Near Disaster - Chinese battery

[sundog]

I've got to say I use Zippy's, Turnigy's and Rhino's and have a lot of them. I have had my problems, usually a bad solder connection, or I ask too much of a low C battery and it puffs. Never had one puff in storage or while charging (I charge at 1C). I can't afford those other pricey batteries, and so am always careful with the cheaper lipo's that I do choose. I have searched the web for information on proper storage and it seems the manufacturers don't think it's necessary (or their lawyers suggest not to admit there is a problem). No videos anywhere of lipo's combusting in a sealed ammo box. Either it has not been done, or it wasn't an interesting experiment (nothing much happened). But found many videos of lipos being purposely overcharged in the open and in unsealed or vented containers - burning, smoking and blowing the lids open. So while I understand the 'venters' reasoning, I believe a lipo gone bad runs out of fuel (oxygen, moisture) right away in a sealed ammo can. The seal under the lid is not a pressure seal, but a moisture and dirt seal, and will most likely vent any pressure in short order (hissing like a pressure cooker). But this is all conjecture, and until someone documents a test with a sealed ammo box, that's how I'll store my collection of (inexpensive) lipo's.

[m4a1usr]

I believe a lipo gone bad runs out of fuel (oxygen, moisture) right away in a sealed ammo can. The seal under the lid is not a pressure seal, but a moisture and dirt seal, and will most likely vent any pressure in short order (hissing like a pressure cooker). But this is all conjecture, and until someone documents a test with a sealed ammo box, that's how I'll store my collection of (inexpensive) lipo's.

A sealed ammo box is and can very well be a bomb in the making with lipos in a deflagration state. Read this, http://www.rcgroups.com/forums/showthread.php?t=355739. Where I work we do work for the DLA. Part of that work is POP testing, Performance Oriented Packaging, and we do test for pressure as part of those tests. There is no published information available to the public. But if you search the web somewhere that info should come out. Depending on what size and type of construction ammo box you have (there are lots and lots of different size metal storage containers, aka Ammo Box) there is the possibility of pressures you dont want to be standing next to when the box fails. My own favorite lipo storage "ammo box" is the large linked 40mm grenade box. I line the interior with woodstove/ firebox bricks. But a 20mm ammo box with brick lining would be much better as it has way more room.

John

[sundog]

A sealed ammo box is and can very well be a bomb in the making with lipos in a deflagration state. Read this, http://www.rcgroups.com/forums/showthread.php?t=355739.

John

John, yes I read that a while back and it was not a sealed box. It had a large vent in it, which helps make my point. And we are not (over) charging our lipos in said box, we are storing them at 70% charge. Vented boxes allow run-away deflagration. A sealed box may prevent it. I prefer the smallest box that I can all my batteries into.

[BHChieftain]

After reading the post John referenced, I've gone from my seal-removed ammo can in the fireplace to lid-removed ammo can in the fireplace.

I am concerned there is too much O2 in a sealed box to enable rapid gas generation before any smothering effect can happen. If there was a way to vacuum pump out the air after the box was closed that might be something to consider. But at this point I'd rather the lipos just burn up in the fireplace with a box that points the fire up the chimney.

Chief

[don ferrette]

Like I mentioned before I store my Hyperions in compartmentalized lipo sacks from Woodworks - http://www3.towerhobbies.com/cgi-bin...?&I=LXYTF6&P=7 then gently rolled and placed inside a 50 cal. military ammo can rated for tracer rounds. The compartmentalized sacks will aid in keeping an ignited pack (should it ever happen) from easily spreading to the others in the can plus the rolled up sack gives very little extra room inside the can to support combustion and actually can help smother the fire since it's designed to surpress flame. As others have posted that seal on the lid really is more of a moisture seal. Fill an ammo box with water, close it and turn it upside down and see what happens. While water won't come rushing out you'll see it ain't exactly watertight either. Plus you could always add 1/8" holes at the top most section of the cans at each corner just for a little extra "pressure relief". Does the idea of a pack igniting concern me?? You bet it does otherwise I'd just put them on the same shelf as my nimh RX packs but I have to wonder about some of what I'm reading in this thread. I also have to seriously question some of the "reference" materials that are both rather dated (2005 for instance on the link John posted) and how these "tests" are done under extreme overcharge conditions. I think the quality of packs has improved a good bit over the last few years as well as the charging technology but I personally would rather spend the extra $$ to buy the better quality lipos. And even though packs like the Hyperions can handle a 5C charge why stress them when you don't have to. I charge my 45C 5000's @ 1.5C max. as I also want them to last, it's no secret that the harder you charge them the sooner you'll take the life out of them. Personally I believe that if you buy good quality packs, handle them carefully, charge and store them properly then you should be in good shape as opposed to getting all freaky over the chicken little the sky is falling videos and such we see out there. I'll be the first to admit when I was considering getting into FE seeing some of that made me really wonder about how safe this stuff was until I started looking into the technology in detail. To me it seems like anything else, buy the best stuff you can and avoid cutting corners..............

