MM/Feigao cogging

[glassdoctor]

AA, I have no answer for why the MM would decide to cog... it's been very rare in these setups.

BUT, once it did cog that bad... something may have gone wrong in the esc... like fried caps or something. Try swapping out the MM and see if the porblem follows the esc or the truck.

I had a MM cog real bad once and after than it was a constant problem... it smoked something cause it was unusable after that even though it did continute to operate (never smoked literally). I still need to send that one in to get fixed...

AAngel, what motor are you running? Depending on the motor you may still be over geared. Or what GD said.



On my CRT I'm running 9/51 on 4s with a 2200kv Neu motor/ Quark esc. It runs really good and fast. I can tell I'm a little over geared though. It was fine while the outdoor temps were low, but now that it's getting warmer I can go about 10 - 12 minutes before it thermals. I really should have gotten a much lower kv motor and I would have been fine.

GD, I wouldn't say that it's a constant problem, but now I'm always worried that it will happen again. I'll pull it apart and see if I can visually determine if anything is fried. If I find something, I'm sure that digikey will have it in stock. If not, I'll have to send it in and pay whatever it is that they charge.

Cart, I'm running a Feigao 7XL. I'm not having any thermal problems. It's just the cogging that's making me crazy. Once it's rolling, it's never a problems. I usually isn't a problem taking off from a dead stop either. It's just once in a while.

I suppose that it is decision time. I'm going to have to do something about this unit, but I don't like to wait, so I'll have to order something else. Do I just get another MM for ~$135, or do I bite the bullet and spend the $300+ on the Quark?

[BrianG]

That is a tough decision. Time to list the pros and cons of each and figure out what feature/spec means the most to you...

Originally Posted by BrianG

That is a tough decision. Time to list the pros and cons of each and figure out what feature/spec means the most to you...

or get the mm replacd for 50 bucks (thats castles flat free replacement no matter what happened to it rite?) and use it till the mmm:018: thats the best idea imo

I tried to contact Castle by both email and phone and no dice either way. I don't know what's up with Castle lately, but the support has been down. I guess I'll try to call them again.

Just to keep anyone interested up to date. If you are thinking of doing a Muggy (or similarly heavy truck with heavy, large tires) with a MM esc, there are a couple of things to keep in mind. Apparently, the Muggy in its stock attire is too much for the little MM on 4S to handle.

Today, I got all of the vehicles that I converted and started playing musical chairs with all of the components. I swapped motors and escs among all of them and found a couple of things. What lead me to this is an email that I got from Joe Ford. He suggested that I do what I did and suggested that, if all of the setups exhibited the same behavior, it was an off the line current draw problem.

When geared 14/46 with the stock 40 series tires, the Muggy cogged no matter what esc and motor I had in it. At 12/46 it began to run about like I wanted it to with the 8XL. At 10/46 it was acceptable with the 7XL. At 10/46 with the 8XL it was as smooth as silk, but the top end really suffered. If I had to guess, I was getting about 30 mph. Hardly nitro stomping material.

Although I emailed Castle with my results, I'm not going to hold my breathe waiting for a response. Phone calls aren't getting returned and emails take days to exchange.

At this point, I have to take a guess and say that the Mamba Max has a really hard time getting a 13lb vehicle with tires of that diameter and weight moving. I'm picking up some Maxx size wheels and Crimefighter MTRs tomorrow. Hopefully the reduced diameter and (more importantly) reduced weight of the tires will allow me to gear the Muggy for performance similar to that of my buggy on the track.

Unfortunately, before I did all of the swapping, I assumed that something was wrong with the MM and I was going to have to send it in. I ordered another to use while mine was being repaired. Now I have a MM that I have no need for, especially knowing what I now know. I could have put that money on a Quark. OK, now I'm just whining.

GD,

If you see this, did you ever try 100% punch control with your MM esc and the Neu motors? If so, what effect did that have on the cogging? Do you notice that your 1512 in the buggy cogs less than the 1515 in the truggy? Have you tried undergearing just to see what effect this has on cogging?

