chazdraves

Well, a buddy of mine (for those of you familiar, it's the same guy as is trying to sell me the JR Venture 30) recently (yesterday) ordered up a REX 600 and was getting himself all educated on Li-Po this morning. I'm sure by this phase we're all fairy aware that Lithium-Polymer is flammable and capable of starting some nasty fires that are a bugger to put out. Anyhow, he came across this site: http://www.utahflyers.org/ which contains some very interesting videos on these batteries catching fire. Here's my question(s):

How do you charge your batteries? Do you set them in an ammo box? Cynder block? Wood countertop? Just beneath your wife's origami collection and numerous dried out plants? I would love to get the opinion of everyone who reads this!

Secondly, have you or someone you know (a story you've confirmed) ever had a Li-Poly fire under normal circumstances, e.g. you were doing everything right (not charging too fast, over-discharging, random oops, etc.) and the bugger caught fire?

I think it would be good for us all to have a real-world reference for just how dangerous these batteries are or aren't.

On that note: I've never had any issues with normal use. I do have one battery where something is apparently wrong (one part is visibly goofy and I only get 4 minutes of flight time vs. my normal 15), but I think it must have been dropped or something...

Thanks, guys!
- Chaz

HeliTB

I've heard the horror stories as well. Call me crazy, stupid or dumb take your choice. I've been charging my Lipos in my helicopter in the house by my 52" HDTV for over a year now and have had not one issue. I guess key is, if you buy and use subpar lipos and chargers be very careful. I only buy and use quality lipo batteries, charger and a balancer (Thunder Power).

It's one of those things you get exactly what you pay for and a little more (Headaches and repair costs). You make a $500+ investment and skim on the batteries. That's just not sound thinking, when the batteries actually powers everything in the $500+ investment.

Go figure. My 12 cents worth.

ksechler

I run a jumper cable from the car to the ground and then place the battery on a brick or in a clay pot. I'm not all that concerned about fires since I don't push my batteries either, but I want something that will contain the fire if there is one.

Now HeliTB, you said, "You make a $500+ investment and skim on batteries" as a justification for not taking safety precautions. How's this argument, "You make a $200,000 investment and skim on safety?" I figure the chances of a fire are fairly low, but the disaster potential is huge. I don't feel like buring down the house and everyone in it because I was too foolish to put my battery in a $10.00 clay pot outside while I charged it.

DebianDog

Every fire I have ever heard of is either:

- Cheap/Wrong Charger
- Cheap Packs
- No Balancer
- Trying to charge damaged packs
or a combination of the above


I know pretty much the whole Flightpower Team... we have probably charged 1000's (if not tens of thousands) of packs and I do not know of one incidence of fire.

BUT I still charge in a ceramic bowl with a lid and keep a fire extinguisher handy

chazdraves

Well, we were on a bit of a roll here.

Are we the only guys charging batteries? :P

- Chaz

credence

My Feedback: (2)

I've got to second what debian said.

I have never heard of a lipo going up under normal use. You've got about as good a chance of setting off a lithium pack if it's properly taken care of, as you do of setting off a jug of fuel sitting in your garage.

While I don't have any real statistics to back it up, i'd say 99% of all lithium fires are user error.

Wrong settings, poor judgement on pack condition, pack abuse, or any combination therein.

That said, it certainly doesn't hurt to be cautious. I charge in a metal tin. It's enough to contain the flames should something happen. I've been using and selling lithium packs for quite a long time, and never personally experienced, or had someone mention to me something about a lithium based fire.

HeliTB

ksechler...my brother in law lives in Frederick near Liganore HS. But anyway I guess what I said was hypocritical about skimming. My $300,000 investment is worth a whole lot more than $500. Where do you get a ceramic pot with a top from?

DebianDog

The kitchen section of any good store. Even Walmart. You can get an extinguisher there too.

You could also use a clay type pot from Lowes or home depot. Just put the part that is supposed to catch the water on top of the pot.

evan-RCU

How many people take the battery out of the aircraft before charging?

I leave the battery in the airplane or helo because I have one battery per craft and take multiple craft to fly. I charge usually on the way home with the craft next to me on the passenger seat or before I leave either atop my flight box or in my car down in the parking lot unattended. I think that most of the fear is from a paranoia caused when lithiums first came out and people were not charging them right or from damaged/ misused batteries.

chazdraves

^--- Which is precisely what prompted me to start a thread. It seems that there is a lot of superstition out there, but I think it would be good for all of use to have a thread where we can share our real-world experiences with these things to help determine fact from fiction.

Let me express that I'm not trying to encourage folks to charge without any safety measures, I'm just hoping we can determine how concerned we have to be and choose our individual precautions based on that.

I would encourage anyone that reads through this thread and has experience with Li-Poly to post their experience(s)!

Thanks, guys!
- Chaz

broke-again

I agree that there is a lot of myths, even scare mongering about lipo packs; so much so i decided to find out for myself just what damage a lipo pack would have to substain before flaming. I had an Apex 11.v 3 cell pack with a puffed cell that i used to experiment with and let me tell you up front - it took a hell of a lot of abuse before it gave in. To start with i simulated a hard crash by throwing the pack as hard as i could onto the ground - concrete. The packs compressed and seperated into seperate cells. Despite the major damage - no leak, no smoke, no flame. I then selected the most damaged cell and dropped a very heavy brick onto it. It took two hard drops to make the pack fail. The amount of smoke emitted surprised me - there was more smoke than flame and it was very short lived. I had expected major flames, but the opposite was true. Whilst is did burn fast and hot, it was all over in a few seconds.

Bottom line is that lipos, if severely abused will fail & flame. Naturally, I treat all my packs with respect, but my understanding of their limits gives me some faith in their overall safety.

The other 2 cells were disposed of safely in a bucket of water - lots of fizzing, reminded me of an alka seltzer commercial!

chazdraves

^--- Well, I find that interesting and believable as a buddy and I recently did about the same thing. In our tests, we weren't even able to get smoke. The cells squished and re-formed in different shapes, but they never blew out. I certainly don't plan to throw care to the wind, but this thread has helped me feel a little better about these batteries despite the horror stories of just a few years back. I think the truth is what most folks have said so far: If you are careful and treat them respectfully, they will do there job.

- Chaz

w.pasman

Turn on charger. Plug in the pack to cycle first half. Wait until finished. Check that full. Swap to charge second half. Wait until finished. Check that full. Doing slow charge and always at 4.2V should safe me from most possible mistakes that can blow a LiPo.

Wood countertop, no ammo box. Fire alarm right above the heli.

I know best is to charge in an ammo box but the pack is built deep in my heli and I don't have space for an ammo box the size of my heli.
The pack is deep because that's the only way to get the right COG.