LiPo batteries in model vehicles: correct storage, charging, transport and disposal
LiPo batteries in model vehicles: correct storage, charging, transport and disposal. Model vehicles can be fun as an enjoyable hobby and almost an art. However, just like drones, for example, RC models generally require at least two batteries: one for the remote control and one for the control system in the model. Apart from gliders and RC sailing boats, the models also need a motor as a drive. More and more electric motors with LiPo batteries are being used in RC cars, model boats and model aeroplanes. These LiPos (lithium polymer batteries) are a special form of lithium-ion batteries in which the electrolyte is not liquid, but gel-like or even solid. LiPos for models have both a high energy density and a high power density. As a result, LiPo batteries have enough power to keep up with RC racing, for example, and at the same time ensure high endurance.
However, LiPos also pose a latent fire hazard. In particular, damage caused by accidents, incorrect storage and improper charging can lead to thermal runaway of LiPos, which can cause severe burns and trigger fires. The fact that some modellers carry several LiPo spare batteries (to be charged and stored at home) in order to be able to use their RC models for as long as possible increases the risk of fire even further, as the flames can easily spread from one LiPo to the next.
As a manufacturer of fireproof containers for rechargeable batteries, we can provide useful tips for the storage, transport, charging and disposal of modelling LiPos:
Storing and charging LiPos safely
Precise information on how to store and charge a battery optimally can be found in the operating instructions. There are certainly differences between the models. In general, the following basic rules apply when charging and storing LiPos:
- Only use approved chargers for charging, preferably the original accessories. Even a small excess of the end-of-charge voltage can destroy a LiPo battery, for example.
- LiPos should be kept clean, dry and in their preferred temperature range. Room temperature is usually ideal. This applies even more to charging, whereby the battery should be given time to cool down or warm up before charging. Spare LiPos should also not be exposed to frost or stored in the car in direct sunlight.
- LiPo batteries must be protected against short circuits during storage.
- Storing fully charged LiPos for long periods can shorten their service life. LiPo batteries with a low charge level, on the other hand, could become deeply discharged and thus unusable. For this reason, LiPos should have a medium state of charge when stored for long periods.
- Due to the fire hazard posed by LiPos during storage and especially during charging, precautionary measures should be taken. This can include charging under supervision, installing smoke detectors or separating them from other flammable materials. If you want to be on the safe side, you can also charge and store your LiPos in a battery protection box. However, such containers must not be gas-tight, but need special outlets for hot gases and usually fire protection cushions. Otherwise an explosion or the escape of jet flames may occur.
Due to the fire hazard posed by LiPos during storage and especially during charging, precautionary measures should be taken. This may include charging under supervision, installing smoke detectors or separating them from other flammable materials.
Transport LiPo batteries safely
Not every fan of RC models realises that LiPos are considered dangerous goods. In fact, there are very detailed ADR special regulations for the transport of lithium-ion batteries. Among other things, these regulate how LiPo batteries must be packaged and labelled during transport. Due to their hazardous nature, LiPos can only be sent by post or transported by aeroplane to a limited extent. The reason for this is the fire hazard posed by LiPo batteries, which is further increased by movement during transport.
The good news: According to ADR 1.1.3.1 a, private individuals are exempt from the transport regulations if
- the LiPos are intended for leisure and sport, among other things, and
- they are ‘packaged for retail’ and
- measures are taken to prevent the contents from being released under normal conditions.
The last two points in particular leave room for interpretation. Modellers are on the safe side - not only with regard to the regulations - if they transport their LiPos in a special battery protection box such as the RETRON BOX. The RETRON BOX is UN-certified and therefore also approved for the professional transport of LiPos.
In general, modellers should ensure that the optimum storage conditions are also observed when transporting LiPos. Impacts and other mechanical stresses should also be avoided.
Obsolete, defective and bloated LiPos
LiPos in RC models in particular are often exposed to high mechanical loads, e.g. due to accidents. This can lead to damage. Other LiPo batteries have simply reached the end of their life cycle. In some cases, LiPos may also be deeply discharged or inflated. In these cases, they should be disposed of quickly.
LiPos do not belong in the normal waste bin. This also applies to button cells. The mechanical stress caused by pressing the waste or during recycling can cause short circuits that trigger fires in waste collection vehicles[7] . Instead, LiPos can be handed in at retail collection points or recycling centres.
Damaged, deeply discharged or inflated LiPos must not be recharged or reused under any circumstances. They should be disposed of as quickly as possible and stored safely until then. They pose an increased risk of fire. We therefore recommend that you do not simply throw them into a collection container at a retail outlet, but instead hand them in at a recycling centre and indicate that they are damaged. It is not possible to send such LiPos by post (e.g. return to the manufacturer).
In individual cases, a LiPo battery may appear to be deeply discharged because the internal battery management system has disconnected the cells from the terminals to protect them from deep discharge. Such LiPos can generally be ‘revitalised’. However, this should only be done by experienced professionals who have the right equipment and take strict precautions.
