Earlier wrote up a bit about questing for: Lead acid battery reconditioning on my EVT 4000 - PulseTech versus Battery Life Saver? ... and have some positive results to report.
I got some PulseTech units and have had a 12v unit hooked up to the four 12v50ah batteries. They were wired in parallel, of course. The last time I'd ridden the EVT 4000 it barely had any speed or range and that was with the pack supposedly fully charged. If you read the above post I tell that I installed a set of 12v 18ah batteries that were lying around, and found it had full speed with those relatively new batteries. That indicated the scooter didn't have any electrical or mechanical problem, it was the batteries.
Both the PulseTech and Battery Life Saver units take a smidgeon of power from the battery pack and send out a pulsing wave form. Supposedly the wave form has the right frequency signature to target dissolving the sulfate crystals. Sulfation is part of what causes lead acid batteries to die, and the theory is dissolving the sulfation extends the battery pack life.
As I said, the batteries were connected in parallel so it'd be a 12v pack, and I had a 12v PulseTech connected across the pack. Because the PulseTech takes some power, I also connected a 12v SLA charger to the pack. That way the PulseTech could take power, but the charger kept the pack pegged at full.
It's been approx 2 months now ... yesterday took the pack apart and reinstalled it in the EVT 4000.
Very good. It has full speed now - whereas before it was more like 20 miles/hr max using these same batteries. Range is difficult to tell because the odometer doesn't read accurately. IIRC the accurate number is 1/2 whatever is shown on the odometer. Yesterday I rode it for approx 20 indicated units, or about 10 miles. Today I rode it for approx 24 indicated units or 12 miles. At the end of todays ride the pack read 47.7 volts and the dashboard indicator was behaving right for that voltage level.
IIRC the best this particular pack ever did was 15 miles anyway. In any case the 10+ miles it gives right now is more than enough for my commute.