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Desulfate

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I stumbles onto vids about desulfate a Lead Acid Battery and I was wondering if there is anything to it. If its true then how would a lithium be better if you can keep a lead acid going forever?
 
PsychoticEpisode said:
I stumbles onto vids about desulfate a Lead Acid Battery and I was wondering if there is anything to it. If its true then how would a lithium be better if you can keep a lead acid going forever?
Click to expand...
It's technically called equalize.
It over volts the cells to balance each cell to itself, the bottom wet part to the top part that is now dry.

It doesn't really work that great. It does prolong the life of the cells though. Maybe 20% more life.
 
Equalize is for Open Lead Acid. NOT recommended or suggested for Sealed Batteries nor most AGMS (some can take it but not many) It is usually run for 1 to 2 hours and essentially a High Voltage charge which is to level up cells within a battery, to undo stratification of the electrolyte and to reduce crystallization. This is a normal process for FLA Batteries and generally suggested at 60 day intervals. Depending on Manufactures Instructions - it does vary a little.

Desulphation is similar to Equalize and uses the same process BUT it takes 4 hours to run this process which effectively "boils" the acid in the batteries. This process is also generating more Hydrogen off gassing so venting is suggested and de-capping the batteries to allow them to breath.

CAVEAT: NEVER EVER Try to Equalise or Desulphated with low electrolyte levels ! The results can be very ugly !

Always refer to your specific battery manufacturer's documentation & instructions.
Good doc on FLA Battery Care Generic" https://www.solacity.com/lead-acid-battery-care/


Extensive detail starting on Page-19 of the Rolls Surette Battery Manual:
 
Desulphators and uqualizing are not the same thing. Equalizing is applying a steady voltage a little higher than normal to even out all of the cells in a lead acid battery. Desulphators on the other hand use much higher voltage pulses, some on the order of 100V or more into a 12V battery.

Many years ago I played around with desuplhators quite a bit, from the basic to a programmable one in which I could set pulse length, frequency and voltage. I never managed to revive a truly dead battery. I did manage to get a small amount of improvement in a few cases. The only time I got a significant recovery was in a brand new car battery that had been let to sit for a few years. It wouldn't hold a charge at all when I got it. With about 2 weeks on a desulphator I managed to get it to hold some fraction of its original capacity, maybe 1/4 to 1/3. I used it as a starter battery for my 15hp air compressor and it lasted 2 or 3 years. Of course, occasionally starting a small engine is much different than starting a car every day.

Over all, as usual, there is no free lunch. You can't keep a battery going forever.
 
Hmmm... I have several deep cycle, and starting batteries that fail to hold over 11V... any chance desulphating will work?
 
You could keep lead acid going much longer if charge controllers were all designed for multiple bank switching. Instead of one large bank, 2 or 3 smaller banks get swapped out daily and have time to fully dissolve sulfation while the other is being discharged.
 
Desulfaters aren't just EQ charging at a higher than normal voltage. It is about the pulses of much higher voltage. As outlined above, I had limited success. The fanciest one I built was MCU controlled and I could change any parameter, voltage, length, rise time, etc.. If you look at the ad copy for desulfaters they are snake oil for sure, with stuff about them being the only ones with their pulse profile and so on. I think there is some use in them but they won't magically restore a dead battery.
 
Jay2020 said:
Yep, as i understand sulfation starts immediately upon usage and gets progressively worse as voltage drops, idleness....

Maybe not having high voltages (8.1/16.2/32.4...) has rendered a lot of good batteries to the scrap heap, particularly when the hydrometer shows low specific gravity BUT the only problem was insufficient HIGH charge to remix the bottomed-out acid through bubbling action over a good amount of time.

I have multiple banks, and will create more, for specific purposes ( idea based on a breaker panel concept).
Click to expand...

Youre right. But solar only last ls a few hours, a battery can only be charged so fast, and clouds.
 
Jay2020 said:
I care not for desulfators but I do care for getting my batteries up to a high charge now and mixing the electrolyte very well to add the "ounce of prevention is...."

Considering peeps throw out batteries willy-nilly, I would be more than eager to take some and do some "Frankenstein" experiments on them, I believe i can resurrect them. ??

