Consider also placing a UPS in that does LINE CONDITIONING. This will, for example, take input voltage of between 74 VAC to 149 VAC and clean it up to go out at the 120 VAC that our computers like.
The APC batteries are good, but have a tighter tolerance of what they can accept.
Further, a good, and simple (USD$ 200) solution is to put a simple line conditioner in SERIES with your UPS unit so that the UPS battery receives a clean 120 VAC power.
The grid can suck!
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