A day of learning:

Two 6 volt, 220 amp batteries joined to make one 12 volt battery has 220
amps. Even though the guy at the battery store told me otherwise.

My old 8Ds had a rating of 215 amps. 220/215, not much gain there.

The cost of the 6 volt batteries is about 1/2 the cost of an 8D. A
little more or a little less. $65 + $65 = $130. 8D, $140. Not much
gain there.

What this means is that there is little gained, initially, by going with
the golf cart batteries. Since I have to buy battery boxes, it will
cost me more.

The golf cart batteries SHOULD be good for many more deep discharges
than the 8D. The golf cart batteries are easier to move around, and
have a smaller foot print. The battery boxes have more options for
dimensions.

I'm buying the golf cart batteries from a battery store. A few dollars
higher than Costco. Five dollars each battery. I get the cables free
from the battery store, so it's actually cheaper than Costco.

I'm upgrading my charger to a Xantrex "True Charge" 40 amp, 3 stage
charger. The "Equalizer" function is important to maintain the batteries.

The old battery boiler charger is going in the trash.