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View Full Version : New 3S LiPo packs + Safety Freak = Concerns


Slent thndr
08-20-2005, 11:13 PM
I am going to be getting two 3S Lipo batteries for my new Formosa. These will be my first LiPos. The charger I will be using is a Triton with an optional temp sensor. I have read threads about Lithium batteries blowing up and causing fires, and of course you can never be too safe.

I am trying to find something that I can safely charge, store, and carry the batts in. The main goal is so that if they blow up, nothing outside the container is damaged. It hast to be portable so that I can bring the batts to the flying field in it, and I also would like to be able to charge the batts in the same box. I have a relatively air tight metal money box that I was thinking of storing them in. I don’t know how much power these things blow up with, but would a metal box hold it or would the metal just break and ricochet around the room or something?

If that doesn’t work what else could I use?

Steve
08-21-2005, 12:11 AM
Ok...first I have to preface this with the fact that I had the same concerns before I got my Lipos. I read all the scary threads and watched the videos.

If you treat them carefully and with respect, you'll be fine. I have yet to see anything that even suggested there was a problem.

I purchased a ceramic "battery bunker" and use it when I charge my batteries. I too use the Triton with the temp sensor.

I only charge on the concrete floor of my shop IN the battery bunker..away from any combustibles.

I keep batteries ready to be charged in an ammo box which is NOT sealed shut. I keep charged batteries in a century safe that I got at walmart for about $17. I always keep it UNLOCKED so if there is an "event" it will not explode. Others drill a 1/2 hole in the top of the box to vent if needed.

About 98% of lipo "events" are caused by improper charging. Others by physical damage from crashing or other such unfortunate events, and a handful from exposure to extreme heat.

I DO NOT keep these batteries in the house as a general precaution.

Slent thndr
08-21-2005, 12:42 AM
Yeah I plan to triple check everything before starting the charge.

I did a Google and found the people that sell battery bunkers. I will probably get one. Approximately how heavy are they though? Is it a pain to drag to the field or is that not an issue?

I will only have two small LiPos and I will be charging them consecutively so I really only need one other container to store them in. The money box will probably work if I can find it; otherwise I could get an ammo box at a surplus store to do the same thing. Thanks for telling me to leave it unlocked, that way it will just fly open and closed in the event of an explosion instead of blowing up like a grenade.

Steve
08-21-2005, 02:15 AM
http://www.batterybunker.net

It's light and quite portable..sort of like a large stoneware jar. About 8" tall and 5" across.

ragbag
08-21-2005, 12:01 PM
Another thing that I read somewhere was a TV table. Do all charging on the TV table outside of the vehicle. The nice wood ones are like $20.00 for four with a stand. I had a picture to go with this idea, but can't find it.

I guess I'm lucky, I have several packs, so I do all my charging in the shop and try to do it when I get home.

The realy nice thing about LIpo's is the fact that they do not need topped off before using, they don't lose a power of any signifigance after charging. Ready to go when I am the next time.
By George

Slent thndr
08-21-2005, 12:58 PM
:p oh my gosh this is starting to be alot of things to remember to bring

I have a wooden folding tv table, like the kind that you eat on, but doesn't that count as a flamable surface?

Steve
08-21-2005, 03:37 PM
If I'm outside, I don't worry about it. Just use a charge cable that's maybe 3' long. If a pack goes up in smoke you're out in the open and no harm done.

Slent thndr
08-22-2005, 12:35 AM
ok. I found the money box. It has a small 5 mm wide hole in the bottom corner but it will probably be fine. I am thinking of not getting the battery bunker and just charging in this. Is that ok? I will charge them in the garage probably if you think its not wise to do it in the house. I also found a small coffe can type thing that might work as a secondary charging station... unless you think the metal would melt or something:o . How long do these fires typically last assuiming that there is no flamable material exept of course the battery?

Steve
08-22-2005, 01:07 AM
Another alternative is to use sheetrock. Build a sheetrock "box" around the battery and just cover it with the sheetrock while it's charging.

I guess the batteries can spin around while they're burning, so you'll want to contain them in some way just in case.

Slent thndr
08-22-2005, 02:20 AM
ohhhhh. Thats a good idea. Have tons left over from the basement. I can perhaps insulate the inside of the money box with it???? Lipos generate very little heat during charge right? You could probably fry a NiMh just by charging it in one of these contraptions.:p I allways have to train a fan on them during charge.

