My yyk 80a vs my yyk 50a controller

Hi guys. I have 2 e scooters, one on 60v 50a yyk matched with 1500w motor, batt was mj1 60v 21ah 60a . Free load spin was at 100kph on this. Was able to hit 80 kph when i tested. However, on my 60v 80a yyk matched with 1800w motor, batt was 60v hg2 15ah 100a. Free load was only 80-90 kph. Max speed achieved was 54kph when tested. Likewise, freeload on 3200w was only 110kph. Was expecting the kph on my 80a yyk to be higher than 50a yyk.

Any idea what is wrong?

The simplest reason: 1800w motor has a lower max rpm

Take for example the infamous QS205 motor V2 or V3. Same motor, very different performance characteristics depending on how the motor is wound.

7t = 7 turns per slot = 300rpm Slow, but has massive amount of torque
3t = 3 turns per slot = 1275rpm Fast, like 70mph+ fast, but has very little torque

Try to find the specs for max rpm for the 2 motors you have, if the 1800w one is rated for less rpm, there is no problem.

Right, its the motor not the controller. 50A or 80A is the current limit. With the wheel off the ground, you will not be anywhere near the limit so the controller rating won't have any effect.

These controllers most likely have a 3 speed switch. Make sure you have the switch in the high setting. If no switch is connected, it will default to speed 2.