Can my batteries be saved?

[Sternwake]

I have had one group31 USBattery not respond to EQ voltages less than 16.

I was afraid to bump voltage up that high, but when it did not respond after hours trying at 15.5, then 15.7v, the 16v hail mary did the trick. At least on that particular, peculiar battery which was rather masochistic in its required absorption voltage and duration and finishing charge in daily deep cycling duty and only 200 watts of solar recharging.

I'd not trust the EZ red hydrometer either. When EQ'ing, electrolyte temps increase, and the level on the float can read the same, but when compensated for the increasing temperature of the electrolyte, one can find the SG is actually increasing despite the level staying the same on the float.

I know EZ red plastic hydrometers and plastic ones like it say they are temperature compensated, but I am not sure exactly how they achieve that function, or if it is just the marketers taking liberties with physics when designing the literature and stickers, as they love to do when they dream of their bonuses.

I like the OTC4916 hydrometer for its thermometer on the business end which tells you how much to add or subtract depending on electrolyte temperature. The Middle cell(s) warm up more than those on the edges too during an EQ and the thermometer makes it obvious, especially on a 6 cell battery with an add .002 on the outer cells and an and .008 on the innermost.

I've tested a Napa clone version of the EZ red, and the OTC4619 side by side on the same cells at about 75f , and the plastic clone was not repeatable or reliable on each cell. Sometimes it agreed, other times it was wildly off and I never saw the bubble sticking to the float on a high reading or saw any drag for that needle to read low on some other dippings to yield such unrepeatable readings. It acted possessed, while the glass turkey baster style was reliable and repeatable as long as one looked for bubbles sticking to the float and knocked them loose.

Best of luck getting them to respond.

[phantomracer]

Thanks sternwake... i appreciate that

Battery has been on charge for 12 hours now, volt staying at 7.7 and the amps are at 4.0 (0.1a decrease over 7 hours). the SG bumped up a little to 1250

unsure how long this should take. Maybe its a bit cool in the basement and need to bump it up to 7.9? will let it run for a few more hours and recheck.

at least its doing something!

[phantomracer]

been on charge over day, the amps haven't dropped in 24 hours. I am assuming this is as far as it will drop? The SG hasn't gone up in 24 hours either, still at 1250. basement is at 60F.

should i charge the other battery and discharge and recharge them again?

[Sternwake]

At 60F ambient, I would be much less worried about approaching Rolls' 16.2v equalization voltage.

Are any of the cells getting hotter than others? Check the very bottoms too. My screwball group31 will get hottest on the bottom of the cell closest to (-) terminal, but still has not fully shorted that cell.

16.2v Hail mary EQ voltage, compensated for that 60f Ambient temp might do it, or might not, but if lesser voltages have yielded no rise in SG, what's there to lose by bumping it up higher, as long as you are there to keep temperature from skyrocketing and keep sparks at bay.

[phantomracer]

Originally Posted by Sternwake

At 60F ambient, I would be much less worried about approaching Rolls' 16.2v equalization voltage.

Are any of the cells getting hotter than others? Check the very bottoms too. My screwball group31 will get hottest on the bottom of the cell closest to (-) terminal, but still has not fully shorted that cell.

16.2v Hail mary EQ voltage, compensated for that 60f Ambient temp might do it, or might not, but if lesser voltages have yielded no rise in SG, what's there to lose by bumping it up higher, as long as you are there to keep temperature from skyrocketing and keep sparks at bay.

I kept an eye on the temp.. the case was cold, room temp cold. not warm at all during the entire process. No loss of water but steadily bubbling away.

Maybe just needs even more time.. days instead of hours?

[Sternwake]

Every EQ charge I have performed, the battery temperature was rising the whole time.

If SG was still below desired levels, I ended EQ when amps required to maintain EQ voltage began to rise again, which usually corresponded with rapid temperature rise. I'd then try again once battery cooled, sometimes with positive results, other times with a realization of futility.

Giving further recommendations about EQ'ing your batteries are outside my comfort zone, and lowly status on this forum.

I can say that I felt that achieving higher battery temperatures via the charge current was related to the successful rise of Specific gravity on more than one sulfated battery, But I have also been called a battery boiler before too.

I do not recall personally performing an EQ much below 70F ambient, and usually the absorption charge had the battery upto 10 degrees F higher than ambient when I cranked up voltage to near EQ levels, trying to keep amperage to no more than 5% of original stated 20hr capacity.

If you do decide to push the batteries to a temp compensated 2.7 volts per cell, please take all the precautions you can in terms of eye protection, sparks, ventilation and monitor case temperatures aware of the possible beginnings of thermal runaway, which can happen quickly in my limited experience.

I've never applied EQ voltages for more than 4.5 hours, and have nowhere near the experience or knowledge of Mainesail in this regard.

