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Forum Index : Solar : Adding electrolyte to empty deep cycle: Recommissioning
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| olNick Newbie  Joined: 11/03/2020 Location: GreecePosts: 14 |
Hello all, New user here, very informative forum. Off grid since about 2000. My old bank, 2 12 volt strings, 1500AHr total (OPzS 2 volt cells) finally gave up the ghost; simply refusing to take any real charge, and alot of shedding at the bottom. Had the them about 14 years. Shame, I really abused the heck out of them, yes, classicaly never having enough PV and always undercharged. Live and learn. Been given a set of 6 OPzS, 600AHr that were in service for 2 years Sitting for 1 1/2 years w/o electrolyte since :-( (emptied to as they were too heavy for them to move). Sealed caps on them. My "friend/dealer" took over filling them, and giving an initial charge. Had some very sunny days and I've charged the batteries @ 45 amps 'til I got about 2% current going through them. Voltage reads ~ 12.58 v after resting. Have not had a chance for a load test yet. I checked the SG though and it's only 1.13-1.14 Friend says to keep charging and the SG will come up. I really doubt that. THE QUESTIONS: Should I either add acid to them to bring SG up to 1.24 (recommended SG by manuf.) Easier said than done.... Or, easier for me is to FULLY DISCHARGE, empty them and add acid at? AT WHAT SG? If I add 1.24 SG acid and then charge, is the SG going to rise and stay high? (Used batteries don't forget) What do you guys say? Most likely I will be given another identical 600AHr set of six(originally a 48v bank) to parallel with these, also wo electrolyte. edit: Forgot to mention that these batts have no sulfation, shedding etc. (look like new) as the PO replaced the 48v bank with a much higher capacity VRLA (OPzSV) set more suited to his needs. regards, Nick Live in Crete btw |
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| bob.steel Senior Member  Joined: 27/02/2020 Location: AustraliaPosts: 188 |
The SG comes up with charge. If you fully flattened them you could add pure water and as they charged the SG would rise to normal . Thats what I read but never done it as flatten to zero and the battery would die. Try battery university for their take maybe. |
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| Warpspeed Guru  Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
+1 for Battery University, the information there on any battery chemistry is excellent. I have zero experience myself with lead acids, so cannot otherwise comment. Cheers, Tony. |
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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
These are the ones you have correct? Hopefully the dealer filled them with the correct amount of electrolyte. Also the commissioning charge process here may not have been done correctly. I would email the manufacturer. They will probably tell you to do the commissioning charge process again, or possibly an equalise charge. Nice batteries BTW, look after them! Edited 2020-03-22 08:06 by renewableMark Cheers Caveman Mark Off grid eastern Melb |
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| olNick Newbie Joined: 11/03/2020 Location: GreecePosts: 14 |
Thanx for the replies, The first set of six with the low SG only charge to 12.4 volts full. Ordered acid and they sent me nitric.... Anyway, got 97% pure acid and will correct as best I can. Really vicious stuff... The other 6 are waiting to be filled and recommissioned. I will do the commissioning charge again on the first 6 after I correct the SG. I saw somewhere here? or anotherpower? that said Volts = SG + 0.8 something... Can someone clarify the formula? It makes sense that the batts are not giving me me 12.7-8 volts with the weak SG The batteries are more or less like the link above, but from another maker, Winner Ajax https://www.winnerbatterien.de/Produktdatenblatt/AJAX.pdf Really hope these work out, fingers crossed. Nick Edited 2020-03-23 05:14 by olNick |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Nick, PLEASE contact the manufacturer before adding acid. Those are a really nice set, don't wreck them. Cheers Caveman Mark Off grid eastern Melb |
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| olNick Newbie Joined: 11/03/2020 Location: GreecePosts: 14 |
