Current MM still ok on 4s?
 

Hello,

So I've got (and love) an old MM which I got at release basically. I use it on 4s and with a Neu motor without any problems at all. Of course I'm using an external BEC.

I'm about to get another MM, there have not been any hardware changes that might reduce the reliability of the MM on 4s have there?

I just want to make sure I can use a brand new current MM on 4s with an external BEC.

Thanks guys,

Should be fine.

Thanks, I didn't think anything had changed but I figured I'd ask JIC...

well you might not be able to. I had an older mm that ran 14 cells great. ubec of course. then i smoked it after months of awesome use. It would thermal. then i added a fan and the temp barely broke 110. anyways the fan had stopped working, i drove it anyways, hit a jump and peged the throttle and when it landed. it smoked. So i sent it to cc with 50$ they sent me a brand new one. and it wont go on 14 cells. Runs fine on 12. but it wont run on 14. there are lots of threads about the difference's between newer one having fewer fets 12 i think than the older ones (15 fets). The the concences is the newer ones also have some sort of overvoltage protection. Some have said you can get around it by turning off the lvc, but that didnt work for me. Now 4s is lower than 14 cells nominal, so you still might get away with it. But i wouldnt be suprised if you couldnt.

4s peaked is 16.8v. 12 cells peaked (~1.4v/cell) is 16.8v. So it should work fine. 14 cells peaked is almost 20v, so I can understand why that may not work.

I have a MM that is less than year old and I have no problems running it on 4s and a UBEC

Are any of you guys using a fan on it? I was thinking of picking one up when I am waiting on the MMM. I could always sell it on the bay or keep it as a spare in the event the MMM craps. I would be running mine with a 1.5 Tekno Neu and 2 2s 8k maxamps packs in series so 4s total.

dont see why not, a monster max just sold yesterday for $310 bucks, sure hope that one doesnt kill itself, id be pretty annoyed :lol:

Would he even have 12 months warranty as it is 2nd hand even though the product is still new?

http://cgi.ebay.com.au/ws/eBayISAPI....MEWA:IT&ih=009

Price gouging... gotta love it. :sarcastic:

price is 310 ausd.. our dollar is a bit weaker than the USD

ps MM on 4s is sweet . i dont understand how castle can make a esc thats rated at 2-3s lipo 100 amp and is very quite realiable even when over driven into 4s. yet the failure rate on MMM looks to be huge . im going to stick with mgm and MM until MMM problems have been fixed.

PS why doesnt the kontronik jazz 63V have brakes look at the specs of that esc . its the ultimate !!!!!!!!!!!!!!

Also, I used a MM that I just got back from CC as a replacement on my Rustler on a 5S discharged to 20.6V. Worked fine for a couple speed runs until it thermalled. I then realized that I had forgotten the y-harness for the cooling fans. The Rustler was pulling wheelies when I gave it full throttle at 76+mph. Can't wait to put the MMM from RC-Monster in there. Should see some good numbers...

My MMM just smoked, completely melted down. Setup is 4s Neu 1515 1/Y/F 13 tooth pinion in a Losi 8ight-T. My question is can I run a MM (and cc bec) with this setup with no problems? Neu 1515 1/Y is rated at 2200kv. Will this be ok because I'm done beta testing the MMM and don't want to wait for it's replacement.

Using my original MM, I have that exact setup (with a CRT) and it's perfect.

It makes me wonder: with the MM performing great far beyond "spec", is the MMM a disappointment?

I don't think so. The MM is a great 12 cell/4s ESC rated for 100A. The MMM is a great 18 cell/6s ESC rated for ~200A. Almost triple the power capability for about 30% more cost. Much better bang for the buck IMO.

The MMM just needs the little bugs ironed out is all...

When the release grade MMM ships, it will be awesome.

That's what I'm hoping.

I was just thinking out loud that we have a great ESC in the MM already. I am really not missing the MMM because I haven't got mine yet :neutral:. The MM's (I have 4) are serving me well even though they handles about 5V less than the MMM and can handle 150+ amps with proper cooling. All my MM's are on 4S except one which is on 5S (double duty between my Rustler and truggy) and are reliable.

Can't wait for the 2nd batch of MMM's to start shipping...

BrianG, I agree with you that the MMM is an awesome deal for what we will be getting out of it.

Do many people have problems running 5S off the MM?

The only problem I've had was when I forgot to run the cooling fan. Also, I have to bring the pack voltage down to about 20.6V. MM's a champ!

