The dyno motors have arrived.
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Well… As I suspected it turned out it wasn’t the greatest of ideas. Too much disturbance. As singles they both doing fine at 75A, but in this dual sandwich style config…
75A sad DRV 
50A happy DRV 
Looks like best practice is to have the heatsink acting as a shield between the focers.
Will verify for science 
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I read through the assembly guide on Github and when I click on the blue link for “this Guide” for the bootloader and firmware installation, the link is dead. Can someone please post a link for bootloader/firmware installation?
Thanks,
Phil
Ah yes the other forum from electric skateboard builders is gone and it was a reference to that site.
I also need the assembly guide for the bootloader. Need to flash my 5 pieces 
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gr8 timing lol
I’m gonna take a crack at this. This is partly from memory and partly from my notes from the v0.9 build…
- Download installers and docs for the ST-Link utility here:
https://www.st.com/en/development-tools/stsw-link004.html#get-software - Install the ST-Link utility on your laptop
- Connect your ST-Link programmer to your CFOC2 board:
3.3V, GND, SWDIO, SWCLK, and RST - Plug your ST-Link programmer into a USB port on your laptop. This will power up your CFOC2 board. Do not power it separately while flashing bootloader and firmware.
- Run the ST-Link utility (see first pic below).
- Click on the “Connect to Target” icon on the ST-Link utility (looks like a plug with a little lightning bolt).
- You should now see a bunch of addresses and such come up in the ST-Link utility. (see second pic below)
FLASH the BOOTLOADER:
- Click on File/Open in the ST-Link utility and navigate to Cheap-FOCer-2-master\firmware\bootloader
- Double-click on “BLDC_4_Bootloader.bin” to open the bootloader.
- Click on the “Program/Verify” icon (3 to the right of the “Connect” icon)
- Check the window at the bottom of the ST-Link utility to make sure the process was successful.
FLASH THE FIRMWARE:
- Click on File/Open in the ST-Link utility and navigate to Cheap-FOCer-2-master\firmware\FW5.01
- Double-click on “BLDC_4_ChibiOS.bin” to open the firmware.
- Click on the “Program/Verify” icon (3 to the right of the “Connect” icon)
- Check the window at the bottom of the ST-Link utility to make sure the process was successful.
Click on the “Disconnect from the Target” icon.
If your CFOC2 bricks or lets the smoke out, I guess this is wrong. But I don’t think so.
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Thx man! Really appreciate it!
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If any of you use my notes above please let me know how it goes. If you find any issues I can update the post and update my notes. Thanks.
In other news… is JLCPCB expected to start carrying the DRV8301 again? If not, do we have an alternate part? I apologize if this has been covered.
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Thanks for addressing the boot loader question @ziploc
And yes based on some previous conversations in this thread, it looks like JLCPCB won’t be restocking the DRV8301. It’s a bummer…but I’m not stopping the CFOC2 release and development over it. People will just have to figure out the DRV8301 on their own. Not the worst in my opinion since JLCPCB was apparently using a bad batch of DRVs
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Its really not that complicated, and its a good skill to have. But that said, if you [the perspective builder] cant do it or dont want to, usually there are several people building several of these at a time that you [the perspective builder] could get a few from for a small surcharge.
IF I didn’t have literally(see figuratively) a billion things going on right now, like getting my network/servers setup for 10Gbit/s internet, I’d consider building these out for US based turnkey buyers as mentioned in earlier in the thread. Maybe into the winter ill find the time assuming there aren’t already people doing it at that scope/level or if there even is a demand that warrants it for them.
Edit: used the wrong sentence for the quote.
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What kind of motors are they? The connectors are automotive?
I’ve done the DRV’s a few times, but it’s just fiddly enough for my old fingers and eyes that I’d rather have JLCPCB do it. Maybe I’ll go ahead and do a batch. I could use the practice.
Just a follow up on my experiments.
I have now tested these three sandwich styles with my focers.
Unfortunately they won’t place nice with me as a sandwich at 75A motor. I keep getting the DRV issue.
EDIT. I did some more testing and it seems like 70A is new highest motor amps I can run in my sandwich mode. Better than I expected… Wow!
//
(Again, running them one at a time at 75A is no problem)
@stratoglide What motor currents are you running?
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They’re hybrid starter-generators from Kia/Hyundai hybrids. Rated 8.5kW @ 270V, but run just fine at FOCer voltage levels.
Is any sandwich better than the others or did all of them perform about the same?
Someone get this man some mumetal!
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60 motor Amps+50 battery Amps. Mounted to a 3mm vapor chamber. Didn’t have any issues.
I’ve had some friends who where able to kill the cheap Focer’s by braking downhill with a discharge bms, which I’ve had happen to my old esk8.de 1.2 controllers with no issues.
I wonder if the newer design is less tolerant of these issues or if simply the DRV’s weren’t of the highest quality and couldn’t handle the fault, as these where DRV’s with the faulty batch number that tested good.
Gotta throw some new DRV’s on there and do some more testing.
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I never tested again with the other sandwiches at 70A since my preferred setup worked out for me in the end.
At first I though this “EMC/EMI” was a bigger issue than it actually was.
Reason is… At the first drv issue at 75A, I changed to 60A but forgot to restart the focer. This led to other faults since the DRV was still messed up from the earlier fault. I therefore made the false assumption that 60A was too high as well and only 50A would work.
Seems like reducing max motor with 5A was all I had to do. 
Btw. Two focers side by side didn’t work at 75A either for me. Only when running as singles.
Good point… my focer DRVs are from the bad batch. I have abused the crap out of them with lots of DRV faults. They have not broken yet 
Its Importaint to restart the focer once there is a drv fault and not keep on driving. I have set a fault time of 5s to keep me from doing this. (But from now I dont expect that to happen anymore 
)
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Can you tell me more about this? I’m not familiar with that parameter. Does it disable the FOCer after the timeout time so that you have to restart it?
Thanks.
There’s like a fault stop time in the Vesc tool. I’m guessing giving the DRV some extra time before trying to reboot is a little easier on the electronics
I’ve mostly seen people decrease it for less of a hiccup when experiencing a fault but never increase it to something like 5 seconds.
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It was discussed earlier somewhere in the thread that if you pull too high motor current, or there are fast shifts in current direction, the DRV can reset its internal registers.
In simple terms… it will drive the FETs with the wrong settings, which seems quite harmful for the DRV.
Whenever the DRV fault code shows the info in bold below, there has been a register reset and the focer needs to be restarted. It will then restore these registers with proper values.
These register values are HW dependent and I think @shaman will change the v1.0 HW in such way that the default register values can be used.
Then if this DRV fault occcur, it would be possible to continue operation without restarting.
Setting a longer fault stop time will make me aware that I need to stop and restart.
I chose 5s since I could get into a stop using my disc brakes within that time. Hopefully faster 
. The focer will resume operation after the fault stop time has passed automatically but It has to be restarted.
If I have too short fault fault stop time, I might accidentally do throttle or brake and the focer could blow the DRV.
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