Brian,
I just replaced both batteries, in my Westy.
The "house" battery, is a combination unit,with deep cycle capabilities,
as well as starting, and the other is an 850 CCa, starting battery only.
I think that a deep cycle or the deep cycle / staring combo would work
fine.

I got the house battery at Sams Club, for $49.99, and it has 1000 CCA's.
The other i got at Wal-Mart for $49.99 also, and they both are 2 years
no questions asked, replacement warranty, and 5 years pro rated.

Not a bad deal.

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Terry
74 Campmobile (Clementine)
85 GL
86 BMW 325 ES