BroMikey at the other forum has much to say about the
Alum (Ammonium Aluminum Sulfate) Converted Batteries.
He describes how two of his batteries (100AH) lost capacity
after abusive "normal" charging methods. After conversion
he claims that the lost capacity has been restored and that
the capacity has even increased.
Observing an increasing capacity with lead-acid batteries is
a common phenomenon and it is actually by design. At some
point in the life of the battery its capacity will begin to diminish,
usually due to accumulating sulfation, and it will drop below its
rated capacity. To assure that the battery will have a long, useful
life each has built into it more than its rated capacity which will
begin to show up after the first several charge/discharge cycles.
I wish BroMikey had done a comparison with:
(1) A Lead-Acid Battery pulse charged, fully desulfated and load
tested periodically to establish capacity,
and
(2) An Alum-Converted Battery, also pulse charged, fully desulfated
and load tested periodically to establish capacity.
Unless those kinds of comparisons are made it is very difficult to
know with certainty whether the Alum-Conversion has accomplished
anything more than what Pulse-Desulfation is able to accomplish.
As other experimenters have pointed out, Aluminum Sulfate is acidic
as is Ammonium Aluminum Sulfate. Potassium Alum and Sodium Alum
are less acidic and tend more towards neutral since Potassium and Sodium
are highly alkaline.