Ok, finally got the fan DC amps figured out. Took me forever to find a piece of wire long enough to actually have some resistance I could measure, LOL.

Each fan uses 2.5 amps @ 12 volts, so basically it's using about 30 watts per fan, all 4 would use 120 watts if connected in parallel.

Now, I think both of these batteries are rated at 5 hours, so 12 AH / 5 = 2.4 amps of current draw for the hour. At 24 volts, that's 2.4 X 24 = 57.6 watts of power the battery should be able to run for the first hour before it's discharged (safety).

Each fan is connected in series, so it's 24 volts / 4 fans so each fan can get 6 volts @ 2.5 amps which means each fan is only "really" using 15 watts of power. 15 watts X 4 fans = 60 watts. Being that the battery is actually pushing out 24 to 26 volts, this brings the watt range to 57.6 to 62.4 watts. Basically means the 4 fans are a good match for a 12 AH battery.

Now, given the run time of the batteries, the NiMH came closes to a "perfect" 12 AH runtime, and the SLA was close behind.

The NiMH is about 98% of it's 12AH rating and the SLA is at about 95% of it's 12AH rating.

Dang, glad I finally got the math right on that one, LOL. Was driving me crazy.