Dashboard Alternator light

eric1514 wrote:
First test.

I ran the batteries down a bit and then plugged in the coach to shore. I have a PD converter and I let it bring the batteries back. When the starter battery was at 14.3v started the engine. That brought the voltage down to about 14.25. I couldn’t get the voltage back up. I suppose if I idled for a while I might have been able to raise it. The current was at about 6 amps. The dash alternator light didn’t come on.

It’s still too hot here to uncover the RV, so I was using the converter/charger to simulate the solar panels. What I think I learned is that the PCM is tolerant of voltage above 14.2. So right now I think if I change the profile in the controller so that it never goes above 14.2v I should not see a light.

I think you have it backwards. If you idled for a while the alternator voltage would taper to 13.8ish. meanwhile the PD set to 14.4 might eventually get the batts to near that. with voltage drop on the PD wiring you might never see 14.4 at the battery even with the low amps at the high SOC meaning almost no voltage drop.

Solar's low amps means little voltage drop unless thin wiring, so you could set that to 14.5 and get 14.4 which might ot set off the light.

You have to test for how high you can set the solar without the light coming on when the house batts are full. If they are full you don't need to be doing that at all, so if you did have a way to turn off the solar when the house is full while driving, you could get to the campground with the house full, no red light, and alternator charging looking after the starter batt.

BTW, do you have the charge wizard or pendant to make the PD do 14.4? If not, it will only do 13.6. What are you doing with that for testing?