Edit: Here's a data log from my Rustler on 5S from a few weeks ago pushing around 1995 Watts:

http://i256.photobucket.com/albums/h...8EagleTree.jpg

Is a cooling fan needed on 4s?

The ESC is rated for 3S (i think) so it would be best to, some even run 2 and running on 4S will require the external BEC

I have a habit of using cooling fans on MM's above 4S. Definitely helps. The only thermalling I've had is when the fans aren't working.

If I run the MM with 4s and a Neu 1515 1/Y do I "Have" to put a thicker guage wire in or will the stock be fine with the stock bullet connectors? I think I may stay off the track since that's where everything seems to break or burn.

O man what a lifesaver thanks, i just charged up two 7 cell packs let them sit for a few. till they dropped below 10v and walla they run. Awesome. Now i will be a little more patient for my mmm to come.:party:

Nice! Glad to be of help.

Sunny --

Don't forget that the Eagletree response time is a little slow, and does some averaging on current. We measure 1200A peaks on our systems that the Eagletree shows as 120A peak. :tongue:

So some setups (especially those that use very low resistance motors like the Neu motors) can be tough on an ESC.


As for the voltage on the MM -- when we changed from 36 FETs to 30 FETs on the MM, we also changed from ~2.2 milliohm FETs to ~1.5 milliohm FETs, so the newer MM can actually handle MORE current with fewer FETs (we reduced the FETs to make the MM easier to build.) The MM is copper limited on how much current it can handle (the limit is no longer the FETs, but how much copper we can cram into the circuit board.)

The MMM has 36 of the newer FETs, but a LOT more copper area to handle the current, and a LOT more cooling than the MM. It handles more than double the current of the MM.

Patrick, thanks for posting, let me cut through all the technical mumbo-jumbo. I want to buy a MMM but I need it in the next two weeks, should I just buy a MM or is the fabled "Second (coming) Batch" going to be shipping soon?

Hey there Patrick,

I didn't really think about the response time and current averaging. Man, I'd love to have my cars hooked up to your machines to see the real currents under load.

But not to worry, I use cheapo Feigao/Traxxas VXL motors, so the ESC's are safe! :rofl:

Thanks for the info on the differences in the old and new MM. Given that, It's a good thing that I design my systems to top out at about 120A - 125A (albeit read off an EagleTree). The only time I've had failures were when A123's were involved, due to negligence on my part.

I also have a MMM on the way from RC-Monster. Waiting is very hard, especially knowing how much better it is than the MM. Any idea when the 2nd batch will be in our midst?

The second batch is a hot topic. I am waiting for the second batch to get my first batch esc which was sent in for repair and unrepairable. I know I and the others for repair are supposed to be at the top of the list and the second batch was expected to start around now, hopefully a word soon?

The second batch is coming soon -- we are finalizing a circuit change on the "brain" board. Production will resume about 1 week after changes are finalized.

So how long do you estimate before they will be back in the stores? I am in basically the same situation as MacII. My erevo will be here today and I really think it will drive me nuts just looking at it while a wait for an esc.

So do you have any updates on motors? How far off are we for those? Thanks

Sorry gixxer -- I can't really give a firm answer -- it depends on some testing that will happen over the next few days. The 1 week lead time to production might start this Monday, it might be the Monday after that. I wish I could give a better answer, but I don't have enough data yet to give a better answer.

Just curious, what was changed? Is it actually a design change, or a component change? I'm just wondering what those of use that have working (so far) ESCs can do to keep them working.

Component change. Nat Semi hasn't been able to answer my concerns about their switcher controller to my satisfaction, so it looks like we'll be changing to a Linear Tech switcher controller. It is more expensive, but is rated almost double the specs of the National part. We aren't positive about the part selection yet -- that's why we are going to run some testing next week.

That is great to hear Patrick! Better components = us happy

Were you eventually able to replicate the failure...

That's great news, how many will be made for the 2nd batch?

Thanks for the info. That doesn't sound to bad. The only down side is the erevo just showed up today and I wont run it with the stock electroncs (sell them while they are still worth something).

Anyways can you give any update on the nue style motors?

how cares about the neu motors :P ( actaully i really do) but first concentrate (like you have, more than expected, hope you guys dont get sick from lack of sleep!) on the MMM and get it out to the people, it wil be highly rated for sure and motor sales will follow! what id like to know is how much better are they compared to the cheap feigao's(and the other copies), medusa's and neu's?