I ordered one 
Im so hyped to start building now! 
That’s correct. All you need is have the DAVEGA connected to a VESC that’s on the same CAN bus as the FlexiBMS. It should work out of the box. No special setup needed.
BTW, I got a small batch of Flexi’s from Simo and you’ll soon be able to order one from shop.davega.eu along with a DAVEGA and save up a little bit on the shipping cost.
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That is just awsome! 
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Solved, it was related to the wiring of the CAN bus cable.
In case it can be helpful to others: I’m using a Flipsky Mini FSESC4.20 based on VESC 4.12 and that’s how it worked for me:
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Not completely sure but you shouldn’t connect the ground, doing that creates a ground loop that may cause problems
IIRC, the bms is powered by the main terminals. So CAN only with the data lines.
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So do I have to remove the cables between opto-enable ↔ 5V and CAN-GND ↔ ground (the " - " on the image) and just leave CANH and CANL connected?
Someone in the project can confirm this?
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The GND now I’m sure, the 5V may be needed for the BMS to be powered on when the VESC is turned on
I’m not sure if my beta board has the opto in it, @SimosMCmuffin can confirm
Yes I can confirm as I was just troubleshooting this. The opto enable needs to be connected.
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Do I have to have a metr or davega to check battery voltages in the middle of a ride?
Will the vesctool app BMS interface work with flexi in the future?
Are you wanting a second opinion? The VESC app already will display battery voltage. Although I might trust the FlexiBMS number more.
I want voltage per cell 
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16S and 18S models?
The metr pro uses the vesc battery voltage for the total voltage flexi the diebiems has its own total voltage displayed in the metr pro app
So can the GND cable cause problems?! I have to remove it? (I ask because I have to disassemble the enclosure…)
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Better wait for @SimosMCmuffin answer, he might have included some ground loop breaking circuitry
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Please add more parallel mosfets for charging at high currents.
Also some easy mounting holes for a heatsink to catch all heat producing components.
I really like your bms and would like to support by buying it for my next pack, but my current 12S 12A charger would make me too anxious to charge it without proper cooling, and future upgrades in the 16-20A territory would be clearly impossible
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What is your loop key on the - or the +?
If it’s on the + then your fine
If it’s on the neg then you have made a parallel path with the canbus ground and can overload it when your remove/turn off the board
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He is devolving the software to communicate between 2 flexi light in parallel for this reason
Heatsink would allow more bleed resistors to run for longer and higher charge currents the issue is once saturated inside of a encloser not mutch advantage. Most bms use heatsinks to cool the discharge mosfets that are not a issue on this bms.
What I want to see is the flexi lite trigger the vesc soft and hard battery cut off relating to indervidal p groups not just the overall voltage the vesc currently dose. I think this will probably depend on how Trampa implement there BMS with in the VESC software
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