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Old Aug 02, 2011, 02:51 PM
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Originally Posted by hoppy View Post
Though infrequent, they can catch fire, mostly during charging.

IMO, the safest way to charge is to be in the room with the packs and observe them. Lipo packs will swell quite a bit before igniting so there is a time frame of many minutes (5,10 +) where if the modeler notices the swelling, the charge can be stopped.

Equally safe would be to charge outside in a firesafe area.

Next would be indoors inside a metal box, BBQ grill, LipoSack or similar firesafe container.
Well, I'd pretty much have to charge them indoors (need to use AC power), so I guess I'd need to use something to contain it to be safe. I'd even be hesitant to keep it in line of sight after watching some of this videos.


Quote:
Other things to consider...
Don't keep damaged lipos. When they start to puff or are physically damaged, they should be discharged and tossed.
Even though a firesafe box can prevent fire damage the smoke can cause a lot of damage which is why the best method is to keep it from happening or do it outside.

Remember, the likelihood of this happening is very small, especially if you keep your packs in good condition....use only 80% of capacity...follow the manufacturers use directions, etc. But like me, you are concerned that it could happen as there are no guarantees with lipos, so take the precautions and enjoy. If possible, baby sit the packs while charging, safest way IMO....if you see anything unusual, stop the charge and check it out. I store, charge and transport my lipos in firesafe containers just in case.

Go up to post #2 and look at "Videos of LiPo Container Tests." It'll give you an idea of what other people have done and what happens during overcharging.

Again, remember that if you use packs in good condition and charge with a balancing charger witnin the C-rate specified by the manufacturer, the chances of an ignition are very low..........but just in case, watch them or box them.

I've got 8 yrs experience with them without an incident as have many many other modelers, but still I don't trust them enough to leave them out of the firesafe boxes, just in case.
Any other questions?
I am wondering about the storage. I went through some of the documentation on this and the previous thread, and I didn't really see anything about discharging. Should Lipo batteries always be discharged when put away for storage? Or is this just damaged batteries... and do I have to worry about anything when the batteries are being drained (like overheating)?
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Old Aug 02, 2011, 02:56 PM
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Not sure what that would do.

The most important thing you can do is never charge unattended.

Use a quality balance charger designed for LiPo batteries. Check out CellPro.

Charge away from flammable materials. Many use fire proof charging bags for charging and storage. LiPo Safe is one brand.

Arrange a safe storage location or vessel. A covered ceramic pot makes for worry free storage. There are many possibilities. Here is one. Battery Bunker
Are these fires purely chemical? In other words, if I oxygen starved it, would it prevent combustion?
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Old Aug 02, 2011, 03:27 PM
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Lipos should be stored 1/2 charged - 3.85V per cell, especially for long term storage.
For short term storage (days), 3.7-4V/cell is considered OK.
Fully charged storage will degrade the battery.

In regards to the fire process, 2 fire processes occur. First comes the internal thermal runaway of the pack which doesn't need atmospheric oxygen to occur. This releases copious quantities of vaporized organic materials which can burn in the atmosphere if an ignition source is present.

Ignitions inside a firesafe box are probably solely the energy release of the battery breakdown. Lots of smoke.
Ignitions outside of a box my also exhibit flames from the the volatile organics also burning. From those videos, did you notice the ones where the lipo cell was covered with sand? Mostly smoke, no flames.

In regards to bags expecially, some are completely worthless as a fire containment device. Check that any bag you might buy has been tested with the size pack you intend to charge in it. LipoSack is a proven tested bag - LipoSack.com Videos of a LipoSack test are on the site I pointed out to you.
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Old Aug 02, 2011, 03:52 PM
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Originally Posted by hoppy View Post
Lipos should be stored 1/2 charged - 3.85V per cell, especially for long term storage.
For short term storage (days), 3.7-4V/cell is considered OK.
Fully charged storage will degrade the battery.

In regards to the fire process, 2 fire processes occur. First comes the internal thermal runaway of the pack which doesn't need atmospheric oxygen to occur. This releases copious quantities of vaporized organic materials which can burn in the atmosphere if an ignition source is present.

