Did I desulphonate my battery

[Reno]

After trying to recharge a 12V battery that I neglected over the winter I had given up so I thought, it's worth a shot.

The symptom was very low reading on my hydrometer (well within the red). All 6 cells were reading about the same with the end cell a little worse off but not much.

I tried recharging it in automatic mode at 60 amps, 20 amps and 2 amps and in all cases the charger shutdown on a Battery Full.

Since all the cells were reading the same I assumed it was a sulphur problem so thinking I had nothing to lose I swithed the charger to manual mode set it 20 amps and put the time to 1 hour. Next chance I had I went to check the battery, the chargers charge cycle was off, I did a hydrometer test an to my surprise the battery hydrometer reading was well within the white almost to green on all cells again the end cell a little lower but marginally. I Have put the charger back on for another hour but at 2 amps.

I think the fact that it was a quality battery allowed for this abuse a cheapo who have probably failed.

[Nando]

RENO:

You need to charge the battery at high equalization voltage, in this case, around 3 Volt/cell with careful attention at the current to determine when it starts to drop and in that moment reduce the charge equalizing voltage to 2.6 volt/cell.

Depending on the sulphation level, the current may start low then after some hours to increase then it comes down a bit, that is when you need to lower the equalizing voltage to 2.6 observing the current behavior for flatness and possibly incrementing which should limited to 0.1 battery amp-hour limit -- so if the battery is 50 amp-hour limit the current to 5 amps.

Stop charging if temperature rises to 110 + degrees.

load the battery at not more than 0.1 amp hour and stop loading at 1.85 volt/cell and repeat the cycle may up to 5 times.

Nando