# reconditioning 9 8v lead acid batteries



## Coley (Jul 26, 2007)

It is good to experiment, but the results on this one are poor. Once they are going bad, not much will bring them back. IMHO


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## Ziggythewiz (May 16, 2010)

Sounds like a fun experiment. I'm trying to boost some of mine a little. One seeming success I've had was dumped the old acid (while fully charged) and filled with new. Voltage after commute was then 12.5 on this battery vs the 12.2 it was before (13.2 is full, brand new ones are at 12.7 after commute and 11.9 is dead, so it seems fresh acid got me a 20-30% boost).


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## poprock (Apr 29, 2010)

search in batteries for a method using a mig welder. Works 4 me


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## rdh190 (Sep 4, 2011)

This is the feedback I was looking for and as expected, predicting the results I am dreading. If we could get 40% of the original range I would be happy. I will post the results.

As for the $3 lightbulb charger, am I ok to charge all the batteries in series at once (72V total) or should I charge each battery individually? Does it matter? My guess is I might as well charge all the batteries in series since the supply is fixed current and the spikes go up to 120V when not hooked to the batteries.


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## Sunking (Aug 10, 2009)

Go ahead and try, as long as you do not spend much money trying you won't loose much. But after 35 years of experience once the lead sulfate crystals have hardened off, there is not much of anything you can do to dissolve them.


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## Ziggythewiz (May 16, 2010)

Another thing I was going to try is to charge the battery, dump the acid and fill with dw, do a few charge cycles and repeat, then fill with fresh acid. Maybe throw some epsom or something in with the water too.

My thinking is that as you charge sulfur dissolves into the electrolyte turning it more acidic (when fully discharged it's basically just water) and the lower the acid content the more willing it should be to dissolve.


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## poprock (Apr 29, 2010)

http://leadacidbatterydesulfation.yuku.com/directory


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## rdh190 (Sep 4, 2011)

Thanks for the link poprock1, I will definitely read thru this.
We finished the first phase of the experiment- added a heaping teaspoon of epsom salt to each cell and charged with the homebrew 0.5A pulse charger for about 1 day per battery then charged the whole system with my friend's 72V charger. 

My friend took the car for the first drive before adding salt and pulse charging and the car made it 2 miles before it would no longer drive, he did not monitor voltage and current. My run (after the pulse charging and epsom salt) yesterday was the first time I drove the car so I monitored voltage and current heavily. Under load (on the 72V, 200A, 40hp, DC series motor) the voltage would drop to 60-63V, otherwise remaining at 72V for the duration of the drive. This was consistant over the entire drive. For the first mile or so the current meter would go up to 200A under full load. Half way thru the current meter would only hit 140A under load and this continued to decrease. On the last hill (which is very steep) the current meter would not exceed 80A and I must have been travelling about 5 mph... *Should we expect these voltage drops and gradual drop-off of current characteristics?*

I travelled 5 miles on my drive and there was still some power left but not much, I may have been able to make it one more mile so we made an improvement but the car does not yet have the power and distance it needs. I've been told that it takes months for the epsom salt to fully dissolve especially when adding them to cold batteries (it is ideal to mix salt in heated distilled water then add, I couldn't do this). If I continue this experiment I will add one more teaspoon of epsom salt per cell and stick the 0.5A pulse charger back up for a more extended period but I am not sure if I want to at this point, I don't expect much more improvement.


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## Ziggythewiz (May 16, 2010)

It's not hard to heat up a battery. Just drive it to low and charge it up with a real charger (10A or more). It should be pretty warm.


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## Sunking (Aug 10, 2009)

If the battery is below 50%, you are only making the crystals even harder.


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## rdh190 (Sep 4, 2011)

Based off of the first experiment I ran, I obviously made an improvement by being able to travel twice the distance so the super-low current pulse charger and epsom salt is doing something. The first experiment was very mild.

What all can I pull from the current and voltage drops I experienced as mentioned in my previous post? Anything more specific and scientific other than just saying the batteries are shot? 

Thanks again for your input.


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## Guest (Oct 18, 2011)

Have you checked the specific gravity of each cell when the pack is fully charged? Have you checked the specific gravity of each cell after your pack has been discharged? Have you checked and logged all this information including the voltage of each battery after charging and allowing to sit for at least an hour and after you have discharged the pack? This will tell you a bunch. You may find that only one or two batteries are the reason for the poor performance. Allowing the other batteries to feed into the bad batteries is not a good thing for any battery.


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## rdh190 (Sep 4, 2011)

Update and close-out of this post: I put the second 'serving' of espom salt in the cells per my instructions and put my light bulb pulse charger on the full stack for several days. Topped it off with the 5A charger then took the car for a second drive. Results improved even more on the this run but still not close to original range.

On this run we saw at least an 8 mile range and current never dropped below 100A at full throttle. There is no doubt that there was a significant improvement and theEpsom salt was still not completely dissolved.

My friend decided to stop messing around with these batteries, pulled them and put new batteries in his car. Bummer but understandable.

gottdi- thanks for your post. I printed out a chart to record all the parameters you mentioned and was ready to get started but found out right afterwards that my friend decided to go with new batteries. 

Had this been my car and at my house I would have for sure run these tests and kept pulsing and allowing the Espom salt time to fully dissolve but to me this is more of a science experiment and the owner wanted to get his car back on the road so I can't argue with his decision.


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