If you're in the U.S., there's only two suitable batteries to use under
the driver's seat as an auxillary.  After you finish comparing specs and
costs, you will discover there's really only one:  the optimus deep
cycle battery...I prefer top post (see archives: "auxillary battery" or
"Optimus".  They are about $185.
steve

William Carden wrote:

> Can someone tell me what the electric device is under the receptacle
> is in a westy?
>
>   And what would be the best type of battery for the auxiliary, marine
> deep
> cycle, or a car type battery? And would you know what size?
>
> Thanks in advance