"Jim Wilkins" wrote in message
news

The 5-year-old 12v 4.5Ah UPS battery I tested this AM delivered
2.45Ah at 3A, which is the average current my laptop draws while
browsing. Table 2 shows in the 1 Hour Rate column that it should be
good for 2.75Ah at 2.75A current.

-jsw

That wasn't a good example. I have a 12V 12Ah AGM battery that is down
to 1 useful Amp-hour because its voltage droops to 10V so quickly.
Afterwards it recovers above 12.2V.
-jsw