Originally posted by Lightninghorse:
And keep in mind that the charger will not charge at 10 A rate unless the battery is WWWAAAYYY down.
The battery will be WWWWAAAYYY down after a power failure that lasts long enough for the UPS to completely exhaust the battery.
It is a fact, documented repeatedly in the body of literature which encompasses the subject of lead-acid batteries, that a higher charge rate reduces battery life. The optimum charge rate is somewhere around C/10, which for a 7amp hour battery is 700mAH.
A 10-amp charge rate is more suited for something like a group 24 deep cycle marine battery.
The float charge voltage on APC UPSs is also too high, which also contributes to short battery life.