VESC6 still uses the DRV chip, which is the bottleneck, and you really shouldn’t drive it with more than 10S

It’s not a bottle neck. Texas Instrument’s DRV830x chip is currently the only chip on the market to run with a max 60V. You have to go for a different design and topology using dedicated mosfet drivers and a 12V circuit to drive higher voltages and currents.

1 Like

Which means it’s the bottleneck

It is the part of the design constraining it to 60V. That’s literally what “bottleneck” means, because this thing replaces all that but only goes up to 60V

2 Likes

@Jmding… the KT constant is torque per amp… so the torque is directly proportional to the motor current, not the battery voltage. you cannot expect the same torque with 80% of the motor current by increasing the voltage from 10S to 12S.

for example 10S vs 12S, 60a motor current limit, 60a battery current limit, full throttle acceleration – during acceleration you get the same torque, same heat and same efficiency from both motors, but the 12S can spin faster.

3 Likes

12s fully charged is nearly 10v short of the drvs voltage limit. If the vesc cant handle 12s its not because of the drv. Ive been running 12s now for hundreds of miles, however i use active cooling with increased capacitance too.

This is 100% false. I’m not going to repeat this very many more times unless I start invoicing for my time. If you’re not an electrical engineer yet are speaking as-if this is fact, then maybe take a step back.

Firstly, when you are driving inductive loads (like motor windings) the voltages spike plus and minus when fed with square waves.

Secondly, most consumer goods are designed to operate at about 60% of their ratings. This means things keep working. When unexpected things happen, there is room. Things like automobiles and things where safety matter a lot more use bigger margins. So using that formula, it’s only good for 8S. So 10S is even pushing it. For something your life could depend on.

Feel free to push this 12S thing all you want but when you hurt yourself because you don’t listen, I won’t be there for you. When other people hurt themselves because of your bad advice, that’s between you and them.

Also, if you jumped off a bridge and lived, it means I can jump off a bridge and live too.

2 Likes

My first build was 12s with Car esc’s and I had a lot of problems with overheating motors and electronics. When I switched to Vescs, I also switched to 10s and have not had any overheating problems since. I did have a lot more power with 12s and the esc’s. So much that it was hard to control. The Vesc/10s setup was much tamer.

5 Likes

Well I have to recant my statement because there is now documentation for a 100V DRV835X. http://www.ti.com/product/drv8353r

Now the bottleneck it the max voltage of a BLDC motor. It’s great, but Gate Drive is 1A and the buck regulator can only output 350mA because of the high voltage.

1 Like

I have a couple of 12s builds on older vescs(Chaka and enrtion, way before focbox) and they are still alive(knock on wood). But I’m not an engineer or even close to that. Must have gotten lucky with my vescs if they weren’t rated for what I was running them for.

Its not false. and stop being so condescending.

This statement is 100% false. The DRV83xx chip is the limiting factor in the design.

I care about people’s safety and if you were going around suggesting to folks they can safely jump off bridges, I’d do the same thing. It’s not “condescending”. It’s “being responsible and caring”.

3 Likes

Its inadequate design and cooling of the vesc itself not a drv issue. No more debating in this post from me. Enjoy ur boards all.

It isnt, many of your posts are condescending in nature. on many threads, on many subjects. Its just your way

2 Likes

@chuttney1 What about the LM5109 drivers? 100v max. It is not integrated like the DRV so you need 3 if my memory is correct. But it works, I do have 2x VESC built with this at home. It just didn’t receive love from the community.

I think it was stated that the DRV is being run in the VESC above “safe” limits above 40v no? But a lot of people are able to run 12-13s safely with the new ones. So why not.

Yes

No

I may be more accurate :

Anybody here is able to run high voltage without safety. Then A lot of people are able to run 12s and recently 13s without reporting blown ESC during ride after many miles, which I deem safe to a certain extent.

Lots of people go to war and return unharmed. War is safe.

1 Like

There is no single answer as the data is so fuzzy, Im not surprised so many fail, esp the way you see ppl treat them.

Factors like putting them in tiny enclosures with no air rattling about and huge long supply cable not even cabled tied together are all factors that aren’t helping. Many people abuse these things.

Not to mention there seems to be a design flaw, the drv does seem to fail a lot and in a specific spot even at 10s. After studying the datasheet, i made an educated guess on what i think is causing some of the problems and added extra protection on and off chip, as have some of those manufacturing vescs.

Someone really needs to sit down with it with an oscilloscope and do some extensive testing to give you a more definitive answer.

As for 13s, that really is too close to the drv limit, as b264 stated above, you need to leave some breathing room, esp as the stock caps are all 63v and under.

Im off to bed

3 Likes

So between 10s and 12s, the heat is largely the same on the motors with it slightly higher on the wires for 10s due to the higher amp draw from a lower voltage pack? Trying not to get lost in the technical stuff lol

If that was the case wouldnt getting thicker wires mitigate the heat?

1 Like