Quad motor Flipsky 63100 140kV with Flipsky Dual FSESC6.9 build firmware question

Hi, I have a quad motor build with 4x Flipsky 63100 140kV motors. I was running 2x Dual Flipsky 75100 controllers running Jaykup’s 5.2 75100 firmware which worked fine except I wanted a little more current capacity (the controllers were running a bit hot while the motors were cool). So I switched to the new Flipsky Dual FSESC6.9 ESCs which on paper were perfect for my application. However the factory firmware isn’t any good, I get desynchronization and outright power cutouts at higher throttle settings even with current limited to the same numbers I set the smaller 75100 controllers to. In any case, does anyone know how I can get some decent firmware for Flipsky’s Dual FSESC6.9 ESCs? The latest build of VESC does not show any support for these ESCs which is understandable because they are pretty new. Presumably if I used the same firmware I installed on the 75100 units they would explode of something? Any help would be appreciated. Thanks in advance.



BTW the dual 75100s are going to be more powerful than the FSESC6.9. They both use TOLL mosfets with very similar specs.

75100 - HUAYI HYG015N10NS1TA - HSOF-8, 100V, 380A, 1.2 mΩ
FSESC 6.9 - Onsemi FDBL0200N100 - HSOF-8, 100V, 300A, 1.5 mΩ

But the mosfets on the 75100 are placed on top of an aluminum PCB, and the bottom of that aluminum pcb is mounted to the aluminum heatsink. Excellent thermal transfer.


The FSESC6.9 has mosfets mounted in a way that they are cooled from the top. I know this is the single, but the dual is the same thing just x2

Also check out that DRV chip. Missing the TI logo! Much legit. Very Quality.


So back to the main reason for switching… what sort of temperatures did you see in the logs? Or was this a hand test? The VESC won’t start thermal throttling until around ~74 degrees C, (165F) mosfet temp, so the hand test is not a great indicator.

Those TOLL mosfets are pretty good, and the 75100 can measure up to ~500A reliably.

The FSESC6.9, if it’s running the “HW: 60” firmware, can only measure up to 165A, and you need some buffer for the PI calculator to keep the current where it needs to be. So a max of about 110A regardless of what the mosfets can handle.


Load the unlimited firmware from my thread on the 75100s, mount it to an external heatsink, and turn up the amps to like 150A. Those mosfets should be able to handle it, the heat dissipation is there, and it can reliably measure it. Set the ABS MAX CURRENT to 225A and keep SLOW ABS set to FALSE.

Also running a 16 or 18s battery will get more power out of these controllers vs a 12s battery.

Good luck

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What are your gearing, tire size and amps settings you are running at? What battery?

Really tall gearing will also make it really sluggish off the line.

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@Dingodan in addition to what @jaykup asked, how heavy are you? Also, if the built-in heatsink for those ESCs is the only heatsink you have, are they exposed to the outside (air) or are they in a sealed space?

With 4WD you should need a lot less current per motor than a 2WD setup. As an example, I have one 4WD board with 4.37 gearing, 9" tires, and 6384 140 KV motors, and a 96-cell battery and I weigh about 63 kg. Even sustained full-throttle including up huge, steep hills, my ESCs are not drawing more than 30 motor amps and 20 battery amps per motor. In recent rides over the last few days in 20 C heat, my ESCs don’t go higher than 31C with the motors approximately 15 degrees (C) hotter.

If your ESC heatsinks are not exposed to outside airflow, I definitely recommend that you do that.

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Thanks so much for the replies everyone, wow I didn’t expect Jaykup to personally reply! Your FW is awesome BTW l, thanks so much for making it freely available. This is fantastic info and I’ll follow your instructions to the letter. When I switch back to the 75100s I’ll bump the voltage to 16s from my current 12s and that will allow me to run the power I want without excessive current. My gearing is definitely too tall and I am about 80kg but I have a different sprocket on order that will increase the gear reduction a bit. To help with reducing peak current. When I said the ESCs were getting hot, I only meant relative to the motors- they honestly never would have exceeded 50 degrees C but because I have absolutely no idea what I am doing when it comes to electronics I stupidly assumed they were a bit small for the job and the 6.9s would be better. Just so you guys know too, my build is not actually an e skateboard, it’s a quad motor 2010 specialized demo downhill mountain bike.

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Another pic:


50c is nothing to worry about on vescs, you wouldn’t see performance problems until like 75c when thermal cutoff starts kicking in

That build is pretty awesome! How’s the power on it? Have you had any problems with motors fighting each other?

. Yea I think I was worried about nothing and just cost myself money. Anyways I really struggle with ESCs, I fundamentally don’t understand them despite being a skilled and experienced mechanical engineer.

Thanks! It had enormous torque with the first gear ratio I tried, way too much really and the top speed wasn’t enough. I reduced the gear reduction by 20% and I went a little far, now the torque isn’t that great and the top speed is pushing 90km/hr which is scary as hell. So I’ll go halfway between these two points and call it good. It is still extremely powerful and pretty intimidating to ride. the motors don’t fight each other what except at really low throttle when you can feel some motors stopping and starting which feels a bit weird but it’s not a problem at all.


That’s super cool man, good on you for trying something unique. I like it!

Thanks! It definitely draws a crowd when I take it out for a spin. People are very curious about it and generally like it a lot.

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