[suicideneil]

But you're talking about a larger motor, with a lower kv, being geared up to achieve the same speed on the same voltage- I'd doubt it would pull exactly the same current as the 1515 motor somehow- you have no way of knowing how much current each setup would pull without putting them both on a dyno to get exact numbers. Gearing up a low kv motor will place more strain on the system- higher mechanical load so a higher current draw. Using a higher voltage with a lower kv motor & lower gearing though will produce the same speed at a reduced load, so better efficiency in principle.

You'd really need to increase the voltage to 5s & adjust the gearing to match the original setup- I wager you'd get your longer runtimes & better efficiency then for sure. Gearing up a lower kv motor, when its larger and capable of a higher total power output is gonna cause it to draw more current vs the slightly smaller motor with a higher kv motor that has a lower gear ratio ( relatively speaking )..