On Tue, 16 Feb 2016 17:40:30 -0500, Bill Baxter
wrote:

I have a Cyberpower 550VA USP whose battery needs replaced. I see many
options during googling, but I'd like to find something that will last.
I know some of the generics aren't the greatest. Suggestions? Thanks!

Well, the first step is to identify the model number of your
CyberPower 550VA UPS. My guess is that it's a CP550SLG. Then Google
for "[insert model number here] replacement battery". You should find
plenty to choose from. In general, I prefer AGM batteries with the
highest weight (more lead inside). Watch out for shipping charges.
Something like this:
https://www.google.com/#q=cyberpower+CP550SLG+replacement+battery
Hmmm... 12v 5A-hr. Not much capacity and therefore not much runtime.
Let's say you have a new battery and a 100 watt load. The battery can
deliver:
12v * 5A-hr = 60 watt-hr
However, you don't want to totally drain the battery as that would
kill it. So, figure on getting about 50% of capacity out of the
battery or about 30 watt-hrs. A 100 watt load will theoretically run
for:
30 watt-hrs / 100 watts = 0.3 hrs = 18 minutes

Getting longer life from a UPS battery is not going to be solved by
simply buying a better battery. Typically, I see about 5 years of
battery life on commodity UPS's.

Having the power go out for a time, where the battery goes into deep
discharge (i.e. 10% of full charge) a few times, is going to kill most
batteries. To increase battery life, the designers would need to
reduce the maximum charge level, and turn off the UPS when the
discharge reaches about 50%. That would have a BIG effect on how long
the UPS will run on battery, which would give you something else to
complain about. You could do it with much larger external batteries,
but those cost more.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558