I have a 4wd MTB with 4.12 flipsky fesc’s, set to 50a battery current max, and 60a motor current max on 6354s flypsky bldc motors, running on a 12s6p 40a or p molicel battery, rated for 270a continuous current.
I want to raise the battery current max to 60a so that my motor can enjoy all the current. Right now, the vesc’s are the limiting factor.
I ride pretty hard uphills that are steep and some I can’t make it up because I lack the power, even with 4wd.
Anyone with the same fesc have success raising past 50a?
They don’t go over 50c temperature when riding. So is it a matter of absolute current that they can’t handle above 50a? (which I don’t think it is because they can handle up to 130a burst current)
Or is it a temperature game? As in I could set it up to 60a as long as the vescs don’t overheat past, say, 85c?
Which is it? If it’s the latter, then I could raise to 60a.
In fact, a week ago I had put the battery current max at 67.5a because 270a/4 is that (I’ve been absent from eboarding and forgot how to set up correctly), and had motor max at 60a. And I made it up this one hill that I can’t make it up anymore ever since I got spooked and realize that I had set it up so high.
I am thinking as long as I don’t raise motor max above 60a, then whenever duty cycle is 100% the vesc will respond with higher current past its 50a rated current limit as if it was no different than a burst current spike for 10 seconds or so, as long as it takes to get me up a really steep hill.
Increasing battery current is going to give you more power at higher speed , but not have so much impact on lower speeds (which are affected by motor current values).
What are you hoping to accomplish?
Edit- Making it up steeper hills sounds like it might be better served by a gearing change or motor current increase?
I press the throttle all the way to make it up this hill but it comes to a point were the motors wont spin anymore.
So I figured that was 100% duty cycle. Is 100% duty cycle related to RPM? or throttle?
If the former, then maybe you are right, Ill give it a try.
If i increase motor current to 100a then at 50% duty Ill be 2500w which would be the same at 100% duty cycle at 60a motor max if throttle = duty cycle. Cause 50v*50a (battery current max) =2500w.
This seems like reasonable settings already for 4.12 hardware. I wouldn’t push it higher personally. Nobody can tell you for sure what the limit is before you get cutouts or blow up those ESCs.
If you really want more power, pick up two maker x dv6 pro ESCs. You can push way more phase amps with those. The flipsky 6355 are rated to 7nM, which is quite a lot more than you are probably using right now.
Pushing up a steep hill, I assume you are limited by phase amps, not battery amps.
Is it the 4.12 that looks like this with 3 mosfets (the big chips near the motor wires) on either side?
That ESC doesn’t cool very well, but the mosfets are pretty good from a current carrying standpoint.
Do you have logs, like something from metr? Would be interesting to see what’s happening when you are climbing the hill that’s giving you issues. Might be thermal throttling, might be too tall of gearing, or might not be enough amps. I used to run the Torqueboards 4.12 at 60A battery/80A motor for years without issue. My current 2wd 12s vesc 6 board will do top speed up pretty much any hill so it’s somewhat surprising that this 4wd board is struggling to even make it.
100% throttle is not 100% duty cycle on a VESC. In current control mode, it’s 100% of the set max motor current until other limits come into play (battery amps, temperature, voltage cutoffs etc). Logs will also clarify this.
What is your gearing/tire size set to? If the top speed is set too high, it will struggle up hills for sure. Top speed should be set close to what you will actually ride it at for the best hill performance (and range, and temps).
My point is that anecdotes are not going to be super helpful here. Some people run unity’s for 1k miles at 160a phase per side and don’t blow them up. Other people blow them up at 80a per side. The only real way to know for your hardware is to mess around and discover information. I ran my 4.12’s at 50a per side because I didn’t want to risk blowing them up. I dialed the throttle expo way up with made the acceleration feel more aggressive.
@jaykup has helpful advice though. 4wd even at 50a per side should be pretty dang powerful. Are you geared for 50mph or some other pretty high top speed? If so, increase that gear ratio, and you’ll get more force that you’re looking for.
Hill I’m trying to climb for reference. The camera does not do it justice. It’s a lot stepper than it looks. But the phone level reads 26 degrees on the steepest part. It’s got small stones and some loose dirt but not much. If it was cemented it would be no issue climbing that
OK that’s a pretty serious hill. Gearing seems reasonable even if they are 190kv motors
Yeah, as long as you have a bluetooth dongle you can connect with the android app and log it. Assuming all 4 are connected via CANBUS, connect to one of them, then on the start page scroll down a bit and check “Enable RT Data Logging”. Then it can be loaded into the VESC tool for viewing, but if you can upload the log here we can look through it too.
The red rectangle is the hill I cannot climb. Top is low point, bottom is high point of the hill. I tried twice. Once, then at the top the motors, or motor, give out with a squeal, and then I go down. Immediately thereafter I try again and fail.
Circle and triangle are hills I was unable to climb at 30psi. Today I lowered my tires to 20psi and was able to make the climb, although just barely on the triangle.
I forgot to mention I run 140kv motors.
when you say phase amps you are referring to motor amps, is it?
I mention “motor” because 1 runs sensorless. Some issue with the sensor wires so when I setup the motors in FOC, all but 1 show up with hall sensors, and the 1 as sensorless. Not sure how to fix I’ve measured and there is continuity along the wires throughout all the way to the motor, so probably some disconnection inside. It still works though. Not sure if that’s the one that squeals or not.
80a per side should do it, the DV6s. Tempting. I read version 6 is much better as well, although I can’t imagine.
I built this 4wd to be unstoppable so it’s kind of disappointing when I can’t get up a hill that looks climbable.
I’m geared 72/15 140kv, so it’s not that.
Based on the log it seems to be current. It says motor reaches almost 200a and battery up to 65a, total 2800w when I’m struggling. No faults.
Not sure how to interpret the data.
I might try setting battery at 55a, then 60a if all goes well and after first if setting motor max higher doesn’t do it. And if all fails I’ll get DV6s. Seems like a win win to me?
You should have massive amounts of torque with 15/72 with 140kv motors - that’s a 4.8 gear ratio. The 200a motor suggests that you are maxing you phase amps - AKA, you’re being limited by the ESC motor amp (phase) settings.
You could try upping the motor amps a bit, but if you really want to turn this board in to a monster, get the DV6s. It’s capable of 180a per side, which is more than your motors can handle, but you could run 80a or maybe up to 100a and then your board would have no issues with hills.
