I have seen in black and white that while car is "on" it trickle charges the 12v battery from the main battery. But is it "on" when being charged (rather than driving)? I dont do a lot of miles, just down the shops and so on and it can go some time unused. It strikes me its counter intuitive that unlike a car with an alternator, leaving it switched on will charge the 12v battery at the expense of the driving battery rather than flatten it. But I cannot find a confident answer to if it trickle charges the 12v battery when parked, locked and charging?
Technical The 12 Volt Battery (charging)
- Thread starter MikeReid
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Technical The 12 Volt Battery (charging)
No it doesn't. But around 2am every day it will charge the 12v. Mine was in the bodyshop for nearly four months without moving and while the HV did discharge somewhat the 12v was fine.
IanML
Member
I used to have a voltage monitor on my 12V battery, and I seem to remember seeing it did receive charge when the traction battery was being charged in my garage. I also saw it being charged overnight on one occasion when the car had been out of use for a couple of weeks, so I don't think it is a routine occurrence, but kicks in when the voltage has dropped to a particular value.