Ignitions inside a firesafe box are probably solely the energy release of the battery breakdown. Lots of smoke.
Ignitions outside of a box my also exhibit flames from the the volatile organics also burning. From those videos, did you notice the ones where the lipo cell was covered with sand? Mostly smoke, no flames.

In regards to bags expecially, some are completely worthless as a fire containment device. Check that any bag you might buy has been tested with the size pack you intend to charge in it. LipoSack is a proven tested bag - LipoSack.com Videos of a LipoSack test are on the site I pointed out to you.
Thanks for the fast reply.. That is good to know about the storage, as I really didn't see that information elsewhere.

I saw the Liposack video, but I think I am still a little skeptical of -any- bag... but I guess if this is what everyone uses, it probably does well enough. I guess after a crash or something, it would definitely be worth while to have. I wouldn't want to start a fire in my car driving home my wreckage..

Thanks again for all the information, it is much appreciated!
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Old Aug 02, 2011, 04:00 PM
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AgentSmith27,

I charge indoors myself and I find that the safest place in the house to charge is the kitchen. I understand that this might not work for everyone but I open the oven and place the charger and pack on a shelf and charge with the door open. It wouldn't stop smoke but it will certainly keep you from burning down the house.

The most important thing is to not leave while charging. You don't have to maintain a constant fixed gaze on the operation but most destructive fires occur when people decide to drive to the store or some similar errand. You don't have to live in fear of LiPo's or subject your family to unnecessary risk if you respect the potential danger, use common sense, and observe reasonable safety measures.
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Old Aug 24, 2011, 05:31 AM
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Hello everyone, I just signed up to thank you all for posting this information, I feel it could possibly have saved me from a serious fire. I learned a lot, and it is very appreciated. Thank you again for teaching the public about this, and sharing the stories. It's incredibly helpful, and after reading the posts and links, I have decided to give Lipo a try. Safely of course.

I use nicd mostly for my rc cars, but last year I tried out niMH batteries, and liked the longer run times on them. I recently bought a used car online, and it arrived with a new Lipo battery that the previous owner never used, so I sought out some info. I like the lightweight of the Lipo, as it seems about 1/2 what the NiMH batteries are. I bought a charger with an additional add-on that makes sure that the cells get to the right voltage, and charge together evenly. As far as I understand it anyway. I also bought a lipo bag, and an alarm indicator to put on my battery while in storage (3.85v) over the winter. Just to protect it from going too low.

I feel much more confident about these batteries after reading through all the great info on Page 1 by the OP, and also all the follow-up questions, answers, and links. I'm going to follow everyones advice here. I am always careful even when charging nimhs + nicds, I keep next to them, and never overcharge, or store drained.

I know the talk seems to be mostly on heli's or planes, but the battery info goes well across the board I think.

Thank you again!
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Old Aug 24, 2011, 07:16 AM
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Thank you for the kind words.

One word of caution...only the LipoSack to my knowledge has been tested to any extent and shown to be able to contain a burning lipo. Some of the cheap Lipo Bags are almost worthless as a fire containment device. Check out the Videos in Post #2 for LIPO Container Tests.

Enjoy the Lipos, they are great.
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Old Aug 24, 2011, 08:39 AM
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Originally Posted by dominiclange View Post
...I also bought a lipo bag, and an alarm indicator to put on my battery while in storage (3.85v) over the winter. Just to protect it from going too low...
Not sure what type of alarm you mean but all that I know of should not be left connected to the pack while being stored. Any voltage indicator will use current and drain the pack over time.
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Old Aug 24, 2011, 02:48 PM
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Thank you again guys. I guess I misunderstood about the lipo bag and alarm. I think that a firebox is the safest way then, and I like the idea of a fireproof safe, or a drywall box. I have a clay pot I could use right now, which also seems like a good idea.

After watching the video of the one bursting in flames, and reading the story about ZoomZoom's house damage, it's very sobering as far as never being too safe with these batteries.
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Old Aug 24, 2011, 03:07 PM
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There are lots of practical solutions to safe storage if you give it some thought. I store mine in a wood stove during the off season. An unused oven is another safe spot as long as no one is likely to turn it on.
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Old Aug 24, 2011, 04:37 PM
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The wood stove idea is genius. I am going to keep a bucket of sand next to the battery as well when charging, and only charge on the tarmac away from anything flamable. I think that the person ho posted about staying away from dry vegetation was wise on that, because after seeing these batteries flare up, it pops off sparks and cinders everywhere. Those videos really show how dangerous these are.

