Are the ah ratings on NiMH different than SLA batteries? For example, in an EV bicycle or scooter, would a 10ah NiMH give the equivalent of 20ah SLA battery pack? I didn't think so, but my field tests appear to show otherwise.
I've got a 24v Bladez powerboard scooter with 2 12v 12ah UB brand SLA batteries. I've increased the scooter voltage to 30v by serially adding 2 NiMh 3.5ah RC battery packs, both wired in parallel, to the 24v pack. The scooter runs fine at 30v.
After about 30 minutes of riding, the 24v batteries are drained almost to the point the motor is ready to auto-cutoff, if I were to cut-out the extra 6 volts (I have them on a switch). When I go and recharge the 3.5ah NiMH packs, about 2.5ah is typically charged into them. The SLA charger doesn't indicate how much juice is put back into the SLAs during their charging, but given what I'm seeing, it appears the 3.5ah NiMh pack is equivalent to the 12ah SLA pack. I've repeated this scenario many times.
The SLA batteries are broken in and appear to be fine and are giving the same performance as the original pair of SLAs I'd used.