Saving over watered batteries. Suggestions?

SolaRevolution
SolaRevolution Solar Expert Posts: 410 ✭✭
in Off Grid Solar & Battery Systems #1
Any thoughts or advice?

I got a help call from an off-grid client with a generator and battery system. (No solar, no wind, no nada.)
He has 8 Rolls Surrette S530s (inatalled 4/2011) , a Trace SW5548 (1998 ), and a +/- 6kw 120vac onan generator (circa 1957)

The S530s are already suspect, but about a week ago he made the mistake of leaving his automatic watering system open overnight and siphoned about 3 gallons from the resevoir and flooded the same from the batteries into the catch pan.

When he called he said the batteries were "not holding well" and he "had to run the generator every other day" when he could previously go for 3-4 days between runs. When I got there he was pulling about 5 amps for loads and the battery was at 47.8v. He said it had been there for several hours an "did not seem to be dropping much."

I tested the SGs: a wide range from 1130 to 1200 with a temp adjusted Hydrometer.

I'm thinking the electrolyte at the top is very diluted but it is probably not so bad deeper down.

I asked thim to do two, 4 hour bulk charges a day for a couple of days. By then I'll be able to come back and bring them to town to do a corrective EQ from the grid. I just don't think his old onan can handle charging for many hours at high voltage.

Any better ideas?
Do you think these L-16s will come back okay?
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Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Re: Saving over watered batteries. Suggestions?

    at this point he might as well try giving them a good eq. i'm unclear if the batteries were overfilled or was some drained away from the batteries? if any was drained out of the batteries then after retopping the batteries and deeply eqing them he may need to add a bit of battery acid to put them back into the ballpark.
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  • 65DegN
    65DegN Solar Expert Posts: 109 ✭✭
    #3
    Re: Saving over watered batteries. Suggestions?

    How about charging the batteries until the absorb cycle is complete? Maybe what you meant to say was , '...I just don't think his old onan can handle charging for many hours at high current...'.
    I think you have the right idea. EQing is about all you can do but I suspect it may take more than one EQ cycle.
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #4
    Re: Saving over watered batteries. Suggestions?

    Neil,

    He was trying to top them off and accidently left the water flowing into all of the batteries simultaneously. The 3 gallons of water fed into the batteries and water and electrolyte overflowed into a plastic catch pan under the batteries. The water in the catch pan is acidic. (I did not think of doing a SG reading on the spill.) So the batteries are full into the filler tubes now. I would have to remove some to add electrolyte. Is this really necessary?

    His old 1957 Onan generator runs at about 112vac when pulling 28 amps and 128 when idling. I'm no generator mechanic but I understand that high voltage charging is rough on a generator.
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  • 65DegN
    65DegN Solar Expert Posts: 109 ✭✭
    #5
    Re: Saving over watered batteries. Suggestions?

    In view of that information, I would charge the batteries completely, then EQ. I would repeat this at least one more time or until the SG is no longer rising. Then I would remove enough fluid from the batteries so that it was just above the plates. Then initiate a new EQ cycle and slowly add some 1400 SG electrolyte (often available from local battery distributors) until the SG rises to ~ 1275, allowing time for the new solution to mix thoroughly during the EQ cycle.
    Continue until electrolyte is at the proper level. Let them set for ~5 hours after charge current is removed and recheck the SG.
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #6
    Re: Saving over watered batteries. Suggestions?

    Thanks 65DegN,

    I was going to have him do the 4 hrs bulk in the AM, again in the PM for a couple of days to bring the SOC up and maybe stir the electrolyte a little so I can get a good retest before deciding to bring them into town. (1.5 hr drive each way) As for the EQ, it really will require a lot of time of paying close attention and many hours of a generator running very lightly loaded.

    I'm not sure I can get the client to take this on. I think the hydrometer kind of scares him.:roll:

    BTW; the batteries are at about 50F/10C so the EQ voltage will need to be that much higher.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #7
    Re: Saving over watered batteries. Suggestions?

    without a doubt he lost some acid into the pan and the electrolyte is to the top. if it were me i would pull a bit from each cell to get them from spilling more during the charge. after a good eq see about adding just a bit of battery acid to the electrolyte, but not too much to see it boil out upon a second eq charge that i recommend he do. it will take some time to bring these back to where they are supposed to be at. that electrolyte you took out i would put into glass jars or other acid proof containers and allow some of the water to evaporate and maybe you could reuse it later. if any is dirty or contaminated it will need disposed of properly. do not add just straight water in a cell until its specific gravity is back in line to be where it is supposed to be after being fully charged in near future charges.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #8
    Re: Saving over watered batteries. Suggestions?

    You probably should contact the battery mfg / engineers and ask them what to do...

