Engine battery voltage

[Tom Webber]

I have 2006 Monterey with a 350HP Cat engine. A little background information. The coach no longer has an Aladdin system since it had to be disconnected after an electrical strike and the cable between the Allison transmission was Aladdin was causing the Allison transmission to not work. My only engine gauges are on the dash. I have ACM batteries for both coach and house batteries. On two occasions the volt gauge has dropped from 12 to 10 or less. After starting the generator and holding the house assist the volt gauge would go back to 12-13. Leaving the generator running today but not holding the house assist the volt gauge would hold steady but as soon as you turned generator off voltage would start to drop slowly.

Any ideas why?

[Gerald Farris]

Tom,
From your description, your engine alternator is not working. But since the analog dash gauges are so inaccurate, I would verify the chassis battery voltage with the engine running and the generator off using a good volt meter.

Gerald

[David T. Richelderfer]

1) It sounds like the alternator is not charging the chassis batteries.
2) it sounds like your crossover charging system, a Big Boy/BIRD or Echo Charger, is not working to pass the generator/inverter-charger charging voltage on to the chassis batteries.