Buying burnt/dead 65161/65162 maytech or flypski motor

Hello.
Anyone have dead maytech or flypsky 65161/2 motor that is willing to sell?

Yep. Sadly i have a burnt 65161. How much would you give for it?

Can you tell us what happend so we can prevent the same mistake?

My esc was forgotten on for a few hours (it doesn’t have a timeout shutdown) and the current sensor zero started drifting so that more and more current was fed through the windings. Not a happy day.

Hey hello. thanks for your answer…
Idk, how much do you want for it?

We have plenty of fried Maytechs. We needed about 130A out of them, but they melted at about 85A. They also let water in as you can see from the rust.

I can see if we still have the bits. Shipping from Australia would be expesive.

How is that possible, that they burnt at 85A?

Not sure. We had them in a test tank where the water flow would have been less than if they were on something moving through the water, bit they should have had plenty of cooing. They were running a Maytech ESC and Anti-Spark switch (we have quite a few of them fail as well).

i think it is just the batch. Some are still going. We get about a 50% failure rate with all Maytech stuff.

Well I have firduo (HGL tech) 65162, and it is the same as flipskys 55161, just with diffrent front cover… I hope I wont have this problem

Is it the same?

I have asked this question a number of times on the forum.

USD $661

USD $459

The flipsky is USD $200 cheaper.

Notice the shaft sealing is different between the two motors.

Flipsky is 200A while Maytech claim 300A.

Flipsky 3kW (rated) while Maytech claim 8.9kW

I don’t think they are the same motor.

SORRY!!!

You weren’t comparing to Maytech, my bad.

I mean all the resellers for this motor have diffrent shaft sealing, so they can sell the as diffrent product. I think they are all 6kW (maytech is knoen for they lies about productis, like the remote)…

I agree, performance is the same between flipsky and maytech 6516x, i’ve used both. Maytech are basically lying about a lot of their products, i try not to buy from them.

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That is realy bad number of burnt motors.
50% is alot.
Possible damaged windings during winding procces is culprit for that high fail number.

I guess this is referring to phase current? I run both my 65161 maytech and flipsky 120kV at 250A, burning at 85A in water is really low. Could be winding damages, then there would be hotspots in the burned windings, but i think not so likely for 50%, could more likely be poorly matched ESC output. It doesn’t take high current to produce heat if efficiency is low.

I agree that porly mached esc and timing setting could kill any motor eaven on low current realy fast but with porrly mached setting i think failure percentage would be eaven higher like 80-90% of them would die.

Yeah, that’s true. It’s hard to explain a 50% fail rate. Batch issues, 50% were already corroded from leaks, something like this.

The ESCs were the Maytech 300A;

So, should nopt have been a problem.

The only thing we can think of is that we are onlyu running 12S - due to safety legislation.

The Maytech motors at the full 20s are pulling 110A max at rated output. At 50v, they are running 170A at rated output.

We think the motors need to be run at higher voltage to reduce current?

Of course the other issue is the propellor.

The Maytech supplied propellor is designed for a 2hp (1.4 kw) motor with top of about 5 ,000 rpm.

The issues are;

  1. To get the 8.9kW out of the motor, that propellor is now spinning at 31,000 rpm - which it was never desigen dfor and which it can’t operate efficiently. So, you can never actually get the rated output with the supplied propellor.

  2. Assuming that you did get the rated output with the prop spinning at that speed, the other issue is that even the 190kv motor and full voltage will only give you 13,000 rpm.

So, there is actually no way the motor/prop combo can deliver even a half of the power advertised.

Sooo… we designed our own propellor to increase power at lower rpm. This worked, but Maytech then blamed our propellor for burning the motor.

:scream:

Higher voltage reduces battery current for a given power but not motor phase current, this is dependant on the esc setting, rpm and motor load.

The problem with using chinese motor ”specs”for system design is that 1) they’re at best a value that the motor can take as input for a second or 2) it’s arbitrarily made out of data from three different motor kVs or voltages or 3) completely made up like this maytech figure.