pieces of technology. But incorrect transportation, charging or storage of a drone battery could lead to serious damage to property.
Follow these rules when charging and using your lithium polymer (LiPo) drone batteries
1. Use only a charger approved for lithium batteries
The charger may be designed for lithium ion (Li-ion) or lithium polymer (LiPo) batteries. Both batteries are charged in exactly the same way. Some older cell phone chargers may charge the batteries by 0.1 volt too little (4.1 vs 4.2), but that will not harm the battery. However, inexpensive lithium chargers are widely available and the use of cellphone chargers is highly discouraged.
2. Make certain that the correct cell count is set on your charger
Watch the charger very closely for the first few minutes to ensure that the correct cell count continues to be displayed. If you are unsure, don’t charge the batteries at all until someone has shown you.
3. Use the taps
Before you charge a new lithium pack, check the voltage of each cell individually.
Repeat this process on every 10th charge. This is absolutely crucial as an unbalanced pack can explode while charging even if the correct cell count is selected. If the cells are not within 0.1 volts of each other, charge each cell individually to 4.2 volts so that they are all equal. If the pack remains unbalanced after every discharge, you have a faulty cell and that pack must be replaced.
- Taps are provided on most new lithium packs. Taps give you the ability to check individual cell voltages and charge one cell at a time
- Make sure you get the appropriate connector to go into your taps
- Don’t try to stick you volt meter probes in the taps to measure voltage. They could slip and short your cells
- Don’t try to charge more than one cell at a time from the taps. Unless you have an isolated ground charging system, you’ll short your batteries out. Refer to your individual cell maker for tap pinouts
4. NEVER leave your batteries unattended while charging
If left unchecked they could easily heat up, start smouldering and cause a fire. This is the number one reason for houses and cars being burnt to a crisp by lithium fires.
5. Use a safe surface to charge your batteries
This will help to mitigate damage if they do happen to burst into flames. Vented fire safes, pyrex dishes with sand at the bottom, fireplaces and plant pots are all good options.
6. DO NOT CHARGE AT MORE THAN 1C unless specifically authorised by the pack vendor
Today’s highest discharge batteries can supposedly be safely charged at greater than 1C. However, evidence strongly suggest that doing so shortens the life of the pack. It’s better to buy three packs than to try to charge one pack in triple speed.
This may change at some point, but as at February 2017, 1C is still the recommended charge rate.
7. DO NOT puncture the cell… ever!!
If a cell balloons, quickly place it in a fire-safe place, especially if you were charging it when it ballooned. After you have let the cell sit in the fire-safe place for at least two hours, discharge the cell/pack slowly. This can be done by wiring a flashlight bulb of appropriate voltage (higher voltage is ok, lower voltage is no) to your batteries’ connector and attaching the bulb to the battery. Wait until the light goes out completely, then throw the battery away.
8. If you crash with your lithium cells, they may be damaged
Sometimes a drone crash results in an internal short in the battery. The cells may look fine but if you crash in ANY way, carefully remove the battery pack from the aircraft and watch it for at least 20 minutes. Many fires have been caused when drones with damaged cells are thrown into a car – the cells have potential to catch fire later and completely destroy the vehicle.
9. Charge your batteries in an open ventilated area
If a battery does rupture or explode, hazardous fumes and material will spew from the battery.
10. Keep a bucket of sand nearby when you are flying or charging batteries.
This is a cost-effective way to extinguish fires. It is very cheap and absolutely necessary.
11. It CAN happen to you
Do not think it won’t happen to you. As soon as you do that, you’ll be trying to rescue your kids from your burning house or car!
Learn about ITOO’s drone insurance offering, here.