[phantomracer]

that why im starting off slow and conservative.. even after a day on charge at 7.7v/4a the battery was room temp.. i figured it should be warmer.. figured the cool basement might have something to do with it..

at least the SG on this battery (lower of the 2) now matches the other battery, so all the cells are very close to each other (best I can tell with the ez red hydrometer). thats something.

might try hitting it harder.. figured id ramp up to higher volts/amps rather than start too high.

earlier in the thread main sail suggested (in post 25) using lower volts for a long time "If the batteries are not dropping below 1% accepted current at absorption voltage then sulfation has set in and you may need to hold absorption voltage even longer or drop to a high float for a number of days such as 13.8V - 14.0V then revert to EQ voltage..."

so i might drop to 7.0-7.1 and leave it for a few days to see if there is any progress

[Maine Sail]

Originally Posted by phantomracer

Thanks sternwake... i appreciate that

Battery has been on charge for 12 hours now, volt staying at 7.7 and the amps are at 4.0 (0.1a decrease over 7 hours). the SG bumped up a little to 1250

unsure how long this should take. Maybe its a bit cool in the basement and need to bump it up to 7.9? will let it run for a few more hours and recheck.

at least its doing something!

While your batteries are cool I would not push EQ beyond 4-6 hours at a burst. I tend to hit them then use a high float of about 6.9V for a few days in-between. Cycle them, deep, re-charge to 100% and repeat a 4-6 hour EQ then back to high float. Witha few cycles like this you may begin to see some recovery.. At your 60F temp a 8V EQ is ok.....

If the current eventually drops under high float we will know the plates are very sulfated and it is just taking a looong time for the energy to get in there.

I have an AGM battery on my bench right now that would not get to below .5% of Ah capacity, at absorption voltage, even after 10 hours held at absorption voltage. I dropped it to a high float 4 days ago and it is just now, finally, below .5% after 4 days at high float when I turn the voltage back up to absorption. This battery is likely toast, based on how it resisted a full charge, but I needed to get it full before doing a 20 hour capacity test. On-board the boat this battery was falling off the proverbial cliff because it was too sulfated to get back to 100% SOC based on the egg timer chargers 2 hour absorption algorithm.

[phantomracer]

made some significant progress..

finally got the worse off 6v battery to respond. turned the heat up in the basement.. seemed to have helped a bit. got it to 1 or so amp at 8v.. SG went up a notch on the hydrometer. the other battery seemed fine. did a couple hits with the charger at absorption v and it went to an amp or under..

hooked them up and getting good results on the meter. low amps at absorb voltage

will do a couple discharges and recharges and see what kind of shape those puppies are really in.. but optimistic..

[phantomracer]

I know everyone has been on pins and needles waiting for an update

Got a wiring harness for car headlights to make discharging a bit easier to hook up and discharge.

Hooked up 3 60w headlights to the batteries ,about 15amp (closest i could get to 13 )

about 48 degrees F, in the basement. SG was 1260 in all 6 cells. Battery rested over a day since the last charge. 12.7v at the terminals.

The voltage went from 12.7 to 10.0 in about 20 minutes!

Not a rocket scientist, but I think that is bad! The Voltage dropped like a rock. So there is, like, virtually no capacity.

[btrayfors]

Paul,

Yep, you're right!

Sorry about that, but those puppies are TOAST.

Wouldn't play with them any further.

Bill

[Maine Sail]

Originally Posted by phantomracer

Hooked up 3 60w headlights to the batteries ,about 15amp
The voltage went from 12.7 to 10.0 in about 20 minutes!

Not a rocket scientist, but I think that is bad! The Voltage dropped like a rock. So there is, like, virtually no capacity.

They're toast...

[phantomracer]

That's a buzz kill! I was optimistic!

Good time to try out the firefly batteries. See how fast I can kill them!

Sent from my SAMSUNG-SM-G900A using Cruisers Sailing Forum mobile app

[phantomracer]

Thanks everyone. I learned a lot in this process, so it wasn't a total loss.

Sent from my SAMSUNG-SM-G900A using Cruisers Sailing Forum mobile app

[phantomracer]

Just an update.. I know everyone has been on pins and needles waiting

As mentioned in another thread, I replaced my FUBAR batteries with 2 Firefly group 31 batteries.

Launched the boat yesterday. spent 24 hours on the boat so far, 20 hours with the engine off. fridge on, laptop charging, lights on..etc.

I DID (last year) get a small 30w solar panel, as it was small enough to store when not in use.

1) thank goodness the batteries fit in my battery box (I did not measure correctly the first time)!!

2) NICE to have the fridge (or water pump, lights, etc) come on and not have the voltage drop so low that the fuel cell comes on (in fact, has not come on in 24 hours!). The small panel seems to be keeping up with the draw (it is pretty sunny today). I did get a gensun solar control to install for the panel. For a few days, the supplied cheap controller will just have to be good enough. The panel is showing 12.8v now, so its doing something!

3) when it was on the hard, I noticed that the new batteries recharged fairly quickly (using a power supply) after I used them.. then again they were not discharged a lot.

Was kinda funny. the water pump came on, it was a louder and faster, than when I had the FUBAR batteries, that the wife wanted to know WHEN I installed the garbage disposal! The thing was pumping with some nuts!

But its nice to actually have some usable amps on board. I suspect I will go through less methanol for the fuel cell this year.