Cousin of OSW (Open Sim Wheel)

The modules are poorly designed and constructed. The vias are generally not filled with solder, so don't allow good heat transfer to the other side of the board. Second to that, the heatsink rarely contacts adequately with the board anyway so heat transfer away from the fets is just bad all round. You feel the heatsinks and they're barely warm but the fets are toasty - This is because there is very poor thermal transfer to get the heat out.

Fill the vias with solder and add a thin heatsink pad between the board and heatsink. Top it off with a fan with decent flow. This helps a lot. With these mods, I have not had one fail in several years (3 in parallel, 80+A at 12v)

Was thinking about this - is this the same as pulling both RPWM and LPWM on the BTS to 5V and putting the PWMs from the microcontroller on their respective EN pin (BTS) for 2PWM mode?

I actually had read about the poor heat transfer of these boards so when I got them I put some good thermal paste which I think helped bc my heatsinks used to get pretty hot (either it helped or the fact that the heatsinks got hot means the chips got extremely hot lol). Thanks for the tips, I'll try your method for the new ones I receive.

The main thing is to not tie the EN lines high so if my brain logic is serving me correctly, I think yes, that should achieve the same outcome. The key is, the wheel should feel no resistance when powered on and not being driven.

Possibly ignore this bit - I can't recall if you were using the STM32 or Leonardo, it only applies if you are on STM32
Bare in mind - You should be driving the modules at 3.3v, not 5v though. Driving the modules at 5v and the logic at 3.3v technically puts the buffer chip out of spec and has proven cause issues in some scenarios. There are quite a few documented cases here (and probably in this VERY long thread) where it has produced reliability issues and failures.

Hi, please help i am not getting the game of voltage and amp required for motor to drive
That 12v vs 24v and about ampeher, i under stand everything but not about psu and motor stall, can you brief me about exact problem ongoing between power supply and motor stall

What spec is your motor ?

Doesn't it work like this that my motor is xxV and xxAmp and I give xxV and xxAmp and winner winner chicken dinner

Mine is my1020 48v 1000w

As I read before your motor is 48v 1000w and you are using 12v 80+A, will you help me in this.
I this forum i recently read about this 12v thing and amp using hp server power supply and not using 24v or 48v Power supply
I am new to it and just reading the complete forum

https://www.rapidtables.com/calc/electric/Volt_to_Watt_Calculator.html

What specifically do you need help with?
You're looking for a HP DPS-800GB. They are cheap, easy to mod, very quiet and there is plenty of documentation available on how to do this. I went with 8ga wire between the power supply and the H bridge drivers.

We have to run them at a lower voltage (than rated) because almost all of the energy used is being given off as heat. This is only 20-30% if used 'normally'. If the windings in the motor get too hot, it will melt the enamel and short the motor.

Ok by re-reading the entire forum and from your reply i understand that I need to give my motor near 12v below it rated one, to prevent heat.( No matter what motor rating is 24v 36v 48v) Just give near 12v with high amp.
Will this fix the problem of heating and sometimes noise produces by motor.
That's why you are using 12v with high ampere


I am just getting confuse here what rating Power supply should I go with my motor is 48v 1000w My1020.

Sorry for my English, I wish you understand what I am asking about

Yes, my motor is the same one. Run it at 12v with a server power supply capable of 80-90 amps and it will work fine.

I must say though, the 80 amps is at 100% power (wheel config) and trying to push it past the logical 'hard stop'. You do not want to sustain this, it will damage the motor fast. In general game use, it will use much less. My max power is set to about 70% and it is still easy to feel the hard stop.

