Big controller small motor who wins

I bought a yescom 1500 watt motor and was using it with my power velocity BT 15 fet controller and it went South the combo I tested the motor the motor works fine had melted the solder on the 4 mm male bullet ends. Resoldered bullets and motor test fine on ebike tester. I put the tester on the 15 fit controller and it stopped working. Bad controller Good motor yescom 1500w. So put on the edge 1500 watt aluminum stator 35 mm with one inch holes cut in the side cover three each on alternate sides. Now running powervelocity 18 fet Bluetooth controller and stop working on the 1500 watt motor. All this is happening at 72 volts but different amperage for different controllers.

So can a small motor back up into the controller and Fry components because the batter is delivering so much current to the controller which can't pump it into the motor and the motor would thien melt but the Fail-Safe is in the controller question please help poor brain.sorry in advance used talk to text so it's probably for Natalie(, phonetically )correct and I'll try to review it but don't hate. Lol Hi Justin

Phase connections fail, very often damage the controller. Phase wires and connectors need to be of proper size and quality.

Now that makes sense

I was running a 1,500watt yescom and fired a P.V 15fet controller and the 4mm solder where melted.
I controller stopped working. So now a 18fet P.V. controller with a edge 1500watt three holes on each side and cooling fins the controller stopped working and when tested with ebike tester and tester went out tried second tester and it went down Is it a bad coincidence ? Or what's happening ? The yescom tested find before tester went out. And now running a Lyen 9fet 30amp with the edge only the controller will get warm on one dirt hill. Don't think the motor will get hot with holes and find. All on 72v.

Ok so running a 1,500 watt motor with drilled holes and cooling fins at 72 volt 50amps. The motor doesn't heat up but the motor is to small to use all the wattage and with holes and cooling fins sends the heat back to the controller and it blows. How does that sound could that be the right way of thinking ?

Whatever motor you are using, once it gets saturated, any extra watts will mostly be making heat. It's good that you are letting the heat out instead of allowing it to build up, but I wouldn't go over that power level.

You might consider adding temp sensors to your controller and motor. The battery should remain the coolest of all the components if you want it to last a long time.

This is just my opinion, but...I think the motor should be kept below 140F, and it should last a lifetime. I think the controller should be cooler than that. You should be able to put your hand on the controller under all conditions.

Cooling holes are not a big help for heat dissipation, but it is a cheap and easy way to help delaying the overheating. Still, after you feed a motor to saturation point, frying it is a matter of seconds, holes or not. Bigger motors can be fed higher power, because their total mass does shed the heat better and their copper mass does tolerate more current. Best ways to cool a motor without building an active liquid cooling system, are smaller wheel diameter and ferrofluid. Reasons are simple: air is not a good heat transfer media. Ferrofluid does optimize the heat transfer from the stator to the outer casing, and the smaller wheel spinning faster does help the casing to shed the heat.