    My guess would be along the lines of:
    1. Recharge then equalize until each cell's s.g. reaches a constant number.
    2. Drain each cell and refile with factory spec'ed electrolyte.

    Go on with life.

    If the electrolyte is too expensive to drain it all and replace with 1.265 sg--You could try just dumping some electrolyte and refilling with the 1.400 sg (or whatever you can get)... I wrote a set of equations on how to dilute from 1.3 to 1.265 sg--but you can change them around to go the other way (start with 1.1 and add 1.4)... However, I am not sure it would really save much money if the sg of the cells is currently quite low:
    BB. wrote: »
    If you want to try and dilute the battery electrolyte to normal specifications--this is some math that should help (as always, check the math yourself--never trust anything you read on the Internet).

    Example #1 (assume you dump the entire battery contents of 1.30 electrolyte into a clean plastic or glass container and want to dilute with 1.00 spg distilled water down to 1.275 spg):

    Let X=amount of 1.00 water you want to add, and assume 1,000ml / 1.0 Liters is the amount of 1.300 liquid electrolyte per cell; the result will be 1.275 spg electrolyte--ready to pour back in battery:

    1000ml*1.30 + X*1.00 = (1000ml+X)*1.275
    1300ml + X = 1275ml + 1.275*X
    1300ml - 1275ml = 1.275*X - X
    25ml = 0.275*X
    25ml/0.275 = X = 90.9ml of 1.0 spg distilled water per 1,000ml of 1.30 electrolyte

    The other method, assume you know that the battery has a capacity of 1,000ml per cell. The cell/battery is charged, and the spg of the electrolyte is 1.300. And you want to remove Xml of 1.30 electrolyte and add Xml of 1.00 spg distilled water to the cell to get 1.275 spg electrolyte (basically, draw out just enough of the existing electrolyte and then add back 1.00 distilled water):

    (1000ml - X)*1.300 + 1.00*X = 1000ml*1.275
    1300ml -1.3*X + X = 1275ml
    1300ml - 1275ml = 1.3*X - X
    25ml = 0.3*X
    25ml/0.3 = X = 83.3ml (draw 83.3 ml from charged battery, add 83.3ml of 1.00 distilled water for 1.275 spg)

    So, charge the battery, draw 83.3ml per 1,000ml of battery cell capacity, then add back in 83.3ml of 1.0 distilled water. Put battery on equalize (for an hour or two--whatever is the Mfg. recommendation) to generate some hydrogen to "stir/mix" the electrolyte with the distilled water.

    The numbers look "sane"--so I think I did everything correctly.

    But, again with the warning. I have forgotten most of my 7th grade math--so double check my equations and math to your satisfaction before doing attempting the work.

    Also, I used a place holder for battery capacity (1,000 ml / 1.0 Liters)--you will have to either measure the amount of electrolyte you drain, or ask the vendor for the cell fluid capacity.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #9
    Re: Saving over watered batteries. Suggestions?

    It's going to be messy.

    1) slurp some fluid from each battery, and save it, 1 container per battery. (reserved)

    2) charge with long absorb times, till all batteries are bubbling well, and eventually, fluid levels will drop, replenish each cell from it's reserved stock.

    3) if SG don't recover, fully charge with long absorb times, and when SG does not rise any further, add strong acid (not battery strength) till it's right. Or change out fluid completly.

    spil tray fluid shoudl be disposed, not reused.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
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  • Joe_B
    Joe_B Solar Expert Posts: 318 ✭✭✭✭✭✭
    #10
    Re: Saving over watered batteries. Suggestions?

    I would not charge those batteries until the you get the electrolyte fixed. He replaced H2So4 with water thereby diluting the electrolyte. The only way you are going to be sure things will go right is to drain the diluted stuff out of the batteries and replace it with the proper ratio of acid to water at the proper level. Then you should charge them slowly as the manufacturer does at the factory or the installer does when he first adds the electrolyte. If you attemp to charge them with diluted electrolyte it is almost guaranteed you will damage them. This is not an ideal solution but given the cost of those batteries, its the best you can do.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #11
    Re: Saving over watered batteries. Suggestions?

    Interesting Joe--I am curious as to why recharging the batteries with dilute electrolyte can damage them? Deeply discharged batteries have dilute electrolyte already, and the physical act of recharging drives the sulfur ions back into the electrolyte.

    My concern is that if the batteries where not fully charged before the over watering incident, then recharging with new factory strength electrolyre would drive the electrolyte specific gravity much higher than factory fill--Which, I believe, has its own problems.

    I am certainly not a battery engineer and I highly recommend calling the factory for their recommendations. This is an expensive and new bank--I would hate to see them damaged if it could have been avoided.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #12
    Re: Saving over watered batteries. Suggestions?

