Battery Light stays on

[NAtide]

I crossed the jumper cables when jumping off the mh (bad brain lapse). I corrected them correctly and it started and ran fine. I then started the generator with the engine running and it stopped the engine. I Shut down the generator. The engine wouldnt start again on its own..I took the engine battery to be tested and it was dead. Installed new battery and engine starts fine. Generator also runs fine while engine is running. My issue now is the dash battery light stays on. I'm getting a meter and testing the alternator this evening but wanted to know if there are other things I may need to also check (in the event the alternator checks ok).

If I hadn't crossed the cables initially I'd think alternator for sure but now I'm nervous I may have caused other issues. Any input is appreciated. The mh is a 2008 hurricane 34b ford.

[NAtide]

Thanks for the replies. I tested the battery and it was 12.3 before I cranked it and 12.2 after. I got to the alternator and it showed 11.1 while running. I'm going to grab a new alternator. I guess that one is still doing some but probably on the way out.

Thanks again for the input.

[DiskDoctr]

Your generator likely has a circuit that charges BOTH the house and coach batteries, interconnected with an automatic 'switch' between the batteries. Many add an isolator between the batteries so using the coach doesn't leave you stranded with a dead starting battery.

It's possible you killed BOTH batteries in your accidental (high amperage!) short. Your generator *may* be drawing power from the coach battery or both to start, masking the other dead battery/shorted cells.

Did you have both batteries tested?

You can stop at Advanced Auto Parts and they will test your batteries for you, free of charge.

As mentioned, check the voltage across EACH battery at rest and while the engine is running (charging) for testing the charging to each battery.

If I were to guess? You toasted the house battery and when charging it is pulling way too much amperage from the alternator as it tries to charge both coach and house batteries. But I wouldn't bet my entire stake on it 😉

[Harvey51]

Just a voltage check should do it. If your battery voltage rises to 14 when the engine is started the alternator must be working. If you have a DC clamp meter, measure the current coming out of the alternator, too. The last time I had an alternator failure, current went in to the alternator rather than coming out and starting the engine lowered the voltage across the battery.

[K_Charles]

The fusible link is there to protect the wire from a short and most likely won't be bad.

[wa8yxm]

When you improperly jumped the engine, You toasted your alternator. As the other poster said you may have a fusable link and if you do and it fused on you.. Buy lotto tickets.

More than likely you toasted the diodes.. The fixs (2 versions) involve removal of the alternator and then either:

1: Replacement
2: Transport to a rebuilder, pay the man, and re-install.

[64thunderbolt]

If the alt would go first what's the point of the fusable link??

[K_Charles]

Some alternators have a fusible link wire in the wire from the battery but the alternator would most lickly go first.