I think i have found the limit of my MMM V2

[joeling]

My X2 conversion has been running in a very stable condition for quite a few weeks now. Yesterday I took it out again for a bashing session at my local track harassing a bunch of nitro buggies. Believe me, the guys felt the heat as one of them commented that he was under pressure from my truggy coming fast tail gating him.

Anyway, after quite some time, felt like an hour but closer to 15 minutes maybe, I thought I've hit the voltage cutoff as the X2 was pulsing at the throttle. Changed the battery to a fresh one & experienced random shutdown especially after big jumps. Did some check check & the deans connector on the esc side had a lot of burn marks on it. Maybe this was causing poor contact so I changed it. However, the problem didn't really go away. Occassionally, shutdown would still occur. By shutdown, I meant that there was completely no power. No BEC supply as well. I did a switch off & back on & things were back to normal again.

The MMM V2 in the X2 was slightly modded with the fan directly connected to the 5V supply at the receiver. So, the fan was on at all times. Just before I packed up for the day, I noted the temperature of the battery (PQ 5S 5000mah) was in the mid 40's deg C, the MMM was around 60+ deg C while the motor was about 50+ deg C.

My LHS owner who runs nitro exclusively commented that maybe it's the thermal cutoff at work. What do u think ?

Some additional info. The track was dry & dusty that day. So traction was limited. Ambient temperature was hovering around 30deg C not too hot nor to cool either.


Here's an old pic of the X2

Regards,
Joe Ling

[MetalMan]

Have you considered removing the switch? That could be the easiest fix if it is the problem, and several other members have had MMM issues go away after removing their switches.

[e-mike]

do you have check all your wire???so i never seen a mmm who reached 140f and then the thermal cut off come in!!??

[Sammus]

With the newwer 1.20 firmware it wont let you run again until its cools sufficiently, sounds like it could be a wiring/connection problem somewhere. Either that, or as just happened to one of my V2s (common story on the board) they start shutting off randomly until they dont work at all...

[What's_nitro?]

I'm banking on the switch being at fault. Like Sammus said, if it were the TCO it would not run again until it cooled down. Switching it on/off wouldn't help.

my bets on the switch too.

[joeling]

Hmm...I better check the switch then.

Regards,
Joe Ling