hi, i have a motor my1016(24v 250w) is nearby and i test it and make some search through chatgpt about gear ratio and torque will you please take a look and tell me is this correct
I tested that at 15cm this motor make torque/ force on scale around 1.4kg

to make easier this is

1. Gear Ratio Calculation:
   • Given: Number of teeth on input gear = 11, Number of teeth on output gear = 70
   • Calculation: Gear Ratio=70/11=6.3636
2. Torque Calculation:
   • Given: Mass (m) = 1.4 kg, Distance (r) = 0.15 m(15cm)
   • Calculation: T1=1.4×9.81×0.15=20.58 Nm
3. RPM Calculation:
   • Given: Input RPM = 3000, Gear Ratio = 6.3636
   • Calculation: Output RPM=3000/6.3636= 471.75 RPM
4. Torque After Gear Ratio:
   • Given: T1= 20.58 Nm , Gear Ratio = 6.3636
   • Calculation: T2≈20.58 × 6.3636 = 130.99Nm
5. Torque Conversion:
   • Conversion from Nm to kg-m: 1 Nm=0.10197 kg-m
   • Given: Torque after gear ratio = 130.99 Nm
   • Calculation: Torque in kg-m = 130.99×0.10197≈13.36 kg-m
6. Torque for Steering Shaft:
   • Given: Radius of the steering shaft = 150 mm = 0.15 m(i put steering dia is 300mm)
   • Calculation: Torque (m-kg)=Torque (kg-m)×Radius (m)
   • Calculation: Torque ≈ 13.36×0.15≈2.004 m-kg
7. i just wanted to know the torque/force on steering in kg for better understanding

It's not really relevant because the RPM is effectively 0. ChatGPT is useful only when you give it good input.

That motor (you wrote 250W, but used 350W with ChatGPT) has ~0.9Nm for torque at full power. Torque is going to be multiplied by the 6.3:1 ratio so 0.9 X 6.3 is about 5.5Nm MAX.

However, you can't sustain that! remember, 0 RPM so almost no energy is being converted to rotational energy, and is almost exclusively being given off as heat.

You can't dissipate 250W as heat only, it will melt the motor fast. At most, you want only 30% of that energy to be used, because that's roughly the amount of energy it's designed to give off as heat.

In reality, your usable max torque is closer to 2Nm for the 250w motor and marginally more for the 350W version at 24v and that gear ratio.

The way we get around this is running it at a lower voltage, then we can pull more amps at the same wattage. In this scenario, a crude equation is more amps = more torque but you still need to stay within about 30% of the rated wattage.

As technical as all this is, I think you are making it way more complicated than it needs to be and confusing yourself.

ok i understand.
thanks for your reply

how can i know how much torque or force motor will make on steering wheel.
take this 24v 250w dc motor as example. which make weight of near 1.5 kg(15cm length of rod connected to motor shaft) on weight scale with 24v 10amp power supply, what if i connect a 11 teeth gt timing pulley to motor shaft and 70 teeth to the steering wheel shaft with xl120 belt how much force or torque on steering wheel you think will me made(like how much avg i can feel)
help me how can i get these value or you can tell .
now what will be the value with 30%(you mean 72w, 24v 3-4 amp, with stall torque(i don't know the exact meaning of stall, i think this is force when holding steering wheel at fixed position) amp consumption will be high ? )


just curious about information, so that i can adjust steering wheel size with what power dc motor to get required amount of torques

forgive me if I am making you angry with my question

I saw in your YT post with the 7.2 NM test that you ran 3x BTS7960 in parallel — did you simply split each wire into 3 different paths or something more complicated? Other people say I would need a fanout buffer with the stm32 because of current liminations.

Yes, everything is just run in parallel in my setup. Power and signal wires. You don't need a buffer chip, the BTS7960 module already has one! Just make sure you power them with 3v for the logic and not 5v. If you power them from 5v and only use 3v logic, you're running them out of spec, which can cause failures. Personally, I run an external 3v regulator just for powering the BTS7960 logic as some STM boards only have weak 3v regulators which may not be enough. Do you need 3 BTS7960? I don't know but I've never had one fail on me with my setup.

I don't know if I really need 3 IBTs but I know we have pretty similar motors (same power, ~1100W) but mine is rated f0r 12V. I'm also planning to use a belt driven design with like a 5:1 reduction so I don't know if that means it will draw more amperage.

I would definitely recommend 3 in that case. The amperage will be higher than a 48v motor @ 12v because the resistance will be less in the windings but that's at 100% power, full stall. If you're 5:1 and not DD, then you will not need to turn up the powere as much to get a powerful wheel.