FlipSky Dual FSESC4.20 Info/Review

This is my review of the FlipSky Dual FSESC4.20 100A. This dual ESC is the same price as many other single VESC’s, it’s definitely a value. I am so surprised at how well this ESC performed. Your not going to build a racing board with it, but for a mid-range ESC it performs above average.

Before I get into performance, which can vary based on the gear used on abuild I want to list the gear that I used.

Moonshine Hooch 38in Deck
97mm ABEC Flywheels
x2 170kv BLDC Motors
11/36 Gearing
10s4p Samsung 30q Battery Pack

I got speeds as high as 27 mph, which is as fast as the gearing allows on this build. It took some experimenting to find the “sweet spot” in the config to get the most speed & torque while conserving the hardware and battery life. This is the configuration options I ended up using.

Motor Current Max : 30A
Motor Current Max Brake : -30a
Battery Current Max : 50A
Battery Current Max Regen : -40A
Absolute Maximum Current : 120A

I did FOC detection in the beginning, just to make sure it would work, and it did. I then went back to BLDC as I wanted to get a feel for the ESC’s operation without losing the sound of the motors to get a better feel for performance.

I have put around 100 miles on this ESC, done much experimentation and its still running strong. I am about to rebuild this whole board using a different gearing setup and larger wheels to see if I can break 30 mph, I feel confident.

That being said, I did have some issues. I initially tried to run the Dual FSESC on 12s power, that didn’t work. I experienced intermittent cutouts and reboots. Once I moved to 10s power and found the sweet spot mor motor amps (30a) I have had no more cutouts.

My recommendation for the FlipSky Dual FSESC4.20 100A is this…

Get one, build a board and see how well it performs…you will be a believer. As long as you stay within the config specs and aren’t building a racing board you will be glad you saved the money.





those settings are for each side correct? how come you set the batt max higher than the motor Max? (edit: forgot to say good to hear, a mate just bought one @danieloath)


Good news @J0ker3366 Thanks for the review mmaner. Was getting worried the 4.2 was a complete flop


Contrary to your findings I had quite a lot of trouble with this little esc. Differences in our set up could be the reason.

Dual 170kv 6355. 10s5p 30Q. 190lb when loaded. 107mm wheels and 16/40 gearing.

I used your settings and went up and down a few notches to see if there was a sweet spot for me. Unfortunately the cut outs were rampant and the power delivery on my wheels and gearing was pretty poor.

I’ve benched this esc for now and will pop it into a flat ground small motor commuter on 8s some time in the future.

With all that said… I appear to be in the minority of people having trouble on 10s. Perhaps I have a faulty esc? I’m talking to flipsky now about that possibility. Customer service is a challenge.


I was wondering when I would see this review here, it was uploaded to the flipsky website first :stuck_out_tongue:

I’ve ordered one of these for my 10s4p battery, cause of the good reviews on this site about flipsky fsesc’s . I hope I get a good one.

Yes, both sides. It’s not uncommon to use higher battery amps than motor amps, sometimes makes for a smoother ramp up on lighter gearing.


I wanted to give them the opportunity to see it before I posted it, just trying to be respectful . FlipSky had been great about communication. Sone manufacturer’s aren’t so I wanted to reward that.


Thanks for the review! Now are you running on FOC or BLDC?

That’s pretty aggressive gearing, nothing wrong with that it just might be too much for a mid-range VESC.

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Ok he has less Torque, but as long as he has more conservative setting shouldn’t it be ok for the vesc to handle it?

I would think so, but without actually doing it I could say. New product, new issues, new solutions.

Gotcha. Thanks for the review! Can’t wait for this thing to arrive.

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IMHO, This ESC reminds me of overtightening soft bushings on say cheap trucks, They stop the wobbles but just go 4 km/h faster and you have the same issue.

Focboxes run at 13s fine and that’s over the rated spec of it But this dual 4.2 ESC is rated for 12s 100a (50x2) and it has cutouts on 10s 70a (35x2)!

Would you let your wife and or kids go on a board running that esc?

I am running one of these.

FOC, 10S, 15/67, 6" pneumatics, 6355 190kvs

I have not stress tested it much yet but so far it has worked fine for me. YMMV


Dude, this is half the price of 2 FocBox’s, do you expect foxbox performance?

If I built it yes, if you built it no.


its the perfect commuter esc, cheap and reliable on conservative settings. maybe if they rework their design in the next batches.

No, But the thing is that the focbox is rated at 12s and has headroom for safety reasons.

But here you have an esc that’s Rated for 12s 100a and has all kinds of faults at that point, So you go down to 10s still having faults and then try to find that sweet spot with no glitches that could cause a crash and end your life in some situations.

And at 30a you are like 95% to the point to where failures are totally known and to be predicted.

Bottom line if the components are rated for 12s and it doesn’t work with 12s then it’s Faulty and should be considered unsafe.

Do you get cutouts? I’m running 5055 270kv with 13/35 gearing and FOC still give me cutouts. 10s battery btw.

Isn’t 270kv kinda high for 10s?

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Thats where you went wrong bud. You expected. When you expect something, you’re always going to be let down. Think of it like this. We are DIY’ers. We love taking things that aren’t up to par and finding that @ different variables they can be par. We build board after board cause we love this ho (Hahaha you though I was going to say it.). We love it though. We love tinckering with things. Yes you can go buy a focbox and never have a concern about it cutting out or what have you. Then again thats what consumers do. But me, a diy’er, I love that I bought a 4.20 and it may not be reliable @ 10s. No worries, I’ll build an 8s that will eat pretty much any 10s prebuilt its next to. Its called science and WE LOVE IT!