FlipSky Dual FSESC4.20 Info/Review

Oddly my 4.2 duel wont run sensored BLDC on one side but runs sensored FOC (on the bench) fine. In BLDC it just cogs up the motor and hits maxabs. Runs fine in sensorless BLDC too.

That’s right, FOC. No cutouts thus far for me… Oh yes sensorless…

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I already have one Torqueboards Vesc, should l get another TB Vesc for dual or just grab a dual 4.2? I have a 10s setup

I think the general consensus is that the 4.2 isn’t as good as the 4.12 due to limited ability to deal with high amp draw

So its an issue with the hardware version? All 4.12 vsec layouts have less issues than say all 4.20 vsec layouts?

Just re-read the FAQ.


I had cutouts at 40 motor amps per side but at 38 motor amps per side i get no more cut outs (tested by increments from 30 amps up).

I am running 9s in FOC sensorless. 2x 260kv motor with 12/40 pulleys and 83mm wheels.

Current setup is motor: 38, -30 battery: 38, -8. The brakes are good enough to come to a complete stop going down a pretty steep hill.

I haven’t tried BLDC mode yet. I may have to, if people are having more luck with it as I need more power to get up hills as with full riding gear I am 240 pounds.

@ervinelin are you running BLDC or FOC? Have you gone full throttle as that is when I got my cut outs. It was never just cruising around. It was when I asked for as much as possible from the ESC.

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FOC… But no I have never gone full throttle yet… Again my testing has been more cruising… But people seem to have cutouts even at lower throttles?

guys. is FOC able to give smooth roll off from stationary on sensorless motors?

Unfortunately no, there will be some cogging still. Not as bad as BLDC however.


Just to make sure, you have 38 bat max on each esc or total (19+19)?

Does anyone know if Flipsky is trying to right this clearly incorrectly advertised product? I understand it’s an inexpensive alternative to the 6.6 and the Unity - But it’s being advertised as something that it’s not.

Has anyone messed with upgrading the caps to see if it resolves some of the cut-off issues?

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It’s not incorrectly advertised, it definitely supports up to 50a per motor (battery amps).

I really dont get why so many people are down on this. Its literally the cheapest dual VESC available, yet people expect it work like a FocBox. If you want FocBox performance, then buy a FoxBox.


It seems wrongly advertised to me with the up to 60v compatibility while simultaneously stating 50a continuous. I’m not saying I expect it to be a Focbox or Flipsky 6.6, but it seems this box doesn’t like to run much above 38a at 9-10s.

I’m just saying I think they should change their claimed specs, leave the price.

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The caps on this 4.20 are the same as their single 6.6. People have been saying good things about the 6.6. Their single 4.12 is good too. So not sure what they changed to make this dual 4.20…


Yep. all settings are for each motor.


The caps are very different.

6x 220uF on the 4.2 and 6x 470uF on the 6.6.

The single 4.12 has 3x 680uF so has more than the total of the dual 4.2 on a single.

I should clarify that I have added 4x 470uF capacitors close to the FSESC as the negative battery cable is quite lengthy in my setup. runs nearly the completed length of the wheel base.

I have not tested whether the board acts differently with less capacitors at 38 amps.


My experience is that BLDC needs a push to start but FOC stutters slightly and then starts moving.

But I am 240 pounds and when my brother who is closer to 180 pounds rode the board with my old setup of a single 4.12 in BLDC he was able to get the board moving from a complete stand still with no cogging at all.

so weight is a huge factor.

I know adding sensors will make it a hell of a lot smoother but have not had a chance to use sensored motors as yet. although I have 2 here waiting on my next build.

I’m talking about this:

Continuing the discussion from Flipsky 4.20 DRV8302 error, but still working?:

i didn’t realise the single one only had the 220uF capacitors.