The 12V auxiliary battery is one of the least expensive components on any electric vehicle. But replacing it incorrectly or not knowing it needs replacing can cause problems that go well beyond the battery itself. Here is what EV owners need to know.
When to replace it
Any used EV where the 12V battery history is unknown is a candidate for proactive replacement, particularly if the vehicle is more than three years old.
If you are experiencing any of the warning signs
- slow key fob response
- delayed startup
- intermittent warnings
have the battery load-tested immediately. A load test takes minutes and gives a clear reading. Do not wait for complete failure.
What replacement involves
The battery itself is a standard automotive 12V unit, available from most motor factors and online retailers. The cost of the part is low.
The labour involved varies by vehicle on some EVs the battery is easily accessible, on others it sits behind trim panels or in the front compartment and requires some disassembly.
Any competent garage can replace the physical battery, this does not require EV accreditation.
However, some EVs require a software reset or system recalibration after replacement to correctly register the new battery.
This step is not universal, but skipping it on a vehicle that requires it can cause ongoing warning lights or incorrect system behaviour. Check the requirement for your specific vehicle before booking the work.
Jump starting in an emergency
If the 12V battery fails completely, recovery is required. Before that happens, know two things.
First
Where the manual door release is on your vehicle, most EVs have one that bypasses the electronic lock when the 12V system is completely dead. Check the owner's manual now, not when you are locked out in the rain.
Second
The correct jump start procedure for your specific vehicle. Connecting jump leads to the wrong terminals on an EV can damage sensitive electronics. The procedure varies by manufacturer look it up and bookmark it.
