To charge a LiPo battery safely, use a balance charger set to the right battery type and cell count, charge at 1C (one amp for every 1,000mAh), keep the pack in a LiPo bag on a hard surface, and stay with it until it finishes. Never charge a pack that is swollen, damaged or still hot.

That is the whole method in two sentences. The rest of this guide explains each step, the voltages worth remembering and the kit that makes it easy. If you are still choosing a battery, start with our LiPo vs NiMH guide.

LiPo charging in seven steps

1. Let the pack cool. A battery straight out of a car is warm. Give it 15 to 20 minutes before charging, and never charge a pack below freezing.

2. Inspect it. Look for swelling, dents, torn wrap or damaged leads. If anything is wrong, do not charge it. A swollen (puffed) pack is finished.

3. Set up somewhere safe. A hard, non-flammable surface, away from curtains, carpets and paper, with the pack inside a LiPo bag. Not in a car, not on a bed, and not in the model.

4. Connect both leads. The main power lead and the small white balance lead both go into the charger. The balance lead lets the charger see and equalise each cell.

5. Choose LiPo Balance and the right cell count. The label on the pack says 2S, 3S and so on. The charger should agree with the label. If it shows a different cell count, stop and check.

6. Set the charge rate to 1C. Divide the capacity in mAh by 1,000 to get the amps. Only go higher if the battery label says it is rated for faster charging.

7. Stay with it. Charging takes about an hour at 1C. Stay in the room, and unplug the pack when the charger says it is done. Do not leave a battery charging overnight or while you are out.

The voltages worth remembering

Every LiPo cell has the same working range, whatever the size of the pack. A 2S pack is two of these cells in series and a 3S pack is three, so multiply by the cell count for the whole pack.

Storage matters as much as charging. A LiPo left full or empty for weeks loses capacity and can swell. If you are not using a pack in the next few days, use the charger’s storage mode to bring it to about 3.8V per cell, and keep it in a LiPo bag somewhere cool and dry.

If a pack is swollen or damaged

Stop using it. Do not charge it, do not puncture it and do not put it in the household bin. Keep it in a LiPo bag or a metal container away from anything flammable, and take it to a household waste recycling centre that accepts batteries. If a pack starts to hiss, smoke or get hot, move away and let it burn out somewhere it cannot spread, if it is safe to do so.

The kit you need

A balance charger, a LiPo bag and a cell checker. That is it. The USB chargers supplied with many ready-to-run cars do work, but they are slow and tell you nothing; a proper charger is the best upgrade most people can make, as our guide to the hidden costs of RC cars explains.

Etronix PowerPal Mini AC

Etronix Powerpal Mini Ac 6a 60w Balance Charger/Discharger (Uk Plug)

Mains powered, 6A, 60W, balance charge, discharge and storage modes

£36.99

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A compact mains charger with the power supply built in, so there is nothing else to buy. It balances, discharges and has a storage mode, which covers everything in this guide. For one or two packs of ordinary size it is all most people need.

Etronix PowerPal 3.0

Etronix Powerpal 3.0 Ac/Dc Performance Charger/Discharger (Uk Plug)

AC or DC input, up to 10A charge rate, cell balancing, USB socket, servo tester

£39.99

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The 3.0 charges at up to 10 amps and runs from the mains or a 12V supply, so it can come to the track. It also has a USB socket and a servo tester built in. Choose it over the Mini if you run larger packs and do not want to wait.

Etronix PowerPal Compact X4

etronix powerpal compact x4 ac/dc charger (uk plug)

Four independent 100W outputs, XT60 connectors, LiPo, LiHV, LiFe and NiMH programs

£74.99

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Four independent 100W outputs, each programmed separately, so four different packs can charge at once. If you have several cars or a family of drivers, this ends the queue for the charger.

Gens Ace iMars D300

Gensace charger Imars D300 Dual Channel 300W (UK) White

Two channels, 300W, charge and discharge, recognises Gens Ace G-Tech smart batteries

£149.90

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A two-channel 300W charger from one of the best-known battery brands. With Gens Ace G-Tech smart batteries it reads the pack and sets itself up; with any other battery it works as a conventional charger. This is the one for large 4S and 6S packs.

Pink Performance LiPo safety bag

Pink Performance Lipo Battery Safety Bag Large (200x90x90mm)

Large fire-resistant bag for charging, transport and storage, 200 x 90 x 90mm

£8.50

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A LiPo bag does not prevent a fault, but it helps contain one. Charge inside it, store packs in it and carry them in it. For the price of a takeaway coffee, there is no good reason not to own one.

LiPo voltage checker and alarm

Lipo Voltage Checker and Alarm

Plugs into the balance lead, shows each cell, low-voltage alarm adjustable from 2.7V to 3.8V

£5.95

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Plug it into the balance lead and it shows the total voltage and each cell in turn. Use it before charging to spot a weak cell, after a run to see how low you went, and as an alarm in cars with no low-voltage cut-off.

Frequently asked questions

Next: the fast RC cars guide shows what a good battery can do, and every other guide is on the RC buying guides hub. If a car cuts out early or will not hold charge, the RC car troubleshooting guide and the free RC Car Diagnostic Bay can help.