MMM V3 problem with heatsink

[Dagger Thrasher]

No offence, but after all the issues the MMM has had and all the work Patrick/CC have done to get them up to scratch, I *seriously* doubt that Patrick's about to let thousands of MMM V3s leave the factory if they apparently have such an obvious flaw. If there actually was a problem, there's no way he'd be daft enough to say there wasn't after they've tested the issue to death.

Besides, electricity will always take the path of least resistance. The MMM has 0.0003 ohms per phase resistance, which is probably considerably lower than that of the aluminium heatsink (even with the anodizing worn away), so won't be an issue. What happened to your friend's battery?

Sorry, I'm not trying to get on your case! It's just that Patrick has explained and stated that this isn't a problem and has never denied any of the issues that presented themselves in the past...so I just think we should perhaps (IMO) take his word on this one. He's the electronic engineer.

[BrianG]

Originally Posted by Dagger Thrasher

Besides, electricity will always take the path of least resistance. The MMM has 0.0003 ohms per phase resistance, which is probably considerably lower than that of the aluminium heatsink (even with the anodizing worn away), so won't be an issue. What happened to your friend's battery?...

That statement is not totally true. Assuming the battery is not completely shorted (causing all the battery voltage to drop across the battery's internal resistance), a partial short will cause some current to go through the heatsink and some to go through the load (ESC/motor). True, more current will go through the path of least resistance, but not all.

Look at it like this: If the load presented a 0.25 ohm load, and the heatsink partial short is 0.01ohms, 96.15% of the current will go through the 0.01ohm heatsink "load", while the other 3.85% will go to the real load. Of course, in reality, the battery voltage will drop substantially even with a partial short...

I still don't think the HS/bullet proximity is "safe" IMO. But, even if the HS did partially short out the bullets, the contact area would not be ideal and the resulting arcing will eat away at the offending contact.