I found a supergel cycling battery that fit perfectly under the drive's
seat.
Here are some spec:
Trojan supergel
Type: sg-30
30 amp/hours
Dimension: L - 7.5/8 (194); W - 5.3/16 (178); H - 7 (178)
Price: aprox $70

Would like to hear from someone that has used this battery if it is
worthwhile buy it?
Can I used the relay and the smaller stock wire that came standard with the
westy or do I still need to replace the 30 amp relay with a 40 amp one?
and is it better to change the smaller wire with a #8 wire?

Thanks as lot to everyone for your help.
You are really a great family.

Marco Biancardi
star@maui.net