Seems like some kind of 3 phase disconnect switch on each motor would be required or physically disconnecting the motors.
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If there is no connection between motor na vesc there will not be any problem
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i donât think thatâs what the question is though. Also dangling phase wires is a concern if you disconnect 
if they accidentally touch, itâll send you flying.
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someone mentioned it above and thought it worth mentioning and I wondered about it a lot:
you can go down hill as fast as you want as long as you donât go over the erpm limit it wont damage esc but if you go over your no-load speed, based on your kv and voltage, your throttle will turn into a brake.
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Hmm does that mean if I roll my board enough with the circuit not completed, Id blow out my vesc?
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Thank you for all your feedback guys, but I feel that a lot of untestet theories are being thrown in the air here 
Some says that nothing happens, and some says that it will blow up.
Is there any people here with actual experience what happens to the vesc, if the vesc loses battery connection at high speed (eg, if a plug/soldering disconnects )?
Or even better, a vesc electronics developer is present in here?
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I donât think anybody is saying it will blow upâŚjust that you could degrade components if theyâre constantly charged and powered by the current from the motor. There are a lot of variables that come into play into how long youâde have to do this to cause damage
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I assemble, repair, I donât think âmakesâ is a fitting term 
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thereâs a reason I put âmakesâ in quotes 
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This is what i have seen too. And if everything is on, and you pass the ERPM limit, youâll either pop stuff or get âenforced with negative torqueâ if thatâs whatâs set up in your vesc.
the idea that the motors only generate enough current âto matterâ when the vesc is on is ridonkulous.
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What nobody is saying in this thread is that without power to the vesc you canât really turn those FETs off.
To pull the gate of an NFET low (turn it off) you need a current sink
Where is that gonna come from? Thus the tiniest amount of charge floating around (maybe a faerie farts on your vesc and deposits 10 nano coulomb) can turn on a FET and allow current flow
ERPM limit is meaningless if your FETs are truly off and youâre freewheeling. You donât have to âkeep upâ with the changing polarities. Ofc if you wanted to apply brakes youâd need to be under the eRPM
If you can truly disconnect from the motor phase wires then you could run your motor downhill for days and never care
Just disconnecting power from your vesc is a bad idea since you just have an indeterminate state of phase FETs - and with a solid state switch like in the antispark as Chaka said it will still allow backwards current.
If you really want to tune in, turn off and drop out put a dual throw triple pole switch in shunt with your phase wires and flip that bitch off. Now freeroll all you want
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I donât think anybody is saying it will blow upâŚjust that you could degrade components if theyâre constantly charged and powered by the current from the motor. There are a lot of variables that come into play into how long youâde have to do this to cause damage
It wont hurt any components by allowing current to flow intermittently in either direction. You can corrupt the firmware from too low of voltage for an extended period but I have only seen this happen once. Might have been a fluke.
One thing that surprises people is the motors will generate power whenever they are spinning. Even if we are on the throttle they are still generating power. During heavy braking they can generate more current than we use when on the throttle. This is a big reason why I build massive battery packs, they can take heavy regen without having the voltage spike too much.
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Word. I would go so far as to say that is the cake, while further mitigating voltage sag and providing more power and range in general, not to mention the robustness you can get from the additional cells, is the icing.
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Hmmmm - Thank you for the good answers. So what I hear is that it may not break my vescs, but then again it may still break them over time 
What to do.
My idea was that I could drive with rwd as a daily driver, and make it 4wd when itâs going to be fun or at hill climping. Therefore, I made the opportunity to disconnect the motors with an anti spark unit.
I searched for a electrical relay, and a mechanical button to integrate in the enclosure, but havenât really found anything with three poles / contacts that fit into my build. Maybe iâm doomed to always be running in quattro-mode 
I guess that one day i will forget to turn on either fwd /rwd and then we will see what happens.
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you could run individual eswitches. but unless you disconnect the phase leads youâre going to be throwing current at the entire system the entire time from whatever ESCs you cut power to.
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This is wrongâŚThe motor is a generator. I have personally melted motor wiring as well as burned out mosfets. The motor does generate power and it has to go somewhere. If the board doesnât turn back on to allow energy through, things will melt.
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Your momâs going to melt.
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If you have a mosfet switch, the current will run though the internal diode of the mosfet and back to the battery. Even if the fet is open (off)
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With this you are saying that it is okay to to leave the vesc off, because the current is just going through the vesc -> anti spark -> BMS -> Battery?
This is the antisparks: https://dqzrr9k4bjpzk.cloudfront.net/images/7570530/480656861.jpg
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