Disconnecting chassis batteries

[Neemer]

I need to disconnect the chassis batteries and load test them. My SOP for doing this on my automobiles is to disconnect the ground then the positive cables.

Is it the same on these motorhomes? Google is giving me conflicting information. Who has actually done it?

 

[Neal]

I believe @Chuggs prescribes positive off first as if you leave positive connected it can find a ground through some other path. With positive disconnected there's no chance of a stray tron.

Also, be sure to turn off the chassis disconnect before anything to prevent passing anything upstream.

Edit: Protect the positive from making contact with something unintended such as wrapping it with a towel multiple times.

 

[scottramer]

I have load tested and replaced my chassis batteries and I dont feel.it makes a whole lot of difference. I always disconnect the neg first but remember, your inverter charges the batteries and it does not run through the switch, that cable connects directly to the batteries. So unless you have shut down the invertor you still have power feeding into the positive cable. Plus, you have a small amount feeding from the little solar roof trickle panel if you have one. I always wrap the pos cable end when I disconnect it.

 

[Avalon]

As Scott noted, the battery charge-bridge solenoid is connected to a secondary line on the chassis battery and bypasses the cutoff switch. You should shutoff the inverter, but I also recommend disconnecting the charge-bridge line from the battery post to isolate the batteries fully from that circuit.

The rooftop solar panel battery connection is indicated by the magenta arrow on the left in the photo.