Airplane/Heli 12S ESC for ESK8 - Success

This is going to be a fairly short write up as this is still in testing phases.

My first build has yet to come to life, as I’m waiting for parts to arrive. I luckily live about 30min from the US West distribution center for Hobby King. I was able to go pickup basically all of my electronics. I took a risk ordering some components I wasn’t sure were going to work together properly for ESK8. In the mean time, I decided to get soldering and test a bit.

I’ve seen the idea kicked around about using boat ESCs in ESK8 setups. It seems as though a few guys on YouTube have had some success. They’re a cheap solution for 6S capability, most have proper inputs for throttle, brake, and reverse, therefor ready to be used with a car TX/RX. Now, 6S is pretty meh, and for a few bucks more you can get a 6S car ESC such as the FVT, that’s been proven to be a budget ESC solution for ESK8 usage.

Most of us want more than 6S. Only and handful of options are out there to safely and reliably power ESK8’s with 8, 10, and 12S battery setups. VESC is known to be the “BEST” solution out there, but unfortunately has gained a somewhat bad reputation of frying due to user error. It’s a fantastic system built from the ground up with ESK8 in mind, however in not necessarily a plug-in-play solution. Not only this, but it comes with a pretty hefty price tag as well. Other companies such as Torque Boards, Alien Power Systems, etc… Have developed up to 12S capable car style ESCs. However, again come with a nice price tag.

I personally wanted to truly build a budget board, with at least 8S capability, and the safety and reliability of at least a car ESC. With a heavy background in competitive surface RC, short course, buggy, truck, you name it, I decided I could probably make a plane/heli ESC fit the bill. They’re spec’d well. VERY well. A HV (5S-12S) air ESC will run you in the range of $80-120.

I went with this, Turnigy K-Force 120a OPTO ESC: http://www.hobbyking.com/hobbyking/store/__38782__TURNIGY_K_Force_120A_HV_OPTO_V2_5_12S_Brushless_ESC.html?strSearch=k-force

Notice how similar this ESC looks to Torque Boards 12S ESC. The description in fact is almost identical. I suspect they share the same OEM, however TB has reflashed the ESC possibly? I digress.

I got the ESC all wired up, a BEC was needed as the ESC does not have one. First test, turn everything on, motor starts spinning up to what seems to be half throttle. This was the problem I was expecting. The ESCs end-points out of the box for planes and helis, are drastically far off from a surface TX. Not only this, but these ESC’s also do not have input for braking from the transmitter. It does offer a programable “brake” which is basically a drag brake, ranging from soft, normal, to hard.

A surface radio’s “bottom throttle point” is in the middle where the trigger rests, “top throttle point” is fully depressed toward the grip, and “brake/reverse point” is forward with the trigger. With no brake reverse endpoint to be set in the ESC, I had to crack into the radio housing to change the throw of the trigger assembly.

I already repositioned the spring prior to this photo, it was originally connected vertically behind the trigger just in front of that phillips head screw. Above the keyed shaft the trigger slides onto is a retaining bumper. This piece allows the trigger to sit neutral in the middle, and have resistance when the trigger is moved backwards or forwards. Removing this bumper allowed the trigger free range of movement. A reposition of the spring, and we now have a linear throttle throw from top to bottom.

Power on the ESC and rescale the throttle top and bottom endpoints, and boom. We have a perfectly functioning high voltage ESC, aside from a proper trigger actuated brake. I will be doing testing to see how the drag break performs, or somehow find a way to potentially reflash the firmware and add a brake/reverse input.

Overall, success. 12S capability for $120, no complicated programming setup or risk for toasting the board like a VESC. THIS IS NOT A VESC ALTERNATIVE. It still does not have the features VESC offers especially for ESK8, but hey its cheap and simple.

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Seems like a lot of trouble to save $25. And the Torqueboards esc has proper brakes

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In my case, the $35 savings was worth it. ($10 shipping), also I got it faster than next day shipping (my benefit I realize). The moral of this story is however, there are options out there for 12s for well below what I paid. Only reason I went with this particular one was it was all the US West warehouse had in stock. Plenty for $100< that will function exactly like what I’ve found.

And don’t forget…for science :nerd_face:

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MY GOD WE’VE DONE IT!!!:tired_face:

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I think it’s fortunate for you that they were out of the cheaper ones because it’s very doubtful that they would hold up under the high current demands of esk8. I just sincerely hope that you don’t find yourself in a situation where you end up wishing you had spent the extra $35 for brakes.

Who knows! I’m not horribly worried about the brakes, I’m almost positive the drag break system will work fine. Also this was more or less purposed to be a temp ESC while I wait for my damn Enertion VESC. Yes I know… Should’ve got one from Chaka. Oh well.

Well, once you’ve tried the Vesc you are gonna be spoiled! When it does arrive and before you power it up, open the shrink wrap and lift the red power wire and trim the pins sticking through the pcb from the socket on the top side. People have had there vescs blow from the wire shorting on those pins. Then power up with a 3s Lipo or 12v battery or power supply and update the firmware to fix a current ramp bug. Then use the low power to do initial settings and motor detection. And you should have no problems.

I’m going to put down some solid miles with this ESC to get a feel for it, the switch to the VESC. See how much difference I can feel! It will then either become a spare, or I’ll move it on to someone for cheap. I appreciate the tips there, I’ll make sure to do those. Luckily I have a few 3S packs lying around, perfect for testing.

Drag brake sucks… That means you can’t coast lol.

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Trust me, the difference between the Vesc and other Esc’s is beyond huge. Like night and day.

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Damn true. Well I’ll have to see if I can crack the firmware and develop something to implement a break. Also quick note, my order of the mount kit is on hold with you guys? WAZ GOIN ON :sweat:

I have done the same after buying hifei160A-KII-12S esc, but eventually it sucks. The drag brake was frying the esc, so I had to turn it off. Without brakes it’s too dangerous so I’ve ordered vesc this week.

i’m in the process of flashing the firmware to basically make the ESC behave like a car ESC. Proper brakes and all. Hopefully within the next few days I can get it dialed. Need a USB adapter which I’m picking up tomorrow morning from the hobbyking warehouse.

I’ve got about 5k miles on K-force 120A’s. I hope you get that firmware working, it’s a really solid esc and deserves more options. The drag brake isn’t bad at all, and doesn’t actually kick in until the throttle is back to bottom, so you can let off the trigger almost all the way and coast down to 1% throttle. I can’t find your kv, but I can tell you that the drag brake is useless if you are geared too low.

Nice work with the gt2b, I think I’m going to try that.

@rmkao I admire your ingenuity; but agree with @Namasaki that usable brakes are a very essential feature on an esk8. Please be really careful when you test out this build. Wear all the protective gear you’ve got and stay out of traffic. We want you intact so we can see your progress!

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You’re late to the party

This build is going to be utilizing a 245kv SK3, Geared 16/36, 8S. It’s a fast setup, not a lot of torque, but I’m an extremely light rider and no big hills in my area. I’ll do extensive testing prior to taking it to the streets to ensure safety.

I’ll keep you all updated on the firmware, and do a write-up when I nail something down.

Whatttttt :sweat: Dang I was just trying hang with the cool kids

haha but im happy you found success!