Lipo gone thermal!

[Nitro Blast]

Well I can now say it has happened to me. Had it not been for my fire-proof charge container, I cannot say I would be writing this with a happy mood

I was charging my first bought, WBC #1 battery. Yeah, an original china cheap as hell lipo that is a couple years old now.

No fault with the charger, no fault with the operator, a simple recharge and a scary few minutes.

I was in my shop working on the Mentor's lights (adding a stripe up the rudder, and on the bottom of the fuse), and put the battery on a (left nameless) trusted charger. About 10 minutes in, I leave and go refill the coffee, and return. Another 10 minutes and I think I am smelling something.... I turn and notice the smoke coming from my charge container!

The charger did not fault out, or time out, it was charging at about 1.75 amps. I got no alarm other than from my nose.

I take it outside and wow.... close call as it is hot and pufffing, and venting hard. Sorry if the pics dont get the smoke well, the breeze was blowing.

I am so happy it is my REGULAR PRACTICE to charge in a fire safe container or a Lipo Sack. I've never had it happen before, but now I am glad I payed attention and took proper risk mitigation practices to heart.

[tdrnmartin]

scary! Im glad you caught it. safest way to charge is while you watch it.

[xmech2k]

Why'd it have to be a Wattflyer batt?

[mumblinaviator]

Originally Posted by xmech2k

Why'd it have to be a Wattflyer batt?

Yikes. Seriously. I'm still flying two of those from the original group buy...

I transport them in ammo cans, and charge in clay pots.

[flydiver]

Out of curiosity, had this one ever received crash damage (even a tiny bit crumpled) or had to be 'revived' from below 3.0v/cell somewhere in it's past? It was one of your early lipos you said so it may have had some mishaps along the way.

[constantCrash]

I'd also like to know if it was being charged through balance connectors, or via the power wires only.

[Nitro Blast]

Charging via main leads only, the balance leads came off months after I got it.

I didnt notice any damage to speak off, and it had not had any mishaps while airborne.

I dont think it was pulled down too low, it had no puff puff before.
In all accounts, it seemed like a 100% normal battery before I let the magic smoke out.

[flydiver]

Originally Posted by Nitro Blast

Charging via main leads only, the balance leads came off months after I got it.

I think you are going to get a lot of 'there you go' from that info.

Cheap lipo, right? Probably a Long Max with crappy leads. Good lipo, nasty bad balance taps.
The less expensive the less likely the cells are well balanced to start. The middle cell on a pack is ALWAYS warmer, and ends up getting hammered a little harder over time. Without the ability to balance this discrepancy between cells, especially the outer and inner cells, will get larger over repeated cycles.
Middle cell ends up getting overcharged.....sometime.
Not a sure bet, but a pretty high probability.

[Big Johnny]

This my sound weird, but I charge my Lipo's on my grill. If it flames out, it aint going burn down the house. I store them in the house in a .50 cal ammo can.(Air & Water tight) I have a bunch of these I have found on Fishing trips in Ft Bragg. It's like they just throw them away. Afriend once found 2 cases of MRE's Watch out for the cheese, it will stop the ole pipes up, better than imodium.

[Nitro Blast]

Originally Posted by Big Johnny

This my sound weird, but I charge my Lipo's on my grill. If it flames out, it aint going burn down the house.

That aint such a weird idea. Matter of fact, I think its a great one. One of those little portable ones would work indoors in someone's shop just fine.

[TM4197]

Good idea! I like it.. I use a sterno stove (folding type) I have the charger in the stove which is well vented...and I place the battery on the grilltop.

[BroncoSquid]

Originally Posted by mumblinaviator

Yikes. I transport them in ammo cans, and charge in clay pots.

Yikes is right. transport in ammo cans? Charge in clay pots or on grills? Burning the house down? I guess I need to read up on LiPo Batts. I don't even own one yet. There is alot of good info here.

