Lipo puffed and caught on fire!

[Dbnjzb]

So, I was running my RC8.2e like normal and out of nowhere this happened! ESC was cooked but rest of car is ok I think. Why would this happen if I do take care of batteries? Crazy!

 

[Metalhead Matt]

What were the temps? Over gearing or over discharging are the usual culprits. I see a lot of grass....

 

[Dbnjzb]

What were the temps? Over gearing or over discharging are the usual culprits. I see a lot of grass....

This happened right after a 10 minute break. Don't know temps and yes I was in the grass when happened. The batteries did sit for awhile in between runnings, oops! Maybe that was why? At least it happened with this Hobbyking ESC before I get my RX8! Thank you!

 

[Metalhead Matt]

You really gotta watch temps in grass. Gear way down.

 

[Dbnjzb]

You really gotta watch temps in grass. Gear way down.

Hmmm didn't know that, thanks!

 

[Metalhead Matt]

Like ya said, at least you didn't have really expensive electronics on board! Grab a selection of pinions or at least one that is 3-4 teeth smaller than stock. Then shoot for around 150 degrees on the motor and esc. Any hotter is getting close to the danger zone.

 

[Dbnjzb]

Thanks, I was running a 20t also have 11, 15, 18, 19 tooth. I'll check temps and if high try something smaller! Thanks! Now question. The pinion could cause the batteries to have this problem or...?

 

[Metalhead Matt]

Sure. Tall gearing requires more torque to get the tires moving. Add a high resistance surface like grass and it can be too much for the esc. A good example is a car tire. Push a car tire as hard as you can on flat pavement and it'll roll damn near until it hits something. Push the same tire in grass and it'll roll 30-40 feet. The grass eats all the inertia, absorbs the force and the tire stops.

 

[Grave]

What were the temps? Over gearing or over discharging are the usual culprits. I see a lot of grass....

IMO I stay away from running in tall grass myself....

 

[Dbnjzb]

Sure. Tall gearing requires more torque to get the tires moving. Add a high resistance surface like grass and it can be too much for the esc. A good example is a car tire. Push a car tire as hard as you can on flat pavement and it'll roll damn near until it hits something. Push the same tire in grass and it'll roll 30-40 feet. The grass eats all the inertia, absorbs the force and the tire stops.

Great analogy and explanation! Thanks so much it makes sense now! No more grass for me! Rather not chance it.

 

[SchrodeMode]

Also, make sure you have a high enough C rating, too low and you'll over stress the battery and ESC. Someone correct me if I'm wrong, I'm still learning electrics & lipos.

 

[slowngreen]

Grass is just a killer. If its not on the batts, its gonna be on your esc or motor.

Esc still looks usable though, is it? Wires still intact. Lucky it wasn't a Mamba Monster or some crazy expensive setup.

 

[Metalhead Matt]

Most of my play area is grass. More clover than grass really. So I'm forced to deal with it. Usually just gear down 3-4 teeth from stock and run heat sinks. Yeah, grass sucks.

 

[hamz9561]

Nice carnage pics! We all have days like yours running our "toys." Like Matt said gear it down about 3 or 4 teeth and that will help with the heat.

 

[Dbnjzb]

Nice carnage pics! We all have days like yours running our "toys." Like Matt said gear it down about 3 or 4 teeth and that will help with the heat.

Thanks!

 

[Dbnjzb]

Grass is just a killer. If its not on the batts, its gonna be on your esc or motor.

Esc still looks usable though, is it? Wires still intact. Lucky it wasn't a Mamba Monster or some crazy expensive setup.

Yeah ESC burnt up inside a little too! I junked it don't want to risk it. I'm saving for an Tekin RX8 so thankfully this happened now and I can learn from it!

 

[Dbnjzb]

So, what's the longest u should store a lipo at full charge??

 

[Metalhead Matt]

Really never. Storing them at 40-60% is ideal.

 

[Dbnjzb]

Thanks!