Alien 200A 3-16S vs Seaking V3 130A vs Flier 400A

I’ve played with my Flier 200 16s software but I can’t tell which of the setting should be the freewheeling one… Got that for cable size and the hi current limit (it’s the watercooled) but now seems not that good idea…

Sorry, this theory is definitely wrong in every aspect.

Why in every aspect? The fets have a certain Rdson, cables and stuff have certain resistance to and PCBs have an amp limit. So all this resistance will produce heat with P=I^2*R. So keeping the Amps low will solve many problems.

Hi PowerGlider, please elaborate.

What is your plan, maybe i did not get it?

The motor and battery current is in most cases not controlled directly by the ESC, except the VESC and some EV controllers. So the current (at full throttle) is dependent on the battery voltage and the load of the motor and its Kv. So using a smaller ESC with less Ampere rating will only lead to a burnt ESC. Maybe it will protect itself from Overtemperature in some way, but all the burnt ESC in the RC-world and also here, show this protection is insufficient.
To reduce the motor current you can do mainly these things:

  1. Choose a prop with less pitch and/or diameter
  2. Reduce the voltage of batteries
  3. Choose a motor with less Kv
  4. Choose a higher reduction gear
  5. Reduce the applied throttle signal (Dual rate it was called in former times, you can do this in your transmitter by the settings, e.g the enertion controller allows to half the max throttle, called beginners mode)
  6. Choose a ESC which has shunts or other measurement for the motor phase current to limit it.

Every solution has its pro and cons, and most times a combination will give the best results. E.g. if you go for 6. you might additionally choose one of the others to reduce overall motor current to increase the overall efficiency.

I have done so after burning a too small motor with a well cooled YEP120A HV watercooled ESC, which failed itself when the watercooling was not working anymore. Afterwards i chose a larger motor (6374 -> 6384) which burnt my VESC because i increased the temperature limit settings without having a proper cooling.
So next step is a better cooling for VESC in combination with a smaller prop (175mm -> 140mm) and a motor with less Kv (6384 130Kv -> 6384PG 100Kv). Direct drive outrunner with direct water cooling

So the misunderstanding here is that the ESC will limit the motor phase and/or battery current. The currents specified are a rating what the ESC can withstand without damage, often limited in time and always presumed you have a very good cooling.
So typically you end up with overdimensioned ESC, motor, batteries and cables to get the performance you want, burning some of the components from time to time, especially when the conditions change. This is intended by the RC industry, so they can earn more money. It could be solved easily with a phase current limitation which is matched to the motor and battery capabilities. The VESC provides all these features, but has the drawback that the original cooling is very bad. There are better cooled and designed VESC available, but the cost to performance ratio goes through the ceiling. You can try yourself to improve the cooling by water or air.


Hi PowerGlider!

Thank you very much for clarifying. I’v only worked with “real” controllers, Sevcon, before so I took for granted that the ESC had a shunt that would limit amps.

Choosing the right components and dimensioning them all to match the ESC is key. Cooling is another crucial point. Im going to perform some surgery to my YEP120A to make sure that the FET’s are cooled in a proper manner. Heatsink AND water cooling would be ideal.

My guess is that the temp rises FAST when water is blocked and the ESC could burn in a few seconds depending on the load at the time.

In building a version of the Hiorth brothers foil so I know my amps, 70A at peak and 50-40 at cruise.

Thanks again


There is a problem with the YEP120HV WC: The cooling pipes have connection to the battery. If you have a “open” cooling circuit you make a good contact to water and if you have a single isolation failure somewhere else it hurts you, might risk your life.
So i decided for myself not to have any watercooling or anything else which connects from inside the battery/ESC housing to outside. I also want to eliminate the kill switch, because it can kill you. So there is only one connection out from this housing and thats the motor leads, IP68 protected. If there happens a single failure in the isolation there, it is easy to detect in salt water and you have to go home, make it better. I would also recommend not to use switches which have a metal housing, because if you have water ingress into the box, it might create a short between the switch housing and battery. So in the moment you touch the switch you get shocked.

