L16 battery question

shockman · November 2018

So I let by battery bank discharge to a DEAD state and acid did get below plates, long story! I have since charged and to the best of my ability equalized. SG did come up to varing levels. So realizing that I have probably lost the good remaining life of these 51/2 yr old batts, I have one dead cell that will not give me a reading on SG. I have removed it and one other from bank. My question is can that cell be brought back to life?

shockman · November 2018

Okay, have not been on here for a long time and wondering where system details that used to be below went LOL

Estragon · November 2018

The battery is probably a goner, but you might want to do a search on the forum for "battery water treatment" thread. IIRC, a member here ( @mcgivor ?) had some success recovering a sulfated battery with distilled water.

mcnutt13579 · November 2018

5 1/2 years on L16s, they were already gone.

Estragon · November 2018

Mine are coming up for 5yrs, and I'm hoping they're only middle-aged!

BB. · November 2018

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In my humble experience, once lead acid batteries get more than a year or two on them--If they are taken "dead", the can recover but tend to be unreliable and can "die" again in a few days or a few weeks (my experience with automotive batteries).

If you are up in BC Canada, and the batteries have been kept on the cool side (say off grid cabin and get below freezing in winter), they can last you quite a few years longer than folks that live in warm areas.

Of course, batteries with low specific gravity (discharged) will freeze in cold weather and (flooded cell batteries) probably crack the case(s).

-Bill

shockman · November 2018

Thanks for replies. Batteries are in a sort-of root cellar under house, so temps are pretty consistent between 10C in winter and 20C in summer. Today with 2 batts in system I charged with Iota and morning sun to float stage then got 3hrs of Eq. Before leaving sg was 1,185 on one batt and only 1.165 on other ?? Guessing that week one will drag other one down? So I guess I'm off to the battery guy to drop some big bucks LOL or should that be COL (crying out load). Now I need to know from above comment on L16's, what should I be buying. When I bought the present ones I expected 10yrs. To be fair to existing ones I like to think they have been well charged and filled properly until a couple of months ago when I was not around to babysit and left electric fridge on. So would Bill's experience tell us that if not allowed such abuse I may have gotten 10yrs??
make those eq #'s 1.285 & 1.265

BB. · November 2018

Exposing the plates is another issue that can kill the battery bank pretty quickly...

I am guessing that you would have lost some of the batteries by 7 years... And had a few that lasted >8 years. The colder they are, the longer (aging life) they would have. (every 10C drop below ~25C, they age 1/2 as fast--Of course, the slower aging would only be during winter--Your none-winter temperatures are pretty mild).

-Bill

shockman · November 2018

So is there a best bang for the buck? 6 golf cart 240ahr or 4 380ahr L16's or are you pretty much buying by the pound? And what about AGM, my experience with AGM(Optima) and various wheel chair 12v is that they take far more neglect as far as charging??

mcnutt13579 · November 2018

Go to Deka's web site and pull up all their spec sheets for AGM, gel, L16, and flooded steel tray (fork lift style/industrial) side by side.

Check the DoD (Depth of Discharge) vs expected cycles.

You will find the steel tray to last somewhere on the order of 3x the L16s for the same DoD. And experience seems to indicate even more.

Steel tray batteries are the way to go if you don't mind watering. Yes they are big and heavy. But you only have to do it once (or much less often). You can also get one string any size you want, for the most part.

mcgivor · November 2018

Estragon said:

The battery is probably a goner, but you might want to do a search on the forum for "battery water treatment" thread. IIRC, a member here ( @mcgivor ?) had some success recovering a sulfated battery with distilled water.

Been almost 2 years since I did the water treatment, the battery, in particular the cell is doing fine, it kept the battery in service in a lesser role of water pumping, perhaps using 40-60 Ah per day on a 260 AH 24V nominal system, which it handles fine, the SG has been steady matching it's team mates within a couple of points
To be honest it's a time consuming process, if the resources are available with nothing to loose I would recommend it, here is the link to the thread, should one be interested https://forum.solar-electric.com/discussion/351467/water-treatment-for-over-sulfation#latest

shockman · November 2018

Thank you! will check the thread out,

Estragon · November 2018

shockman said:

So is there a best bang for the buck? 6 golf cart 240ahr or 4 380ahr L16's or are you pretty much buying by the pound? And what about AGM, my experience with AGM(Optima) and various wheel chair 12v is that they take far more neglect as far as charging??

Personally, I'd go for a size that gives me the capacity I want in a single or at most two series strings. IMHO, AGMs are no less sensitive to charging neglect than flooded, except for the watering part. Flooded probably tend to handle overcharging better, and both will lose capacity with chronic undercharging. AGMs tend to have lower self-discharge, which could be a factor in some applications (eg seasonal cabin with no float power available).

L16 battery question

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