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phorner
04-27-2010, 12:39 PM
I noticed today that my house batteries are receiving too high voltage from my 12 volt alternator when the bus is running.

The inverter panels display an "over charging" warning and I confirmed this with the analog gauge on the dash as well as measuring the voltage at the alternator output terminals.

I'm reading 17.5 volts across the terminals and about 16.5 volts on the dash gauge.

Any thoughts? I'm assuming that the voltage regulator is built in to the alternator? By the way, this alternator is less than 3 years old.
jack14r
04-27-2010, 01:55 PM
If you have the 270 amp alternator the voltage regulator is not in the alternator.Mine is in the right side door with 4? wires going to it.Within the last couple of years the regulator was improved.Paul,It is very easy to replace if it is like mine.
jelmore
04-27-2010, 02:20 PM
Paul, my regulator was replaced a couple of years ago with the newer style. There's a screw for adjusting the voltage. If yours is the older style, it may be adjustable also. I would imagine it's a standard part and easy to replace.
phorner
04-27-2010, 03:38 PM
Jack and Jim,

Thanks for the response. The alternator in question is my small, 12 volt alternator for the house batteries. I have replaced the voltage reulator for the big 50DN, oil-cooled alternator. My bus has a 12 volt house electrical system as opposed to those with 24 volt systems.

I found a very good local auto/truck electrical shop and they will be repairing it. Should have it back in a day or two. Interesting to note that my alternator provides 3 step charging from the internal regulator.
jelmore
04-28-2010, 12:46 PM
Duh, I wasn't paying attention. Did that overcharging cause any problems with your 12V house systems?
phorner
05-04-2010, 09:12 PM
My rebuilt house-battery alternator has been received and installed. I was mistaken a bit about the voltage regulator being "3 stage". It was, in fact "3 step", meaning that the output voltage was only adjustable to one of 3 set points.

The replacement regulator has a variable output adjustment over a specific range. Mine is currently set at about 13.3 volts. Cost of having the alternator rebuilt was $225 including the new regulator.

No more "over charging" warnings!!

And I managed to replace the belt while I was at it.