Dimensions are a 70mm x 70mm PCB. I tried for 65mm x 65mm, but I was tight on space. I tried going for a 2-layer design, but ran into issue routing all the traces between the DRV8301, ST32F4 chip, and everything else. So it’s 4 layers. I got rid of the NRF24L01P and MPU9150 portions present in the schematic as those were not part of 4.12HW. PCB mounting holes are for M2.5 button head screws.
Bottom of PCB. Ignore the blue capactiors as I didn’t figure out how kicad would reder it. I’m missing a few models also.
Yes, files would be awesome! Really need someone to modify it so it can be a more reliable 4.12, without extra bits that we don’t need for eskate that drive up the price.
I plan to max out the specification of components used such as using as much automotive grade components. It’s is not required because the components listed in 4.12 BOM have been proven to work well. I am taking into consideration how to solder the DRV8301 since it was such a pita soldering the DRV8302 when I went the DIY route on VESC 4.7.
I really want this to be super reliable such as mission-critical, the DRV cannot fail for it’s intendend application. I still need to understand why the DRV8302 had such a high failure rate before Vedder increased PCB trace width, made fixes, resulted in the VESC6 version with fewer DRV errors. I’m thinking this relates to the voltage transients between the MOSFET and the DRV itself.
How does this compare to the VESC v4.12 and v6.4? I see that you plan to max out the components. I just don’t fully understand the point of modifying/downgrading the v6 schematic to be more like v4?
Genuinely curious. I’m an aerospace/mechanical guy, not an EE
I’m assuming at least part of it is lower the cost to build. Most people don’t need all of the features of the vesc 6, like the accelerometer. So by taking the parts that were added that don’t impact performance but were just added to give more features, you could lower the cost quite a bit. Just my thoughts at least…
Not much other than the NRF24L01P adds built-in control for VESC and MPU9150 is the accelerometer. I’m not if Trampa sells the VESC with both of these.I read on the VESC forum that the NRF chip is not included due to certifications with the FCC cause it operates in the 2.4 GHz spectrum for buyers outside the EU. Tramp sells two different version for EU and Non-EU regarding this chip. The other thing, Vedder used the current sense amplifier for the DRV8302 on HW 4.12 and not on the DRV8301. I’m assuming it because the chip only allows for 2 amplifiers and it’s not good enough. I just learned TI has the DRV8323R utilizing the SPI interface found in the VESC6.4 and 3 current shunt amplifiers. The buck converter, however, does only 600 mA versus the DRV8301,1.5 amp supply.
Cost wise, the BOM for HW4.12 is ~$75 versus HW6.X at ~$100. It 50/50 for me; my call if I need to. Price-wise, cheaper wins for the consumer as the general consensus. I’m not cheaping out on my version.
I’m not an EE. I got a chemistry degree. This is all a hobby/education into what the world is moving towards.
You are right, most of the problems come from there.
That’s why people who use 10S have far less problems.
It’s very important to reduce the transients at the DRV and MOSFETs Pins.
Have a Nice Day.
Thierry
Is the ability to communicate with the DRV through SPI a feature that helps also to protect the DRV against failure ?
Vedder showed in a video the Overcurrent limit setting of the DRV8301 :
I was convinced that it definitely helped into get rid of DRV failure.
Gotcha! I agree with you. The accelerometer and NRF chip aren’t needed for most purposes and just add cost. Good luck on the project! I’ll keep an eye out
Nope. A good PCB layout of the components matters more. SPI is just a bus interface. I read as much as fast I can. A mosfet and the motor driving chip can be killed from the flowing current from having too fast of a switch on or off time from the gate. There is a relation of that to a voltage transient I have not figure out how is generated. Think of “water hammer” and explains why you have to put a resistor on the gate.
