Battery Light ??

TC&Z...Any update yet?

The battery light will come on for both NO charge from the Alternator and EXCESS charge(hi voltage) to the chassis 12 volt system. When this happens, do you have the Genset on also? When it happens try turning the headlights ON(if they are off) and the Dash AC ON if it is off and see if the light goes out. This puts a higher load on the system and if too high voltage, it will drop the current about 1/2 to 1 volt. If on Genset, the Inverter/Charger if you have one may be in BULK charge which will send a higher voltage to the chassis system until the Inverter/Charger goes out of bulk charge. Did you replace the Alternator for the same problem? Doug

Ok the battery light is a misnomer. it's the alternator light for what it means is the alternator has stopped charging.

Now a question.. What was the wetter like. (That's a pun on weather) Dry or well. Wetter? I have not had this happen on my Workhorse.

But several cars. Including the one I drive know will stop charging and turn on the light if I hit a puddle of rain or melted snow and soak the alternator.. Soon as it dries out .. Light out voltage up.

I think I'd check the tightness of the serpentine belt.

Why was the alternator replaced and was it replaced with an aftermarket alternator?

So it the light on at start up or 20 minutes into a drive down the highway at 60 or around town, etc.?

Any work done lately? Any accessory used more often lately? Have you observed voltage during the episode?

Are you sure your battery isolator is functioning correctly? A 2 volt spread seems large.

Battery voltage at 12.5 is a little low. Put a slow charger 2 amp for a day or so and see how they hold up after they are fully charge. Check them the next day after taking off the charger. Do you have a way to check each cell.


https://modernsurvivalblog.com/alternative-energy/battery-state-of-charge-chart/