Based on the additional info you provided. I agree w/ edward t it is time to replace the batteries. The batteries die from lack of charging for 2 years. This is kinda like the myth that says if you store a battery on a concrete floor they will discharge. They only discharge from lack of use as humid air will act as medium to conduct electrical charge. This why idle batteries need periodic charging whether they are on a concrete floor, storage rack, in your boat, etc.

Certainly do not add a mircale cure to the batteries to try to "rejuvinate" them.

If you are looking to save a few bucks try contacting an Interstate battery distributor they may have batteries of your size that were "warranty returns" but were checked out and still good. I pay about $25 each (no warranty) and have had good luck with them so far.

just get new batteries and save the head aches and danger of adding a product other than clean water to the batteries. if those products really worked, every gas station and forklift and golf cart place would be selling them, not drugstores.
the amps go up because the batteries are bad, I am pretty sure you will see a more familiar response from the charger once good batteries are installed..
weak batteries will cause problems (wear and earlier than natural failure rates) in all the other components of the power control, including the motor and it's brushes. the money you put out for good batteries will more than equal the money you save by not having poor batteries cause added wear.

Thanks
I don't know how old the batteries are, the last time they were charged they were fine and water was fine.
I also put the battery on a smaller charger, but the battery charger was heating up to.
I never charged a battery that the amps went up as the battery was getting closer to a full charge. As battery voltage goes up amp rate goes down.
I have some info that you put something from the drug store in the battery to desulfate the cells but I can't find it.

Because the batteries have not been used for two years the plates in the batteries have more than likely sulfated which makes them hard to impossible to recharge. Idle batteries whether they be 6v auto type batteries or industrial type need to be charged at least every 6 mos (every 90 days is ideal).
Some times you can get them to recharge by putting them on a a "equalize" charge cycle (a slow charge rate for a long period of time maybe 12-16 hours). If that doesn't work you'll need to replace them.
You didn't mention how old the batteries were or if you needed to add water to the batteries to cover the plates before charging. If the cells are dry then they won't charge. Add just enough to cover teh the top of teh plates. Then add more (to about 1/2" below the fill hole.

Good luck.