i have a charger that for years i have been saving batteries with. a guy that runs electric cars told me about them. he gets free batteries and saves most of them. i have saved many over the years with it and it has a system built in to leave it on a battery for years. i have done just that. i have a few used batteries i keep around for use in sleds, cars, electric kiddy cars and once in a while i move the charger to the next battery just to keep them all fresh. the charger has never missed a lick. when the rx1 came out, yamaha started selling them in the accessory book. they are called the optimate charger. they will desulfate a battery and charges it on a series of pulses that it is constantly regualting and somehow all that magic actulally works.
for the first year i had this thing everyone started bringing batteries to me to try to fix. i can only think of one that i could not get to charge. it is even dummy proof, you can hook it up backwards and it just shuts itself off.
if your going to get a tricle charger, you may as well have one that you can use for more than just that.