Lesson CHEAP CHINESE MONSTER MOTO CLONES AND PROBLEMS

In doing the research to see if there was any benefit to cooling the JRKs from below (there is), I read the data sheet for the VNH2SP30 H-bridge that the JRK and Monstor Moto both use.

(http://www.st.com/content/ccc/resou...df/jcr:content/translations/en.CD00043711.pdf)

In there they discuss the thermal pads on the bottoms of the chip that are designed to remove the lion's share of the heat developed in the chips.

I'm not in any way knocking the MM's but if you compare the circuit boards used in those with the JRK's you can see the Polulu takes full advantage of the thermal pads and vias the heat out to the bottom of the circuit board. The MM's do not.



Cooling the VNH2SP30 through the plastic overmold with a heat sink and fan certainly helps, but the MM's probably need to have more care and attention paid to setting them up than the JRK's do even though their board area is probably greater (see the section on power dissipation vs. board area in the VNH2SP30 data sheet).

Edit - @OZHEAT pointed out that MM's do indeed have thermal vias though not directly under the pads. They would be better if under the pads and filled with solder but better than not having them.

https://www.xsimulator.net/communit...cts-as-a-single-motor-driver-more-power.5482/

Yep. Pit wrote a great tutorial on paralleling them for more power. It's a way to use cheap MM's in higher power applications but it also adds boards, wiring, takes up space, and you generally would still need to cool them. And you can still have balance issues. It's not a perfect technique.

And if you look at the last paragraph of what you quoted, I say that paralleling them is a way to get more power - exactly as Pit's tutorial explains how to do.

You don't really say what you are replying to since all you do is quote me and add the link to Pit's tutorial, but I think that's it and I mentioned that but thanks for the link. It will probably benefit others.

Edit - deleted part about MM's not having thermal vias since they do as @OZHEAT shows below.

Yes it replys directly to you just as intended. Its what happens when you press the "reply " button. You mention parallel. I was just pointing in the direction. Good day sir.

@Zed
Is this what you are looking for?

SeatTime had a pic of a desoldered board.

@OZHEAT - yep, that is it exactly! Thanks! I had not seen those. So the MM's do have vias. Still not as many as the JRK's and not directly under the bridge pads, but they are indeed there. I'll correct my posts.

It's always pesky to delete the stuff you aren't commenting/replying to to make posts clear. I understand not taking the time to do that. Thanks for explaining how reply works, too. A proverbial wellspring of information! Good day to you.

Editing past posts for the sake of an argument.... Ok if that's your thing. I'm not sure what your intent is? Trolling the forum possibly? Everything you said has already been discussed here in great length. If you make a suggestion or bring up a subject that has already been solved or at least has a viable solution, please post a link so others can find the information. My purpose/intent for being here is not to re-discuss past issues or argue moot points. I can only repeat myself and regurgitate information so many times so occasionally you will only get a link. I am not sure why this would offend you? Furthermore, I would think someone who claims to do research would actually have some of the "research" equipment on hand to test. There are pics all over this forum of monsters without a chip showing the pads. I applaud your eagerness to contribute, it is what makes this place what it is..... A place to build and help others build DIY simulators.

Beginner's question here:

The starting current of my motor is 80A (rated current 20A).
I wonder if it is safe to connect IBT_2 (43A) with the motor or the starting current would burn everything at the moment that the motor begins to move.
Besides the unexpected behaviors of clone chips, theoretically.

Thanks a lot!!

As long as you're not running your motors near stall during normal operation you should be fine. Look at page 6 of this document:
https://www.mouser.com/ds/2/196/Infineon-BTN7970-DS-v01_01-en-785560.pdf

The nature of motion sims means that the motors are running near stall for extended periods of time (every time the motor experiences a direction change, which is often).
Run two IBT-2 in parallel and add active cooling to the chips.
Also buy some spares as some chips may not reach the full performance stated and burn out.

But for the simulator, aren't there a lot of running near stall (while changing direction) ?

True, the motor will consume stall current for a brief period of time during direction changes, but that's pulsed current, not continuous. It depends on how heavy your rig is in relation to how much load your motors are rated for, so we'd need specifics to give you a definite answer.

If you give the clones enough cooling - they seem to last ok. I've hacked an old intel CPU cooling fan. Keeps them nice and cool.

Has no effect if they are faulty when you buy them.

If they work they work I have a few which still power my fans nearly 5 years on.

I just had a brand new faulty one - had a real strange problem - it drove the one motor fine, however, the other motor only worked well in one direction. It was after a recent rebuild to my sim. took a while to troubleshoot. Anyhow - I'm also adding to my pile and that one's on it .

Yeah common issues, you could still use it as a single for something less stressing as one side is still working ok

hi guys
Just thought id mention that I purchased 4 MM's from Flux workshop on amazon 3 months ago. I only needed 3 for my smc3 half bridge that I'm using but thought id get all 4 that were available in stock at the time due to the failure rates that some members have seen. Now either I'm the luckiest member on here or the seller (Flux workshop) just sources good quality clones/copies or was just a good batch because all 4 are tested as per @SilentChill example video and 3 have been working for the last 3 months in my sim with no faults and temps no greater than 60 degrees. Not bad at only £8 each.
Like I said may have been a complete fluke but I myself am not complaining.