Mechanical brakes like the nitros use...

Wow, that is unbelievable. I didn't realize such a mod could be done on a BL machine like the Revo!

Well, vehicles converted from nitro to electric will be easier because it was designed for mechanical brakes (has the discs, pads, linkages, etc), but electric-specific models like the E-Revo may require some fancy modding since they are not initially set up to have mech brakes. But it can be done.

Just be aware that if you go to mechanical brakes, you won't have reverse unless you use CH3 to activate the brake...

Sounds like a nightmare. A better solution would be to just watch your gearing and lipo combination and you would ASSUME one would be just fine.

However, on something like an LST2 conversion, it sounds like a possible good idea and much easier! Which btw... and LST2 conversion is in my future anyway!

It can be. Personally, I would only use mechanical brakes in heavy vehicles and/or setups that use high voltage (6s+) because back-EMF generated during braking becomes considerable at higher voltages...

CC HV-200 @ 90v FTW!!!!
hmm....barbie jeep anyone.
shaun

I'm starting to buy into the theory that running the MMM V3 with 6s is possible, but it comes with "use extreme caution".

Maybe it's just me, but that sorta goes against CC's marketing for this controller. They make it sound like 6s is the only way to go. But i'm starting to wonder if maybe 4s is the sweet spot, and 6s is for occasional use only. I dunno though.

That being said, I might pickup a set of 2s Lipos and run them together as one 4s. My only question though, is do they make 2s packs with a discharge rate of 30c? Or do only 3s and beyond supply that? The reason I'm asking, is because I'm thinking of buying some Zippy Flightmax Lipos. I seem to recall hearing that if you're going to buy "cheaper" Lipos to run w/ the MMM, you need to make sure they are at least 30c

Is that accurate?

You should really just post some links on what you are considering. You can get 30C 2S packs just like you get them in 3S packs, just depending on how you want them built. I dont think they offer the 30C is 2S for the flightmax lipos. Just the C rating is not going to help. 2200 30C lipos wont work, but some 8000mah 20C lipos will. Are you looking at the 5000mah lipos at 20 and 30C?
You really want to look at the continuous current rating of the battery. I think someone posted 120A or over is a good number and I think I agree. So some 25C 5000mah packs should do nicely.

Hey Bondo... thanks for the link! I hadn't looked at that brand yet.

I was thinking of getting some of these to have when my Flightpower 3s's are charging.

https://www.hobbycity.com/hobbycity/...idProduct=8587

Maybe those aren't a great choice though. I guess I'm now scared to run 6s in my ERBE for fear of smoking the ESC. But maybe that shouldn't happen if properly geared, and maybe then I shouldn't be concerned. I'm just now all paranoid that running 6s w/ the MMM is literally like playing with fire! I shouldn't have to be worried though, esp if CC is advertising the MMM as such, but I just don't know. I'm not convinced that the MMM is a RELIABLE 6s capable ESC. Maybe it is, with the right tire and gearing combo. But then how much you brake becomes an issue, terrain, etc. I just hate having to be now be paranoid whenever I hit the brakes.

I don't want to get into a debate here... but does Tekin provide the same sort of warranty and repair that CC does? just wondering...

I think running 6s is a bit excessive personally. With 4s there is more power is on tap that can be used when bashing anyway ?
I have 5 M.M.M. and a couple have had hundreds of runs using 4s with zero issues, I have several friends whom like the 5s & 6s with their trucks and these guys have problems occasionally. Usually heat issues and other minor stuff,no smoke letting (yet).
When we are out running together even though they have more power on tap they can't use it because of where we run,surface,obstacles ETC you just don't get a chance to wring it out.
The Castle ESC is a awesome affordable controller but I beleive a lot of extra care and consideration to the set up has to be made to run reliably with 6s to do it with no heat issues and do it safely. Then theres always the luck of the draw that some of these guys who run 6s might have a defective ESC, shit happens.

From what I've read about some guys experiences with their problems Tekin was right on it resolving the issues. Same great customer service as Castle

I agree with Bondo. 6S really isnt required for a 45mph or below setup. I was just hoping to milk cooler temps with my 6S setups, but maybe it just doesnt matter. 4S will get me the speeds and torque I need given the MMM current handling abilities. On 4S the controller is going to get warmer than what I would like so I figured a 6S setup would be better for cooler running electronics. 5S has been the sweet spot for me for the 2200 combo in terms of temps, power and reliability. Even on 4S there is enough power on tap to shred as many RC parts as you can buy.

One thing I forgot to mention, In most of my trucks I have 6.5" or larger tires and geared for 40-45mph and live in Fl. My ESC fans very rarely come on with 4s.

A rather broad statement with nothing really backing it up. In a revo, yes 4s can be fine, however in heavier trucks like an LST2 it makes a world of difference. The biggest advantage to higher voltages is the ability to use lower KV motors and the ability to keep the same performance while lower amp loads.

6s in itself is fine, but people should not be using the heaviest wheel/tire combo then gearing for 60+. Then they wonder why the setup blows. 99% of the failures I see on here on 6s are setup related.

Hence the "personally". In my LST2's I run 4s with no probs,my buds who run 5s & 6s in there LST2's have problems. It's just a general statement based on my experiences. Not rules or guide lines that anyone has to follow ?

I do agree with your 6s setup reference

Please don't rip me for posting this thread from the TRX forum. But I thought it was worth noting.

http://monster.traxxas.com/showpost....2&postcount=44

Doesn't seem to me his setup was all that bad at all. But it seems we may not know the whole story. I dunno.

