Charging and storing LiPo batteries safely

The right charger and charge mode

Select the correct battery type and cell count on the charger. A standard LiPo is full at 4.20 V per cell, a LiHV pack at 4.35 V. Many small 1S whoop chargers charge to a fixed 4.35 V: fine for LiHV packs, but they will overcharge a standard LiPo.

Charge at the current the battery manufacturer specifies. If none is given, 1C is the safe default: the capacity in amps. A 450 mAh pack is then charged at 0.45 A.

Multi-cell packs (2S and up) have a thin balance lead next to the power lead. Connect it to the charger: with balance charging the charger monitors each cell separately and brings them to the same voltage. A 1S pack has only one cell and therefore no balance lead. Chargers for your packs are in the LiPo chargers category.

Safe charging: the fixed rules

• Charge under supervision and near a smoke alarm, as the Dutch fire service advises.
• Charge on a non-flammable surface, away from anything flammable, and not while the pack is still in the drone.
• Let a warm pack cool down after flying first. Do not charge it in direct sunlight or in the cold.
• Never charge a pack that is damaged, deformed or swollen.
• Stop immediately if a pack gets hot or swells while charging. Disconnect it and put it outside.

A LiPo safe bag limits the consequences if a pack catches fire while charging or in storage, but it does not prevent it. So even with a safe bag, always charge under supervision.

Storage: storage voltage and temperature

A LiPo wears faster when it stays full for long. BetaFPV advises not to keep a full pack for more than three days and to hold 3.8 to 3.9 V per cell for longer storage. Tattu gives 3.6 to 3.9 V per cell for long-term storage and a temperature of around 23 °C.

If your charger has a storage mode, use it. A simple 1S charger often cannot do this; in that case charge your packs shortly before you fly, and do not leave them full after flying.

Disconnect packs when you are not using them and keep them in a fire-resistant, non-conductive bag or box. Do not let loose packs lie together: if the terminals touch each other or metal, they short-circuit.

Swollen or damaged LiPo

Stop using a LiPo that puffs up, is deformed or was damaged in a crash, not even for one last flight. According to the Dutch fire service, a damaged lithium battery can ignite spontaneously. Disconnect it, put it outside in a safe spot in a fire-resistant bag or box, and hand it in as soon as possible.

Smoke or a chemical smell? Call 112 and leave the room.

Disposing of LiPo batteries in the Netherlands

Empty and broken batteries do not belong in household waste. In the Netherlands you hand them in at shops and supermarkets that sell batteries, at the municipal recycling centre (milieustraat) or at the chemical waste collection (chemokar). Damaged batteries in a refuse truck can short-circuit and start a fire.

Flying with LiPo batteries

Spare lithium batteries may only go in your hand luggage, not in checked baggage. According to the Dutch aviation authority ILT, you need no permission up to 100 Wh per battery; from 100 to 160 Wh you do, and above 160 Wh they are not allowed. A 1S 300 mAh pack is about 1.1 Wh. Tape over the terminals or keep each pack in its own pouch, and ask your airline beforehand how many batteries you may take.