Battery Disconnects

[Bikestuff]

Gang,

I have another "Inquiring minds" type of question. The other day when the Newell guys were welding on my coach they said that they were going to turn off my power. (Unplug from shore, and turn "OFF" the engine batteries and house batteries. I understood that to mean turn the battery disconnects to the "OFF" position. Now is when it gets weird. They disconnected shore power and turned both disconnects to OFF. Yet...I still had AC power. My coffee maker was still working, I still had AC on my laptop. I told them...and they did some magic around the inverter to shut down power.

Talking to Jim G (Newell) I found out that the disconnect is on the Negative side of the battery and isolates the batteries from the ground. He said that they do this on aircraft and that is why Newell does this. On my coach, I think that there must be a path between the batteries and the inverter that does not go through the disconnect.

I am interested in the subject because I have been building an iPhone checklist app, and I was working on an Emergency Procedures checklist in case of an accident, fire, etc. One of the things that I want to in an emergency is to turn off ALL power to the entire coach. In my simple brain, all I had to do is flip those disconnects. Not so!

So...here are my questions:

1) Why is the disconnect on the negative side of the battery? Why not the positive side. Is there a downside to having two disconnect switches...one on the positive and one on the negative.

1a) Can I use the inverter panel to shut power down...it seems to keep providing AC no matter what I do to that panel. Is this correct?

2) Do you agree that in an emergency it is a good safety practice to shut power down to the coach?

Cheers,
bill