The Power-Gate Dual Rectifier isolator by Perfect Switch looks like it would be a good replacement "isolator" for our vans.
http://www.perfectswitch.com/isolators/ ... -isolator/
It has a useful "Battery Combine" feature.
We're pleased to announce the addition of a "Battery Combine" feature now available on Dual Rectifier devices. This optional feature enables the user to combine or join the batteries together for applications like self-jumping or winching without the use of jumper cables. Simply trigger a conveniently placed momentary switch and allow current to transfer from your healthy battery to your depleted battery....it's that simple.
Models available for up to 300 amps.