Beginner Question Thread! 2023 Edition

Today is the day. First test run of my board!

This is what I’m thinking for the VESC settings. Everything looks good?

2 Likes

I’d personally raise the battery regen, I have a feeling -5A will be too weak.

4 Likes

I’d start with -20A regen

1 Like

Yeah, never personally go below -15.

1 Like

Lower high speed braking to -15A, I would not go above that

1 Like

Voltage cutoff looks too low. Great way to junk your new battery.

2 Likes

I have a 205 kv motor set to 90 motor amps and at stall I can very easily hold the can still with my hand. That feel like a very small amount of torque to me. Is that normal?

It may be normal at zero speed, yes. At more than zero speed, you may not be able to stop it. Output power crashes as speed approaches zero.

3 Likes

I personally recommend not trying :sweat_smile: that shit burns

2 Likes

Try openloop at 25A, it may be a different story

I just redid the FOC motors setup. Still 0 under “Motor Lq-Lq”. Should I be concerned?

Thank you all for the feedback! Regen current lowered (edit) to -15 (3C?)

I was under the impression to NEVER go above 1C when charging a lipo. (In this case, that would be -5A for my 5000mAh lipo) This is outside my depth so I’ll trust you guys :slight_smile:

-15 is lower than -5

2 Likes

That’s generally the case when you’re actually charging it continuously, but when you’re braking the regen current only goes up very briefly before dropping as you slow down, so it’s not going to heat up the batteries much if at all. Plus being able to actually slow down is more important than whatever small degradation the battery will get from these bursts.

3 Likes

Anyone have moon eros hubs and mounted mbs pulleys on them? They seem to need m3 screws.

Does anyone know the length?

Can someone explain Current in vs Motor Current? Does the VESC act as a voltage regulator, lowering input voltage and increasing amps?


Looks like the Motor Curent is double the input current from the battery. Which one should I use for VESC limits? Ex: Xenith has 80A continous for each motor, is that the Current in (from battery) or Motor Current. Name implies I should go with the Motor Current, which is higher, but I want to be sure.

You can set your motor current much higher than your battery current as the controller and the motors interact differently than the battery and the controller. You should set your “current” which is the amperage coming from your battery based on the specs and config of your pack. For e.g. I’m running a 12s4p pack of Molicel P42a’s and the battery current is set at 100 amps which the cells can handle without generating much heat.

Conversely, you can set your motor current based on what your controller and motors are rated for. For e.g. a Xenith running 6374s will do 80/-80 without difficulty as long as you heat sink the controller. Without a heatsink, you may consider lowering the current to reduce heat that is generated.

For a more detailed description of battery amps, motors amps and duty cycle, you can read this thread:

2 Likes

This thread goes off the deep end quickly.

The way I like to think of it:

From a stop, you hit the acceleration hard.

Your motor amps go very high while your battery amps remain lower as you take off.

As your board starts to catch up to a stable speed, the motor amps drop off and battery amps start to take over.

There’s a good shitty graph of this effect somewhere here… I’ll try and find it.

5 Likes

Thanks! My 12s4p 40t can do in theory 120A, but I wouldn’t go higher than 100A. For my Xenith, I should use battery current 50A for each side, am I right? Since it acts as a dual vesc

3 Likes

Yep, motor and battery settings act like this:

So each side of the esc gets full motor settings and half battery

*focbox unity specific FW (not vesc branches) are the only outlier to this

4 Likes