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May 11, 2006, 11:57 AM
Permaculture de NEW Technology
Rondog's Avatar
Osprey,

I had an ETec 3s 1200mAh pack in storage that did the same thing only it was stored in a nice cool garage. I just chalked it off to the pack not being used for two months and the voltage got too low to which it went bad. I guess the pack could have had a bad cel from the start but never thought that much into it.

Anyway that is a possibility since I have like 10 Lipo packs right now and only that one puffed on me.

Reno.
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May 11, 2006, 02:05 PM
Registered User
jalves's Avatar
Quote:
Originally Posted by Larry3215

Do NOT put it in salt water.

Larry
Excuse for my lack of knowledge about lipos chemistry, but I think the salt water use is to extract the Litium ions from the lipo.
Obviously, we can't put a charged lipo pack in salt water, mainly for two reasons, the salt water works as a shunt and do a short circuit to the lipo pack and in this process happen the hidrolisis of the water with the formation of hidrogenium, a explosive gas.

I remember I read somewhere, that we should do a very slow discharge of the lipo (don't remember if complete or not) and only then put it in salt water, do some puncture work in the pack to allow the exit of the litium ions to the water (maybe the sodium ions of the salt replace the litium ions in the lipo, converting the lipo in a mass of inofensive salt)

For all the readers of this post, I can't defend what I write here, take this information with reserv, I gladely change or erase the all post if I am wrong.

This the way I deal with faulty lipos, with good results so far, but keep in mind that I am not sure that this the right way, I will change my procedure if someone demonstrate I'm wrong.

Jorge
May 11, 2006, 11:36 PM
That thing's operational!
birdlives1955's Avatar
I've been meaning to ask someone about this, but it has kept slipping my mind until now. I've only got one li-po pack, and I keep it stored in a little Sentry fire-safe box I got at an office supply store, and you can only open the box with a key. It seems like a pretty stout little box and the fire-proof material it's made out of is very thick. The thing is, I'm relatively new to li-pos in general, so I was wondering, is the fire-proof box idea something that's generally accepted as safe for li-po pack storage?

I'm generally not paranoid about these types of things, but I just want to make sure that it's safe because I store the packs in the box in my room indoors. I've heard so much about the instability of lithium-polymer batteries and I just wanted to make sure I'm doing the right thing for safety.

I leave the pack inside my room and since I'm not there most of the day, I just wanted to make sure that if something were to happen to the pack while I'm away from my room, that it would be safely contained in this fire-proof box. Is is okay for me to leave it in there? I also charge the pack in the fire-proof box, and right now I'm at college so I have to charge indoors, but I monitor the charge the whole time and I don't even leave the room for a minute. I also never charge the pack at more than its C rating, so it should be in pretty good shape.

Thanks for the help!

-Matt
May 12, 2006, 09:55 AM
Permanently Banned
LIPOs R not unstable, it's the people who r using them the wrong way or any way

U cannot overwork them and yes they do need rest like U 8 hours of sleep will be fine
May 12, 2006, 11:12 AM
Fly a LiL' Lower Will Ya!
mrm1's Avatar
agreed with mister hall,

got one word for you .... cell phone I know I will take the "your being irresponsible" beating for that, but all I am saying is no one thinks twice about sleeping next to one, leaving them in hot cars, throwing them around etc.

I would NEVER do that to an RC Lipo, not the same protection circuits. But lets face it, people abuse cell phone Li-ions and Lipos. So would not call it unstable, just do it responsibly.
May 12, 2006, 02:25 PM
That thing's operational!
birdlives1955's Avatar
Hhhhmmm, Okay thanks for the help guys! I appreciate it. I mean, I know it might not be the best idea to sleep next to my li-po box, but then again I'd want to be the first one to know about it if something were to happen to them while I was asleep. However I just found a unique safety addition that anyone can make to their li-po storage box.

