What causes lipo fires?

[aj0170139]

Ive heard and seen a few pictures of cars smoking. What causes lipos to catch fire? What temps are safe for bat, motor, esc?

[ksb51rl]

The Lipo Sack marketing department.

[bigfol]

Gearing to tall, low c rating batteries and high temps, I ran all weekend at the farm on short grass geared, 62spur/22 pinion with no problems, then decided i needed more speed and geared up to 54/25 and my erevo had a complete melt down, blew the caps in the MMM and it caught fire, the lipos went up in flames the whole thing was a melted plastic mess by the time i got the hose to it. Never mind it was my own fault, now i get to build a complete new one. Oh well it only money!!!

[afterdarkgames]

PEBCAC error

(Problem Exists Between Controller And Car)

...and usually proceeded by "hey watch this" or "here hold my beer".

A little bit of education, pre-inspection, and common sense would prevent MOST of the lipo fires. There are a few that are manufacture related but they usually show up the first time you use the battery (also another reason it is good to run it through the cycler on your battery charger a few times before you put it in your truck)

[Mammuth]

The Lipo Sack marketing department.

Nope, it's another factor the responsible of the fire, it's called " chemistry ".

Lithium paired with oxygen react together triggering a fire show.


Off road cars may incur into hits, due to their own nature, therefore producing a hole into a lithium cell is not an option to exclude in advance.

Then, those fire reactions may be also triggered by a wrong way to charge LiPos, but that's not the case aj0170139 is referring to.

[Revo¹]

Actually, it's almost never the batteries that catch on fire, instead it is the ESC that catches on fire. But, in a lot of cases, the batteries are the cause of the ESC catching on fire.

[billyboy]

Actually, it's almost never the batteries that catch on fire, instead it is the ESC that catches on fire. But, in a lot of cases, the batteries are the cause of the ESC catching on fire.

Can you please explain why this is the batteries fault?

[hoovdog]

Can you please explain why this is the batteries fault?

In short the batteries cannot supply what the ESC is demanding so current goes crazy, heat, etc. then poof!!

[Rusteh101]

Things that can make the ESC demand more current than normal can be things like binding somwhere in the driveline, geared to high or any general excess drag caused to the truck like running through long grass.

So your batteries may run perfectly for hours and hours running clean bearings with stock gearing on road but if one of your bearings seize, you change your gearing for more top speed and you go bashing in grass you're going to pulling a lot more amps and could possibly blow the ESC because of this. As such the above failure would be down to user error an not a problem with the controller itself.

[ksb51rl]

Actually, it's almost never the batteries that catch on fire,[/B] instead it is the ESC that catches on fire. But, in a lot of cases, the batteries are the cause of the ESC catching on fire.

Yes, see my earlier post, which was mostly a reaction to all the paranoid people who point to the youtube videos of LiPo batteries exploding. Never mind that they were intentionally abused or overcharged.

I realize I have not seen everything (by a long shot) but it seems to me that a well-kept and cared for LiPo pack is going to neither catch fire on one's work bench nor in one's vehicle.

Nope, it's another factor the responsible of the fire, it's called " chemistry ".

I'll try not to read that as having a condescending tone.
If you don't think that there is purposely generated hype regarding the "dangers" of LiPo batteries, then you are not close to as cynical as I am.

[Revo¹]

Can you please explain why this is the batteries fault?

The MMM has strict requirements, and needs a minimum amount of amperage (discharge rate [C] & capacity), which isn't always met. 9 times out of 10 when an MMM fails, it's because the user chose batteries that did not meet the requirements of the MMM or their application. Because of this, the ESC tries to get more power from the batteries than they can provide, and the ESC fails. There is a thing called "ripple current", which is made much worse by batteries that don't meet the requirements of the MMM or the application.

Even if the batteries meet the bare minimum requirements, over-gearing the truck or running huge heavy tires, or driving the truck beyond what the batteries can handle, all will cause the MMM to fail because with the over-gearing and/or added weight makes the batteries no longer meet the requirements.

This is exactly why I created the battery chart I did, and why we always say to buy batteries that produce more amps than you need just to be safe.