[C320-list] Flooded acid battery and refrigeration questions

[Scott Thompson]

The heeling is what worries me, but it should affect all of the cells 
equally and so does not explain differential degrees of fluid loss. 
Maybe it's more about sloshing, which could be ever so slightly worse 
for outboard cells. For one cell to lose more water than the others I'm 
thinking it must be more sulfated and thus have lower capacity, causing 
it to reach full charge earlier than the other cells. Like you, I've 
also noticed that the cell closest to the positive terminal seems to 
suffer more.

In any event I've pretty much convinced myself that it's time for new 
batteries and possibly a new fridge. I can't complain much about 7 years 
for the batteries and 22 years for the fridge. My winter maintenance 
list will also tackle the anchor locker drain hose, the stuffing box, my 
shower sump pump, and new lifelines. It's always something! I've not yet 
replaced other items that have failed for other owners (e.g. the muffler 
or fuel tank) so perhaps I should count my blessings.


On 11/15/2021 9:46 PM, Troy Dunn wrote:
> 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

-- 
Scott Thompson
Surprise, #653