    I had a similar situation happen with one of my boat owners. After looking at it, to me it seemed that once the battery filled, the water just overflowed out the vent hole and there was very little mixing. I took a bulb filler and removed the excess and called it good. I EQ'd them after and there were no issues. With the auto water systems we have they just dribble the water in. Not to say this one is the same.
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  • Joe_B
    Joe_B Solar Expert Posts: 318 ✭✭✭✭✭✭
    #13
    Re: Saving over watered batteries. Suggestions?
    BB. wrote: »
    Interesting Joe--I am curious as to why recharging the batteries with dilute electrolyte can damage them? Deeply discharged batteries have dilute electrolyte already, and the physical act of recharging drives the sulfur ions back into the electrolyte.

    My concern is that if the batteries where not fully charged before the over watering incident, then recharging with new factory strength electrolyre would drive the electrolyte specific gravity much higher than factory fill--Which, I believe, has its own problems.

    I am certainly not a battery engineer and I highly recommend calling the factory for their recommendations. This is an expensive and new bank--I would hate to see them damaged if it could have been avoided.

    -Bill

    Bill, my concern is he will not know what the SOC is and might grossly overcharge them. The battery chemistry is set at the time the electrolyte is introduced. Then the plates are formed by slow charging. This in my mind is a closed system where a set balance is maintained. By diluting the electrolyte to an unknown concentration, he has lost all reference as to the SOC. He will not be able to tell based on SG where he is. Since these batteries are a high dollar commodity, I was erring on the side of caution. If he replaces the electrolyte, he can monitor SOC by applying a known voltage and then watching the current tail off. At that point, he can infer a 100% SOC, then the electrolyte concentration can be adjusted by dilution with H2O.
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #14
    Re: Saving over watered batteries. Suggestions?

    I did not get a chance to call rolls/surrette today. It'll be interesting to hear what they have to say. I am definately going to try to talk to Pasqual tomorrow.

    I was trying to get an idea of how diluted the electrolyte got. The s530 spec sheet does not say what the electrolyte capacity is but judging by the difference between the dry and wet weight listings there is 27 lbs of electrolyte in each battery. H2SO4 at SG of 1.265 weighs about 10.55 lbs/gallon so there should be about 2.56 gallons in each s530, or almost 20.5 gallons in all 8 batteries. The worst case would be if 3 gallons of water went in and 3 gallons of electrolyte went out. If this were the case it would have diluted the electrolyte by less than 15%. If they were at 100% SOC (not likely) and the electrolyte was diluted by 15% the SG should be around 1.225. My readings were much lower. I very much doubt that the SOC was 100% but if the highest reading (1200) is used as an indication they may have been around 1.235 SG or 75% SOC. The reading of 1130 would show a dilution of 60% from 1225 SG.

    This indicates to me that the water only diluted the electrolyte at the top of the cells. Of course it is also doubtful (and the SG readings indicate) that the water was distributed evenly among the 24 cells. If he gets the electrolyte stirred up well, I should be able to get some better readings and could then get an idea of how much each cell was diluted.

    Does this make sense and does it seem credible?:confused:

    I'm starting to like the idea of "out with the old in with the new" for the electrolyte.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #15
    Re: Saving over watered batteries. Suggestions?

    Your numbers sound reasonable... Try fully charging and equalization--measuring the sg every 30-60 minutes until all cells stop rising. Hopefully, the electrolyte will be mixed and you can decide if you want to replace a portion or all of the electrolyte.

    I did like [BlackCherry04's] the idea of pulling the water out of the top of the cells before they get mixed with the heavier electrolyte below. But after charging/equalization/mixing--That may not be possible.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #16
    Re: Saving over watered batteries. Suggestions?
    BB. wrote: »
    I did like the idea of pulling the water out of the top of the cells before they get mixed with the heavier electrolyte below. But after charging/equalization/mixing--That may not be possible.

    Oooh. That was a good idea.
    Oh well. Live and learn.
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #17
    Re: Saving over watered batteries. Suggestions?

    I just spoke with Jeff at Rolls/Surrette.

    He says:
    - remove some electrolyte to prevent further overflowing.
    - Bulk charge to stir the electrolyte
    - Take new SG readings
    If they are not too low (I'm thinking above 1210) do an EQ for a couple of hours and check again. (If the SGs are still wildly off -call back.)
    They will probably correct over the next few weeks with +/- 3 hr, Bulk cycles at 57.6 v.

    I doubt a "couple of hours" of EQ will be too much for the old Onan. I was afraid it would be a long process but Jeff seems to think they should be able to recover fairly well.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #18
    Re: Saving over watered batteries. Suggestions?

    i guess what i said before nobody could see because i'm invisible?

