Did anyone actually look at the current rating of each FET?
MMM --> NTMFS4108N = 30A x 36
HW --> 150A NTMFS4833N= 180A x 36

WTF?

We just hooked up the HW150 last night with the 36-74-2350 motor from HW and WOW. What a nice setup indeed...

The NTMFS4833N is rated for 26A at 25C and 19A at 85C. The NTMFS4108N is rated for 22A at 25C and 16A at 85C. This are the numbers I like to go by. Patrick did mention that datasheet specs are not really that useful. He probably saw an advantage on the 4108N over the 4833N.

At least we have someone who actually looked at the datasheets..well done lutach. viva brasil.

Got any vids? I'm trying to decide between the HW150 and the MMMv3.

There is more to an FET spec that just current and voltage figures. Some other ones are Rds_on, gate capacitance, slew rate, temperature coefficient, etc. Slew rate alone (which is just how long it takes for the FET to switch from 0 to max or vice-versa) can make a big difference in temperature.

BTW: I have some more results from running, but want to get a little more time before posting my observations...

Read here....

http://www.rc-monster.com/forum/showthread.php?t=19171


We are still pondering what is the difference, and why so big of a difference.

Edited my original post to add my operation observation (at the bottom of the post).

Great review. Given what my mtroniks truck Esc did I didnt think 80A was enough to push around an MT. The part that irks me though is my 7xl 38mph emaxx setup only pulls around 35A at WOT which could be considered continuous. The peaks are 78A. So why wouldnt an 80A continuous rated speed controller work that has peaks of 270A?

To me It seems like all this stuff is not rated correctly. You have to buy Escs that are overrated. You have to buy batteries that are overrated. If you do the math on my setup a 10C 4000mah battery with 10C continuous and 20C burst would work just fine, but you would puff a battery rated that small in an MT.

Now I just measure or estimate the peaks and I buy equipment where my peak is its continuous rating and that seems to work. But I really shouldnt have to do that.

Yeah, I know what you mean. It seems like car ESCs are rated the same way aircraft ESCs are, but airplanes pull a much more constant amperate, but the average is higher than car use.

Personally, even though the FETs are rated conservatively and derated properly for temperature and the size of the heatsink, I wouldn't run anything near its amp spec because cars are very peaky and bursts will hit much higher. Burst ratings are much more applicable rating IMO. Plus, there are FET switching losses (the square waves are not perfect square waves) and losses due to the rdson value, both of which cause too much heat in an area too small to be cooled effectively.

So, I too tend to look for ESCs with a continuous rating close to what I think my burst will be.

Hopefully soon, there will be a guide to help people select the right system. :wink: :whistle:

results from the mmm or the 150amps hobbywing??BrianG

What do you mean?

what resulat you got.it the mmm or hobbywing 150amp

The HW 80A...

Just wondering if you guys consider the MMM a budget ESC also. It seems the HW 150A matches the MMM in specs at the very least (the FETs can actually handle a bit more current), so I'm wondering why everyone considers it a budget ESC. Is it because it's from a relatively unknown mfr?...or because it's from China? I just picked one up. Haven't hooked it up yet, but considering it was considerably less than the MMM with similar specs, similar level of components, good commercial-grade mfg (I'm in electronics mfg), etc.