I was not overly concerned with electric shocks for myself until now. Your hints are still good advise for developing the electronics. Am i missing something if I assume 12S voltages are always safe (<60V DC, in wet environment)? In Germany there are the rules for extra low voltage(„Kleinspannung“). I have had some encounters with ac and dc at 50V and you can feel it, but not really much.
:hotsprings:️However, I consider boiling water and/or molten metal shooting away from shorts as a higher danger, after seeing it with wrong settings while spot welding.
Thanks again for keeping some security advise alive, that is always appreciated.

A car battery with 12v can together with the coil and breakers produce sparks of 10 000 volts or more for the sparkplugs. The esc can produce voltage spikes that kan kill the esc itself (if you do not have enough capacitors) so it is not impossible for it to be harmful, if it is likely that is another story.

Please have a look at the new thread opened:

The electricity is and has been my main concern from battery chemical fires, to hot wires to ESC’s shorting out, to getting shocked. I touched on this is a post a couple months ago and PowerGlider has shared some great info above in the link confirming this.

On a lighter note getting shocked with AC from the motor is better than DC… DC forces your body to lockup until you die or disconnect, while AC provides the pulsing allowing us to react and let go. The good news is that if you get shocked while riding… it won’t be long before you fall and disconnect :slight_smile:


Ok, do you know if it’s a direct connection between - and the pipes? My guess is that that would be the same for the esc:s using heat sink and wc as well? Fet:s are normally connected screwed to the heat sink in which the pipes run.



The cooling pipes are grounded (there’s a link through the PCB to the negative terminal).

At last it worked!!! I powered the Flier 200A 16s (same as the Alien) and it works, cool. But, just save me quit cursing, it’s impossible to set just by the beeping and remote, definitely an absurd method. So, all pumped up by the sound of the SSS360 revving I got the Pl2303 usb to uart, disconnected everyrhing and… The usb don’t work!!! Seems a driver issue but I tried everything, any driver from 2007 to now. Nothing. Error 10 message, no way to plug ESC to computer. I ordered a different adapter… Let see next week. No answer till now from Flier

could you get your PC connection to the Flier to work? I’m asking because I’m also considering buying a Flier 200A 16S for a SSS56104/420KV motor with 12S LiPos and 5:1 gear.
I’m just no sure about cooling, I don’t like the idea of water cooling with a pump, over complicated, needs tubes down the mast. I’m thinking about putting the ESC in a separate alu box inside the board, close to the bottom and connect it to an alu plate which is part of the board, maybe even a heatsink, something like this:
Like this, the heat absorption would be quite high when accelerating (wet heat sink coming out of the water, would evaporate water which is good for cooling) and probably still OK after the board lifted (depending of the size of the heat sink and the ESC’s power loss during cruise speed).
Any thoughts?

Yes, I bought a simple USB to Uart adapter, few Euros and I managed to set plug the ESC to my computer. For watercooling I’ve a cave carbon rod all the way down the mast, very simple, flow granted by a membrane pump, feeded by step up converter 5 (UBEC, for receiver) to 10V for the pump and 2 PG7 to get silicone tube in/out of sealed ESC box. (metal box IP67) There are 2 things which scare me: pump plastic nipple eventually giving up while the pump is running and that carbon rod which cause bad galvanic with the aluminum mast. Solvables, both.

Flier ESC seems ok, I added 2 low ERS capacitors in parallel to the battery cables, 5cm before the ESC, 270uF 100V, from Panasonic, because 4 battery harnesses, serial-parallel, antispark switch, from main box to ESC box… my cables seemed too long! Never tried under load yet… it still too cold, I’d very rare chances to go lay epoxy in the last months, unfortunately I miss a warm lab.
Heat sink works fine for many guys here, so it should work.

Got the Flier ESC (240A, 22S Air Version with Boat SW). PC connection with provided USB2Serial adapter works. MaB, what timing angle do you use with your Flier ESC? My motor is quite close to yours, it’s a 6 pole 420kv SSS56104.

I’ve the boat version, I left 0 degrees of timing, linear soft accelleration, no reverse, Set point automatic and for now automatic starting power, I want to try with propeller a fixed value at which the motor starts, the lowest possible, to avoid that surge when the motor ignites from zero rmp. My motor should be 10 pole (360kw, 56114).

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Hey guys, just received my Flier 200A 16S (car version), but when i connect it, it bips ten times every 10 seconds and nothing happens…any suggestion?
I tried same configuration with Maytech ESC and works like a charm…