What happened (MM and Lipo)
 

Hi all,
I have a friend that did a very bad thing, However I am curious about what happened, and of course this may help to serve as a warning to others.

Here is what the story is.

A rc10t running 3s2p 2500MAH pack, broke the diff, So my friend flipped off the MM switch to off , and removed the Dogbones trying to trouble shoot stuff. However he did not unconnect the batteries and left the y harness on also.

3 weeks later he looks at the truck. Both packs are puffed :(
Then he notices that all three motor wires on the ESC are unsoldered.

What happened?

I am wondering if the Voltage did not get low cause the MM still draws power when it is turned off? That could explain puffy packs but what about the Motor wires. Perhaps the ESC went to full throttle and the Motor over reved and heated up shorting the windings and causing the wires to unsolder?

Just some crazy a$$ guessing going on here. Any chance the ESC/motor would be covered under warrenty? I think it is about 6 months old. He bought it when there was a sale going on for a MM/motor combo 25.00 off with online code.

Anything like this happen to anybody else or is my friend just unlucky.

Highflier

I forgot and left one plugged in one time for 2 or 3 weeks, the pack didn't puff, but wouldn't take a charger. It was a 3s pack, and I was able to recover 2 of the cells, and honestly I haven't really noticed any drop in their performance. Seperated them, and charged them at .25 amp nicad setting to get them up to where they would take off on lipo setting. I don't really understand if it was switched off the the extreme draw. I could see if he turned off the transmitter, and put the truck up, without shutting off the switch, then it glitched wide open or something. That is wierd.

Can confirm that the esc still draws current when its turned off. You have to disconnect the batts otherwise you can kill your lipo as your friend found out. This is pretty common knowledge though so its nothing new.

No clue about the unsoldered motor wires though. If it did get that hot by whatever mechanism, he's lucky it didn't start a fire.

The capacitors can still draw, hold, and release current when the ESC is switched off. It is always best to unplug your batteries.

Tech Support at Castle has told me the on/off switch only effects the circuit that supplies juice to the receiver but the rest of the circuity still gets power even when switch is turned off. I confirmed this when a wire for my switch tore off the circuit board. I plugged in a 4 cell AA pack to the receiver and everything worked fine.

I had two Novak HV ESC go up in smoke the same way. They were turned off by the switch but the batteries were still plugged in. It wasn't over a couple of weeks though. It was a matter of hours on one and less the 15min on the other. They were fried, burnt, toast. I now unplug the batteries no matter which esc I'm using or how short of a period. Kudo's to Novak for replacing them under warrenty. Even though one showed signs of water damage.?:whistle:

The batteries were fine.

I took Castle's recommendation and just cut he switch out of the loop and soldered the two wires together and tucked them out of the way. Now to turn it on and off I just plug in the battery or unplug it.

i do this too, after i hit a wall at full speed on my TC cause my switch fell out and the wheel turned it off :(

I to have removed the switch. And yes he should unplug the batteries and knows that now.

Thanks for the comments but...

I would say the slow discharge caused the battery to puff but..... that would not explain the esc motor wires unsoldering from the board. Thus the question still is
what happened and do you think the motor is Fubar? Do you think that ESC can be saved? Any chance castle would warranty this quipment?

Highflier

Castle has some great CS. I had a MM that had one wire come unsoldered while I was running it and it smoked the ESC. It tooks some time but CC covered it under the warrenty. I would say the odds of them replacing it are pretty good. What kind of voltage were the batteries at when the puffed up? Must of been well below the cutoff. I've revived some lipos that were below the LVC but never had any get so low they swelled up. The motor is probably fine. Atleast my motors were never damaged from similar events.