Voltage on Dash Display

[motofamily]

What is the voltage supposed to say on the little digital display on the dash of a freightliner chassis motorhome with a cummins 300ISB I am trying to figure out if I have a battery issue or alternator issue. When I first start up the coach it goes into fast idle says low voltage 13.4 -13.8 then goes away after I tap the break.

[goodtime]

Quote:

Originally Posted by motofamily What is the voltage supposed to say on the little digital display on the dash of a freightliner chassis motorhome with a cummins 300ISB I am trying to figure out if I have a battery issue or alternator issue. When I first start up the coach it goes into fast idle says low voltage 13.4 -13.8 then goes away after I tap the break.

thats ok diesel use a lot of voltage to start .

my diesel go to 12 volts then back to 14 all the time i start it.

[motofamily]

I am showing 13.6-13.8 volts on the dash display and 14.1 at the batteries when running

[Gary RVRoamer]

Mine usually shows 13.6v when running.

[Skip426]

Quote:

Originally Posted by motofamily I am showing 13.6-13.8 volts on the dash display and 14.1 at the batteries when running

Voltage of 14.1/14.2 at batteries would be normal, regulated alternator output, and JMHO a drop of .3v in the wiring from the batteries to the dash, and considering the possibility of gauge inaccuracy (+- 2%) also normal.