"SparkyGuy" wrote in message
obal.net...
Gell-cell batteries in UPS's: other than loading with a known load and
timing
how long it takes to drain the battery, is there a simple way to measure
the
health of a gel-cell? Impedance?

Yes, you are already at the door of the solution.

Charge it up and load it significantly and measure the output voltage (which
really sags under heavy load as the battery ages, due to its increased
internal impedance).

In the automotive realm, it was once called "cranking voltage." The
ignition system was disabled so the battery voltage output could be measured
while the starter motor was running. Now, decent garages have test gear
that does a high current load test without all the muss and fuss.