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View Full Version : What's the safest way to store lipos?


FirstShirt
11-23-2005, 04:22 PM
Most of what I've read regarding fires caused by lithium polymer batteries is related to improper charging, crashes, using damaged packs, etc. But what about safe storage?

I'm considering storing my lipos (currently eight 2&3 cell packs ranging in the 800-1200 mah capacity) in a small fire safe. My concern: if anyone of them goes bad and catches fire, I'd expect that they will all burn. If they all go at once, will the fire safe become shrapnel?

Is this a legitimate concern or am I being overly cautious? How are you storing yours?

Thanks,
Pat

Jimmy Hoffa
11-23-2005, 04:29 PM
How are you storing yours?

At my friend's house. :D He He He! Seriously, I don't think that there is much danger during storage. I store mine in the house because I think the stable temperature is a good enviroment. I don't even use a container. Now for charging, that is a whole different matter. I only charge outside and in a ammo box.
Phillip

larrymcg
11-23-2005, 10:16 PM
I store them and charge them in a metal bucket in the garage. The lipos sit on a bag of sand and there is another bag of sand on top of them. Both bags are plastic food storage bags. I think the theory is that if the batteries get too hot or catch fire the plastic melts and the sand puts out the fire. Luckily I haven't had to find out if the theory is correct or not! :)

--Larry

Matt Kirsch
11-25-2005, 01:41 AM
Truthfully, I really don't think you need to go to the extent of setting up "booby traps" for your LiPolys like that. I am willing to stick my neck out here and say that there isn't a single documented case of a LiPoly catching fire just sitting there, that can't be attributed to prior mishandling, mischarging, or physical damage from a crash.

As far as your safe becoming shrapnel, remember that these batteries do not explode. They burn, and quite violently, but the energy released is far from the instant release of ALL stored energy as is involved in an explosion.

Fires also require oxygen. Does a small fire safe really contain enough oxygen to burn several thousand mAh worth of Lithium cells? I know it doesn't take a simple candle very long inside an overturned quart jar to burn the oxygen to the point where the air inside the jar will no longer support fire.

Bigfoot21075
11-28-2005, 03:00 PM
I store mine in an old ammo can (the lid closed not locked) in my house, each pack in a ziplock (so they can not accidently short on something). I charge them on the grill on my kitchen range (I have one of those big industrial ranges with a huge hood). Really the times that need caution are charging and evaluating after a good crash. Storing them they are safe, these things are batteries not plutonium.

I_Love_My_ABC
12-03-2005, 10:04 PM
I store mine in an old ammo can (the lid closed not locked) in my house, each pack in a ziplock (so they can not accidently short on something). I charge them on the grill on my kitchen range (I have one of those big industrial ranges with a huge hood). Really the times that need caution are charging and evaluating after a good crash. Storing them they are safe, these things are batteries not plutonium.

I agree, bit I think you can often be overly cautious about using LiPos, the general rule I use is the rule of common sense!! Have a close look at the cells after every discharge cycle and inspect for swelling.

Look even closer after a crash are hard landing and only ever charge them in a fireproof container. I use a clay pottery biscuit barrel during charging and I have always charged my LiPos indoors which seems to work very well. I have not always used a fireproof container either but have watched them very closely when doing so.

Try to check them regularly for overheating during the charge cycle and if you have the spare time, try to only charge them at a low charge rate. I usually charge my 7.4 volt 850Mah packs at 0.2 amps and never over 0.5 amps and have never had a problem.

Actually, I have a lot of RC friends who also use LiPos and have never heard of any of them ever having a problem either. I know you should never charge LiPos unattended but I have been known to do it from time to time.

I do check them every now and then for overheating but I figure that charging at such low a rate and being inside a clay pot should be OK... and even If the worst did happen and the pack miraculously burst into flames I'm only down one $15.00 pack and none of the headaches associated with over-stressing about it.

Don't get me wrong, be careful but don't stress out too much!! A few minor precautions and you'll be OK. :) :)

Matt Kirsch
12-04-2005, 04:11 AM
Frankly, the only thing that charging them at low rates like that does is make it more likely that you'll say, "Aw the heck with this! Nothin' bad's gonna happen. I'm going grocery shopping!" (You know what happens then.) Charging at a full 1C rate doesn't shorten the battery's life expectancy, and it gets the job done in about an hour so you can get on with doing other things.

I_Love_My_ABC
12-04-2005, 06:59 AM
Frankly, the only thing that charging them at low rates like that does is make it more likely that you'll say, "Aw the heck with this! Nothin' bad's gonna happen. I'm going grocery shopping!" (You know what happens then.) Charging at a full 1C rate doesn't shorten the battery's life expectancy, and it gets the job done in about an hour so you can get on with doing other things.

Yeah, point taken, but all I'm saying is that you don't need to suit up in radiation resistant body coverings and stand behind a lead lined double brick wall to handle LiPos. Just exercise a bit of common sense like regular close inspections of the cells and charge in a fireproof container where possible. I do try to always supervise my Lipo's whilst charging but like Bigfoot21075 quite rightly said... "these things are batteries not plutonium." :rolleyes: :rolleyes:

Bird
01-29-2009, 08:47 PM
I have my LiPos in an ammunition box with some bags of sand in the box to smother a fire if it should start. Is the lithium fire dependant on oxygen or is it a chemical fire that will burn without it? It makes a difference where I will put the ammunition box. I have probably had rough landings or crashes with all my batteries. One has a dent in it and shows problems on the Thunder Power balancer. I think I should just throw it away to be safe but, what do you guys think?

Murocflyer
01-29-2009, 08:55 PM
I live in the camp of better safe than sorry. If my LiPos are damaged, then I drain them and discard them. I heard of some say that if the foil is not broken they use them. I think FiremanBill had a dented one that lasted for many more months so it's really hard to say for sure.

But for me, if it's damaged/dented/torn, they're gone.

Frank

everydayflyer
01-29-2009, 08:55 PM
Couple of points. A liPloy fir can generate a great deall of pressure so venting is really necessary ,also they produce their own oxygen and can even burn while under water.

Charles.

birdDog
01-29-2009, 09:31 PM
I store mine is ammo can's, lids closed, unlocked. I keep the ammo cans (3) in a 2x3x6' metal locker in the basement. I think the bigger concerns is closing the lid of an ammo can on the battery leads. In any case, Be careful and get rid of any physicaly dammaged ones.

I may biuld a simple cinder block locker with a steel lid and some screening in the corner of the basement to catch any run-aways if things go bad.

Bird
02-01-2009, 12:28 PM
Thanks for the advice guys. A friend told me he stores his LiPos in his fireplace. Seems like a good idea. I have put my ammunition box (unlocked) in the fireplace and I have decided to get rid of the damaged battery that acts "funny" on the equalizer.
What do you think is the best or good enough way to discharge a damaged battery. What would happen if I put it in a plastic bucket full of salt water and just let it soak and discharge itself>

Matt Kirsch
02-05-2009, 02:55 PM
I store my LiPolys in the same foam-padded cases that I transport them in. On a shelf. In my shop.

They simply do not spontaneously catch fire for no reason.

Damaged packs get the fire safe treatment of course, as do packs on the charger. Any other time, they stay in their cases.