RE: UB12220 battery system
I've not installed such a setup in my Westy but have used the same type of
battery for other purposes (powering my telescope mounts) in the past, had
several of them in the 17AH size.  And they are very sensitive to getting
the right charging.  I've been watching the threads that come up from time
to time about this setup in a Vanagon and Craigs post confirms my
suspicions:  Be very careful how you set up the charging circuits or you
won't get much 'distance' out of them.
And don't ask me how to charge them right in a Vanagon because I don't know.