The great thing about the lipo batteries from what I can see is obviously the longer run time, but also how light they are. That's my main factor, as it puts less stress on the components of my r/c car, and I think it can pick up quicker, so better performance is always fun. I can imagine for flying the light batteries are key too, maybe even more so than cars, as you guys have to fight gravity more.

This thread is so helpful, and I am sure it has prevented some misuse of the years. Really nice to see.

Thanks again!

Edit: Also, I mentioned about the extra part I ordered with a charger, it's called a battery balancer. It makes sure that the 2 cells are balanced before it charges them. Never can be too safe I think. From what it advertises it also tracks that the cells discharge at the same rate evenly as well. I think this could potentially help the batteries last longer by starting off safely each time. I was going to go with just an a/c adaptor cheapo charger, but I use those for my nimh and nicds, and it's not very precise, so it probably ruins the batteries fairly quick compared to a charger that has some intelligence built in. A multi charger that offers safety features across the board for r/c batteries seemed like the safest, and best idea.
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Old Aug 24, 2011, 05:24 PM
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Be careful using the balancer. There is no need to balance packs that are discharged. What they need is to be charged up to storage level - about 3.85 volts per cell - or fully charged if they are going to be used and balanced at full charge. Balancing should be done at the end of charging not before charging. In a discharged state if a balancer is used some cells could drop to levels at which damage will occur. There is no harm in balancing at storage levels but there is no real benefit either unless the packs are significantly out of balance. I will sometimes balance at storage level if I am not going to use them for a long time. No harm in that but the important thing is that they are balanced before use when fully charged.

Now some new chargers , like the CellPro, will start balancing right when charging starts but that is a different matter then using a stand alone balancer before charging. LiPo packs should only be charged with chargers designed for them and preferably a modern balance charger.
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Old Aug 24, 2011, 08:18 PM
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Thank you so much Turner2. I went with one that had a stand alone balancer, but it works hooked up to the charger itself. So then the charger can balance both cells even, is this right? So then it is best to charge using the charger, and then, hook up the balancer and let the machine (charger) make sure the cells are balanced, and if they are not, it will correct them?

When you say, "LiPo packs should only be charged with chargers designed for them...", do you think that chargers that can also charge nicd and nimh as part of a multi-charger are no good?

Thanks for the help, I appreciate it, as safety with these is crucial!

edit: On the first page it states:

"3. Use the Taps. Before you charge a new Lithium pack, check the voltage of each cell individually. Then do this after every tenth cycle there after. This is absolutely critical in that an unbalanced pack can explode while charging even if the correct cell count is chosen. If the cells are not within 0.1 volts of each other then charge each cell individually to 4.2 volts so that they are all equal. If after every discharge the pack is unbalanced you have a faulty cell and that pack must be replaced.
Taps are provided on most new lithium packs. Taps give you the ability to check individual cell voltages and charge one cell at a time. Make sure and get the appropriate connector to go into your taps. Don't try to stick you volt meter probes in the taps to measure voltage. They could slip and short your cells. "
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Old Aug 24, 2011, 09:52 PM
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Many LiPo chargers can also charge nicd and nimh. No problem there. It's just important that the charger stop the charge when the pack reaches full charge. It sounds like that charger stops the charge when the pack reaches 4.2 x the number of cells. I don't see any problem using your balancer during charging. That would seem to be the safest option.

A balance charger has an extra layer of protection because it will stop the charge if any cell goes above 4.2 volts. I don't know if your charger does that. It doesn't sound like it. You can use your charger and balancer together and do it safely but you will have to pay close attention to it. Never leave it charging unattended.
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Old Aug 31, 2011, 07:37 PM
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For a cheap charging containment device, consider an old crockpot. Its ceramic and insulated. You can usually find these really cheap at garage sales. I know of a few guys that use this. One also has a small bucket of sand nearby.

How long would you recommend keeping batteries at around 4V/Cell. I have mostly 1S, and a few small 2S, and 3S 2200mAh. I usually can fly some or most of the 1S and 2S once a week / 1.5 weeks. The 3S can be 4-6 weeks depending on the weather.
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