I took it on another test ride and everything seems to be fine, except for the the remotes weird readings. Like it rides smoothly, if I am not looking at the remote I would not even know that anything is wrong.
The wrong speed readings on the remote can be fixed through vescs tool by setting your wheel size and motor specs.
You can also leave it and don’t care
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Its not showing the wrong speed. The numbers keep jumping from the actual speed to the max speed and then back to the current speed, whenever I accelerate. To clarify the actual speed doesnt change just what the remote is showing
@ceasium lots of shitposting and trolling going on in your thread, but to add some actual useful information, here’s what you should be thinking about.
Your TBDD are low kv motors. Low kv is achieved by using more windings of thinner wire. This results in a motor with higher resistance compared to a higher kv motor. Pushing lots of amps through a high kv motor will result in resistive losses (aka copper losses), and produce heat.
If you try to push 100a it’s very likely that you are going overheat the motors. Direct drive motors have their benefits, like drag free and silent freeroll, but they are not torque monsters. I’d recommend running 50-60a, and if you want more torque start looking into building a gear reduction setup either with gear drive or belt drive.
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Some people think they know what they’re talking about but don’t.
Low kv motors don’t get hotter. Regardless of the motor kv you get the same resistive losses assuming the same amount of copper mass. Low kv means high kt meaning they produce more torque per amp. It’s the same km meaning same heat to torque output.
The manufacturer says u can do 80amps w those motors and if u look around this forum you can read many doing that with no problem
They take anywhere from 1-2 weeks to get to the US from China.
Or if you need them faster, you can get them here. Couldn’t find anything cheaper but if you search, I am sure you can (search JST PH 2.0mm 6 pin male to female)
Amazon.com: ktolplao JST Connectors 2/3/4/5/6Pin Female Male Adapter Cable Plug PH2.0mm Pin Micro Electrical Wire Cables Female Ribbon Kit Pitch Female Socket Pre Crimped Colors Terminal : Electronics
This is wrong. A 75kv motor will have higher resistance vs a 190 kv motor of the same copper mass, due to more windings of thinner copper wire.
Try running the TBDD with pneumatics and tell me what happens to the motor temperature (you will overheat the motors because they are low kv and high resistance.)
That’s not wrong but you’re misunderstanding the logical conclusion.
a 75kv motor run at 80a will produce more torque than a 190kv motor pushed at 80a.
It’s also true that a 75kv motor run at 80a will overheat due to resistive losses faster than a 190 kv motor run at 80a.
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Yes. And it will have more inductance and need less amps to produce the same torque. More turns or wraps of wire making a coil makes stronger magnet.
Sure, but you told him to crank the amps to 100A because he was unsatisfied with the amount of torque. So clearly YOU are not comparing setups which produce the same torque. Evan is right.
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Just as I wrote. I’m talking in relation to torque output. Low kv motors produce the same heat to torque as any other kv
This is true.
Sure… but u get like half the torque with the high kv.
If u want to say low kv motors get hotter, it has to be in relation to a given amount of torque output. Or you could say the lower kv gets hotter with a given amount of amps
If want to compare setups with the same torque the low kv takes less amps.
You will overheat the motors not because they’re low kv but because have no gearing to add speed to the speed x torque= power equation. All power is being made by resistive losses because can’t spin the motor fast.
This thread is giving my mind resistive losses
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This is why it’s a bad idea to run 75kv direct drive motors at 100a. They’re going to overheat. Lots of people have experience overheating TBDD motors.
Keeping torque the same is completely irrelevant to OPs question in this thread.
You could also overheat them at only 30 amps and results depends on time and ambient temp. They have a temp sensor and if someone is worried about heat, which is the real problem and not the max current you run, they can reduce the temp the vesc will shutdown. If someone is looking for the max torque the motors can do though they can run them at higher current just not as long. In my looking there’s lots of people running at 80 amps and even with giant wheels and the seller states that’s the max. Do u want to run at 20 amps continuously or 80 or even 100 for bursts… makes no difference as long as don’t overheat them.
If someone is trying to race a short course for example it would be silly to keep the amp limits low and essentially be wasting the motor’s potential.
I think that’s right.
for a given torque the heat generated (copper losses) is the same for the same amount of copper.
lower kv with more and smaller higher reistance windings require lower current to hit the same torque as a higher kv with less resistance and it balances out. (for same amount of copper)
Raising the motor current limit to an obscene limit won’t immediately blow the motor. it depends on how it gets used. but it will take away some protection from blowing the motor or the fets in the event of current spikes that are way to high or holding the high current too long .
So it’s a pretty subjective space. and if people have experience running TBDD saying they get to hot at 100A motor current limit, that’s worth listening too. it probably means that what a normal rider will do is run them for longer at higher currents, enough to overheat them.
if you understand the nuances of being able to use a short current burst at the low end and watching temperature so the motors don’t get too hot. and you believe the higher motor current limit and existing ABS max will protect your ESC and motor from so a high a spike it won’t blow winding or esc. then you can definitely play with a little higher motor current to get a little more oompf off the line.
RC ESC users don’t have a luxurious motor current safety check. they just have to keep it safe with gearing or caution to avoid spikes that are too high.
even with motor current and ABS MAX limits vescs (and any ESC) can still be smoked in an instant by overgearing / over kv / asking too much current from them. The ESC has to have time to react to ask for less power (drop duty_cycle) to reduce current. Dash blew several ESCs this way hoping to get by using motors he had available that were too high KV.
so caution is warranted.
You guys are debating about where that line is again.
but other than that you’re all mostly right.
thanks for reading this far