What should the battery charging voltage be?

[Landy4ducks]

Does anyone know if there is range of voltages that are correct for charging the battery.

I was told that anything over 14,7V means that there is a problem.

I checked my battery today after not use my 90 for a week and it was 12.8V on my meter. That's about right as far as I was told.

After starting engine and a good rev, I check the voltage again - this time is was 15.65V

put on head lights - dropped to 15.42

put on main beam + 2 linked spot lights - dropped to 13.90V

Is this about right?

[Puffernutter]

Offload voltage sounds rather high and could cause damage to the battery. Off the top of my head 13.8v to 14.4v seems to ring a bell as the charging voltage range.

Dropping on load is not unusual. Check the "sense" wire to the alternator. A poor connection can make the alternator think it's not charging and so it will ramp up the output voltage. I've had that experience on my TR7 with the volts shooting off the RHS of the scale!

Cheers

Peter

[vulcan bomber]

It does sound like your alternators overdoing it to me.. I was under the impression they shouldnt go above 14.4 volts.

[Landy4ducks]

Thanks guys for the replies - I have done some more research in the web - it could be the Voltage regulator?

As the Alternator was only purchase at Christmas - part STC234, I have gone back to the supplier to get a new regulator under warranty.

Just checked my Invoice - guess what?? yes, its a Britpart - that's a case of you get what you pay for!