[C320-list] 4D Battery Replacement Advice AGMs

[Joseph A Tamucci]

Thanks everyone for the responses.  From what I've read so far I think
there is confusion between AGM (Absorbed Glass Mat) and Gel cells I'm
considering.  According to the literature I've read on batteries, the AGMs
are technically wet cells like the standard 4D lead acid but have the
electrolyte absorbed in a mesh of boron-silicate glass fibers. As such they
are true no maintenance batteries. They can be charged with conventional
chargers without fear of damage from overcharging. They are advertised as
having the same charge characteristics as the lead acids but are more
rugged, discharge at a much lower rate, and will not suffer from freeze
damage.  The only downside I have read is that they cost twice as much as
the standard lead acid.  Since I leave the batteries on the boat all winter
in NE that's the big selling point to me.  At 140+ lbs each I'll pay the
extra $300 to leave the batteries on the boat for the 6 mths winter storage
(don't you southern boys laugh now) without being able to recharge during
that time.  I'm also expecting they will last longer although I'm not sure
that has been proven. I also won't have to remove the seat cushions to
periodically check the water level. 


Joe Tamucci #619