Rolls Batteries and a low cell: what to do?

inthejungle

I am in need of some help


I currently have two s-430's from rolls connected in series, so a 12volt bank of 350ah,

I currently am charging them through my OB FM 80 14.9 for 4 hours, float of 13.2, I check the sg's every Friday just to see where we are at the end of the day. I check each cell. About a 6 weeks ago I noticed that one cell was low all cells reading 1265 and this cell was reading 1255. I spoke to Steve at Rolls and he suggested the above increase to my absorption time and voltage.

I have been doing this for about 6 weeks and here is what I have ended up with. At the end of the day I have every cell at 1275 except that cell, yesterday is read 1270. Usually it reads at 1265. I was very happy. I decided thought to do a check and see what it looked like in the morning.

This is where I am wondering what to do, all my cell read 1255 but this one problem cell. It was reading 1245.

Do I have a problem? What Should I do?

Also when I checked the cells this morning, in one of the cells I noticed a red plastic shaving kind of like a drill shaving, it looked like the red plastic casing color: any thoughts?

Thanks

ITJ

Blackcherry04

Re: Rolls Batteries and a low cell: what to do?

That much difference is not unusual at all. A .005 to .015 or so is pretty normal. It seems consistent as it goes up and down. Most wouldn't recommend a EQ until they are a.030 or so apart. The Shaving, something that fell into the case during Manufacturing ?? or off the top ?

It's good you are checking them, Wow once a week. It's hard to get some to do it once a year, if ever.
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vtmaps

Re: Rolls Batteries and a low cell: what to do?

inthejungle wrote: »

I currently am charging them through my OB FM 80 14.9 for 4 hours, float of 13.2, I check the sg's every Friday just to see where we are at the end of the day. I check each cell. About a 6 weeks ago I noticed that one cell was low all cells reading 1265 and this cell was reading 1255. I spoke to Steve at Rolls and he suggested the above increase to my absorption time and voltage.

I have been doing this for about 6 weeks and here is what I have ended up with. At the end of the day I have every cell at 1275 except that cell, yesterday is read 1270. Usually it reads at 1265.

How long ago did you commission those batteries? For as long as you've had them (up until 6 weeks ago) you were undercharging them (sg=1.265). Now you are charging them properly and have gotten the SG up to 1.275. The question is did you sulfate them by undercharging them? Apparently, not too badly because you seem to be getting the SG back up to where it belongs.

inthejungle wrote: »

Do I have a problem? What Should I do?

The official answer is: corrective equalization.
If that doesn't work, then Yes, you have a problem.
What should you do? Everything you can... which unfortunately is not much

btw, I have the same problem... two of my cells are a bit lower than the others. I can't cure it with equalization. At manufacture, no two cells are ever exactly the same, and they diverge further as they are used. Your battery bank is only as good as your weakest cell. Your weak cell will determine the lifetime of the entire bank.

You may have a normal lifespan for your battery bank. When a manufacturer declares the lifespan of a battery, they know about cell variability. They warrantee the battery for what they think is likely to be the weakest cell. If you get lucky, all your cells are above average and you get more than a typical lifespan.

One more thing... you should count your blessings that you don't have batteries in parallel. one weak cell in one string will bring down the whole bank. If you want to be lucky when setting up a battery bank, buy as few cells as possible (just one string). The more cells you buy, the more likely you are to buy a weak cell. And your weakest cell determines how lucky you are with your battery bank.

This same logic argues for lower system voltage... less cells means less chance for a weak cell. I suppose the best you can do is have a 2 volt system voltage :roll:

--vtMaps

waynefromnscanada

Re: Rolls Batteries and a low cell: what to do?

vtmaps wrote: »

How long ago did you commission those batteries? For as long as you've had them (up until 6 weeks ago) you were undercharging them (sg=1.265). Now you are charging them properly and have gotten the SG up to 1.275. The question is did you sulfate them by undercharging them? Apparently, not too badly because you seem to be getting the SG back up to where it belongs.

Except that lately Surrette has been filling them with 1.265, not sure when that started, but was the case with mine and 1.265 is stated in their battery manual.

vtmaps

Re: Rolls Batteries and a low cell: what to do?

waynefromnscanada wrote: »

Except that lately Surrette has been filling them with 1.265, not sure when that started, but was the case with mine and 1.265 is stated in their battery manual.

Good point, Wayne. If he started with 1.265, then the only way to get them up to 1.275 would be to drive off enough water to concentrate the electrolyte.

--vtMaps

Blackcherry04

Re: Rolls Batteries and a low cell: what to do?

vtmaps wrote: »

Good point, Wayne. If he started with 1.265, then the only way to get them up to 1.275 would be to drive off enough water to concentrate the electrolyte.

