Lithium polymer batteries provide enormous power at a very low weight and have become an essential part of RC modelling. However, a battery can be damaged by a crash, hard landing, deep discharge or incorrect charging – even if the outer covering still appears normal.
A swollen, unusually warm or mechanically damaged LiPo battery must not be used or charged again. The same applies if the battery develops an unusual smell, starts hissing, leaks fluid or shows significant differences between individual cell voltages.
Typical signs of a damaged battery include:
• Swollen or deformed cells
• Damaged wrapping, dents or crushed areas
• Unusual heat generation
• Sweet or chemical odour
• Hissing, crackling, smoke or leaking fluid
• Significant differences between cell voltages
• Abnormal behaviour during charging or discharging
What should you do?
Stop using or charging the battery immediately. Disconnect it from the charger or model only if this can be done safely. Never squeeze, puncture, open or intentionally short-circuit a damaged LiPo battery.
If the battery is already hot, hissing or producing smoke, keep your distance, warn other people and call the emergency services if necessary. Never put yourself at risk by attempting to move a battery that is already reacting.
A damaged battery that remains cold and shows no signs of an active reaction should be isolated from other batteries and combustible materials in a suitable safety container. Exposed connectors can be insulated against short circuits, provided the battery can still be handled safely.
After a crash: inspect before charging
Impacts involving RC aircraft, cars, helicopters and drones can cause internal cell damage that is not immediately visible. Carefully inspect the battery and observe it for a period of time in a safe location. If there is any doubt about its condition, do not recharge it.
Damaged lithium batteries must never be placed in household waste or sent in an ordinary parcel. Before taking the battery to a recycling centre or suitable collection point, clearly inform the staff that it is a damaged or swollen lithium battery. Special dangerous-goods regulations may apply to its transport and shipment.
Our recommendation is to charge RC batteries only while supervised, on a non-combustible surface and with the correct charging program. A fire-resistant battery safety box can help limit the consequences of an incident.
Suitable solutions for safely storing and charging RC batteries are available from Voltmaster.de.