Lithium Polymer (LiPo) batteries are commonly used in drones, but they can become hazardous if not handled properly. The inevitable question for RC hobbyists is how to get rid of old and damaged LiPo safely. Disposing of LiPo batteries is a delicate process that requires caution to prevent fires or explosions. Here’s what you need to know to safely dispose of LiPo batteries.
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When To Dispose LiPo Batteries?
Lipo batteries used in FPV drones should be disposed of when they start to show signs of damage or wear and tear, or if they are no longer holding a charge. It’s important to dispose of them safely and responsibly to prevent any potential safety hazards or environmental harm. It’s also recommended to regularly inspect and monitor your lipo batteries for any signs of swelling, punctures, or leaks, and to store them properly when not in use.
This article explains how to determine whether a LiPo battery is old enough to retire.
Methods of LiPo Disposal
To summarize, when disposing of LiPo batteries, it’s important to discharge them completely to reduce the risk of fire. This means bringing the voltage down to 0 volt. Once discharged, take the battery to a local recycling facility for proper disposal.
Here are several ways you can discharge the battery.
Your LiPo charger might be capable of discharging your battery though extremely slowly. However, many chargers are not designed for discharging LiPo completely and have a 3V cut-off voltage for safety. If this is the case, you might want to use other methods outlined below. One example is the SkyRC BD350.
Discharging LiPo batteries with a light bulb is an affordable and speedy option.
In this tutorial I will show you how to built a halogen bulb LiPo discharger.
Avoid LED bulbs due to their forward voltage, which means they would stop discharging below certain level and there will be a small amount of charge left in the battery. LED are also more energy efficient which is not a desirable quality as a discharger. Halogen bulbs are a great choice.
Resistive loads, like radial ceramic resistors, are great options too. For 2S or 3S LiPo batteries, consider using 150ohm 2W resistors. 5W 47ohm for 4S.
I covered many good ways to discharge your batteries ready for disposal in this article, including dedicated battery discharger, and high power resistors.
Discharging LiPo batteries using salty water is not the most recommended method as it is slow and ineffective. Salt water discharges the battery slowly over time, but it might not completely discharge the battery. Corrosion can also take place, where the exposed metal of the connectors/wires will have a layer of insulator building up in salt water. This might eventually stop the discharging entirely. However, many people still favour using salt water over other methods because it’s relatively safer as the battery is entirely immersed in water.
To discharge LiPo batteries with salty water:
- Get a plastic container and fill it with cold water
- mix it with salt until it dissolves completely. Use about 30g of salt per litre of water.
- Put the battery in the salty water, and leave it somewhere fireproof for two weeks or longer, depending on the original charge.
- Finally, wrap the battery with paper, and dispose of it at an authorized battery disposal facility.
Physically Destroying Battery
I’ve seen people do this on Youtube, the physically destroying method is not recommended and considered the most dangerous. We strongly advise against using a gun, a nail, a hammer, or a brick to puncture, shoot, or break the battery. Not only is this method fire hazardous, but the resulting smoke is harmful to inhale. It is better to use one of the other methods described in this guide to safely dispose of your LiPo batteries.
I normally use a halogen light bulbs to completely discharge the battery first.
Check the voltage to make sure there’s is indeed no charge left. Voltage should be close to 0V. Note that most battery checkers don’t work well when voltage drops below 3V per cell, and will report “no cell present”. Therefore it’s best to use a multimeter in this case, buy one here if you don’t have one already.
Then cut the connectors off, strip the wires and twist the discharge leads together to ensure there is no charge left in the pack (+ and -). You might get a spark when the wires first touch, the pack might even get warm, but it shouldn’t be an issue if the battery is empty. If you didn’t discharge it completely first as I mentioned, then you could get an overheat battery or even a fire if you short the positive and negative wires.
It only takes under 30 mins to dispose a LiPo which is far quicker than dipping the battery in salt water for weeks.
Don’t forget to save the XT60 and balance connectors for future use! If you have damages on a good pack you can use them for replacement.
- Oct 2014 – Article created
- Jul 2016 – Updated
- Jul 2018 – Updated “Other discharging methods”
- Feb 2023 – Article revised