Well... maybe I'll pick up some 2s packs, or maybe stick with 3s and not worry about frying the ESC providing I'm geared to run those big tires, and about 40mph tops. That's plenty fast for what I do. The ESC shouldn't fry on 6s alone. It's got to be combo of things. In my case, I fully realize now that I was overgeared and hadn't taken that into consideration when mounting up the tires. I was just so excited to run them, that I spaced that little detail.

I really don't think people fully understand the impact tire/wheel combos have on their systems. It's not just dead weight which is one thing, it's rotational mass which has a much greater effect pound for pound in regards to stress than virtually anything else. If you are going to do speed runs (in a monster truck anything above 50) then you need to try and get the lightest tire wheel combo possible. It's not just the acceleration but the braking which greatly affects your system. Even HPI states in the Flux manual to use phaltlines when doing high speed runs.

I would also note that a thorough inspection be done of your vehicle after each run to check for binding and for any items the could be lodged in the drive train. I know for a fact both the HPI and TRX manuals state do this on all their RTR's.

As for the TRX forums, I gave up posting there. People just whine and moan when you explain to them there are limits on these systems.

I have been running 6s succesfully with a V2 MMM for a year now in my E-Revo, E-maxx 3905 and LST2 conversion.

yep, another one here. Reading all these stories I kept thinking of how to attribute it to user error, till mine did it today.

Brand new MMM, ran about 20min in my revo geared very conservatively. Went to plug in my battery and it made a much bigger spark than normal. melted one of the metal connectors and some of the solder in the battery packs (breaking the circuit).

I plugged it in on the bench with 2s A123, and it armed fine, made tones etc. Then I plugged in 6s lipo - big spark and a flame (about the size of a cigarette lighter flame) out from the where the neg battery wire goes in. Unplug the battery, the flame goes out. Plug in 3s lipo - arms fine, plays tones and the right lights etc, but I can see all sparks and stuff inside next to that neg battery lead, and something glowing. It still seemed to work, I don't really wanna push my luck though so I've boxed it ready to ship out asap.

Sounds like it could be a fet shorting or something thats causing this - weird that it did it just on arming, and even after the flames, it still seemed to be working.

^^ that is some good info and testing:yes:
could prove valuable to the castle staff, maby put it in the MMM failure sticky at the top of the forum?

Mamba Monster flammage
 

This will explain it all....
http://www.rc-monster.com/forum/showthread.php?t=21973

I wish people would quit posting it, that doesn't explain ANYTHING. All it does is show that you get voltage spikes under braking, not how an FET burns out when the ESC is arming.

This just looks like a faulty FET, nothing more. Perhaps a better FET supplier is required?

Yeah... I reckon its the same as what happened to muted, plug in, arm, flame.

Theyve got some fancy new secret FETs for the MM pro, here's hoping they upgrade the FETs on the Monster... I doubt they wont, its probably the main reason they sourced the new fancy ones in the first place.

Well... I still don't have my camera to take pix of the motor. So instead, here is a screen shot of a Neu motor, and I just drew on it to represent what the coils look like.

As you will see... the wire from one of the three motor wires is what is burnt looking... and I'm guessing that can't be good. So, did the ESC cause that to happen, or did the motor fail and fry the ESC? We'll probl never know.

I called and left a message for Neu to call me back late on Friday, but haven't heard anything yet. I'll follow up on Monday I guess. I'm assuming that the motor is going to need repaired. I doubt that I'll get lucky and it not "be a big deal". I've not been able to test the motor either. I'm scared to when I get my ESC back, for fear it could smoke the ESC! I'll see what Neu says.

http://i143.photobucket.com/albums/r...ucoilsdraw.jpg

Remember that the motor pulls current, the esc doesnt push it, so in likely hood a phase shorted out somehow, causing the esc to fry also (nothing like trying to deliver current to a shorted piece of wire to cook your FETs)...

Is there any damage to the wire/ insulation where it enters the motor can?

Hey Neil...

No apparent damage to the wires leading into the can, no. Yer talking about the Blue, Red, and Yellow wires right? They seem ok. But I noticed that whatever wire has blackened, it's that way thru the entire can because it's the same way on the opposite end.

SURELY this the motor is going to have to go in for repair to Neu right? I'd have to assume it's repairable too. It would need rewound, but i'm sure it can be fixed. The motor spins freely by hand, but that's doesn't mean much.

My motor wasn't even plugged in...

The motor will definately have to be sent in for repair/replacement, but Im not sure whether Neu will cover it under warrenty though- they could argue the esc was to blame, or user error, or act of God- until you talk to them and they've had a look at it, its in the lap of the BL Gods...

Ok, here is an update on where I'm at. Still waiting on the MMM to come back from CC. However, something interesting has came about regarding the Neu. I sent pix to Neu and they responded saying that it looks like one of the wire leads had shorted, which means it will have to be sent back in for repair. He said that they would have to replace the stator.

A friend of mine was telling me that Neu now does something different with their leads because they were having problems with them shorting out on the can. This makes me think... what if the motor shorted out and THAT is what smoked the ESC?

YES, I was overgeared, and YES that isn't good. But as I've said before, I hadn't been running the truck hard AT ALL with those Moabs, only by PURE LUCK. My situation wasn't such that I was able to get on it. I was only putting around the yard and low to med speed, and only for about 20min tops. Sure the tires could have did the ESC in, but I don't think the ESC fire caused the motor to short. Wouldn't it seem more like the other way around? Just a thought.

Thanks!

Im sure thats what I've said about 3 or 4 times.... :whistle: :wink:

:rules: :lol:

Sometimes this section of the RCM forums reminds me of another forum........:whistle: I'll let everyone figure out "which forum" by their own clever deductive reasoning. :wink: