LiPo batteries can be highly dangerous, and many people have no idea.
For years, lithium polymer batteries (LiPos) have been known to be dangerous and unpredictable. Dropping, denting or crushing can shorten the life of the battery and even cause an internal short — a recipe for fire. There are a myriad of guidelines for storing, charging and transporting them. Even among experienced RC users, they have led to fires.
Luckily, LiPo batteries have become far safer over the past decade, thanks to improvements like DJI Intelligent Flight Batteries, which are capable of monitoring and reporting battery status in real time, offer overcharging/discharging protection and even have smart tech like low-temperature protection.
Related read: 15 things every LiPo battery user should know
But not even the smartest of LiPo batteries are completely immune to potential explosion and fire risks. Take these steps to properly care for your LiPo batteries to reduce the risks to nearly zero:
How to store LiPo batteries
- Keep batteries separate: Never store loose batteries together. The batteries’ terminals may contact one another, causing a short circuit.
- Store batteries in a cool, dark place: Never store batteries in extreme temperatures or direct sunlight. The battery should be stored within -10℃~45℃ range environmental condition. If the battery has to be stored for a long time (more than 3 months), the environmental condition should be:
- Temperature: 23±5℃ Humidity: 65±20%RH
- The voltage should be 3.6V~3.9V range per cell.
- Always disconnect Batteries when not in use and store batteries in a non-conductive and fireproof container.
- Never alter, puncture or impact Batteries or related components.
How to charge LiPo Batteries
If you can only have one tip on charging LiPo batteries, it is to never leave a LiPo battery unattended during the charging or discharging process. That said, there are some there LiPo charging tips that can help extend your battery’s life, as well as ensure safety.
Before charging LiPo batteries
- The #1 tip here is: RTFM (Read the Freaking Manual!)
- Always check the voltage of batteries before each charge session in order to ensure they are at or above the minimum safe starting voltage. If their starting voltage is below recommended levels then your batteries have been over-discharged or have experienced a failure and should NOT be charged.
- Always check the battery before charging for any type of damage. Check the battery packaging, wires and connectors for defects, which may cause a short circuit and eventual battery failure.
While charging LiPo batteries
- Only use a charger designed for a lithium polymer or lithium-ion battery. Do not use a NIMH/NICD/LIFEPO4/LEAD ACID charger. If the charger can support different battery types, make sure to select the Lithium polymer (Lipo) mode on the charger.
- User should always charge batteries in an open area away from flammable materials, liquids and surfaces.
- Never charge batteries inside of your drone
- Never charge batteries below freezing (0°C, 32°F)
- Never charge batteries that are hot to the touch (above 100° F).
- The charger should never be set to charge batteries at a rate greater than 1C (one times the capacity of the battery in amp hours)
- Never overcharge batteries over their rated maximal voltage (4.2V/cell for a LiPo).
- Using a LiPo sack is suggested when charging to ensure the charging safety. Stop charging when the battery is fully charged.
What about discharging LiPo batteries?
- Never discharge batteries at amperage rates higher than specified on the label
- Never allow the temperature of batteries to exceed 140° F during discharge.
- Never discharge battery to a level below 3V per cell under load. For most drone batteries, the recommended cut off voltage is 3.5V per cell.
- Batteries can still accidentally leak for about an hour after discharge, and that reaction with air may cause the chemicals to ignite. Keep batteries in a safe area away from any combustile materials and observe them for an hour after discharge.
If that all sounds stressful to you, don’t worry at all. Balance chargers and dischargers make it easy to charge or discharge your battery to the perfect level, and they usually cost less than $50 (ensure the one you buy is compatible with your own set of batteries).
For DJI customers, DJI also builds high-quality DJI charging hubs (again, check to make sure the specific hub you buy is compatible with your DJI drone).
General LiPo Battery Safety
And just to wrap up with some final LiPo battery safety tips:
Interacting with LiPo batteries
- Never strike a battery with any sharp edges.
- Never open or deform the folding edge of a cell.
- Never drop, hit or bend batteries.
Getting rid of LiPo batteries
- Never disassemble the cells. The disassembling may generate an internal short circuit in the cell, which may cause gassing, firing, or other problems
- Never incinerate nor dispose of batteries in fire. These may cause firing of the cells, which is very dangerous. Additionally, never be soak batteries with liquids such as water, and especially not soft drinks, juices or coffee (never thought I would have to add that one as a tip!).
And when it does come time to get rid of old batteries, follow proper disposal protocols.
Traveling with LiPo batteries
While drones are allowed through TSA security checkpoints, not all batteries are allowed. All spare, or otherwise uninstalled lithium ion and lithium metal batteries, such as drone batteries are only allowed in carry-on baggage (meaning they can’t be in your checked baggage).
There are also limits on watt hours, where travelers are limited to a rating of 100 watt hours (Wh) per battery (you can typically find the Wh in your drone’s user manual). Travelers with batteries exceeding that may still be able to fly, but must receive specific airline approval. And even still for drone batteries with 101–160 Wh, you’re only allowed to bring up to two such batteries, according to the TSA.