Battery Tender on E450 Chassis? Shore Power does all?

I know for sure mine will charge the chassis battery when the coach is plugged in. It's easy to check, plug in to your outlet, then check the under hood battery for voltage. If it's over 13v, you're charging. Let it sit for some time before checking though, it can take a while for the relay to connect them up (in my experience anyway).

It's not a function of the Ford portion though, it's a fuction of how the motorhome manufacturer wired up the chassis/house batteries.