Thorough and careful attention to the following steps often will restore a sulphated battery to good operation condition.

1. Clean battery;
2. Bring electrolyte level to proper height by adding water;
3. Put battery on charge at the prescribed finishing rate until full ampere-hour capacity has been put into the battery based on the 8 hour rate. If at any time during these procedures the temperature of the battery exceeds 50° C. reduce the charge rate to maintain temperature at or below this point. If any cell gives low readings (0.20 V less than the average cell voltage of the battery), pull and repair the cell before continuing with the procedure;
4. After full ampere-hour capacity has been put into the battery, continue the charge at the finishing rate until the specific gravity shows no change for a 4 hour period with readings taken hourly. Record voltage and specific gravity readings. Correct specific gravity readings for temperature. These readings indicate the state of charge;
5. Place battery on discharge at the 8 hour rate and during the test record individual cell voltages and overall battery voltage at the following time intervals: 15 minutes after test is started, then hourly until voltages on one cell reaches 1.80 and from then on at 15 minute intervals. From this point on the cell voltages should be under constant observation and the time recorded when each cell voltage goes below 1.75 volts. Terminate the test discharge when the majority of the cell voltages reach 1.75 volts, but stop the test before any single cell goes into reversal.
6. If the battery gives rated capacity no further treatment is required other than normal recharge and equalization of gravity.
7. If the battery does not deliver near-rated capacity, continue the discharge without adjusting the discharge rate until one or more cells reach 1.0 volts.
8. Recharge the battery at the finishing rate as described above, again charging until there is no further rise in specific gravity over a 4 hour period, readings being taken hourly.
9. Discharge again at the 8 hour rate and if the battery gives full capacity, recharge and put into service.
10. If this procedure does not result in full capacity, repeat once more as noted above.
11. If battery does not respond to this treatment, it is sulphated to the point where it is impractical to attempt further treatment and battery should be replaced.

2 TREATMENT

Thorough and careful attention to the following steps often will restore a sulphated battery to good operation condition using a MMF charger and a Discharger/Analyzer.

Clean battery;
Bring electrolyte level to proper height by adding water;

Initial Charge Current (I) : 4-5% of the battery capacity,
Constant Voltage (V): 2,4V/cell
Time of charge: from 12 to 24 hours

During the charge process keep under control the battery temperature that must not exceed 50°C.

If any cell gives low readings (0,20 V less than the average cell voltage of the battery), pull and repair the cell before continuing with the procedure.

4. The sulphated batteries have an high internal resistance; when a sulphated battery is put on charge the battery voltage reaches in few time the value of the Constant Voltage set and the charger current is very low.

Continuing to keep the battery on charge for long time with this very low current the lead sulphated is removed by the plates. The battery voltage would tend to decrease but the MMF charger increases the charger current to keep the voltage constant to the value set.

The charge process have to last a long time, from 12 to 24 hours.

If it's possible, keep under control the specific gravity of the electrolyte. If, during the charge the specific gravity doesn't increase for about 4 hours the charge process can be stopped.

After the end of the charge process, record the specific gravity of the electrolyte. The density of the electrolyte indicates the state of the charge.

Place battery on discharge at the 8 hours rate.

If a unit is used to discharge the battery it's advisable to set the discharger with the following parameters:

Discharge Current: 1/8 of the battery capacity
Time of discharge: 8 hours
Final Battery Voltage: 1,70V/cell

The discharger is fully automatics and stops the discharge process if the time of discharge or the minimum battery voltage set are reached. During the discharge, keep under control the individual cell voltages and overall battery voltage at the following time intervals: 15 minutes after test is started, then hourly until voltages on one cell reaches 1.80 and, from then, on at 15 minute intervals. Stop manually the discharge process if the voltage of one of the cell falls below 1,60V .

If the battery, with reference to the discharge parameters set, gives at least the 80% of the rated capacity no further treatment is required other than normal recharge and equalization of gravity.
If the battery does not deliver near-rated capacity, execute a new charge/discharge process.

Again charge the battery for long time between 12 or 24 hours and/or until there is no further rise in specific gravity over a 4 hour period, readings being taken hourly. Keep under control the battery temperature.

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A sulphated battery is one which has been left standing in a discharged condition or undercharged to the point where abnormal lead sulphate has formed on the plates.

When this occurs the chemical reactions within the battery are impeded and loss of capacity result.

This document does not cover all the electricity theory and technology involved in the process of sulfation in battery operated system. For more information, please refer to specialized literature.