House battery not charging properly. Bypass solenoid?

Agree, 12.7 VDC at the chassis battery with engine running means an alternator/regulator/wiring problem.

Same for no change in voltage on house battery when generator is on and presumably powering the converter, charger or inverter/charger.

And, yes after you solve either of the above, you can bypass the defective solenoid to charge both banks. BUT, have you confirmed 12+ VDC to the signal terminal of the solenoid. If no, disconnect the POSITIVE signal wire from the signal terminal and take a small wire (will be supplying less than an amp) from the large lug that has 12.7 VDC to the positive signal terminal. If solenoid closes, you know the solenoid is OK. If not the solenoid is bad.

Safest way to bypass the solenoid: Mark (tape, paint, etc) all the wires on one large lug. Remove them and ADD them to the other large lug.

Be sure to return wires to their original position when finished.

Do NOT use a jumper wire to do this with engine running or driving, as the jumper could "jump off" and create a dead short directly from a battery.

Salvo wrote:
This doesn't make sense. When the Onan is running, you should be getting more than 11.8V at the house battery.

First, be sure that a coach battery disconnect switch hasn't been accidentally thrown. That will stop it from charging from ANYTHING.

AND with the engine running, you should see more than 12.7 at the engine battery too.

I'm not sure that "bypassing" anything is a good idea, not knowing exactly what is wrong.

There may be more than one fault at work here.

This doesn't make sense. When the Onan is running, you should be getting more than 11.8V at the house battery.

mdecorso wrote:

With my Onan generator running, I get a 13.8 reading at the engine battery and engine battery side of the solenoid, and an 11.8 reading at the house battery side of the solenoid.

ThaNks.

First you must find out if the control voltage of the solenoid is there before you throw the baby out with the bath water.

Of course you can bypass the solenoid. Just pile up the big wires on one side or the other.

Before doing that check the small terminals on the solenoid. You should be getting 12 volts on one and zero on the other. This is the control voltage. If you have a blown fuse somewhere the voltage might not be there.

mdecorso wrote:
Well, I push the button on it and it starts. It is mounted on the vehicle. Is that answering you question? And does that yes you posted mean I can bypass like I am thinking? Thanks again.

Yes, you can bypass the solenoid. My curiosity was about the distances but now that you've explained that your arm reaches from Europe to Alaska, I'm all good.

Well, I push the button on it and it starts. It is mounted on the vehicle. Is that answering you question? And does that yes you posted mean I can bypass like I am thinking? Thanks again.

Yes but a casual reader might ask--How do you start a generator when you are in Europe?