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BLHeli S

BLHeli S is a new multirotor ESC Firmware available that is “an improved version of the base BLHeli code”.

This firmware claims to provide a host of improvements over the stock BLHeli.

  • BLHeli_S will have the same good Sync holding properties as base BLHeli. Maybe even better.
  • BLHeli_S generally does Startup better than base BLHeli.
  • BLHeli_S does damped light. Only.
  • BLHeli_S has motor PWM that is Synchronous to the MCU master clock, as it is generated by hardware. This makes the motor Silent.
  • BLHeli_S has very Small throttle Steps. The resolution varies between hardware configurations (MCU clock speed and driver type), and is between a nominal 512 steps and 2048 steps.
  • BLHeli_S supports very high motor Speeds. A BB1 MCU will support 350k erpm, and the limit of the BB2 is not yet known, so the code is set to limit at 500k erpm.
  • BLHeli_S supports regular 1-2ms input signal, as well as Oneshot125, Oneshot42 and Multishot. Autodetected when the ESC sees an input signal.

We at definitely excited by the possibility of this firmware, as it seems to be following similar design principles as the design of the legendary KISS ESCs.

However as with everything there are a few drawbacks, firstly only a few ESCs can currently support them. The ones we found that could support them are the MassiveRC/Aikon SEFM 30A.  In addition this firmware is very much still in Beta, so there still may be issues with the performance, but judging from the way Borisb flew them this week the performance worries my not be warranted.

There have been some Thrust test released by Electric_hertz’s on RCGroups.

Thanks to BuddyRC I was able to get my hands on a set of the new AIKON ESC’s last week. Ran them up on the test stand. I used the new Emax 2205 2300KV motors as it seems to be the popular motor right now. I used the ZTW Pro HV 2S-6S ESC for comparison since it proved to be the top of the chart. I tested using 3 different props (Gemfan 5×4.5BN, Dal 5×4.5x3BN, and HQ 5x4x3). The included chart shows an overview of the test using both 3S (12.6V) and 4S (16.8V).
I was expecting bigger numbers in thrust and efficiency than it produced, however they still threw out big numbers even though they were only equal to the ZTW. The biggest thing I noticed was the vibration on the AiKON was half of ZTW. Also noted was the response on X,Y,Z axis was much faster than the ZTW. Just listening to the motor run up on the stand seemed smoother and quieter.

I will have to admit that after the bench test I didn’t think these ESC’s would perform  differently than others considering the thrust/ Eff were not any better than the comparable ESC. I will have to eat my words on this one. In flight I could not see any difference in overall thrust big or small over the other ESC’s, but there was no lack of power. Where I could really see a difference was in stick response. Active braking (Damped Light) function seemed much smother and gave me a little better control of the motors while trying to get the correct altitude through the gates. These ESC’s flew great. It was more responsive, and I think I could probable get some more response if I tuned on the PID’s a little longer. To be this high on the chart as far as performance is very impressive especially for this being the first couple of ESC’s every produced by AIKON. The thing that impressed me most about the esc ‘s how quiet, smooth, and responsive the motors felt compared to the ZTW esc’s.

3S Chart

3S stats

4S chart

4S stats

Big thank you to Electric_hertz for this work, we lookforward to getting our hands on some BLHeli-S ESCs our selves.


  1. WARNING: There are reports of people having death roll issues when using both the Emax and Aikon BLHeli ESCs. However these are limited to a very small proportion of users. As of 2/6/16 there is no fix.
  2. DYS are releasing some new BLHeli_s escs on the 25th June. We will be getting a sample to review however so watch this space for our thoughts on it.
  3. There are some reports of a certain VReg chip on the BLHELI_s escs causing issues. It is understood that the “The bad chips were present in some pre-production samples and all first-batch production units should have been filtered out, but if you want peace of mind, you can verify via the images above.” Thanks to MassiveRC on RCGroups for this info.

We are still hugely excited by the potential these ESCs have, and cannot wait to see the performance they bring to the table.

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