I added an Exide Deep Cycle Orbital (same wound mesh interior design as
Optima) under the seat of my 91 Syncro Westy. I decided to sacrifice driver
seat swiveling ( a rarely used awkward option ) rather than give up much
needed storage space elsewhere. The existing carpet still covers this
installation. One thing I discovered is the supplied battery relay is for
power to the water pump, refrigerator and refrigerator fan, and not the aft
light bar. Since I live in the Pacific Northwest I was never privileged to
know a fan even existed, but a recent trip to the S.W. brought it out of
hibernation. Now that the ref. fan has a constant source of power, it will
come on when ever the cavity behind the fridge gets hot (i.e. dark van
parked in summer S.W. sun) that noisy little bugger will kick on, even if
the fridge is off! I guess a battery switch is in order. I added some
interior lights and had to re-wire the existing light bar to the Deep cycle.

BTW the owner of my local shop owns a syncro westy as well, but he special
ordered a battery that fits exactly in the shallower space on the drivers
side (not the same our year at least) some odd European battery size deal.

Wayne