My box is supposedly fire-proof already, however if the cells were to somehow spontaneously ignite, I would want to the fire to smothered as soon as possible. My friend Paul keeps his li-pos in a barbecue grill outside, and he said that he tapes a larger ziploc bag full of dirt or sand to the top of his storage place, directly above the li-pos. That way, if the packs do ever ignite, the plastic of the ziploc bag will melt and drop all of the dirt or sand on the fire, hopefully smothering it before it gets out of control. I thought this was good idea and I will defintely try to do this myself, I just thought I'd share it with you guys in case anyone was interested.

-Matt
May 13, 2006, 03:14 AM
Fly a LiL' Lower Will Ya!
mrm1's Avatar
you can also charge them in a bucket of sand with a sand bag on top
May 15, 2006, 11:43 AM
Registered User
Osprey Engineer's Avatar
Typo in my post (#28). It is 11.98, not 12.98.

Thanks for your replies. I never thought about liability when shipping a defective battery.

So I am not sure which cell is bad since they are all within 0.01 V of each other. That was my reasoning for charging the pack. Perhaps the one that is bad will not hold the same charge.

Is there a way to tell which one/ones are bad without charging it. Can I do a discharge capacity test with the battery in it's current state? I'll have to search the posts to see how to do that unless anyone wants to post the proceedure here. I have a digital volt meter. It is a pretty decent one. Can that be used?

Thanks again.
May 15, 2006, 12:06 PM
Permanently Banned
Larry3215's Avatar
Quote:
Originally Posted by Osprey Engineer
Typo in my post (#28). It is 11.98, not 12.98.

Thanks for your replies. I never thought about liability when shipping a defective battery.

So I am not sure which cell is bad since they are all within 0.01 V of each other. That was my reasoning for charging the pack. Perhaps the one that is bad will not hold the same charge.

Is there a way to tell which one/ones are bad without charging it. Can I do a discharge capacity test with the battery in it's current state? I'll have to search the posts to see how to do that unless anyone wants to post the proceedure here. I have a digital volt meter. It is a pretty decent one. Can that be used?

Thanks again.
This really isnt the best place for this particular discussion. We are cluttering up this thread with off-topic things.

How about starting a new thread with that question?

You should get more replys and help too. Post a link here as well and I will try to answer in the new thread.

Thanks,

Larry
May 29, 2006, 10:53 PM
Registered User
Raketemensch's Avatar

But why LiPo instead of LiIon?


I don't worry about my laptop bursting into flames, nor my cell phone, and I charge them both haphazardly and whenever I actually remember to. What's keeping us from doing that with r/c power?
May 30, 2006, 01:48 AM
Proud member of LISF and ESL
You don't discharge and charge your lipos in your computer at the rates we discharge and charge ours. And you can't change the charge settings or over draw them with your computer either. It won't let you.

On the other hand, here you can draw too much, charge too fast, crash, and otherwise abuse the lipos in your planes.

And hopefully you don't crash your hard drive, physically, the way our planes do, sometimes.

Big difference.
May 30, 2006, 09:37 AM
Registered User
Raketemensch's Avatar
Well, I knew there was definitely a difference, I just wasn't sure what it was. Thanks for pointing it out.


- Raketemensch
Jun 20, 2006, 03:24 AM
Registered User
I expect that a cellphone repair place will take a used, dead lipo of whatever description and recycle the lithium properly, and they certainly have the means to transport damaged lipos safely.
Jun 20, 2006, 10:20 AM
Watching the Sky
gmyers143's Avatar
I am currently charging my Lipo's with a triton charger. This charger does not have the ability to balance charge single cells within the pack. Most of my packs are 3 cells and have a balance connector. Does anyone know if an adapter can be made to charge each cell in the pack individually?
Jun 25, 2006, 09:07 AM
Registered User
Mark Winstanley's Avatar

LiPo Balancer


I just (yesterday) bought a battery equalizer that is fitted between the GP Triton Charger and the Battery. You also have to fit balacing leads to the Lipo in order to plug into the balancer. I was able to do this myself (it is not rocket science but you myst be careful not to short out the cells. The balancer did identify out of balance cells and charged accordingly.

The Equalizer is made by Robbe and cost approx 26 Euro which would be about $30. It can handle up to 5 cells.

The part number is 8446 and should be available in the US.

Mark.


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