I killed it... MMMv3 bit the dust

Well I received my v3 replacement about two days ago and fired it up today.......

e-revo
1515/1.5d
no external bec just the internal one
two 3s zippy 4800mah packs in series

it started right up the first time and hooked up to my futaba 3pm 2.4 no problem......like a charm for about 15min..... real fast and suddenly just quit...I had it set custom at 19.2 volts cutoff....low timing......everything else was default except for soft start...kept checking temps after every two runs....batts werre about 150 esc was about 170....motor 150


took it in the house and hooked it back up to my pc and couldn't get it to recognize the monster....but notices that programmer thingy got real hot


real depressing

[Silver_Flame101]

Wow..... That is exactly what I did not want to here; a MMM v3 failure. Hopefully it was just a quirk.

[MetalMan]

Overgeared? MMM at 170 makes me think so. Your batteries weren't enjoying the punishment either, apparently.

[George16]

That's the first confirmed death of a V3.

[BrianG]

I think we are all just a wee bit over-sensitized to any MMM failure, but there are bound to be failures here and there, even with a solid product...

I too think the ESC was a tad hot, especially considering it has a fan. The fact that the link gets hot when you plug it in leads me to believe you smoked part of the brains.

24/58

no smoke or fire...just quit

Wow batts at 150* That is way hot for lipos.

[hoovhartid]

hey man,
I'm gonna go out on a limb here and say that gearing a 12lb truck for over 70mph....
...you're only gonna be able to do a few speed passes before a need for cool down.

dude you're mean to your electronics.

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.8333333333333332
Other Ratio: 1
Spur Tooth Count: 58
Pinion Tooth Count: 24
Total Voltage: 22.2
Motor KV: 2700
Tire Diameter (inches): 5.9
Tire Ballooning (inches): 0
Motor Current Draw: 120
Motor coil Ω: 0.004
Spur/Pinion Ratio: 2.42 : 1
Total Ratio: 12.61004 : 1
Tire Circumference (inches): 18.54 inches (470.8 mm)
Total Motor Speed: 58644 RPM
Vehicle Speed: 81.63 mph (131.12 km/h)
Estimated Adjusted Speed: 72 mph (116 km/h) - 11% loss
Effective KV Value: 2641.62
KT constant: 0.5 oz-in/A
Motor Torque: 0.31 ft-lbs
Final Torque: 3.95 ft-lbs
Final Power: 2664 watts (3.6 HP)


not to say I wouldnt still hold the camera and wear the shin guards
call me up if you need a videographer!

[lincpimp]

Originally Posted by hoovhartid

hey man,
I'm gonna go out on a limb here and say that gearing a 12lb truck for over 70mph....
...you're only gonna be able to do a few speed passes before a need for cool down.

dude you're mean to your electronics.

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.8333333333333332
Other Ratio: 1
Spur Tooth Count: 58
Pinion Tooth Count: 24
Total Voltage: 22.2
Motor KV: 2700
Tire Diameter (inches): 5.9
Tire Ballooning (inches): 0
Motor Current Draw: 120
Motor coil Ω: 0.004
Spur/Pinion Ratio: 2.42 : 1
Total Ratio: 12.61004 : 1
Tire Circumference (inches): 18.54 inches (470.8 mm)
Total Motor Speed: 58644 RPM
Vehicle Speed: 81.63 mph (131.12 km/h)
Estimated Adjusted Speed: 72 mph (116 km/h) - 11% loss
Effective KV Value: 2641.62
KT constant: 0.5 oz-in/A
Motor Torque: 0.31 ft-lbs
Final Torque: 3.95 ft-lbs
Final Power: 2664 watts (3.6 HP)


not to say I wouldnt still hold the camera and wear the shin guards
call me up if you need a videographer!

Jesus!!! And I though my 1521 1y on 6s would be a bit much... The tires must have been 8" diamter minimum at those speeds...

[lincpimp]

Just for comparision I run a 1515 1.5d in my erevo on 4s lipo geared 19/50. It does over 40mph and never breaks a sweat. It does work a pair of trakpowers pretty good though... I have a pair of fp 4s 3700 packs that I plan to run in parallel, that should provide plenty of juice.

yea, a 1515 1.5d on 6s is a bit much...ESPECIALLY AT THAT GEARING!

I run the 1515 1.5d on 4s with 24/62 is goign 45+...

and are your batteries the 15c zippy? sounds like they are COOOOKING

[auto2]

yea overgearded BUT a MMM should shut itself off if it gets too hot no matter what is going on wrong around it.right?

[Dagger Thrasher]

Ouch, that sucks. Those temps are way too hot, though! The MMM doesn't thermal until it hits around 220F, but judging by the temps of those cells, I'm thinking that maybe ripple voltage killed the MMM? They must've been really struggling to provide the current required to get that hot, so the first thing that comes into my mind is bad ripple; and Patrick has said before that high voltage ripple from overstressed LiPos can kill an ESC.

Just an idea, but given that there haven't been any other V3 failures...I'm not sure the MMM is at fault here.

[NickRummy]

My only question is why stress a speed control only hoping that built it safety features save it? Asking for trouble if you ask me.

Those 4800 packs are 25C const. and 35c burst I believe? I'd say you were definitely punishing them! That thing had to be a bullet on wheels while it was running....

[skellyo]

I'm going to have to side with the others here. Running a 2700kv motor on 6S and gearing for 80+mph is just crazy.