A genuine tool battery pack costs enough to make anyone look twice at a listing offering two for half the price. Inside that listing, the saving has to come from somewhere, and in counterfeit packs it comes from the cells, the protection electronics, and the testing, the three things standing between a battery and a fire.
Workshop, van, and house fires linked to charging lithium packs are a growing line in fire service reports, and copied tool batteries are a recurring cause. This guide explains what is missing inside fake packs, the checks that expose them before purchase, and the charging habits that reduce risk for any pack you own.
A modern tool pack is a system: matched high discharge cells, a management board watching temperature and voltage per group, a thermistor talking to the charger, and a case built to vent and resist impact. Copies use low grade or recycled cells with optimistic labels, minimal or missing protection boards, and in the worst cases a resistor tricking the charger into seeing a temperature sensor that is not there. Capacity claims give the game away in print: if the tool maker does not sell a pack with that amp hour rating in that size, a copy claiming more is claiming the physically implausible. The pack will also run hot, fade early, and stress the tool, so even the copies that never catch fire are poor tools.
Weigh the pack against the genuine specification; missing cells and protection show up as missing grams, and this is one of the most reliable quick tests in any counterfeit category. Compare label print quality, date and batch codes, moulding seams, and the fit on the tool and charger: genuine packs click home cleanly, copies often need persuasion. Buy from the makers own channels or authorised dealers, and treat marketplace listings using the brand name in quotes, or described as compatible in the headline and genuine in the photos, as copies until proven otherwise. Keep suspect packs out of service entirely. A battery you do not trust should not be charged experimentally to see what happens, because what happens can happen at 2am.
Even genuine lithium packs deserve a charging routine: charge on a non flammable surface away from exits, use the makers charger, avoid overnight unattended charging where you can, and retire packs that are swollen, cracked, unusually hot, or dropped hard onto concrete. Store packs partly charged, dry, and out of hot vans in summer. If a pack hisses, swells, or smells sweet and chemical, do not carry it through the house; if safe, move it outside away from buildings and call your fire service for advice. These habits sound dramatic until you read a fire report that starts with a battery on charge in a hallway, which is where the drama actually lives.
Suspect and dead packs should go to battery recycling points, not household bins, where they start fires in collection trucks and sorting plants. Tape the terminals before transport. Report listings to the marketplace and the copied brand with photos of markings and weight; battery cases are ones brands pursue seriously because the liability exposure is enormous, and platform safety teams act faster on fire risk than on almost any other counterfeit category. If a copy has damaged a tool or property, tell your insurer what you bought and keep the pack and packaging where safe to do so. The genuine pack premium is not a logo tax. It is the price of the engineering you cannot see, which turns out to be the part that matters.
They use poor or recycled cells and often skip the protection electronics that monitor temperature and voltage during charging. That combination is a known cause of lithium battery fires in workshops, vans, and homes.
Check the capacity claim against the makers own range, compare weight with the genuine specification, look for poor labels and loose fit, and buy only from the maker or authorised dealers. Implausible capacity at a low price is the classic tell.
Reputable third party compatible packs from established makers are a different market from counterfeits using the tool brands name and packaging. Copies dressed as genuine are the risk. If a listing pretends to be the brand, walk away.
Do not charge or use it. Tape the terminals, take it to a battery recycling point, and report the listing to the marketplace and the copied brand with photos and the weight.