How are you going about trying to charge the battery? One that's really badly discharged will get a condition called "sulfation" where the lead sulfate that forms on the cell plates as the battery discharges forms stable crystals that are very hard to dissolve. Charge it at least overnight at a slow rate, 5 to 10amps, then comnpletely discharge it by connecting something like a headlight bulb. Diuscharge and recharge several times, and the battery will begin to recover. Check the acid with a hydrometer to see how well it's taking a charge. Full charge specific gravity is between 1.265 and 1.300.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!