A few thoughts on LIPO charging and the Phantom in general

[miskatonic]

I am fairly new to LIPOs so I was reading a few web sites on the subject and came across this site. Check out the videos of the LIPO fires. Especially watch video #2. I am suddenly looking into a some cinder block bunker for charging...

http://www.crashtesthobby.com/batteries--chargers.html

I have come to realize that flying an RC around isn't about just flying an RC around. I spend more time prepping, soldering, and modifying things on my Phantom than I do flying. Now I have to build a LIPO bunker so that my hobby does not burn down my house

The sad thing is that I have already out grown my Phantom. I have an F550 kit on the way.

 

[Audaciter]

Re: A few thoughts on LIPO charging and the Phantom in gener

The sad thing is that I have already out grown my Phantom. I have an F550 kit on the way.

That means bigger batteries. Better reinforce the bunker.

I had a 3.7v Lipo for a micro heli catch fire, and it was ablaze instantly. Luckily, I had a bottle of water right there,
and dumped the battery inside, before it burned me. It was bubbling away in the water bottle for quite some time.
And that was just a tiny little sucker, a little over an inch long.

 

[miskatonic]

Re: A few thoughts on LIPO charging and the Phantom in gener

Just got fire extinguishers. Lipos are going to the outside storage.

 

[Driffill]

Re: A few thoughts on LIPO charging and the Phantom in gener

I got this ammo box last week, $30 delivered. I've still got some work to do on it. I'm going to divide it up with six individual battery compartments, run a main power and balance lead into each compartment and back to a parallel charging board running from an Imax B6 charger. I'm hoping to mount the charger so I can access it with the box closed. I bought the DC version of the ImaxB6 so I can run it off a car battery while in the field but I've also bought the AC adaptor for when using it with mains power available.

At work two days ago, I was replacing the battery on a motor, just after I plugged the battery in I felt the tube starting to get warm, as I looked at it I could see smoke filling the tube. I'll get a photo tomorrow if I remember. It wasn't because of a faulty battery it was a short in the motor that caused it. I thought I was going to have a li-ion blow up in my face! I was worrying that the cabling had melted thru and was still shorting. When you see a pic you will understand what I mean.

 

[Audaciter]

Re: A few thoughts on LIPO charging and the Phantom in gener

I think those ammo boxes are readily available at local surplus stores. Definitely a cool project.

 

[miskatonic]

Re: A few thoughts on LIPO charging and the Phantom in gener

50 cal ammo boxes are $24 on Amazon delivered. I should have it by Thursday (hooray Amazon Prime.) I shorted out a Lipo today. It was almost discharged so it wasn't a huge deal but if it had been charged I would be in a world of hurt.

 

[Justiceair]

Re: A few thoughts on LIPO charging and the Phantom in gener

I thought I reversed the polarity on one battery a week ago. But, I tried to re charge another battery today, that I was careful to make sure I connected the wires correctly. But, when I pluged it in, I got the Red Blinking, and switching between the first red-light on the charger.

Any one know What I may have done.

 

[miskatonic]

Re: A few thoughts on LIPO charging and the Phantom in gener

It is very possible that you fried something. It only takes a second if you reverse polarity to cause a burn out.

 

[Peter Patricelli]

Create a bomb!

Let me see if I have got this right. You are taking a battery with a small but finite chance of bursting into flames...but a relatively small and possibly controllable flame....then you are putting SIX of them together....which will increase the chance of one of them bursting into flames by SIX TIMES....which then will 100% ignite the other 5...causing a fire SIX TIMES the size of a single battery.....and enclosing them in a box appropriate to contain the fire of ONE of them?

Do I have those basics correct? Now, if you pressure sealed the ammo box...and there is no oxidant in the Lipo mix...there will not be a fire.....but when you crack the box....if there is a live circuit and short...it might explode. If there IS an oxidant in the Lipo mix, contained under pressure....you HAVE created a bomb.

I could be wrong.....but you might want to double check your strategy.

 

[Driffill]

Re: A few thoughts on LIPO charging and the Phantom in gener

Let me see if I have got this right. You are taking a battery with a small but finite chance of bursting into flames...but a relatively small and possibly controllable flame....then you are putting SIX of them together....which will increase the chance of one of them bursting into flames by SIX TIMES....which then will 100% ignite the other 5...causing a fire SIX TIMES the size of a single battery.....and enclosing them in a box appropriate to contain the fire of ONE of them?

