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Requesting eMTB Riding Logs | Direct Drive Development

Hi everyone.

As I said a few times in the past, my final paper to finish my engineering degree is the development and construction of a direct drive motor for mountain boards.

Now that I’m on the sizing part itself, I would like to kindly ask for those who ride one to share some logs, they will be used to determine performance requirements of the motors.

Unfortunately I don’t have the statistics background of @bevilacqua to do a similar study as the really good one he did a while ago, so the analysis will be mostly manual to get the overall picture.

So I would ask for two logs:

  • One for a ride that you describe as the average ride you do
  • One that is a ride where you pushed your board to limits

Also please copy and fill these specs for your board, if you don’t have the motor resistance at hand, no problem, you can leave it blank:

  • Motor size:
  • Motor Kv:
  • Number of motors:
  • Wheel size:
  • Motor pulley size:
  • Wheel pulley size:
  • Motor resistance shown on the detection:

Thanks everyone for the help, and I hope some cool for the community comes out of this

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Just to be clear, your only interested in direct drive mtb logs correct?

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No no, any setup, but I imagine there is hardly any direct drive eMTB, I want to see how people ride, in this case mostly with geared setup, so the direct drive in development can match all the performance metrics, specially consumption, looking at you Raptor 2 Hubs

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Ah yeah pulley sizes should have given that away duh. I don’t have a metr or ack to send full logs but wish you the best in your scholarly and personal pursuits.

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Thanks a lot, it’s been hard to learn everything, specially since most of it is completely out of the scope of my degree, but oh boy, it paid off so far

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Looked up my old logs I still have saved but I do not remember which board and which gearing i used at which log :see_no_evil:
Till which time you are collecting log files?

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I will soon (1 month tops) have a MBS mtb with gear drives, I will be glad to share some rides info. I’m not planning on having a Metr thou, are Vesc Logs OK?

I would love to collect logs like this for my capstone as well, so if anyone has other logs (from both emtb and urethane boards), feel free to send them my way :slightly_smiling_face:

(Preferably PM, I don’t want to threadjack :P )

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Do you care about the (file) format?

@Andy87 no time frame defined, but I wanted to have at leats most of the work done by the start of March, if you manage to gather some new ones I would be glad

I also want to finish mine to ride a lot a gather a lot of data, but I’m more of a chill rider, so if I do based solely on my rides it would probably under perform for the speed demons out there

@Not2tall4esk8 Yeah, no problem, thanks a lot

@Sn4Pz I think @bevilacqua must have all the logs that was sent to him, you could ask if you can have them

@Benjo Anything goes, as long as I can open it and play with you are good

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I‘m in front of a long vacation that’s why I asked. If I can get done rides in after my vacation I will send you two for sure.

@BillGordon maybe we can pin this thread to the top for a bit so that @Pedrodemio get some more attention and enough log files for his study? There so much people with metr modules out there. Shouldn’t be too hard to get two recordings done and send it over :stuck_out_tongue_winking_eye:

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Ok, I will record logs with a custom app when I have my board running again in the next 1-2 weeks. All I can offer is basic stuff like phase and battery current, dc voltage, rpm and esc temp as CSV.

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Yup. I’ll give it a week pin.

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Wow, thanks a lot guys :grinning:

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That’s great! Thx @BillGordon

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For those curious, this is all the parameters needed to describe the motor constant in a motor, the holy grail of the parameters, the one that matters and no motor manufacturer put in the specs

There is still some work to be done for a estimation of iron losses

Then it’s a matter of implementing all in a spread sheet, determining what motor configuration can produce a comparable performance as a geared setup, and further optimization using FEA for both mechanical and thermal simulations

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Very nice diagram Pedro!, I’ll take a closer look in 1-2 days (MA thesis is due in 2 days).

Quite a fascinating project !!

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Thanks Mathias, please do since you have significant knowledge