Battery charging question--again (perhaps?)

[Joe Myerson]

I'm not sure if I post this every year or not, but I'm having trouble getting my lead-acid batteries charged up for this season. Here's the situation:

For at least three years, I've left my batteries in place over the winter. I disconnect all wires and let them sit.

For the two previous winters, I have hooked them up to a "smart" charger roughly once a month during the winter. In spring, I checked the electrolyte level, and charged them again.

This past winter was so cold, and there was so much snow that I did not get to do the monthly recharges

Even though the snow finally receded in March, the temperature remained below 35 F, so I did not hook up the charger. I did, however check the voltage and the electrolyte level, adding distilled water where needed.

Last weekend I left Battery #1 hooked up to the charger for more than 24 hours. The readout never reached "FUL" (or "full"). I never got to charge Battery #2.

Does this mean the batteries are dead or dying, or should I try it again in warmer conditions?

Thanks,

--Joe

[Stan W.]

You should not add water to a battery in subfreezing conditions unless you then proceed to charge it. With no charge, the water sits on top of the electrolyte and freezes, which can damage the battery. I do not know if that is why your battery won't take a full charge, but it is something to consider.

[Joe Myerson]

You should not add water to a battery in subfreezing conditions unless you then proceed to charge it.

Thanks, Stan.
I'm not sure that the temperature fell below freezing since I added the water ... but it's a possibility.

--Joe

[Klem]

Hi Joe,

What is the rated output of your charger? A really small charger on a dead battery can take a really long time. Also, on a really dead battery they will sometimes take very little charge for quite a while then all of a sudden they will start taking a real charge again. I would leave the charger on a bit longer and see how it goes.

[Paul D.]

I'd give it one more try in warmer wether to charge or at least a good charge even now.

I think the best way to leave batteries over the winter is with a solar panel and regulator (might not even need the regulator if you have a small trickle charge panel). Just top off the batteries before the winter, hook it up and go.

[Joe Myerson]

A really small charger on a dead battery can take a really long time. ,,, I would leave the charger on a bit longer and see how it goes.

Klem: That's what I plan to do. The batteries are not dead, I get a reading in excess of 12 v. with my multimeter, and when I checked the fluid for specific gravity, most, but not all, cells were in the positive range. None were rated "dead."

Just top off the batteries before the winter ...

Paul: I don't have a solar charger, but I always top off the batteries before covering the boat for the winter. I forgot to mention that in the initial post, I think.

Because the boat is 85 miles from my year-round home, I have only been able to work on it during weekends. That will change soon--and the weather should also be warmer. Time will tell.

--Joe

[Sea Hunt Video]

Paging Dr. Maine Sail; paging Dr. Maine Sail.

[Astronomertoo]

Actually, the rule is never add water to any lead acid battery unless it is fully charged and stable. The reason for this is as the battery charge goes down, the water level will also go down due to change in electrolyte balance in the fluid, as compared to the plate sulfate level. Thus if you add distilled water to a partially discharged battery you will stand a chance of your electrolyte overflowing when you fully charge the battery. We have all seen the result of that happening in cars when an owner finds a dead battery in the morning from leaving the lights on overnight, fills it with water, then puts the battery on high charge rate. It all overflows. Not good for cape dory bilges either, and not recommended.
After recharging a lead acid battery to full charge, THEN top off the water level to the mfr level guides, if needed.
Plus, If you overflow the levels then the electrolyte will not be the desired specific gravity, which will affect the balance of charge, total voltage available, and the ampere hour capacity of the battery.

This can be a dual problem.
It is particularly harmful to a lead acid battery to leave the battery in a very low discharged state as the battery will not fully recover and come back up to 100% fully charged state with near the original total ampere hour capacity. Plus lead acid batteries like to be recharged from low charge at about a 20% of full amp hour rate, ie, if you have a low 100 ah battery it should see a 20%, or 20 amp hr initial rate for recharging, which with a good charger will taper off to a finish rate, then to a design float charge rate which will maintain your battery correctly (on shore power) and not overcharge or boil the water out of the battery. Cheap chargers, not so good.
All the levels and chemistry are important, as are the newer multi rate automatic rate chargers.

Plus I am sure everyone on this forum understands how dangerous the old Sears or other typical high rate chargers are if used in a boat while in water, ie electrocution, and electrolysis of metals in water due to imposed currents and metal ion flow. Not good for Cape Dorys.

Be safe, fair winds.
BobC
Moon Shine
CD 25 1975 #239

[Joe Myerson]

Actually, the rule is never add water to any lead acid battery unless it is fully charged and stable. ... After recharging a lead acid battery to full charge, THEN top off the water level to the mfr level guides, if needed.

Bob,

Thanks. I should have known this (maybe I forgot). Anyway, all seems well. The batteries charged fully this weekend, probably because the ambient temperature has finally reached normal springtime levels. Luckily, my batteries sit in acid-resistant boxes, which do sometimes have a little electrolyte in the bottom after a season of pounding around on Buzzards Bay.

BTW, my charger is a West Marine 15 amp "smart" charger.

Thanks for the advice, all.

--Joe

[Astronomertoo]

Hello Joe and all.
Question, are your batteries aligned with their cells oriented fore and aft, or port and starboard?
One of the more interesting things I learned this year, which I do not have the source handy at this time, is if aligned wrong you can spill electrolyte when heeled over in normal use. The old CD25 I bought and am reworking had 2 large 12 V batteries set in a wooden box on the starboard side locker, with their cells aligned fore and aft, and the simple wood box was saturated with acid. If you dropped baking soda on the wood it would fizz, so you know that is not good. Which also meant it was in the bilge, equally bad, so I treated it too. Having been intimately involved with commercial battery systems design and maintenance in nuclear power plants I understand the reason for containing any lost acid in proper acid resistant containers. There are many good sealed, ventilated, battery boxes available for boats and RVs out there and it is up to us to improve our craft and figure out how to mount them better in our boats. The smaller boats like my old 25 pretty much need one on each side for better balance and I am still working on it.
BobC
Moon Shine

[hilbert]

One of the more interesting things I learned this year, which I do not have the source handy at this time, is if aligned wrong you can spill electrolyte when heeled over in normal use.

Maine Sail has posted an article on this topic: http://www.pbase.com/mainecruising/floo ... rientation

[Astronomertoo]

Ha! Perfect, thanks.
MAINE SAIL was the correct source for this and many other excellent writeups. Very appropriate, and timely,
BobC
Moon Shine