MMM 0.5 second shutdown on 6s

[shaunjohnson]

i have heard a few people talk about this.
i noticed when i was doing some speed runs (40 mph speed runs LOL, i'm too scared to gear it for a big balled guy speed run)
and i noticed my MMM shut down for about half a second at around the half throttle mark (that's about 1/3rd total throttle on the throttle curve).
other than that i have no issues with my MMM at all.

just wondering if anyone knows something i dont about this...umm...what do i call it lol.

just simply the fact that ive seen/heard a few people have this little thing going on.

shaun

[BrianG]

If geared high enough on a heavy-ish vehicle using batteries that aren't fully up to the task, the voltage could be dipping below the LVC point briefly. To verify, gear down a tooth or two, or shut off the LVC temporarily and try it out.

[shaunjohnson]

it's definatly not too much load on the lipo's.
zippy-H 5000mah 20-30C 6s and geared for 40mph.
motor temps are like 120*f MAX and lowering the teeth count didnt help the issue.

i THINK i was running 17/68 on a 3905 tranny, so that does come out a bit higher than 48 mph so i guess not too wimpy gearing. but temps for that day on the motor never say 110*F and the ESC never hit 150.
that was a MMM combo (2200 of coarse)

my mate has the same thing, he's running 15/68 (42mph) on the same 6s batt and his temps were about 100, needless to say his fan never came on either. but he was also running a mudusa 70mm 2000kv (which i think is a supirior motor to the castle new )

i dunno, i figured it might have come down to firmware, we are both running the new stuff (not 1.20, next one up what ever that was hehe)

not that it's a problem just thought it might be worth looking into.

shaun

[Sammus]

medusa is in no way superior to the castle neu, thats a ridiculous statement.

And zippy-h and poor quality batteries, geared for 50mph it wouldn't surprise me at all if it were the batteries to blame.

[lincpimp]

Originally Posted by Sammus

medusa is in no way superior to the castle neu, thats a ridiculous statement.

And zippy-h and poor quality batteries, geared for 50mph it wouldn't surprise me at all if it were the batteries to blame.

I have to agree that the castle neu is superior to the medusa. The design is similar, but the rotor diameter is bigger and I personally feel the internals are of higher quality.

Zippies are decent lipos, and I am not sure that they are not up to that task. I have noticed that my MMM will cut out under hard throttle when under some power lines... It is not as bad with my spectrum setup, but was much worse with a fm radio. Right next to my shop, and it seems to be worse during the day...

[BrianG]

I agree. Zippies are a very good bang-for-the-buck deal, but they aren't top of the line. The symptoms you describe sounds very much like you are hitting the LVC point momentarily. Under acceleration, current is high and voltage dips. If it falls too low, the LVC kicks in. When that happens, the load is removed so current is reduced and voltage climbs back up and goes above the LVC point again allowing normal operation.

If you don't want to do the previous suggestions, try accelerating more slowly and/or increase punch control on the ESC. Both of these will help reduce the current spikes (and voltage dips).

I suppose it could still be the firmware, but this is an uncommon firmware issue. Or it could be something else. But until you troubleshoot to isolate the problem, you are just shooting in the dark.

[eovnu87435ds]

+1 for the power lines as linc said. its the only place where mine stops like that. and that is even with spektrum dsm. i guess the electrical noise is enough to cease communication with your Rx. try getting a servo tester, with a couple hundred feet of servo extensions. plug it into your MMM and see what happens as you take a speed run!

[shaunjohnson]

yeah i understand where all you guys are comming from.
zippy not top-of-line.
but me and my friend try really hard to drive setup friendly, meaning low amp draw setups and no hard punching of the throttle.
i think my punch is set at 80% and the throttle curve is pretty gradual.
i know i might seem like a bit of a A hole but im not ready to blame it on batts yet

and yeah i kinda didnt make my statment about the medusa thing properly
the castle/neu is a tougher motor, but the medusa runs a bit cooler and has much less cogging, but it lacks rebuildability and prolly has smaller main bearings.

power lines...well we both run spektrum DSM 1 systems (DX2 and DX3s) and he has no power lines at his place...

so hte only thing left is hte LVC like you guys said...and again, no make sence to me as we dont push the batts hard (for that 50mph setup it is a pretty gradual wind up to top speed)

shaun

What is your LVC set at? and how many cycles are on your packs?

Just for the record, I run an E-revo with gearing ranging from 40-65mph and never hit LVC (because of amp spikes, I have because of runtime) with more aggressive settings on a MMM. Normal timing, no punch control, linear throttle curve. I use a 3.3V/cell cutoff, and have used Zippy-r (4800mah), Zippy flightmax (5000mah), and Enerland (5000mah) based packs in these setups. The Zippy-r and Enerland packs have about 100 cycles and still work, their IR has gone up so the punch is less, but they still work.

[SpEEdyBL]

Originally Posted by shaunjohnson

and yeah i kinda didnt make my statment about the medusa thing properly
the castle/neu is a tougher motor, but the medusa runs a bit cooler and has much less cogging, but it lacks rebuildability and prolly has smaller main bearings.

if the castle motor cogs worse than a medusa on a Mamba Monster, then there is obvously something wrong unless you are refering to absolutely no cogging with the medusa and are otherwise very picky. if your batteries aren't up to task (well they may not be for the castle-neu even if they are for the medusa) then you might get increased cogging. Also note the possibility of the zippy solder tabs on the verge of breaking. The construction quality of those packs seem questionable, and a poor connection anywere will cause cogging. A poor connection anywhere on the battery side will cause the lvc to kick in under a load.

[shaunjohnson]

yeah you are right about the zippy pack construction...that's why after i killed one and discovered this issue...all of my packs have special treatment, they have all been re-soldered with deans solder and the ends dipped in plasti-dip (too bad if i have to re-solder again ) to make em water resistant.

my LVC is set ay 3.2v on auto lipo

yeah i'm pickey with the cogging thing...not that it matters..just cool to have less the castle motor is pretty good and i'm not dissing it but when you commence startup of the motor it coggs a tiny wini bit more than the medusa.

shaun