How
dare you make me think!
You have to have two of the 6 sets of mosfets conducting, or there would be no path to complete the circuit. There are 6 steps, during any one of them one set of mosfets stays ON the whole time, while another uses PWM to send current from the battery while controlling speed and/or limiting current. Soooo...during one step, one set is on, period, and a second set varies it's on-off state.
(I'm saying "set" since they're groups of 4 mosfets on this controller)
Here's what's going on whenever a pulse wave is sent:
But wait! There's more fun!!!!
Because...the phase current just keeps looping around...inductors and all. A third mosfet has the phase current flowing through it's "body diode" during that same step, whenever the battery current is NOT pulsed ON:
Sooooo...no matter what, there are 2 sets always with current flowing through them. 33%, not 16%.
All that assumes there's not a second phase still doing something. I thought I read somewhere it was 66%...no, wait, I think that's the current going through each phase wire. Back and forth, AC. Dang. I wasted the last hour trying to figure out why I had 66% in my head. Oh well. I needed the lesson anyway.
I have a niggling feeling I'm not taking phase overlap in to consideration. Maybe it doesn't. ARRRG.
Final answer: 33%.
(Just don't quote me on it. Where's Paul when you need him?)
Back to our regurgitated programming:
Here's the heat sink:
I half expected more - it's identical to the 3000w controllers, other than being longer to hold bigger mosfets - but if you've ever looked in to a normal sized controller, it's a huge improvement. They just have a 1/2" square bar for the mosfets bolted to it. This will pull heat away much better, spread it several times over...the real question is whether the case can dissipate it after.
Mosfet closeup:
So, yes, they're the 4568's...150v, 171A.
I was concerned about those leads, but look at them! They're huge! Well, compared to the scrawny ones you find on the little mosfets smaller controllers use.
Weak link here? Well...it's still heat. Either build up in the mosfets, or build-up in the huge(but still not big enough, if you ask me) solder traces carrying all the current.