Homebrewed Electricity > Storage
Desulphation (Mad Science!) Experiments
ruddycrazy:
I found with N70 batteries they last about 5 years on my tractor then they won't start it again even after being left on a charger for a week.
So decided to try the alkaline trick on one, drained all the acid out of the battery and gave it flush out with rainwater. The flush was kept and is now great for re-sharpening old files. Then using baking soda started to neutralize the acid, did 3 batchs until no bubbles could be seen and did a 4th just to be sure.
Went to the local hardware and bought some pool folluclent (magnesium sulphate) and made a saturated solution in rainwater to top all the cells up.
Then left it on 2 off 5 watt solar panels for a month until I saw 16 volts then back into the tractor it went. The tractor started first kick so now on the roof of the tractor sits those 5 watt solar panels and the battery is still going after 3 years starting my fiat 45hp tractor with no problems.
joestue:
discharged 7 in parallel last night, due to confusion terminated the test long before full discharge. pulled 8 amp hours out, then put 9.5 back in.
discharged the 7 in parallel today, 4.5 hours at 4.6 amps average, ending at 10.80 volts under load. 11.1 volts open circuit after discharge. about 21 amp hours removed. currently charging.
so after a single reverse polarity charge, and 2 charge and discharge cycles at about half capacity, the batteries are at 55% nameplate amp hours.
joestue:
discharged and charged them again in series, removed the weakest battery which appears to have a cell that went partially open circuit.
the remaining 6 batteries were charged and then discharged in parallel: terminated the test after 15 amp hours removed in just over 3 hours. ending voltage at 11.54V under 4.8A load.
--much more testing will have to be done to determine if reversing the polarity is an effective stop gap measure. i think it is. but by the time the battery is at 50% amp hours its likely major plate damage has already been done and reversing the polarity may not be able to stop or reverse it.
Bossrox:
Thx for this post, I've got 3 big batts with bad cells so I'm gonna give this a whirl to see what happens. You might of saved me some serious bux!
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