The new wizard asks now much more information than before and it’s very intuitive however after runing it I get weird high current values suggested by the wizard itself.
Please take a look at them:
motor current max 67.73A
motor current max brake -63.73A
Battery current Max 99A
Battery current regen -60A
These numbers are nutz, I wonder if I need set them up manually or just leave them as suggested by the wizard?, for now I just manually use these settings, just to e on the safe side:
motor current max 80A
motor current max brake -70A
Battery current Max 40A
Battery current regen -12A
On the other hand after runing the wizard I see the the Motor Type is still in BLDC not FOC as stated on the wizard.
I had trouble with it. I got the "too old firmware " message. I updated as usual but after reset the same message over and over. I updated 5 times in a row. No luck. I flashed the vesc with st-link and it worked after that. I am not sure where the problem was. Never happened before
You had no bootloader installed. No need for an ST link. You can upload the bootloader via vesc tool.
You can also use a second vesc to act as a programmer. Interconnect gnd, Io, clk, power up both units, open SWD Prog tab, hit connect, select hardware, flash.
Better: motor max 67A
Motor regen:-40A
Batt max 50A
Batt regen:-35A
Batt regen needs to be high enough to give you good brakes at speed. It’s a value that will never be seen by your battery for more than a very short time. Amps drop fast during braking.
The new tool puts HW4.xx to BLDC to avoid HW damages. You can change that to FOC later.
The new VESC Tool automatically sets weird maximum current values, these values are for the first time assigned by the tool, usually the user is the one that state current limits during ESC setup.
I wonder why Vedder chose to assign there limits automatically.
Vesc-Tool can now figure out the max Amps your motor can take reliably. You don’t need to drop in any values you guessed. 67A is what your motor can swallow reliably.
With regards to batt max: If you would drop in 1000A, motor max would be the limiting factor. You can’t pull more than 67A in our case.
Batt max regen is a bit theoretical, since you can’t push -60A realistically. That would be 3000W braking on a 12S system. You can’t do that without you flying while your board stops. Naturally Amps are limited by your thumb.
The only scenario that would put a lot of strain your battery is an extended high speed run on a very very steep hill. Basically a hill that is steep enough to keep you at high speeds, although you apply hard brakes. In that case you need a big fat amp swallowing pack anyway. Riding such a steep hill without proper brakes is no option.
At 50% duty, you can’t push more than -33,5A (-67A motor regen/2), and doing so, your speed would soon be at 25% duty and your down to -16.75A.
On Regen we usually see short spikes, which decrease fast in value. That’s no problem for modern LiIon cells.
You can lower the values manually if needed (advanced tab). For the now VESC-Tool assumes that your battery performance matches the motor performance, which makes sense in a way. If you want 5000W output power, your battery should be able to deliver that.
We could also assume that per 1000mAh of battery capacity we can pull 5 Amps.
For a 12S4P 12000mAh Q30 pack that would result in 60A batt max.
It assigns the motor current based on the size of the motor(that you select) and on the resistance of the winding. Size decides heat dissipation and winding resistance decides heat production. You can always reduce those limits if you don’t want that big of an oomph.
Heat losses of 60W are very realistic for a wide range of motors we use in e-skate. So it’s fairly easy to determine the max Amps. Stator saturation might be at a bit higer Amp values, but it’s not wise to go close to saturation. If VESC-Tool finds out 67A, it might be possible to push 75A without going into saturation, but at 75A the motor is operated beyond thermal capabilities.
VESC Tool needs to comply with the most ways, not only one.
How many people are using a dual setup with Li-ion ?
Like dual on a xS4P or sometimes less !
Auomation for amp “guessing” is really dangerous
And trust me : I have a lot of private messages since I published a VESC Tool tutorial on YouTube. A lot of people are really confused by those crazy values generated automatically.
I find the suggested values for the motors very close to what I set them if I don’t want to deal with constant overheating issues.
The battery suggestions, although fine in some of my cases can be high and if I were Benjamin or you (which I am neither), I would choose the conservative approach of the previous vesc tool and leave it up to the user to increase them.
Unfortunately most users use way to low Batt regen settings and way to high Motor regen settings. These values should be balanced ( e.g. -45A MR and -35A BR). We will look into a solution to determine Batt capabilities automatically.
Agreed. The problem lies with the fact that many are using discharge BMSs.
Especially the ones that have the same connection for charge / discharge , would shut down if a too high regen value is used leaving the board without brakes.
I know your feelings on discharge BMSs and I share them but I feel it is better to take an approach that would suit the majority.
I use a way too low (-50/-10 dual) setting myself, never had any problems with it, my brakes are perfect for me (and no, I’m not going flat lands, more the opposite)
You should up the Batt regen to get better linearity and better grip at speed. Try it out yourself and don’t be afraid that you will blow your battery. These are spikes and not constant Amps.