    "if it were me i would pull a bit from each cell to get them from spilling more during the charge."
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  • Joe_B
    Joe_B Solar Expert Posts: 318 ✭✭✭✭✭✭
    #19
    Re: Saving over watered batteries. Suggestions?

    Well I guess that I learned something today, where is the humility emoticon?
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #20
    Re: Saving over watered batteries. Suggestions?
    niel wrote: »
    i guess what i said before nobody could see because i'm invisible?

    "if it were me i would pull a bit from each cell to get them from spilling more during the charge."

    Thanks Niel.

    I had figgured on a major cleaning job when this is all over so I was not too concerned with the mess yet. The batteries are sitting in a custom made plastic catch tub. I guess I'm going to have to use some sort of siphon pump or a large suction saringe and put the spill into some heavy duty plastic containers. I wonder if my battery distributor will take it for recycle. There is a scorpion and a mouse in it too!
    :D
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #21
    Re: Saving over watered batteries. Suggestions?

    Coming to the dance a bit late, I would mention a couple of things. I second getting in touch with Surrette and seeing what they would suggest. Failing that, I would fully charge them, then add acid as much as needed to bring the SG up to the proper point. My guess is, as a percentage you probably havent lost too much acid.

    Finally, as for the Onan. Most Onans will up out better than 100% for a long time without damage. The older the Onan the more robust they are. I the cycle is correct at full load, it the voltage is low many of the older Onans had a variable exciter and you cand adjust the voltge by moving the picku up point on the exciter, so you can get 120 vac out with the proper 60 hrz through it the load range.

    Tony
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #22
    Re: Saving over watered batteries. Suggestions?
    SolaRevolution wrote: »
    Thanks Niel.

    I had figgured on a major cleaning job when this is all over so I was not too concerned with the mess yet. The batteries are sitting in a custom made plastic catch tub. I guess I'm going to have to use some sort of siphon pump or a large suction saringe and put the spill into some heavy duty plastic containers. I wonder if my battery distributor will take it for recycle. There is a scorpion and a mouse in it too!
    :D
    I have a old Wet Vacuum that I use for that job. It has a of PVC pipe adapter in the hose with a 2 foot piece of 1/2" hose I use to clean out the trays with. I'll usually neutralize it baking soda as much as you can and then suck it out and then pull some clear water with baking soda to clean the Vac.

    I'v had people fill Batteries with a water hose before., then call me for the clean up. The worse mess I ever cleaned up was from a guy that EQ'd for 8 hrs with the tops off 20 Batteries, the electrolyte was everywhere with NO tray.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #23
    Re: Saving over watered batteries. Suggestions?
    Blackcherry04 wrote: »
    The worse mess I ever cleaned up was from a guy that EQ'd for 8 hrs with the tops off 20 Batteries, the electrolyte was everywhere with NO tray.

    And still to this day I hear people insisting that the tops must be off batteries while they are being charged. Mostly it's the same folks who likewise insist that if a battery is left sitting on concrete overnight, the concrete will "SUCK THE JUICE RIGHT OUT OF IT!". And they proclaim their "truth" with a loud, convincing (to some) religious fervor, even on the spot, making up stories of great personal loss to "prove" their case.
    I just walk away.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #24
    Re: Saving over watered batteries. Suggestions?
    waynefromnscanada wrote: »
    And still to this day I hear people insisting that the tops must be off batteries while they are being charged. Mostly it's the same folks who likewise insist that if a battery is left sitting on concrete overnight, the concrete will "SUCK THE JUICE RIGHT OUT OF IT!". And they proclaim their "truth" with a loud, convincing (to some) religious fervor, even on the spot, making up stories of great personal loss to "prove" their case.
    I just walk away.
    That one was to the thanks of some Engineer from Heart Interface that wrote the Algorithm for a automatic 8 hr EQ. A owner would start it and walk away and 8 hrs later they would have a stinking thermal block of lead.
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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #25
    Re: Saving over watered batteries. Suggestions?

    Disaster averted!:cool:

    I got back out the BFE site to check on the over watered batteries.

    The SGs were back to a much more reasonable range. They have a measured difference now of about .020 but I suspect it will get better after more bubbling. It's no suprise that the lowest SG was the first cell in line of the auto-watering system. The range of voltages for the L16s were between 6.204 and 6.243 with the bank at 49.7v. They were similarly close under C10 or D10.

    I measured the SG of the overspill in the catch pan at +/- 1040 so it was obviously mostly H2O.

    I used a turkey baster to lower the electrolyte levels to normal.

    Thanks everyone for all of the input!

    Alex
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