--vtMaps

Not necessarily, the 1.275 would have to be temperature compensated to actual electrolyte temperature. . Also we don't know what SG acid they used in the paste when they preformed the plates. New batteries from Surrette seem to vary the SG level as the go through their break in cycles ( 50-100 ). Mine have been all over the place and are very unpredictable.

I saw a post somewhere that it was January of 2013, but they offset the manufacture date 90 days forward or something. I looked at the batteries I got last month ( Factory Direct ) and I didn't see anything except some numbers melted into the rim of the case.
.

inthejungle

Re: Rolls Batteries and a low cell: what to do?

Thanks so much for everyone's thoughts, well we are from the US living in the middle of no where in Liberia W. Africa. If I don't check these batteries and keep this system running then no lights and all of our food spoils!

The system was setup on 6-17-13 and at that time I was talking to Steve at Rolls, I got the batteries up to 1260-1265 after about 3 weeks I got the batteries up to 1270 after much adjusting on the Outback. Then we went to the city to make our first freezer fill up run and the Sundanzer was put online this took the SG's at the end of the day to 1255 around Aug. the first week some time. I Again adjusted the OB settings with Steve helping me and after about 4 weeks was seeing consistent 1270's at the end of the day.

Then in October I noticed that that cell was throwing lower numbers, if all cells were sitting at 1275 it would sit at 1265, steve didn't think it was a big deal, just told me to increase absorption time to 4 hours and cut of the end amps setting and give it 6 weeks or so to settle out.

In all of my SG testing it has been a question as to whether temp should play a factor in the numbers. Many people have told me because the ambient here is 90 all the time that 1265 is a full battery and others say that no I should keep them at 1275. Many of my buddies here dislike Roll's because after two years they say they won't hold a charge. I ask about SG's and they are not checking them. This is what I have decided to keep my SG's a little high and try to keep these around for quite a while.

I just didn't like to see that low number this morning when I calibrate my battery monitor.

OK so the questions- I know the drill like shaving is not from me, I am very careful, but I had seen in the past and called rolls that a plastic plate separator was floating around, maybe that is where it came. I guess I just leave it.

With that history of SG's, I am a bit leery to equalize at some cells are at 1280 at the end of the day, if I did an equalize wouldn't it throw these cells up to 1290 or so? Is this OK?

What does everyone think is the best remedy?

Thanks for all your thoughts?

Blackcherry04

Re: Rolls Batteries and a low cell: what to do?

Doing a EQ at 15.5 V in your case will not hurt them at all as long as you can monitor the internal temperatures of the batteries and keep Below 115 F . Even if the SG's go up this not a issue at all. When you do a EQ like this you are cleaning out the pores in the lead and opening new receptors. EQ is not a timed thing, It's when the SG's stop rising ( Check at least every hour ). Desulfation is another issue then what your trying to do.

The above said, there is not a reason that I can see to do it as they are close and within the variation limits. Since your already at 14.9 for 4 hours. Charging is about the 3 variables VOLTAGE = TIME = CURRENT you are changing one for the other.

As I recall you only cycle them like 10-20% a day.

NorthGuy

Re: Rolls Batteries and a low cell: what to do?

inthejungle wrote: »

Then in October I noticed that that cell was throwing lower numbers, if all cells were sitting at 1275 it would sit at 1265.

It is possible that the "bad" cell simply has more water in it, that is the electrolyte level is higher than in the other cells. Have you checked the level? Have you added some water to your batteries already?

inthejungle

Re: Rolls Batteries and a low cell: what to do?

Thanks again everyone for your thoughts- I have been checking the water levels consistently, and I have not needed to add water yet. I would say all of the water levels are about the same.

I don't have a way to test the temp when I do an equalization. What to? I guess maybe I should just keep an eye on it and see if it worsens?

Yes these batteries get brought to about about 88% and then refilled back up each day.


ITJ

BB.

Re: Rolls Batteries and a low cell: what to do?

You really only need to bring the batteries over 90% state of charge a couple times a week.

There is a theory you only need to bring the batteries >90% once every one to two weeks, or even once every 4 weeks for at least one vendor--As long as the batteries are cycling "daily" (charging/discharging--it is sitting doing nothing at ~<75% state of charge that sulfates in days/weeks/months).

Trying to bring to 100% SOC every day "wastes" power, is potentially hard on battery plates, and uses a lot of distilled water (and can run the batteries "hot"--which accelerates aging too--Every 10C increase is a 1/2 reduction in lifetime).

-Bill