Battery at Rest

[Aidi]

Hey all,

If i was to place a multimeter on a car battery whilst at rest - say 12 hours since it was last driven, what reading should i expect to see?

[Niall83]

Hmm not sure, maybe 12v

[tony-1977]

12 - 13 volts

[Das]

Not easy knowing. Batteries voltages have a habit of increasing slightly at rest.

[witty]

What reading you getting???...

[Aidi]

Battery after 2 hours at rest is reading 12.2v - Going to see what it reads in the morning when its really cold under the bonnet.

[tony-1977]

When below freezing (last week), mine showed 11.4 before a cold start. Started up ok (although typical 120 CDTi turned a little slow)

[Critch]

12.7 is 100% charged

12.2 is 20%

[paulhb]

When below freezing (last week), mine showed 11.4 before a cold start. Started up ok (although typical 120 CDTi turned a little slow)

Thats getting towards trouble time as the voltage drops under heavy load (cold starting) to around 10v the can bus system starts throwing loads of errors and stops talking to daft things like rain sensors. It might not last much longer Tony.