FOC vs BLDC Debate

It is time to get down to business with this never ending debate. We need to be myth busters and use real life testing to make a pros vs cons list of both FOC and BLDC. I want to know, why do YOU use FOC or BLDC? Why do you use this vs the other? Why should I (or anyone else) use it?

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some people have been saying FOC is more efficient as well. have you tested this?

when is safe to use FOC i also heard that they are not as realiable or safe for your vesc as BLDC, my set up is 12s 6374 149kv

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I can’t tell any real difference in range after a few hundred miles.

FOC does take a couple MPH off the top speed.

Perhaps FOC riders should gear a touch higher to compensate.

I am enjoying 2.25 gearing 16/36 97mm wheels. Rider weight #145

@link5505 I’ll offer a non-scientific entry; I like the way that FOC sounds and feels, so that’s why I use it. I find that I have much better low-speed performance, and I end up in a lot of low-speed scenarios during my commutes. The quiet operation is more practical for me considering the suburban environment I ride in.

I’m aware that I may lose a few mph at the top end, but that makes no difference to me, the top speed of my build is already faster than I care to ride so I limit it using ERPM. I top out at 22mph and average 12-15mph on my 6-mile rides, which is perfect for me.

I have plenty of torque in FOC mode; I can climb all the hills in my area. I don’t feel like I’ve lost much by using FOC, and I gain smoother starts, silent operation, and overall smooth acceleration that I prefer.

The loss mainly comes in readily-accessible options in BLDC Tool. Since BLDC Mode came first, it has a lot of easily accessible features like “startup boost” and ERPM settings. There aren’t a lot of features to try in FOC mode; you essentially do the motor configurations and that’s pretty much it.

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whos VESC are you using? have you had any issues VESC related in FOC?

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@link5505 I started with a VESC from Enertion with a C18 mod but after about 140 miles I blew the DRV8302 chip. I think it failed because two motor leads made contact.

I’m now using an Ollinboard VESC while I replace the DRV chip in my original.

Build is here: http://www.electric-skateboard.builders/t/the-village-build-s9-faultine-paris-195mm-sk3-6764-diyes-mount-8s-vesc-127mm-pneumatic-wheels/292

Post about DRV failure here:

I use FOC because it’s mad quiet.

I live in a quiet town and I ride at 9 or 10 at night. BLDC would not fly in my hood.

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I’ve been sticking with BLDC on my old 4.7/4.8 VESCs. I have a 4.12 i got used w/ dead DRV. After repair i might try FOC on it.

What i remember reading on FOC was a sacrifice for top speed - slightly more efficient, and better low end torque. Can anyone who’s gone FOC confirm?

I could care less about top speed (reasonably - i gear for about 25 and rarely go full speed). But startup and off-the-line acceleration is much more important. I usually gear pretty low 13 or 14 / 36 on 8s and 83/97mm wheels. 190-200kv motors.

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do you have any good videos that show the FOC noise?

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@devin lmfao… FOC sounds like a lawn mower… :stuck_out_tongue_closed_eyes:

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Man BLDC looks scary fast. :scream::scream::scream:

I didn’t have any videos so I took one tonight. It’s certainly not a good video but hopefully you get some sense for how quiet FOC runs.

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wow that is crazy! I will definitely be trying out FOC whenever I get my VESC.

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