vesc field weakening

Who here doesn’t want to go a bit faster lol


Most here hold reliability in high regard.
Field weakening is still too mysterious/risky

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The onewheel guys who do vesc conversions run field weakening and don’t seem to have any issues with it.

I’ve run it quite a bit too

Functionally the biggest drawback is heat and less range. If you are locked into a hub motor it can make sense, otherwise you are better off changing gear ratios, tire sizes, kv or battery voltage to get additional top speed.

One thing to consider is that if the vesc faults or loses power while in field weakening, the voltage at the motor goes back to RPM/kv which may exceed the mosfet rating. Probably best to use a 20s esc for 12s for example, or use erpm limits to make sure it cannot exceed the 60v mosfets most 12s controllers have


Not a single mention in this thread or the older one on the same topic, on any hardware requirements for Field weakening.

One could assume that a vesc 6 with 3 phase shunts would be safer running FW than like a Focbox 1.7 but no guidelines seem to be around.

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I went from 72t to 66t and didn’t gain any top speed at all, any idea why that happened? I thought it would pick it a bit of top speed, not much but none at all?

How are you measuring your speed?

GPS app on my phone. I was doing it with my remote at first but I couldn’t belive I was going the same top speed with the 66t as before with the 72t so I downloaded the GPS app on my phone and that confirmed that the speedometer on the remote is pretty accurate.

What speed do u get to? Maybe you need to increase ur battery amps to overcome the increased wind resistance

Probably not enough torque to go that speed, need more amps, like @hummieee said

I can feel it stop pulling when it get to top speed, if i back off the throttle a bit I can feel it pull again. Why is that?

No idea.

I just started using it yesterday. I set it to 20 amps and gained 8mph.


You gained 8mph with FW?
My top speed now is a little over 28mph with the 66t, I’m going to have to bypass the BMS discharge to bump up the battery amps. Or should I just try FW the way it is?

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I don’t know. I don’t have any data and don’t know what current is passing. Using FW takes amps. The setting is simple an amp setting.

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Vedder shows how he looks at amps with and without Field weakening here

Wonder how this video was missing from this thread so far huh


I should be watching all his videos to learn what I should be doing


None I’ve seen. Anyone?

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Been using field weakening for several years on my DIY HummerBoard. It’s very usefull on hoverboard hub motor. Don’t know if the benefits on more « traditionnal » esk8 hardware is worth it, but on my Hummerboard I get extra speed (at the cost of amps), enabling it to reach 45km/h to 50km/h, instead of 35km/h on 12s lipos.
I’ve reprogrammed/flashed 2 hoverboard motherboards to power and control this beast.

MakingOf: HummerBoard MakingOf

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So you aren’t using vesc hardware?

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