I got a fantastic deal on a couple 230amp batteries that were bought then left in a barn for a year and some and were subjected to harsh winters, hard heat and were never charged. I brought em back to life ( both charge & specific gravity) and they are great! This was w/o getting them up to 16.1 for a few hours, the highest was 15.4 and that was for a couple minutes.

Once my variable charger arrives i will hit em and hit em good.
Click to expand...

I'm with ya on charging yer batts right and mixing electrolyte. The one battery I did get some life back out of with a desulfator was exactly the kind of scenario that you describe, a new battery that had been left sitting. I only got a portion of the life back and it did take the desulfator to do it. With a regular charger it wouldn't hold a charge. However, back then I didn't have a way to easily do a real EQ type charge.

Overall, I think desulfators are mostly hype and over unity wishful thinking though.
 
Sulfation: The formation of more or less permanent film of lead sulfate on the plates. Lead sulfate is a product of the discharge process; there's no way to avoid the formation of PbSO4. However, if the sulfate is not promptly converted back to lead oxide & lead (+ve & -ve plates, respectively), the sulfate film will harden and reduce the area of exposed lead & oxide surface. This effectively reduces the cells capacity.

The solution is to avoid leaving the cells in partially discharged state too long. Another effective solution is to ensure that the charging, reverse chemical reaction is allowed to proceed fully. A cell's voltage during absorption is not a reliable indicator that the reaction is complete. Measuring the reverse charge flow is the only way to gauge the reaction's progress. For example, on the negative plate, for every two electrons returned to the cell during charging one lead oxide molecule is converted back to lead. By ensuring that amp-hrs during charging is equal to (or slightly more than) what was taken out during the previous discharge, long term accumulation of lead sulfate is prevented. This is exactly what our SC-2030 solar controller does (a shameless plug for our product!) - measures the amp-hrs returned to the battery and lets you put back the last discharge amount and some specified excess charge every time the battery is charged.

The so-called desulfators apply a higher then normal voltage - either steady or pulsed. They do not measure the charge (amp-hrs) returned to the battery during de-sulfation. These usually don't work. The reason is that the device doesn't know the exact level of sulfation (# of molecules of lead sulfate) present and don't send the amount of charge required to fully convert all the sulfate. Repeated use of a desulfating device may reverse sulfation. The user must monitor the electrolyte level and add water, if needed - not an easy task in sealed batteries like AGM/Gel. For these, take care of them from the get go.

Equalization: The process of stringing up the electrolyte so that it is well mixed and the sp. gravity is the uniform all over the cell and from cell to cell. This is done by increasing the charging voltage to a point where electrolysis begins. Gas bubble stir up the electrolyte and help mix up the liquid.

By performing a short equalization step whose duration is determined by amp-hr counting of returned charge regularly, the cycle life of all lead acid batteries can be extended. It is even possible regularly discharge the batteries below the 50% level, provided there's sufficient charging capacity available to promptly recharge them.
 
I ran a desulfation routine today on my Trojan T-105 GC2 6V batteries. The electrolyte level was topped off last weekend after I verified the specific gravity in each cell using a hydrometer. All cells were in the green. Tomorrow I will recheck the levels. While the desulfation was running, I could hear the batteries "boiling". I didn't open the vents, but I did open the battery box to ensure adequate ventilation.

These batteries are three years old and this is the first desulfation run.
 
Funny, I've been restoring some old batteries just for the sake of not buying a new one...

One was a dead (like 2V dead) normal lead acid. I've been charging it very slowly, but steady, with a limit of 1.2A (as that's the peak of that charger. And today, the resting voltage is over 12V- this is after a week on the charger. I'll probably run some cycles on it this coming weekend, as I've been following the directions from a video (yea, nobody likes those, but so far the idea has worked). Interestingly enough, I've been putting this one on my solar charge controller- and that limits the voltage to lower than the charger. Now that I think about it, I should probably disconnect it....

I'm also trying to revive another very dead Odyssey battery, these are totally different. I don't see this one coming back, but I'll keep trying. At least it's gone from 0V to 5V at rest.

This is the video-

The reason I am using this is that I don't have to buy anything I don't have, as my trickle charger is light, and my "big" charger has a setting for 2A max. I'm just trying to be cheap.
 
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