ORIGINAL: danlrc
Kamaz -
I'll be blunt. Your circuit works, but is a nonstandard way to do it. If you use the standard approach I posted above, the battery is totally isolated when the switch is in the center position. No extra jumpers as noted in your post are necessary. to isolate the battery.
That still makes it more complex than it needs to be. Just parallel connect a charging jack prior to the main power switch. I never understood the need for DPDT switches and the like.
Perry