[C320-list] Flooded acid battery and refrigeration questions

[Allan Field]

When we bought our C320 20+ years ago, it came with the ProMariner
battery cooker and lead cell batteries. The dealer told us then that if the
charger was on, there needed to be a load on the batteries. We left the
fridge on 24/7. After about 3 years, it didn't make much of a difference as
the batteries got cooked anyway. We switched to a Xantrex charger and Gel
batteries, left the charger and fridge on 24/7, and never had another
problem until someone ruined the batteries about 8 years later when we lent
them the boat for 2 weeks. We then switched to AGM; again, no issues. On
our current boat we have had for 5+ years, we have AGMs, leave the fridge
and charger on 24/7, and zero issues. However, a marine contractor did tell
me once that with AGMs, we didn't need the load if the charger was running.
I come down once per month during the winter, run the charger for 3-4 days
without a load, the batteries come back to full, they are 5+ years old now,
and still hold a full charge. But I have only let them get below 50% SOC
(45%) once. Not sure if this helps...

Allan S. Field
Sea Shadow - C387, #103 (formerly C320, #808)
Columbia, MD


On Tue, Nov 16, 2021 at 8:21 AM Graeme Clark <cg at skyflyer.co.uk> wrote:

> Interesting discussion. Since I installed solar I have had electrolyte
> level issues also. My boat spends two to three weeks between my visits, on
> a mooring and I guess the solar is boiling it off
>
> I have an MPPT controller which supposedly has a charge regime that
> eventually drops to a low maintenance charge
>
> Problem is I think that at night it resets itself so every day the charge
> regime begins again. Either that or it resets when a load is applied like
> the bilge pump?
>
> Anyway I’m thinking of deliberately applying a small load (LED light?) to
> the battery. The controller allows a load to be connected through it that
> cann be controlled to turn on for (say) 4 hours at a time
>
> I’m hoping this might prevent overcharging as the solar input will be
> charging the batteries rather than boiling off the electrolyte
>
> Could the OPs problem have a similar cause?
>
> But maybe I’m barking up the wrong tree!
>
> Graeme
> #366, 1996
>
> Sent from my phone. Excuse typos!
>
> > On 16 Nov 2021, at 11:13, Troy Dunn <troutwarrior at gmail.com> 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
>
>