John Koloen wrote:

> <snip>I'm planning to install an auxiliary battery, though maybe not under
> the
> driver's seat since I can't find a deep-discharge battery that will fit.
> (I'm still looking.) Is there a need for venting to the outside if I
> install it, say, under the rear bench seat?<snip>

Conventional batteries give off hydrogen gas. This gas can be explosive. Do
not risk locating a conventional battery without venting to the outside.

Gel cell batteries are probably safe as long as they are not overcharged
(overcharging causes gel cell batteries to give off hydrogen gas).

The Optima battery (yellow top) is probably your safest choice. All it gives
off are electrons and long service. If you remove (saw off) the metal tab from
the top/front of the battery box behind the driver's seat, then the Optima
D750S (or D750U) Deep Cycle Battery (Yellow Top) will fit on its side within
the battery box. This battery can be mounted in any orientation with no
adverse affect.

> Also, I'd like to know the size wire I should use to connect the auxiliary
> battery positive to the starter battery battery.<snip>

The wire size depends upon the continuous current that will be drawn (the
bigger the safer). Add up all of your 12v service requirements and select the
appropriate wire. Add a fuse to protect your van and family.

Larry
'86 Syncro Westfalia with Optima D750U