That sounds positive - keep testing and fingers crossed no more failures.
You could post on Vedder’s Forum to see if a solution can be found that enables you to use reverse.
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I didn’t know that forum existed. I got tossed off my board, so there will be a few days before I can further test the release of the brakes without reverse enabled.
@FLATLINEcustoms @dogeatgod @elkick I was poking around on Vedder’s forum and found another person noting braking problems that are similar to ours, which lead me to a response form Vedder: this thread about DRV problems when using FOC
Of note, Vedder suggests soldering an additional 2.2µF capacitor to GVDD on the drv8302 (C18).
So I order some of these from Mouser:
At least one person (Whitepony) reported that it solved their issue with FOC braking. I’ll report back once get them in the mail and try it.
They are nearly the same as others reported, very close to 1.0 and 2.0. Nothing remarkable.
It works with FOC. The C18 mod is basically the update in 4.12.
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Thanks @elkick that’s good to know! I hope my soldering skills are up to par! I think I recall that you use VESC HW 4.7 on some of your builds, did you apply this update to your VESC?
Not on the 4.7 VESCs since I drive them only with 7s and 10s with FOC. I had the breaking problem as well in 4.7, but it was related to BMS/battery cutting off (too high regen current if batteries are only capable of taking 1 or 2A charge current - changed cells!) and/or wrong settings in the min./max. current in BLDC tool.
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I use a 4.7uf 16v capacitor instead of stacked 2.2uf caps. Stacking the caps puts too much leverage on the solder pads and could lead to them being ripped off. I have been using these: http://www.mouser.com/ProductDetail/TDK/C1608X5R1C475M080AC/?qs=sGAEpiMZZMukHu%2bjC5l7YegWuDAL%2b4n3PASDuuxtVww%3D
Mouser is out of stock on the TDX brand but you could use the equivalent from Murata : http://www.mouser.com/ProductDetail/Murata-Electronics/GRM188R61C475ME11D/?qs=sGAEpiMZZMukHu%2bjC5l7YbA1Uz8mFEbwIIDNOsfvAdY%3D
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@FLATLINEcustoms Dang maybe this won’t solve any of my problems. It seems like it is worth a try though, and may improve performance since it is now implemented in the new HW.
@elkick If I apply this hardware update, could I encounter issues with uploading new firmware in the future? That is, are new versions of 4.7 firmware created anticipating that this additional cap is not there… I’d hate to fry my VESC in an effort to improve it!
No you wont have any issues with firmware. It only increases the capacitance making it more robust.
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@dogeatgod @FLATLINEcustoms @elkick @chaka OK my cap for the C18 mod arrive. This thing is really small! Imagine taking a grain of rice and dividing it into 8 pieces… it looks like a tiny breadcrumb!
Time to get out the tweezer and magnifying glass. Any pro tips on adding something so small. I have a pretty good soldering kit with the pin-point tip.
I place about a 500 of those tiny little caps and resistors everyday! I use hot air but you can use an iron too. take your time and breath, but not too hard! Once you get the fresh cap in place you can hold it down rather than grasping with your tweezers and touch each end with your iron. There should be enough residual solder on the pads that it will flow with the aid of a little flux.
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@treenutter any luck? I spent Saturday on some steep twistie mountain roads. Didn’t have the brake release once with reverse turned off.
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@FLATLINEcustoms @elkick @dogeatgod @chaka I got the cap on there! It’s a little bit crooked, but I managed to make a connection on both sides. A few rides have proven successful! The only time I lose braking is if I’m on the board, not moving, and I apply full brake and move the deck forward and backward by shifting my bodyweight. After about six rocks the brakes release. But since that is a behavior that I never need to replicate in real riding, I think I’m good to go! I’m still curious about what causes the release, but I’m happy to be moving in FOC mode!
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Sounds good. Did you cut those hall sensor pins where your cables are running across on the back side of your VESC? If not, you should do that. They can perforate the insulation of your red wire and full voltage will be applied to the v5 pin of the sensor port and that’s bad.
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Mine just released again last night… ugh. No reverse still, maybe it was because I was full throw on the brake?
Bah - worrying.
Intermittent faults are the worse.
I’ve not had it occur since limiting trigger movement - fingers crossed it’s not just a matter of time…
I just posted up over on VESC forum. http://vedder.se/forums/viewtopic.php?f=7&t=222
It has to be the worst feeling on earth… not knowing when the brake is going to fail.