There is a 15% off sale on some deep cycle batteries at Canadian tire.

The camping battery in my '94 westy has been weak this season, and
a couple of weeks ago I suspect one of the cells gave up/shorted (voltage
dropped from 12.6 charged to 10.5) Right now I have a standard lead acid
(in fact the old starting battery from my '82 Diesel)

I was thinking to get a real deep cycle this time. The '94 westy takes
up to two batteries so I can get 1x12V or 2x6V.

Canadian tire has the following offerings:

A regular (consumer grade for your boat, rv etc) battery
205 min reserve capacity => 205/60*25 = 85 Ah for $119 hence cost $0.71/Ah

Or an "Renewable energy grade" Excide 6V battery (Should presumably be more
tolerant of cycling for instance for people who solar power their cottage
and cycle
the battery every night. But who knows, maybe it's just a relabeled golf
cart battery...)
150Ah at 6h rate, $85, Hence cost for 2 batts $170 gives $0.88/Ah

Third option is an AGM (Absorbed Glass Mat -- one of those supposedly new
better technologies)
100Ah at a fishily long 100h discharge rate. $212, gives $0.47/Ah

Which one would you buy?
Any other place I should look?
(particularly a place that might have a retail outlet in Edmonton?)

The smaller 85Ah one is probably enough to run the fridge (compressor type),
lights etc for a nights
camping, but the shallower cycling of the 150Ah alternative might give much
better longevity?
Is the premium price of the AGM worth it?

Thanks,
Martin

PS: If you want to see the choices go to http://www.canadiantire.ca/ type
"deep cycle" in the search field
--
Martin Jagersand
University of Alberta
http://www.cs.ualberta.ca/~jag/