Originally posted by: TwoBills
Most ups brands play it pretty close to the vest when it comes to what battery size is in their unit. The best thing to do is to open it up, or just pull the battery, and measure it. The best place I've found to buy replacement batteries is "Interstate battery warehouse". Your going to have to hunt one down in your area. These are the depots that provide batteries to all the retailers, mainly automotive and marine, but they have a variety of agm and gell batteries. Just to give you an example, a 7ah agm battery (that comes in most 500va systems) costs $12, last time I checked. Get the biggest (ah) battery that will fit in your case.
edit: just looked at the links. According to the 2nd link, that's an 18ah battery. Probably get one at interstate for under $40. I bought a 33ah, a few years ago, for $75. Like I said above, measure the battery and get the biggest one that will fit. Most chargers will handle double what is provided.
