Alternator Failure Warning

[mscully103]

I own a 2008 Monaco Knight...today, while the coach was connected to shore power...120... I started the engine. After about 10 minutes, I got a warning beep. Nothing was visible on the display but as I reved the engine, Alt Failure displayed...as I let it go to idle...it went off...rev...Alt failure. As just a thought, I disconnected the 120 without shutting off the engine. The warning beep stopped and I could rev the engine and no Alt Failure...any ideas?

[YC1]

My 08 HR Endeavor will do that sometimes. I am thinking the inverter charger is putting out a higher than normal voltage and the alternator system may be kicking out due to that. I haven't dug into my schematics because it happens so rarely. Often the alternator warning will come on if the batteries are low and the engine is idling. I have had it happen while driving with low batteries. I believe the alternator circuit breaker will kick off if it gets hot. That said my owners manual specifically says to run the generator to charge depleated batteries and not put that strain on the alternator.

[Rex]

YC1 is correct. The problem occurs when you have been using the batteries enough for them to need recharging. If not connected to shore power, best to start the Generator for a while before starting the engine so you don't place a heavy load on the Alternator, otherwise you may cause it to fail for good.

[bborc]

Our 07 Knight does the same thing. It can be plugged in for days And if I start it with it plugged in the alt light and buzzer comes on. I think it might be because volts are to high. My aladin shows 14.8 volts when it does that. As soon as I unplug shore power it stops the warning.