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Author: Subject: Reversing Lead Sulphation on Battery Plates
Chris_H
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[*] posted on 2-12-2016 at 16:52
Reversing Lead Sulphation on Battery Plates


Hi All Merry Christmas (Yep they go around Faster & Faster!) I am new here so don't be harsh on me please. I am interested in Lead acid battery tech. These batteries are constrained by a chemical reaction that can (if left in discharged state/eventually leaves the negative Pb plates sulphated. The more sulphation the less capacity as the sulphation acts as a barrier. The general chemical equation for this type of battery I believe is : (Charged state) Pb(s) + PbO2(s) + 4H+(aq) + 2SO42-(aq) → (Discharged state) 2PbSO4(s) + 2H2O(l) E ~ +2 V. Apparently introducing sulphates to the electrolyte such as Sodium sulphate, Magnesium sulphate, Aluminium sulphate hydrated with distilled water can remove some of the sulphation on the negative battery plate to become a Bisulphate, I am not sure if this is (aq) or a (s)? Can anyone with some working knowledge give me a chemical reaction/equation that can justify this? Here is a rather good link with some further information on the process:
http://www.rainingspiritdojo.com.au/downloads/alternativelea...

I'd be extremely grateful if any chembots out there could clarify if this is actually possible? Thanks all :)
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Texium (zts16)
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2-12-2016 at 22:55
XeonTheMGPony
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[*] posted on 3-12-2016 at 07:49


Once they are sulfated too badly battery is toast.

But if the battery is worth it:
Note Sg = Specific Gravity

Dump out electrolyte into a large bin, rinse the battery thoroughly with distilled water and dump into previous electrolyte.

Set battery aside, Now filter thoroughly the electrolyte then boil to concentrate, Filter this yet again then bottle and set aside.

Back to the battery: fill all cells to the proper height with pure distilled water, attach a charger and bring the voltage to what ever is needed to get it to 5amps charge rate and place a glass therm in the middle cell to monitor temps.

Monitor the amps and temp of the battery, Check the Sp of the cells as well, as the hard sulfate dissolves in the water the amps will go up along with the Sg.

If the Sp goes up past 1.2 you have hard proof some one has added acid and not water to the battery at some point, drain and refill with distilled water and continue this process till the Sg does not rise in any of the cells.

Get your bottle of concentrated acid, read the manufactures rated Sp of electrolyte at full charge, with clean water mix your acid to water to the correct Sp then fill the battery, place on an equalizing charge (for a 6v that is 7.5v, for a 12v that is 15.5V)

Charge untill all cells are freely gassing, take off charge and allow to rest for 1h, then measure all the cells Sg, adjust as required.

Do do this will eat up an entire day if not 2, So usually not worth the effort for any thing less then a quality 8D battery or a traction cell.

But if just messing around why not, but for starter batteries this won't do mush as they simply disintegrate, so there is just nothing to desulfate, this is meant for traction batteries or deep cycles.
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XeonTheMGPony
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[*] posted on 3-12-2016 at 07:52


All so adding any crap to your battery, Congrates you're screwed! DO NOT DO IT EVER! less it is a dire emergency and you plan to replace the cell, but I live off my batteries (Solar system) So I don't put them at any risk what so ever!

Lead batteries are sturdy critters but there are allot of land mines in their care that can be counter intuitive, you have to look at them as the whole not at any one factor (Mistake that most make)


The only thing you should ever add to your battery is water and energy, nothing more, proper equalizing charges and a good charging system will prevent any hard sulfates from forming, and never pulling more then 50% Depth of discharge will give them a long life!

[Edited on 3-12-2016 by XeonTheMGPony]
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Chris_H
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[*] posted on 3-12-2016 at 16:06


Thanks for taking the time in offering your advice XeonTheMGPony, I will definitely give this a go:). It may take me some time but I'll leave you some feedback on my results. My battery is a 48v 633Ah traction battery (24x2V) cells, so this process will take me quite a while I'm guessing! Quick question? Will distilled water at 5amps remove hard sulphation alone?
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XeonTheMGPony
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[*] posted on 3-12-2016 at 19:59


Yes the hard sulfate is far more soluble in pure water, won't be super fast but with monitoring it will eventually break, you'll see amps start to climb as it dissolves.

Care full monitoring is the key. basically push what ever voltage you need to keep a steady 4/5amp trickle

Deffenitaly worth the effort with those Cells!, Charge them up as much as possible first too, speed things up.
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Chris_H
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[*] posted on 4-12-2016 at 06:28


Thanks again for your advice!

Cheers Chris
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roXefeller
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[*] posted on 8-1-2018 at 10:47


That's a great description of desulfation. Since you live off of lead acid batteries, are you able to speak to whether batteries require a temperature compensated charging voltage. The source I took this from is attached. And other sources below. Is this true of the battery chemistry or just a selling gimmick?

http://batteryuniversity.com/learn/article/charging_at_high_...

http://solarprofessional.com/articles/design-installation/un...

Attachment: 5-How-To-Specify-a-Genset-Battery-Charger.pdf (217kB)
This file has been downloaded 8 times

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