I just dodged a big one!!

[Boulder]

Ok folks,

This is the deal...

I am finishing an Extreme Flight 300-E. I want to run 2100mAh 3-cell Li-Po's, so I grab the 2 I already have and check them out. One has almost no charge at all, I kind of knew that already, I had trouble with this pack last year. The second one showed about 9 volts and change. I hooked it up to my Accu-Cycle Elite and went to do a discharge so I could check full capacity on the charge cycle.

The charger told me the pack was discharged already, so I set it up for a charge and let it run for 20 min. or so, just to make sure it was working ok, everything looked good so I let it charge and went inside. Now keep in mind this battery is sitting on a wooden bench next to my Pattern plane and my new Extra.

I went out in the garage this morning and heard the charger doing 3 fast beeps, pause, 3 fast beeps. I said,"Oh, shoot!" and went to the bench, the pack was 2.5 times it's normal size!!! I didn't think to look at the charger to see what the screen said, I just shut it off, unplugged the pack and ran it outside and threw it on the lawn. I went back to the pack in about 5 min. and cut the Deans connector off, can't waste one of those, and the pack will sit out in the rain all day.

Now before all of the comments come like,"You should know better than to charge Li-Po's without them being in a can!!!!" I know, I know...
I've been using Li-Po's since the first Kokam packs came out, never had a problem charging them, never even got warm. This is the first time I've used this charger on them, so I think I must have done something wrong.

Now I need to make a trip to the LHS and spend a couple of hundred bucks on new 2100 mAh packs, this time with balancers.

I dodged a big one this time!! I never even checked to make sure the house insurance was paid...by the grace of God, it's only the pack that was destroyed.

This could have been a very bad day, folks, PLEASE take this as an additional warning when you charge your Li packs.

Flame suit on, go ahead...I've got it coming.

It sure helps a ton to go to church and say my prayers!

[BDSBob]

I have the Accucycle Elite and always use the temperature probes set at 100 degrees when charging Lipos. This may or may not have helped your situation.

[Boulder]

I've just ordered a set, never had them before, didn't see the need until now.

[BDSBob]

Believe me, they work. They won't fit around the lipos in the stock configuration. I take the clamp off then either tape or use a strip of velcro around the battery to keep the temp probe in place.
You will see what I mean when you get them. Additionally the leads aren't long. Just put some Futaba servo leads on them to extend the length.
-
BDSBob

[Boulder]

Thanks Bob,

That's what I'll do...

I just took this pic,

[Biff]

No need for flame suit Kenneth! I think sharing your "almost" stories reinforce everyone's need to stay on top of thigs. I've noticed that 99% of the "almost" stories on the Giants are submitted by very experienced modelers. They all seem to involve being very experienced with a piece of equipment, know the safety proceedures and have had a bunch of time working with things. The momentary lapse of judgement isn't caused by being lazy or stupid, it's mostly because of years of experience giving us a false sense of security!!

Kenneth, what almost happened to you is the very thing I fear most." Heck I've started that whiz bang 100 a billion times and ain't never been bit. I think I'll go fly it by myself today, really don't need a holder." I've done the LiPo thing too Ken. Heck, I was just going to the house for 15 minutes for a quick sandwich.

I think it's awesome you guys are sharing stories of accidents/near accidents. All too many times we don't want to stand up and tell folks about how we almost pulled a full on blunder. Good lessons here for our new members to the hobby and a little nudge to the well seasoned modeler.

Thanks for sharing Kenneth, big props my brother!

"An ounce of prevention is worth an ass load"

[accaptain]

What do you guys normally put these in to charge? I have been charging mine on my concrete garage floor in case they blow. Do they usually explode during charging? I store them on a plastic shelf in my garage when not in use. Can they blow just sitting there?


Scared now. I usually try to use caution but now this really makes me think!

[Biff]

I keep my LiPos in a pyrex dish with the top on, when charging and storage. I treat them like a pistol. They can always go off.

[Boulder]

	Quote: Originally Posted by accaptain
	What do you guys normally put these in to charge? I have been charging mine on my concrete garage floor in case they blow. Do they usually explode during charging? I store them on a plastic shelf in my garage when not in use. Can they blow just sitting there? Scared now. I usually try to use caution but now this really makes me think!

There are several containers that work well, one of which i will be purchasing shortly.

The one a lot of guys use around here is a surplus ammo box. It is large enough and can be lined with a flame retardant material, I will be using a material that's designed to be installed under fireplace hearths. It is 1/2" thick and comes in a sheet about 3' x 18", if I remember right. It can be found in most fireplace supply stores. You would drill a hole in the side of the can just large enough for your charging wire to go through.

When I get all of my stuff for my charge box, I'll post pics and assembly instructions.

[OverTemp]

You don't want it to be too airtight... it will shrapnalize if the battery explodes... a lot of force with those things!!!

I have 3 of these (had 4... gave one away):
http://mysite.verizon.net/kevinkel/index.html

They officially rock. The material is perfect for containing heat... I know guys that blew batteries in them and they said they didn't even get that warm.

Some mentioned that their LiPos don't even get warm when charging... they NEVER should get warm when charging!!! If they do something is wrong! Check the voltage on the charger!!! I can also be caused by an out of balance pack, which can be caused by the next paragraph (and prevented with a blancer... though the next paragrah is still bad juju!!!):

A little over 9V for a 3S Lipo is not a good voltage. A 3S pack is essentially completely discharged if it is below 11.1V static (lower with a load... don't want to go below 9V with a load on it). The fact that yours was 9V static means that it was likely far below 9V loaded... not good. Also... it is best to store LiPos about 1/2 charged (according to TP research), or about 3.85V/cell static (11.55V for a 3-cell). If you charger wasn't what blew the pack, it's over discharged state may have been the culprit. Check the voltage cut-off on your ESC!!!

Long and short, don't abuse your cells and they won't kill you!!!

[accaptain]

	Quote: Originally Posted by Biff
	I keep my LiPos in a pyrex dish with the top on, when charging and storage. I treat them like a pistol. They can always go off.

Kind of scary when I think about them sitting there on my shelf in the garage. I will be worried all day now at work about it. When I get home I am finding something to store mine in.

[3Dkid330]

Ken,

Glad to hear everything is ok! Very good thing that it did not decide to vent in your house. I have had a 1400 mah NiCd blow on me one time, battery check after charging it up, gets hot, starts to sizzle, throw it in a ceramic bowl, and bang! Vented a one foot flame for a second or two, and left a pretty bad smell in the air. It can happen with any battery type, just have to keep an eye on them and all should be well.

My friend sent this to me today, looks like some cheap insurance for charging packs.

http://www.liposack.com/