Do I have those basics correct? Now, if you pressure sealed the ammo box...and there is no oxidant in the Lipo mix...there will not be a fire.....but when you crack the box....if there is a live circuit and short...it might explode. If there IS an oxidant in the Lipo mix, contained under pressure....you HAVE created a bomb.

I could be wrong.....but you might want to double check your strategy.

I see your point, but some of your math is incorrect. Charging six batteries in parallel doesn't increase the chances of a single battery catching fire. If a battery is going to explode or catch fire when its on charge, it'll do it wether its the only one connected or not. If they are all stacked together than yes, one fire will likely damage the other batteries too, but may not ignite them.

For my charging box, each battery will have its own "pocket" to sit in while charging, separate from the other batteries worst case a fire could damage two other batteries at most. Also, its not likely to be sealed as you need to run a power cable (AC/DC) into the box for the charger, meaning it won't be pressurised. If I put the hole for a cable at the lower part of the box if a fire occurs the smoke will likely fill the box and smother the flames and starve it.

I do have two lipo safe bags that I was using and probably will still use when transporting them etc, but the way I see it is the ammo box is made to carry explosive materials, so using it to store dangerous items is a pretty smart strategy! Heck, if my batteries fired up right now, I'd lose a few hundred in the charger and batteries etc, but my house will still be standing! I could probably still use the ammo box aswell?

If you can suggest other methods to store them securely I may give that a shot too.

 

[porl_hopkins]

Re: A few thoughts on LIPO charging and the Phantom in gener

I have been using lipos for years now and ALWAYS store them in a lipo storage bag. Never had a problem with them

 

[Peter Patricelli]

Re: A few thoughts on LIPO charging and the Phantom in gener

Driffil,
I did not mean to suggest that the chance of any one battery flaming while charging goes up, but that the overall chance of any one of them flaming while charging is additive. That is, if the chance of one battery flaming during charging is 1 in 100, then the chance of a fire while charging 6 at one time is 6 x 1 = 6 in 100. I also don't fully understand the chemistry involved but Lithium is in the same line as Sodium on the Elemental chart which means aggressive reactiveness, a lot of energy absorbed or discharged in changing state, what we harness as battery power, but can just as well become heat and flame.

I don't know what will happen to a cell sitting adjacent to one flaming, do you? But if the chemical reaction causing flaming continues after the electrical current is stopped....which I assume would happen as wires would melt, short out, blow fuses, etc.., then a self sustaining chemical fire based on the chemicals present in one cell would be highly likely to be able to ignite a fire in an adjacent cell. The general rule is to isolate the individual elements so there is not a chain reaction and you have 6 in flames at once.....which will be a considerably larger and more dangerous fire.

And, sealing the ammo box also raises ?'s of whether the burning is self-sustaining even if shut off from oxygen (creating a bomb) OR what happens when you pop the top and oxygen rushes in.

I have lots of questions and few answers......other than to point out the principle of isolating the potentially flammable or reactive elements from each other...rather than pile them all in together. I drive by the Army Ordnance reserve in Boardman, OR regularly where much of the ammunition, missles, bombs, etc. are stored....in small, individual bunkers isolated from each other spread over square miles of desert so a problem in one does NOT set off the adjacent...etc..

Since the danger of flaming is during charging, then the principle would be to isolate charging batteries from other batteries, charging or not, and in some container capable of containing the flames from that one battery.

That is the best I got. Sorry. This is a very vexing problem.

 

[miskatonic]

Re: A few thoughts on LIPO charging and the Phantom in gener

I would hope that those are not the actual odds of a fire. The space shuttle program ended up having 1 in 100 odds of failure.

 

[Peter Patricelli]

Re: A few thoughts on LIPO charging and the Phantom in gener

Miskatonic,
I just pulled those figures out of the air for purposes of making the point. If it were anywhere near that ....they would not be sold. I have NO idea what the actual risk is. That most or all are made in China (?) makes me a bit nervous. Almost sounds as though one mixes a batch of gel from a recipe, stuffs it into a container, shoves a couple of wires with a small circuit board in, and tapes it shut. There is not a good track record of manufacturing quality control over there. And, they might be isolated from legal suits should a house burn down. This is relatively new technology and will be upgraded, improved, or replaced relatively quickly....hopefully.

In the mean time, take reasonable measures, keep your insurance current, then cross your fingers (like I do) and keep flying.