Much of what was stated by DrkAngel is, imo, erroneous.
Take for example, his statement that wet-cell batteries are allegedly "(Not recommended for eVehicle use!)".
Actually, if you go to EValbum.com, you'll see that most of the full-size (car, pickup trucks) EV conversions are powered by wet-cell 6V, 8V, or 12V wet calls, e.g. "Trojan" brand, and fitted with electrolyte recovery systems. (I have hands-on experience -- this is not "guesswork" or just reading about it.)
These Trojans, when charged properly, last 8 years, on average.
Also, the wet-cell marine "starter" batteries can last 20 years on a boat, because old fishermen know how to treat them -- not using the information from the manufacturers.
Although most lead acid batteries do not last many discharge cycles before deteriorating, a major study discovered that the "Dynasty" brand of lead acid batteries have nearly zero degredation after 1,000 charge cycles; proving that it is possible to have lead acid batteries that do not break down. That study, on wheelchair batteries, was on the Internet as of 2006-2008.
"Dynasty" was a battery brand by Johnson Controls.
I could go on.
The point is that most of the info on the 'net about batteries is false/incorrect, especially from the lead-acid battery makers.
The really knowledable people about scooter/ebike lead acid batteries are "Aerowatt", and Scott McGregor from EVdeals.com, two electric scooter dealers, circa 2001-2006.
RE LEAD ACID CHARGERS
Also, the actual charge curves of the Soneil battery chargers, which was, in 1999-2005, considered the best of 24V-48V battery chargers, differed from their published information. These relatively-expensive Soneil chargers saved a lot of electric bike/scooter battery packs from early death.
From the intermittent "berserk" behaviour of Zivan EV battery charger, I am guessing that the Zivan battery charger is designed to secretly destroy battery packs.
LEAD ACID v LITHIUM
Most of the postings on this board are about "Lithium battery problems", or "BMS problems", or "balancing problems", or "LiPO fires", or battery-pack welding.
We didn't have those issues, or concerns, with lead acid battery packs.
Lead acid batteries worked very well. Most of China's e*cycles run on them. However, in North America, incompetent and/or dishonest dealers/manufacturers destroyed the market, with some exceptions.
Lead acid batteries cannot be fast charged, except for the Hawker Genesis, which must be charged at 1C minimum. A 48V scooter on Hawkers was fully charged in 20-25 minutes. These Hawkers had a life of 200-600 cycles. However, if charged at less than 1C, they died in ~10 charge cycles. Getting the correct charger for a Hawker requires doing your homework.
The Peukert effect isn't a problem if you bought Panasonic AGM's. Buy only "high discharge rate" batteries.
If you're going SLA in your ebike on a budget, I strongly suggest: Buy Panasonic AGM.
Never buy gel cells. Never buy Sonnenschein -- they used to be excellent, but this company changed their quality to "bad" imo.