Battery safety for garages and bike shops

Four situations, four different risks

• Customer packs in for service. Unknown history, and the reason a bike comes in is often that something is wrong with it. This is the highest-risk population on your premises.
• Stock packs and complete bikes. Known provenance, high value, usually on the shop floor where a fire is worst for you commercially and for escape.
• Packs on charge during the working day. Several at once, often on a bench, often unattended while staff serve customers.
• Conversion kits. If you fit them, you are assembling cells, a battery management system, a charger and a controller that were not designed together — and you carry the consequences. Self-assembled packs recur throughout serious UK incident reporting.

Many premises in this sector also have a flat above, which changes the calculation entirely: you are no longer only protecting stock.

What to put in place

1. Inspect every customer pack on receipt, before it goes anywhere. Swelling, deformation, heat, smell, discoloration, leaking, a case that has clearly been opened. Record it — a note on the job card protects you as much as the customer.
2. Never charge a pack you have not inspected, and never charge one you have flagged. This single rule removes the most likely scenario.
3. Move charging off the shop floor and away from the front door and any stairs to accommodation above. A back area or an external store, not the counter.
4. Have a quarantine point ready before you need one — ideally external. The moment you find a swollen pack is the wrong moment to be deciding where to put it.
5. Stop overnight charging, or contain and detect it. Closing time is when nobody is there to notice venting.
6. Decide your position on conversions and write it down. If you fit kits, be able to say which components and why.

Because you charge in volume and hold suspect packs, this is a sector where a charging cabinet plus a separate quarantine arrangement usually both earn their place. See also e-bike battery fires in the UK.

Frequently asked questions

Can we refuse to work on a converted bike?

Commercially that is your call, and a number of shops have taken exactly that position. From a safety standpoint it removes a category of risk you cannot assess: you have no way of knowing whether the cells, the BMS and the charger were ever intended to work together. If you do accept them, inspect harder and be explicit on the job card about what you have and have not verified.

What do we tell a customer whose battery we think is unsafe?

Tell them plainly, in writing, that you are not prepared to charge or return it to service and why — swelling, damage, a non-original charger. Offer the disposal route rather than handing a hazard back across the counter. Once you are disposing of it, the Waste Batteries and Accumulators Regulations 2009 apply.

How many packs can we safely charge at once?

There is no regulated number. What sets the practical limit is your total watt-hours in one place, your electrical supply, and whether a failure there would block your escape route or reach your stock. Work out the watt-hours first — here is how — because a bench with eight e-bike packs on it holds more energy than most shop owners expect.