jump pack

I never thought about that. Having a separate circuit on the batteries with a relatively small PSW inverter is a very good idea. That way, one can have some low power draw appliances that will always have power, regardless if one is plugged in, on a generator, or boondocking. This would be useful if one has an inkjet printer or a scanner, for example. Or, if power goes off at a CG when one is doing something very important on the computer, and the laptop battery isn't going to last that long.

Of course, the one thing I'd add would be a fuse that would be the size of the max amperage the inverter will ever use, so a short circuit's damage is minimized.