Further on this... Added acid at a ratio as best as I could calculate/guess... Redid commissioning charge, 0.3*I10, or about 18-20A, till voltage and SG stopped rising. This took about 18hrs. Voltage stopped rising at 15V, (should have climbed to 16V or over) would not go higher even though Amps continued, prolly only heating the cells. Final resting voltage 12.57, SG at 1.235 more or less. Batteries are useable, dropping to 12.25 after ~ 100AHr draw over 5-6 hrs. Question; Should I add more acid and recommission charge, or just hedge my bets and draw here? Regards, Nick |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Did you contact the manufacturer? I personally would be tempted to empty them and start again, however doing that safely would be a problem. My fork battery was sitting around for a while when I got it. After quite a few cycles it slowly got better, but that was more likely due to sulphation. An equalise charge stirs up the electrolyte, you may find the SG goes up too high now if too much acid has been added. I'm no battery expert and would hate to give bad advice and have you wreck the batteries. Best thing is to get in touch with the manufacturer. Cheers Caveman Mark Off grid eastern Melb |
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| olNick Newbie Joined: 11/03/2020 Location: GreecePosts: 14 |
Yes Mark, I did contact. They first said to toss them, then they said slowly add acid to these first six which I did, and then they said on the next six add 1.24SG acid and commission charge them again. I will most likely add a bit of acid to these to bring them up a bit over 1.24. If the formula V=SG + 0.845 is any measure I'm in the ballpark... Yes, I need to equalize again, but after a few discharge cycles.... It's really crappy weather here and need to wait for a bit of sun after charging w/ diesel/petrol.... I don't know... regards, Nick |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Nick, just start using them now then, mine were freikin terrible first few charges and they got better and better. If you have enough sun to charge them again the advice I got was not to baby them too much, that kind of went against my common sense thinking but a good discharge and re charge should bring them up to speed. Anyway I took that advice and the battery got better and better. I'm amazed at what I can pull out of them now. Just don't draw the voltage down too low. Being in this scenario it's incredibly hard, when you have a wife that wants to power every bloody appliance JUST after the bloody sun goes down. Ohhhhh F me, my wife decided to do a load of clothes drying at 6.00pm tonight just as we lost all incoming solar power. F So mate try to train the wife in using big power loads when it's sunny, if you can do that PLEASE write a book and tell us all how to do it, I have clearly failed. Cheers mate. Cheers Caveman Mark Off grid eastern Melb |
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| olNick Newbie Joined: 11/03/2020 Location: GreecePosts: 14 |
Haha Mark, Mine does laundry and machines once or twice a week when I'll also use power tools and welder running the diesel generator. The forecast is for many days of sun so discharge/charge is planned. I am using the batteries for 10 days now, but we've had minimal sun. I'll drain them down to about 11 volts, and recharge with the 100 amp charger and then rely on solar for fully topping up. I also have a small 4 stroke engine running a Bosch alternator, but I only run about 30 amps because my field control rheostat starts cooking above that. Being house bound and working from home due to the virus, it's incredible what one can accomplish being home constantly, I namely have. 1. Done the batteries 2. Built that engine driven charger. 3 Restored a Petter diesel 4. About to rebuild main generator.... 5. Will fill and charge the second set of batteries I'll let you know about the batteries and the "book" Nick |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
I know how I'd do it. Put a relay on the circuits or outlets driven by a solar panel on the roof. Sun gets low or the dummy load off the panel is pulling too much power to let the relays engage, Circuit/ outlet don't work. Could be as easy as a tube over the control panel so only works through the middle of the day as well. Combine that with a second relay that also drops out when the batteries fall below a certain level. No clothes dryer for you just now dear. Spose one could also just use a timer. No power for the Dryer, oven etc between 3PM and 10 Am.... adjusted for daylight savings. :0) I have trained my women folk when they can use the AC, Dryer and take long showers. Winter be sparing, summer do what you want. If they are unsure they ask which is good. We have mains power but I like to have the solar keep the bill in check. One thing I have failed in is stopping them doing is running the hot water in the sink for 30 sec till it warms up before they will put their hand in it to wash a cup. sh*ts me to tears. Every single time I go to the sink tap it's on the hot side. I wanted to put a small heater under the sink when we recently re did the kitchen but that got shouted down. Think I'm going to reverse the pipes to get them out of that infernal habit. |
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