13-12-11, 02:19 PM
From your description the LED torch uses 450mA on 24V (we can assume there is some sort of internal regulator) so the currently in each battery is 450mA. If you run the light for an hour each battery will supply 450mAh (0.45Ah), so the answer to you question depends on the capacity of the battery. I.e. if your batteries are 45Ah type then 0.45A load will take 100 hours, a 22Ah pair will last 50 hours.