[Glacier Girl]

Boy if you think the lipo went thermal, wait till your wife finds out what you did to her crock pot.

All silliness aside, glad it all ended up safely for you.

[CHELLIE]

Originally Posted by TM4197

Good idea! I like it.. I use a sterno stove (folding type) I have the charger in the stove which is well vented...and I place the battery on the grilltop.

Dont be drinking that Sterno Fuel now LOL

Drinking Sterno, unfortunately, was very common for a time, especially during prohibition (in the U.S.) and for a while afterward (which answers the first question, above, about sterno vs. regular ethanol).

[NFA Fabrication]

Originally Posted by Nitro Blast

Charging via main leads only, the balance leads came off months after I got it.

This is definitely a huge mystery as to why your batteries caught fire... I guess we'll never know...

[Bill G]

Originally Posted by flydiver

I think you are going to get a lot of 'there you go' from that info.

Cheap lipo, right? Probably a Long Max with crappy leads. Good lipo, nasty bad balance taps.
The less expensive the less likely the cells are well balanced to start. The middle cell on a pack is ALWAYS warmer, and ends up getting hammered a little harder over time. Without the ability to balance this discrepancy between cells, especially the outer and inner cells, will get larger over repeated cycles.
Middle cell ends up getting overcharged.....sometime.
Not a sure bet, but a pretty high probability.

Yeah you don't hear that talked about much, but when you watch the balancer lights on a 3-cell, you can see a correlation between the center cell of different batteries. It's almost always the cell that is most out of balance with the other two cells. With 2-cell lipos, I imagine there are few issues when charging without balancing. That is unless you're one of those folks who blows them up intentionally, making you tube videos. One thing not talked about much either is the charge rate. I still patiently charge batts at low rates, when working at the bench for hours. 1 amp is about as high as I usually go, even though they claim much higher charge rates now. For the few unbalanced batts I still have, I charge a batts up to a 3s-2100 at .25A, and never over .5A. This batt in the thread here may have not had an issue, if charged at rates that low versus 1.75A.

A lot a batts sure do have lousy balance leads that shear off over time. Why they use locking connectors is also beyond me. I try to not let them quite lock, or you have to be extremely careful when disconnecting them, or you pull on the leads. Some leads just break off the cells, because the assemblers refuse to hand twist the stripped lead ends, before soldering. Twisting leads before soldering will allow them to be flexed thousands of cycles before failure, instead of a few hundred, or maybe even less than 100. Pretty lousy that the manufacturers promote balancing so much, and then make batteries where the leads break off.

[Wrench66]

I have had batteries that have gone weak on a cell, or a cell will take much longer to charge to full............I take full on notice of this and put that battery on the "B Team" and put it through a couple simple tests. These notices and tests are not possible though without the balance taps in place, I wouldn't use a lipo without the balancer....ever. They're on there for a reason

Sorry you had that trouble Nitro and I am so thankful you were there to catch it before any further damage!!

--Ray

[Larry3215]

I had a lipo fire once - also charging without using the taps.

Now, if I have a pack and the tap wires get damaged, the lipo is discharged and tossed. Even if its new.

[Nitro Blast]

I totally agree on all balance points, but on this one (and yeah, I believe it was a balance issue) remember that the wires came off the balance within a month or so, and the battery was 3 years old.

So, even without balancing, it lived my expected life cycle of 2 years, and one bonus year.

Just food for thought.

[dkrhardy]

"So, even without balancing, it lived my expected life cycle of 2 years, and one bonus year."

Except you have had a fire! Thank goodness you know where to charge them so there was nothing important damaged. I even do my charging outside on concrete. Stories like yours do put the fear into me. New folks - take note!

My balance leads all have enough plastic to grasp so there is no need to try to pull on the wires. I am never, ever in such a hurry that I need to just yank on something to disconnect.
Don

[jim2wright]

I blew one up today in a minor crash. center cell.