lysergic

I have a GenIV in a 300zx and when the engine is running the battery voltage reads 13.8 - 13.9 volts. I was under the impression it should read up around 14.5 volts though. Would this be causing a problem and is there anything I could check to see why its low?

1lejohn

iTrader: (9)

That sounds about right. Depending on the load etc you might measure 14.1-14.5. Not sure if these alt. need to rev up for the exciter voltage to come up. Try reving the engine too about 2500 rpm then let off and measure the voltage. I think these alt need to see some rpms one time after start up then the exciter stays on, even if the rpms drop down to idle speed.

jim ravencraft

Hi,
the above is correct,your battery should read 12 volts with engine off and 14/15 with engine running.have a blessed day...jim