Carbon Props Experiment

I have sent an inquiry to Hobbywing about the Serial definition for their various firmware versions.

In the meantime, here is something that could be the answer: when parsing the telemetry data you check that FIRMWARE version is 3. If not, you don’t parse the data!

(line 36) eppg-hub/Src/escTelemetry.c at a97b0ff25535728922b90a92818bf0800b22eda2 · openppg/eppg-hub · GitHub

Right. Thats defined here

Thats the version that all of our ESCs come with so hopefully Hobbywing can give you more info on whats on your ESC

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Zach, I downloaded the source code of HUB version 1.1 and Atollic True Studio.

I can build HUB,BIN with the Debug configuration, but the Release configuration is missing from the source pack (when I go to configuration settings, I get: Orphaned configuration. No base extension cfg exists for com.atollic.truestudio.exe.release.1518366166).

I managed to compile after adding some missing includes, but there are other build steps missing to produce the BIN file, which I don’t really understand.

Would mind sending me a copy of this missing config file?

We havent been building in release mode for consistency so debug mode is what youll want to stick with. That still builds the bin file.
You can also bypass that file flashing method by connecting directly to the hub like explained here GitHub - openppg/eppg-hub: Firmware for OpenPPG hub

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Ok, then I assume that my HUB.bin should be fine. Once I manage to get the controller updated, I will try to figure out how to read telemetry data from my 100A ESCs.

Just a quick update: I have gone through 20 flights and only encountered a problem once.

It was a very windy day, at the sea-side, so I had to take-off and climb at 100% power. After 3 minutes, all 4 ESCs shutdown (either because of overheating, or reaching the 350A limit, not sure). As I was over the water with only 80m of altitude, I had to quickly turn down-wind and crash land in some bushes near the take-off site. A few scratches, but no injury or damage to the PPG.

My experience so far is therefore quite positive. It is a pleasure to fly with props that are durable, and produce a slightly lower pitch noise. I would definetely recommend this Carbon Prop + 100A Esc upgrade to people who fly their unit regularly (VERY IMPORTANT: Read my comments about CNC machining slots).

Ultimately, it would be VERY nice if the HUB became a bit smarter as to how it controls the ESCs, in order to avoid them shutting down (i.e: monitor the temperature and current limit). But right now, the HUB cannot talk to the 100A ESCs because of incompatible firmware, and I have not been able to fix this issue myself.

@8bit-Dude where did you buy the props from?

and is it not a problem, that the CW props have a different shape than the CCW ones?
you can clearly see the difference in your first picture.

Assuming the ESC can talk to the hub what would you expect to happen in the overheating scenario?
Limit the throttle to 50% when the temperature gets to a certain threshold? I assume it would notify the controller of the warning before any action was taken.

I bought them from Iris Engel, for 43.25 Euros each (he gave me a discount for buying four). The different shapes cause no problem whatsover (it should be noted that the slot needs to be 2mm deeper for the thicker props).

Zach, yes, that what I had in mind too. A warning sound (or vibration) when the temperature or current reaches as certain threshold would help the user know that he is nearing trouble.
Then have a second threshold at which throttle limit is applied. But I think that 50% is too drastic though. Perhaps 70-80% would suffice?

Was curious, @8bit-Dude , if your choice of prop was within reasonable limits for tip speed at maximum RPM, so I just grabbed the first hit that came up for prop tip-speed calculator. Depending on chemistry, a fully charged “48V” battery should be in the neighborhood of 55 Volt.

180 KV Motor w/ 22in prop
48 Volt - 8640 RPM, ~0.74 Mach
55 Volt - 9900 RPM, ~0.85 Mach

While that site gives a generous 0.88 Mach maximum, most everywhere else I’ve seen 0.80 Mach as the number to go for. At maximum charge and under load the 22 inch prop is surely under.

I do wonder what RPM your props are actually running though and if you’ve fallen down the efficiency curve. The diagram below (if it loads) is a little backward in my mind since full-speed, unladen, is to the left and over-laden, 0 RPM and stalled is to the right.

BLDC_Motor

“This is as well the reason the ESC’s have capacitors - this on/off switching leads to voltage spikes and the capacitors are there to smooth this out! With longer battery wires there could be voltage spikes of 4-10 volts. More capacitors will smooth this out. BTW most voltage spikes are at half throttle ( more on/off)”

“Ripple Current” - This can be a problem in electric bicycles as well. Hit the wrong mix of cables being too long from the battery to the controller, partial throttle and load, and pfffffffffft - let the magic smoke out of the controller.

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How are these working out for you?

Still working very good. Since the 100A ESC / Carbon props upgrade, I have flown ~30 times.
Not a single chip on the blades, life has got much sweeter than with the wood props!
(P.S: the ESC shutdown occured twice in all that time, but installing an emergy reset button on the power line makes it a non-event)

Were you able to get the voltage readout on the throttle? Which bottom did you use. I just destroyed my props and mesh so I’m doing this now that I’m rebuilding.

Unfortunately no. I sent an email to manufacturer to ask about firmware, but they never replied.
Instead, I am using a simple Digital Multimeter connected in parallel to the power input of Hub.

Note: What do you mean by “bottom”?

I meant to say button.

I had a shutdown on my batch 4 today, luckily I was right over the lz and had an event free landing , can I request you for more information on the power reset button and how you installed it? Since I was low I didn’t have a chance to fumble with the main switch and I would love to have a quick reset option like you seem to have . Detailed description and some pictures would be awesome if possible
Thank you

If it helps any one, I’d been flying for about 15 minutes or so and had been on a steady 85/90 amps for a few minutes when the motors shut down