I was really wanting to get a new motor and considering the difficulty of getting a Lehner, I was going to go ahead and get the Neu for the truggy. I was thinking the 1700kv 1515. Now I don't know. I'm all over the place with indecision. My wife's about to kill me, because I told her that going to electric was going to SAVE money. LOL.

You sound like me. Electric is supposed to be easy. I have a pile of stuff that didn't work so well. Over the weekend I fried 2 motors somehow. One of them was a Neu 1515 2200kv. A phase wire was real loose just barely touching. Must have overheated. Now it just sputters. Oh well.
For a big boy like that you may need one of the big MGM esc's. You may run into thermal problems with the Quark even with the biggest heat sink added.

[glassdoctor]

Well... I have messed with 100% punch a little, in my 8ight. It didnt do anything wierd..... only made it have lag on take-off like a rich bogging nitro.

I dont think the truggy with the 1515 is worse than the 1512 in a buggy.. but I also have the truggy geared more conservative than you... low 30s probably.

My buggy doesnt cog much at all with the motor wires soldered well... only a hard launch from a dead stop will make it cog even when geared tall. But the muggy is a different animal with those tires...

You will find the racing rubber much different I think.

My CRT weighs in at 11.5lbs with the big 12k pack...

[glassdoctor]

Yeah.. this cutting edge brushless stuff can be a headache sometimes... and expensive.... but its a different pain than nitro. Nitro can be a constant all day hair pulling expereince.

brushless can be that way.. but it normally is more setup and r&d headaches at home... not surprises at the track

[gixxer]

gd, was there a noticeable difference after you directly soldered the wires? reason I ask is I have changed all my wire to 12g, and it made a difference but i still get the occasional sputter.

If it takes a difference I will just directly solder those too, I only have two motors (7xl and 9xl) anyways so its not like I should be changing motors that often.

thanks

[glassdoctor]

Yeah I would say it makes a noticable difference... it still can cog in certain situations, but it's very controllable now. The low speed, low throttle cogging is pretty much gone. (taking off slow... easing on throttle rather than punching it form a standstill)

Before it would cog fairly often no matter how much throttle imput... now it only cogs sometimes on 'rabbit starts'... like 3/4-full throttle launches.

Once it's moving even a few inches it's very rare now to see it cog no matter how hard you punch it.

So basicly it's pretty easy to drive it without cogging... you see real quick what NOT to do. I learned to not punch it from a dead stop... that's about it.

gixxer, I was using the big 6mm connectors from Neu, but with all of the trouble I've been having, I said screw it and direct soldered all of my connections. I've found that catching a cold joint like those is pretty easy and it's just one less thing to worry about.

GD, if that is the only cogging issue you're having, I might just go ahead and order a Neu motor for my truggy. Maybe having a more efficient motor with more nuts will run better. I'm thinking 1515/2.5D for more torque. I really wish that I have a 9XL laying around so that I can try that out to see what effect a lower turn motor geared up would have.

Oh...I can't wait until the day that I have everything settled and I know that I won't have any surprises.

I was very hesitant to pull the trigger on the Quark. I know that Mike had good things to say about the Quark/Neu combo, but the thermal path worries me. The manual scared me a bit too. LOL. I also checked out the MGM controllers and the ones that I can justify spending money on really don't impress me with their specs. Maybe I should just quite all of this whining and get myself a Neu motor. At least I'll have it, even if it doesn't play nicely with my MM controller. It will give me something to look forward to in the Monster Max.

GD, that's kind of funny, with the problems you're having, because with my problem, if I punch it from a dead stop and it cogs, it strips the spur gear.

Will going with the conventional monster truck tires, if you know, make much of a difference from the 40 series tires?

[gixxer]

gd and aangel thanks. I think I will just go ahead and solder that up directly then. It doesn't happen much now but if i can get rid of it all together that would be awesome.

one more question. how much of a difference do you think I would notice in temp if I went to a neu instead of the feiago 9xl I am running now? Right now on a 5s pack the motor is in the 160-170 range.