Club 80-90 Forums

Changed the battery on my car a week ago. Today the battery light is on. Checked the battery with a multimeter with the engine off 12.48v and 14.8 with the engine running. Is 14.8v too high? could it be the voltage regulator?

I think the last time I checked my 1.8 Focus it was about the same voltage as yours both running and off.

No that's right the only thing that's wrong is the red light on

It's why it has suddenly come on that's puzzling me.

I'm not sure why the light has come on but the Alternator is doing what supposed to be doing it put 12v to keep the battery topped up and the extra volts it to power the Electrics like indicators lights radio when driving

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Just copied this from an internet post.

if the red ‘ignition light’ comes on it indicates a variation between the alternator output voltage and the battery voltage. If the light gets dimmer as the engine revs up then suspect an alternator fault. If it gets brighter then suspect the battery

Cheers will check that tomorrow.

Dirty and or damp connections, check any plugs and sockets in the loom R0B and battery connections at the battery 

Checked those earlier Steve no problems there. Someone I know suggested on a lot of "Modern" cars the battery needs to be registered using the OBD port. I need to find out if this is the case with mine.

I’m out then , too modern for me if its got a OBD port .

R0B wrote: ↑07 Jan 2022, 19:42 Checked those earlier Steve no problems there. Someone I know suggested on a lot of "Modern" cars the battery needs to be registered using the OBD port. I need to find out if this is the case with mine.

Both my current VWs need the ecu updating with a new battery, 5 second job with VCDS. It is to allow the ecu to recognize the new parameters so that the smart alternator operates correctly and keeps the battery at 80% SOC for the regenerative braking to work.

Somehow i knew OBG would know OBD……

Another forum informed me mine does not need registering. So thats not the cause of the battery light.

There are other forums ?? 

Rob what car is it