LIPO (LIthium POlymer) batteries generally don’t like cold temperatures, when things start getting under 10C or so. While the cold weather does not harm the battery, it does cause an effective loss in performance, lowering the effective C rating and reducing flight times. The cold slows down the chemical reaction process and thus the effectiveness of the battery.
There are a few tips you can use to help maximize LIPO performance in colder weather:
- Keep the LIPOs in a warm location until just prior to use, at around normal room temperature. Keeping them in the car, your inside pockets, or a cooler with some warming device such as hand warmer or hot water bottles can help keep the batteries and optimal temperature. Be careful with any heating devices that they do not get too warm and cause potential LIPO damage.
- Wrap the LIPOs in light insulation if possible on the aircraft to keep them out of the cold airflow. A cover/canopy can also help to keep the blast from the props off the battery which can cool it quicker.
- Use higher C rated batteries in colder weather. This will help with the voltage sag under load from the cold dropping the effective C rating somewhat and keep you in a safe amp draw range for the battery.
- Monitor flight voltage closely and expect to have reduced flight times in cold. Adjust flight timers lower accordingly.
- Be careful of snow getting into the LIPO connectors and causing a short or corrosion.
- Do not charge LIPOs in the cold, ideally charge at normal room temperature. Charging at colder temperatures can reduce the life of the battery.
- Be sure to put your LIPOs in storage charge when not in use for extended periods.