Hybrid 12V Battery Replacement
Also called hybrid auxiliary battery
A hybrid has two batteries. The large high-voltage pack drives the car, while a small 12-volt battery powers the computers, lights and locks and is what actually brings the system to ready. When that 12-volt battery fails, the car will not start even though the hybrid pack is healthy. This job replaces the 12-volt battery only; it does not repair, rebalance or replace the high-voltage hybrid pack.
What the job includes
- Test of the existing 12-volt battery before any replacement
- Correct hybrid-specification battery with the right vent arrangement
- Memory support so stored settings and adaptations are kept where possible
- Safe handling of the 12-volt system with the hybrid system shut down
- System wake and ready-mode check after fitting
- Removal of the old battery for recycling
Signs you need this
- Dashboard lights up but the car will not go to ready mode
- Multiple unrelated warning lights appear together
- Doors unlock slowly or the alarm behaves strangely
- Car sat unused for several weeks and now shows no response
- Repeated need to boost the small battery in the boot or under the bonnet
Not all of these have to be present, and one of them on its own can mean something else entirely. That is what the diagnosis is for.
How we do it
Confirm which battery
The 12-volt battery is tested and hybrid system codes are read so the high-voltage pack is not wrongly blamed.
Shut down safely
The hybrid system is powered down and the correct sequence is followed before any connection is disturbed.
Fit the right type
A hybrid-specification battery with the correct venting is fitted, since a standard battery can vent gas into the cabin.
Wake and verify
The car is brought to ready mode, codes are cleared and the charging voltage from the converter is checked.
How we work
The same on every job, which is why we can write it down.
Diagnosis before quote
We find the fault first. A price given over the phone for a noise nobody has heard is a guess.
The price is agreed first
You approve the work and the cost before a spanner is picked up. Extra work means another call.
Parts you can check
We tell you whether a part is genuine, OEM, aftermarket or used, and what each one costs.
Old parts returned
Ask and we will hand back whatever we replaced. It is the simplest proof that the job was done.
Book hybrid 12v battery replacement
Fill this in and a person will call you back to confirm the time and the price. Only your name and one way to reach you are required.
Before you book
Questions we get asked
If your question is not here, ask it. We would rather answer honestly now than have you find out after booking.