eeek

You haven't been checking your water levels? That's no bueno, here's a video showing how you check and fill them. You should be checking the water levels often, I check at LEAST once a week, and top them off if needed with some distilled water (NOT tap water!). I use one of these to fill the batteries, makes the job much easier and cleaner. Distilled water is usually <$1/gallon at the grocery store, it'll be by the bottled water.

Properly maintained lead-acid batteries should last around 5 years, I think my old charger was over-charging my batteries and causing them to use too much water (by boiling it off when charging). I replaced my charger with a new Lester charger when I bought new batteries, and they haven't used any water yet.

I would go check your water levels (see video above) and add water as necessary. Maybe your batteries can be revived... maybe they're toast. Do you have a Sam's Club nearby?