psk560

My Feedback: (12)

A friend of mine mentioned a strong box that he thought would be a good idear for charging the lipo's. It's 9.96 at Walmart in the stationary department. I purchased a rubber grommet from Advanced Auto parts to cover the hole I drilled in the back for the charging jacks. It's double walled and insulated with a fire retardent material. Even the lid is double walled and comes with a key to lock it. I don't like that it is black because of the heat that it absorbs in the sun but I'm sure it could be painted and kept in shaded areas when in use. When not in use, it will carry my charger. I put a piece of foam rubber on the bottom of it to keep the battery from touching metal and I could cover the entire inside with rubber foam if I needed. What do you think? Is this a good idea?

Craig

psk560

My Feedback: (12)

Not knowing how violent these batteries act when exploding, does anyone out there know if this charging box is a good idea? Do they vent gas when in trouble? Would the gas be explosive and need to be vented? Would this thin but double walled box help or act more like a firecraker and squeezing the explosion? Any thoughts on this would be appreciated.

Craig

Tall Paul

I would think that containing the fire would be worse than letting it burn itself out.
Placing the battery to be charged on a fireproof support, or just plain concrete in the driveway away from anything flammable should be all the precaution needed.

Time Pilot

Excellent question, and one that is on my mind now that I have a Triton.

Do the Lipo's just burn, or is there an actual explosion of any force?

Direwolf

That box will probably contain any molten lithium and sparks that gets expelled from the blaze, but there are a few things I don't like about it. First, if the battery does ignite, then the foam rubber you're lining the box with not only fuel the fire, but it will also produce an immense amount of toxic fumes which will likely drive you out of the room. If you're concnered that the metal box could short your wires, which shouldn't be the case if the wires are properly insulated in the first place, then line the box with something other than foam. Paper would work equally well, or even electrical tape.

Secondly, keeping the box closed while charging is probably a bad idea. You should never charge a lithium battery in a small enclosed space to avoid heat buildup. At least keep the lid cracked open to allow some airflow, or install a small exaust fan.

Finally, be aware that this box isn't a "solution". A lithium fire can exceed 800 degrees Celsius (1500 F). So, even though the box may contain some of the material that gets expelled by the blaze, the radiant heat will still be intense enough to combust any near by combustable materials.

The only real solution is to always follow all safety precautions. It's also not a bad idea to keep a Class D fire extinguisher near by that is designed for lithium fires. This includes powdered copper, graphite, sodium carbonate, and dolomite based extinguishers, which can be expelled from a canister with compressed argon or shovled from a container. NEVER EVER try to put out a lithium fire with water or C02, as this will result in a very strong explosion that will spray molten material in all directions.

cwrr5

My Feedback: (32)

Overkill. I just use a ceramic tile on my workbench. I have screwed up a couple(my fault), it's not dynamite. IF it goes, it'll puff up into a little ball and start to get hot. IF you're there watching(NEVER charge these unattended - just like any other battery), it's a simple matter to just unplug it and set it somewhere away from anything flammable - just in case it does ignite(preferably outdoors).

There's no need to be afraid of them, just be respectful. Fire extinguisher nearby is a must! (see above) I have one in the shop anyway, lipos or not.

psk560

My Feedback: (12)

Thanks for the input guys. I'll get a fire extinguisher and get rid of the foam. The box still makes a nice carrying case for my charging equipment and I'll just take the foam out at the field or at home to charge. I'll also leave the top open. Better to have a good "dish" to put it in than just the floor I guess.

Thanks again,
craig

cwrr5

My Feedback: (32)

Good point, the box is good for carrying them around.... (Why didn't I think of that!)

Bax

My Feedback: (11)

We've done a LOT of testing on Li-Po cells while developing the Electrifly line of Li-Po cells. They will erupt in flames only if they are seriously abused. They have to be grossly overcharged, well beyond the point where they puff up, physically damaged when holding significant charge, or shorted out. Most of the time, even then, you just get smoke.

We use standard Army Surplus steel ammo boxes and have no problems. Close it down and you're OK. Even if the cells erupt, they won't be hot enough for long enough to damage the box.

The conditions for flaming are most likely to happen in a crashed model. The pack has significant charge on it and you crash the model for some reason. The battery pack becomes physically damaged, which can result in eruption. After a crash, the battery pack should be removed from the wreckage as soon as possible and allowed to sit by itself for half an hour or so. Then it can be taken home in a fireproof container.

As said above ALL battery packs should NEVER be charged unattended. They should be monitored in case something goes wrong. Even the common NiCd packs can short and deliver enough current to start a fire. I've seen it happen.

With normal care and prudence, you can use Li-Po cells quite safely.

woodduck-RCU

Park Flyer Motors sells a ceramic battery bunker for storing and charging lipo batteries, but it looks like their site is temporaily offline for upgrades.

http://www.parkflyermotors.com

AndySteere

My Feedback: (2)

I like my Sentry 1100 Fire-Safe. Basically a concrete box with a handle. I use it to store, transport, and charge my lipos. Downside is it weighs 17 pounds empty. They make a bunch of differnt sizes. This is the smallest one. I got it for less than $30 from Lowes or Home Depot (don't remember which). Here is a link to a company that sells all the sizes:

http://www.firesafestore.com/security.htm

mdavies31

Remember fire safes are designed to keep fire out, not in. I wonder how well they work in reverse.