Dead battery charger/converter?

[ShutterStuff]

Today I went out to do some maintenance on the RV that has been neglected since early January. Generator would not start. Engine would not start. I hit the button on the volt meter I installed like many others here and it would not light up at all!

The lights are working on shore power (all 12 volt lights). I grabbed my volt meter and the engine/chassis battery read 0.42 volts. The two 6 volt house batteries read 2.49 volts in series.

I have the Magnetek 6332 that was retrofit with a 7345RV about 15 years ago.

1. Can the Magnetek run the 12 volt side of things and not charge the batteries?

2. There is a battery disconnect switch. If this got triggered accidentally in December when we last used the RV, would this kill the batteries?

3. I know the engine 12v battery is toast but will the Costco GC batteries come back to a useful life? An external charger seems to be doing a normal cycle on them but the 12v battery only made the needle bump when turned on...

Any ideas on what to look for and test before I start replacing things?

Should I think about upgrading to the PowerMax PM4B-45?

[ShutterStuff]

The only charger I have is a 4 amp auto. It is holding steady at 3 amps. I will check in the morning and see how they are doing.

I am not aware of a fuse close to the batteries, but I will look underneath in the morning as there is not one in the battery compartment or where the relay bank is.

[BFL13]

I agree you may have disconnected the batteries from the converter so now they are dead but your lights still work on shore power.

Besides any battery disconnect switch that might have been opened by accident, there should be a "battery fuse" close to the battery on the positive wire. Somehow you might have blown that.

You can try to recover the house batteries by first recharging them to about 14.4ish volts till they won't take any more amps (that 7345 will only do 13.8v so you need a different charger like a manual 6a that is not an "automatic" but which you have to turn off yourself when the voltage gets up too high) then do an Equalize for a while to see if you can get the SG into the green with your hydrometer. This will all take a few days, no instant answer.