1.5AH will mean that it’ll deliver 1.5 amps for an hour. Or 0.75 amps for two hours, or 3 amps for half an hour, and so on and so forth. It’s a measure of the capacity of the battery.
The current is drawn, not pushed, so the battery will provide whatever current the device demands (or at least, attempt to). The only way it’s going to deliver more power is if the drill is intelligent enough to go “ah, a big battery” and make higher demands. I’m no drill expert but I would’ve thought that to be unlikely, but not impossible I suppose. Regardless, if a drill does that then it’s going to be a feature specific to that given product rather than a general rule I’d have thought.
