[C320-list] Flooded acid battery and refrigeration questions

[Troy Dunn]

Scott

As long as the water level never got down to the top of the plates you
could be fine.   I say could only because at certain heel angles for
certain types of battery installations what seems like an adequate level
could be partially exposing the plates while heeled.   Exposing the plates
is bad, and can result in rapid sulfation which at best will reduce your
capacity, but with sulfation the the probability of having a short in the
plates goes up.  This is what ultimately kills the battery.   Avoiding too
much heel is probably a good idea…especially since the C320 starts losing
performance once the windward deck goes past horizontal. (about 10°)

Lot shoulds and maybes above.

As to the curious case of 'rapidly' (two months feels rapid) boiling off a
significant amount of the electrolyte.  It's only while charging that you
typically boil off electrolytes, the higher the charge voltage and accepted
amps the more likely you are losing fluid.   Going for the highest charge
acceptance to charge quickly and the highest bulk and absorption voltages
reccomended by the manufacturer for longest battery life has a potentially
fatal flaw…as you have now discovered.  Those items ignore the ability of
the average sailor (yours truly included) to vigilantly monitor the fluids
in the batteries.    Expose the plates and suddenly that long life goal may
be blown.

Let's face it.   The battery location is less than ideal.   Doing a check
on the batteries mid cruise is a pain in the butt which only further
enhances the likelihood of a screw up here.   I love my FLA set up and
would chose the GC2s over and over again.   Trojan and US Battery GC2 FLAs
are the best choice from a $/Watt-hr perspective.   No other battery type
can be expected to compete based on that metric.    LiFePO4 are the best
where weight and or form factor are a consideration and cost is a don’t
care.   AGMs are a loser on both counts.   Where AGMs shine is that they
are relatively maintenance free.   I guess the AGMs are good if you get
knocked down or I guess pitch poled (not possible in 95% of the
Chesapeake). But if that's your concern you are obviously putting your C320
in situations I hope to never encounter.   I am honestly considering
swapping out my Group 27 reserve for an AGM because it is such a pain to
get to for watering.

As to the question of uneven boil off of the electrolyte.  Yup..that’s
definitely a thing.  A few variables there to consider.   On my setup I
have 4 6V GC2s in a 2p2s configuration to give me 462 AH at 12V and they
are essentially 2 per compartment where the 4Ds used to sit.
Theoretically the cells closest to the middle of these compartments would
get the hottest because the neighbor cells are also heating up.  That has
not been my experience.   My experience has been that the cell closest to
the positive terminal for each 2p config (12V) has the most boil off.   And
I too have pondered why this would be the case.  I haven’t gotten much past
the hmmmmmm that's odd phase of my pondering.

FWIW

Troy Dunn
Hull #514