Crazy ESC Failure = Fire

[TRF201-Driver]

My son was driving my Lunch Box yesterday. It was running the stock ESC, Tamiya Sport Tuned motor, 2s 30c/5000mah lipo and Airtronics radio gear. After a few minutes of him playing with it, I hear it take off full throttle. It gets stuck in a bush, but still full throttle. Smoke starter pouring from it. Immediatly, I thought it was a lipo fire and put it down and waited for the truck to burn to the ground. Very quickly, I realized it was the ESC that was on fire. I put the fire out and surveyed the dammage.

Not really sure what happened. I know my son has a tendency (when the truck is stuck against something and can't for forward any longer) to mash the gas and hold it for several seconds. Maybe the ESC overheated, but it should have thermal shutdown.

The good news is that the truck will run again. The chassis got melted in a few small areas where the ESC was. The rest is still fine. The top of the body where there skylight is got melted a bit, but it's still going to be fine.

The casualty list includes the ESC(!), servo (wires melted) and possibly the receiver (part of the case melted).

[kontemax]

Never seen this before in my life O_o

Max

[Daves956]

Most transistors when they blow just stop firing. It looks like you had a rare fuse shut failure giving full power and probably melted itself down. Unfortunately Tamiya uses Russian made transistors which are the absolute cheapest on the market and not the best when it comes to failures. You have to be glad it didn't destroy anything else.

I've seen it before but luckily the runaway and crash knocked the battery loose and disconnected. I took it apart to find out why and that's how I know what's in there.

[beefmuffin]

LiPo

[alfagta]

that is a surprise , never managed to kill one yet even running 21 turn motors ! buy your lad a cake and pat him on the back and tell him tamiyaclub forums said "good son,,,good",

[TRF201-Driver]

HA! That made me chuckle.

that is a surprise , never managed to kill one yet even running 21 turn motors ! buy your lad a cake and pat him on the back and tell him tamiyaclub forums said "good son,,,good",

[speedy_w_beans]

Time for a brushless system!

[Zac_F83]

That sucks!!!!!

[TRF201-Driver]

He's 2.5! The Sport Tuned was really too fast for him too. Maybe a 35T motor will be in store for the next go around.

Time for a brushless system!

[TRF201-Driver]

I've started the process of cleaning the truck up. So far everything has cleaned up well. The chassis is currently in pieces after its bath in dish soap. Aside from a few melted spots and some singing on the shock bodies, it looks like it will be fine. My next step is to put it back together, rebuild the gearbox and regrease it. I'm going to buy a Traxxas XL5 esc to put in it. The training mode is very attractive to me and we don't need brushless.

[super gripper]

brushless in a Lunchbox is just silly your right.

I haven't heard of an esc with a training mode before, more info and some pictures please.

[TA-Mark]

Brushless in a Lunchbox is fun! But it's not for children or beginners or a stock chassis. The kit motor is ample in a box stock Lunchbox. The slower motor (35 turn) may reduce the wheelie-ness, which could be easily remedied with some well placed weights to balance the wheelies out.

Nasty melt down BTW. Curious, where you using the long Lunchbox brass 10T pinion and the Lunchbox motor adapter, or did you remove the adapter and use an 18T Hornet pinion?

[taliesin]

Nasty melt down BTW. Curious, where you using the long Lunchbox brass 10T pinion and the Lunchbox motor adapter, or did you remove the adapter and use an 18T Hornet pinion?

Mark,

I'm curious, is there a concern with doing this? I recently did this for a VLB that was missing the motor/pinion and adapter, so I just banged a silvercan motor and 18t pinion in the truck and it seems to work fine. I was concerned about it running hot, but neither the motor or TEU-104BK seem to mind at all. No heat issues so far, but I wasn't entirely sure this would work. Not quite the wheelie machine it was before, but it has decent speed and no issues otherwise. If you have any advice or suggestions (or especially fire concerns!!!) I'd love to know. Thanks!

[TA-Mark]

Mark,

I'm curious, is there a concern with doing this? I recently did this for a VLB that was missing the motor/pinion and adapter, so I just banged a silvercan motor and 18t pinion in the truck and it seems to work fine. I was concerned about it running hot, but neither the motor or TEU-104BK seem to mind at all. No heat issues so far, but I wasn't entirely sure this would work. Not quite the wheelie machine it was before, but it has decent speed and no issues otherwise. If you have any advice or suggestions (or especially fire concerns!!!) I'd love to know. Thanks!

In high load situations like lawn, or sand, or mashing the throttle for a few seconds when it's stuck somewhere might cause issues when running the tall gearing. On sealed or low load surfaces with a responsible driver, there should be no issues. It's a bit like the high-low gearing options that are on many toy grade models.

What battery you use will make a difference too. A Ni-Cd or Ni-MH will not supply the 60A that the ESC can handle or the silvercan will draw at stall, so the battery becomes a limiting factor. Plug in a Li-Po capable of supplying 100Amps or more continuously, then things will change. That said, I wouldn't let my kids loose with Li-Po batteries. They are all using 1800mAh Ni-Cd packs, which is great for learners, and simple for them to plug and charge on the delta peak Ni-Cd charger.

[shenlonco]

Hi Lipo plus your motor plus kid driving is what caused this ..your kid was probably driving the truck slowly most of the time and with a tamiya sport tuned or any motor for that matter when you drive long at low throttle your esc heats up much faster and this is what caused it to burn up.

[Wooders28]

Curious, where you using the long Lunchbox brass 10T pinion and the Lunchbox motor adapter, or did you remove the adapter and use an 18T Hornet pinion?

I melted a mech speedo and the Tamiya battery connectors doing that very thing with the hornet pinion (many many moons ago). Super slow pick up but fantastic top end!

[TRF201-Driver]

I was using the stock Lunch Box pinion.

Here's some info on the Traxxas XL-5.

[dyahipfakta]

Xl5 and a 550 would be a great option waterproof too

[TRF201-Driver]

...And the Lunch Box lives to run again!!!

I spent nap time putting everything back together. I had an ESC from my Duratrax Baja Bug laying around and threw that in. Surprisingly, the servo with melted wires and the receiver with a partially melted case still work. I installed everything along with the Sport Tuned motor. After I washed the tires/wheels and body and put the truck back out in the garage for my son to discover. His reaction will be worth all the work.

When funding allows, I still plan to get the Traxxas XL-5 esc so that both of us can enjoy it. We'll hope for no more fires...at least not this month.