[Snowride]

Well I have 4, 3S, 6.0 nanotechs and 4, 5.8 3S 25-35c batteries all from turnigy. They charge well, balance well, perform well so I have nothing but good to say about them. I live in Canada so we get ripped of royally. The local hobby store wanted $150 a battery, yeah right!!! Paid slightly more than that for the 4 nano techs and about 120 for the 5.8,s. I'm a happy camper.

[cybercrxt]

I am still trying to figure out how any of you guys that say " They worked great after I resoldered the cells back together" Have you really talked yourself into saying that is the OK way to look at this issue????? Let me tell you, I had to do that to a couple of turnigy/ flightmax packs, and had to watch 90% of them do the swell/ puff dance after mild use. I just cannot justify putting my family in danger to save $30 a pack or so. Its just not worth it. I switched to hyperion and polyquest packs, and will NEVER even consider owning another one of the turnigy/ flightmax packs. I know some have had OK luck with them, but I guarantee if the same people just gave a hyperion a shot, they would never go back. The hyperions do not get hot, they don't swell, and they sure don't have to have the heatshrink wrap removed to be resoldered. That is just a stupid way of thinking, or doing things.

[U1Racing]

did the pack that caught on fire get shorted out??

[liteumup69]

I have 4 new Turnigy 4.0 4000mah 40-50C, took forever to get from hobby king but so far so good, they are on there 3rd cycle now, packs look good, But I am looking to purchase more, and after reading this.... whats a good battery, I don't mind spending a bit more if there's no issues..

[sailr]

hyperions are worth double the price. they'll last three times longer.yta get what ya pay for.

[Punisher 67]

I sleep with all my lipo's safe and sound under my pillow.........................

[maxmekker]

When ever I get sloppy with lipo's I find a tread like this ,and pull my self together.

BUT, I have severall turnigy 6s for my t-rex, they are 2 years+ and still going strong.
I have for my miss geico 2 nano 2s , I have 2 2s blue turnigy and 2 3s blue turnigy, and 2 3s nano on the way as we speak. I charge in parallel all the time, at 2 to to 2,5 c of the packs. I trust my icharger 3010b , and it always comes out great in ballance(from 4,17 to 4,20 on all the pack's) Not one is swollen, ore loosing power. I run them in my MG untill lvc kick's in and
i normally put in 7500 when i parallel charge the 2s and 3s 4000 packs.
To me they have been nothing but great. But I hope I'm still lucky with my packs to come.

[norbique]

I don't know if it has been mentioned earlier, but as maxmekker pointed out, there is one important thing people fail to consider, that is the charger.
There are a wast number of various lipo capable chargers on the market. Some of them are better, some worse (balancing accuracy wise). A "BAD" balancing charger can ruin even the gazillion dollar costing Hyerions, or polyquests, or maxamps you name them. So you can't approach this problem simply from the Lipo point of view. You must always consider how precise your charger is when balancing the cells inside the pack, as well as choosing the appropriate charging rate.
On the other hand, if the charger supports it, you can lower the individual cell voltage, (like in the iChargers for example). I set up mine to charge the cells to 4.15V instead of the 4.20 factory setup. This 0.05 volts won't cost you more than 3-4% capacity loss, the charger will charge your pack to 96-97% and not 100% this way, but it will give you a BIGGER safety margin, and perhaps somewhat higher cycle number as well.

[sundog]

Sometimes I feel like the Turnigy's, Zippy's and Rhino's get a bad rap because there is no profit margin reselling them. I have had good experiences with all three brands and wouldn't otherwise be able to purchase but a couple of the more expensive brands, severely limiting my fun time.

Norbique, I like that Mark Twain quote you have as a signature. It brings to mind another thought: You want to get your info from the ones winning the races - but would they really want to share their secrets? Maybe they are not such a good source. Gets you thinking anyways.

[sailr]

I am happy for all of you who have had good luck with the turnigy, etc. batteries. I must reiterate however, that the pack that blew up in my cabinet was brand new and had NEVER been charged! So you can rule out any charger factors. Another blew up while on charge at a 1C rate (first time charging) on a top quality Hyperion charger.

For me, no more cheapa$$ batteries. I will spend more for hyperion batts.

In closing, I have tested my boats with brand new turnigy packs and recorded the speed with a gps. Then I put in a pair of brand new Hyperions and picked up 4 mph! I am a serious racer so that matters greatly to me. For those of you who are just sporting around with your boats, go for the cheap stuff. Certainly your decision.