Well I let the battery now stay open circuit for the last several days. 1st of September at 11:27 the voltage was then 10.27 ..

September 1st before midday I added 3 eating spoons of potassium Alum in to every battery cell and charged the battery again for an hour or so.

Disconnected then my charger, cause I used my second new empty car battery ( never filled with acid)  for to fill it with NaSO4 Sodium Sulfate- destilled Watter  electrolyte.


I again used 600 Gramms of  NaSO4 onto about 4 Liters of destilled watter and that was now already charging a few hours on the charger.


At September 1st at 11:32 I wrote:
I will let it charge on the EInhell charger until tommorow morning and then make measurements.


Before starting the charger the battery with the NaSO4 hat a PH-level of about 5 to 6 and a Voltage of 8.09 Volts.
The charger only displayed a charge current of about 4 amps, that is curious as the Alum Battery had a charge current of 6 to 8 amps when discharged and reconnected to
the charger, so the internak resistance of the NaSO4 Battery seems to be higher...

yes stefan.the ph of sodium sulfate is neutral,alum is acidic,thats why the difference in power and conductivity.higher acid more power,more conductivity,more voltage at cathode specificly which is very ph dependant.