Battery Boost not working

Keep us posted on the solution.

Thanks

Might be that chassis batteries pulling down house batteries.
Did you hold the boost down while cranking?

Might also have poor hot and/or ground connections.

Moffittclan, I had that happen once on our previous coach. It was in the storage garage and when I went to start it, dead dead dead!

I held the boost switch and tried to start and 'no go'.

So, I held the switch for a while, about 5 min., that was enough to get it to turn over and start.

The next time, same issue, so I had the batteries replaced as it was about time anyway.

MM.

Mandalay Parr wrote:
Might be that chassis batteries pulling down house batteries.
Did you hold the boost down while cranking?

Might also have poor hot and/or ground connections.

I was holding it down while trying to start. I didn't even have dash lights (even while holding it down). When I dropped the chassis batteries off at Autozone this morning they were only reading about 9 volts...to low to even test with a load...maybe they were sucking all the juice up. I tried to jump it with my Jeep and I got the dash lights but it wasn't enough juice to actually start it (even tried pushing the battery boost while jumping). Makes me wonder if I have something else all the sudden sucking up my power (though it would be new because we haven't really done anything new with chassis power).

Once my batteries are done being tested and new (I expect) ones installed, how can I verify that the coach batteries are connected to the chassis batteries correctly just in case this happens again?

Mr.Mark wrote:
Moffittclan, I had that happen once on our previous coach. It was in the storage garage and when I went to start it, dead dead dead!

I held the boost switch and tried to start and 'no go'.

So, I held the switch for a while, about 5 min., that was enough to get it to turn over and start.

The next time, same issue, so I had the batteries replaced as it was about time anyway.

MM.

Ahhh, I didn't try holding them down for any length of time...just held down while turning key...may try that next time!

If the boost solenoid/switch is powered from the chassis battery and it is dead, then no, the boost solenoid will not connect the battery banks. You could remove the signal wire from the boost solenoid and take a small jumper wire from the house bank lug of the solenoid to the signal terminal. That will close the solenoid.

And, yes a small jumper wire is fine, as it is only carrying enough current to close the solenoid.

Do NOT use a small jumper wire to connect large lug to large lug-- that would melt it.

Easy to check the AUX Start/Boost circuit. Two ways to do but which works depends on how you coach is wired.

Turn on a convent 12VDC light. Trip the house battery disconnect. Light should go out. Hit the AUX Start/Boost switch and light will come back on.

-or-

Turn on a convent 12VDC light. Disconnect the ground terminal from the house battery bank. Light should go out. Hit the AUX Start/Boost switch and light will come back on.

The AUX Start/Boost circuit works both directions not just to send extra power to start the engine but will also feed power back to the house.

Dale.Traveling wrote:
Easy to check the AUX Start/Boost circuit. Two ways to do but which works depends on how you coach is wired.

Turn on a convent 12VDC light. Trip the house battery disconnect. Light should go out. Hit the AUX Start/Boost switch and light will come back on.

-or-

Turn on a convent 12VDC light. Disconnect the ground terminal from the house battery bank. Light should go out. Hit the AUX Start/Boost switch and light will come back on.

The AUX Start/Boost circuit works both directions not just to send extra power to start the engine but will also feed power back to the house.

Perfect! I know what I'm doing tonight while I'm installing the new chassis batteries! Thanks for the help!

These are the moments when you REALLY want some type of pull cord option on a generator. I know many generators on coaches don't have them today, but in my old Toyota Class C it does. My bounder it does not. If you get into a jam with your batts, you fire up the genny by pull cord, starts charging house batts, and boost to start truck.

No way will the house batteries charge dead engine batteries enough to start a diesel by just holding the boost switch down, even for several minutes. If you can start the generator then holding the boost down for 5+ minutes might get enough juice into them to start. Jumping from a car/truck with your average $20 jumper cables will take 20+ minutes of charging with the engine running to maybe get the MH engine to start.