Unbalanced prop
08-22-2005, 05:37 PM
Right now I have seven packs that are seeing a lot of charging and four more that are getting some use. I charge mine when at home, in one of the cavities of a cinder block on a cement floor. At the field I just charge in the grass. I have never had a problem, and try to triple check everything before charging as that is when things can go bad! I store and transport them in a Brinks steel security box.

Doug

luc
08-22-2005, 06:49 PM
and store them in a fridge, that will help avoid IR increase....

Unbalanced prop
08-22-2005, 07:06 PM
I see a fridge has some side benefits too! ;) Whats in that first bottle on the right?:rolleyes:

luc
08-22-2005, 07:37 PM
Heineken beer...
This is a small personal fridge...The green box is a can of worms for fishing....:)

Slent thndr
08-22-2005, 08:38 PM
whats IR increase and why is it a problem?

Unbalanced prop
08-22-2005, 09:10 PM
I am sure Luc and other battery experts can answer that question a lot better, but basically IR is internal resistance. The lower IR the better a cell performs and the longer it will last.

Doug

luc
08-22-2005, 10:46 PM
These lipo batteries (all) degrade with time, at the same time as Internal resistance increases. Shelf duration varies but we talk about 2 to 3 years...
Putting cells in the fridge (temp above 0°C or 37°F), reduces this factor and can get you a longer life (how much is however difficult to predict...).

Slent thndr
08-22-2005, 11:03 PM
So your saying that if I cycled one lipo 4 times a week, and sat the other in my sock drawer both would it would most likely be dead after 4 years?

Steve
08-22-2005, 11:15 PM
It might not be dead, but it will definitely have less capacity. Why don't you run a test and get back to us in 2009. :D

Steve
08-22-2005, 11:19 PM
I've also seen some folks use sheetrock dividers to separate their lipos from each other in the century or brinks boxes. In tests, they have fried lipos in one chamber and the others were unaffected. Other possible solutions are wrapping with fiberglass cloth which inhibits the lipos from getting enough air to burst into flame...they just smoulder and smoke. Some have also used Nomex socks as storage solutions which have the same effect as the fiberglass.

Unbalanced prop
08-23-2005, 03:54 AM
These lipo batteries (all) degrade with time, at the same time as Internal resistance increases. Shelf duration varies but we talk about 2 to 3 years...
Putting cells in the fridge (temp above 0°C or 37°F), reduces this factor and can get you a longer life (how much is however difficult to predict...).

Luc..........If you have a pack fully charged and put in in a fridge for say two weeks, can you take it out and warm it to room temperature and then fly it without charging and get the same capacity if it wasn't in a fridge, or do you have to charge before flying? In other words, is the fridge for long term storage only?

Doug

Matt Kirsch
08-23-2005, 04:17 AM
How these batteries will fare over time is still a big question... I have some Etec LiPolys, the old 6C 1200mAh ones from about 3 years ago... They might get a dozen cycles each on them per year, and they still seem to have the same punch and capacity as they did when they were new. Never stored anywhere but in a pyrex casserole dish at room temperature...

Kinda blows the lid off the rumor that LiPolys are no good after 2 years whether you use them or not, so to speak.

I've also got some Kokam 2000 cells that have been sitting around for about a year. Same casserole dish, same room temperature. Just used them for the first time in a 4S3P configuration... Charged up 4600mAh out of 6000 possible, and had no trouble holding voltage at 90 Amps.

We definitely need a lot more data points to make a determination.

:confused:

Slent thndr
08-23-2005, 01:58 PM
omg 6000 mAH!! Thats crazy!

Slent thndr
08-23-2005, 03:34 PM
Oh guys I ended up buying a Sentry fireproof safe that was on sale for $15. Its rather heavy. I know its designed to keep fire out, but I assuim it can also keep it in. Of course there is no vent in it, so i will have to keep it cracked open for charging. But can I lock it for storage, or do I need to leave it a crack open so that if the lipo blows it can let the pressure out? I suppose I could unlatch it but close the lid. Because the lid is so heavy it will stay closed and airtight in case of fire but will blow open and back down in case of an explosion.

I also coated the money box with sheetrock that i had laying around so i have a secondary container.

Slent thndr
08-25-2005, 02:59 PM
I was just reading some more lipo horror stories lol
I hear that it is a bad idea to completely enclose the lipo, becuase then it will explode, which makes sense. But is it ok to lock my fireproof safe during storage? It seems to be very solid.

Utahflyer
08-25-2005, 06:16 PM
I have yet to see a posting where a LiPo battery explodes without some catalyst (charging a 2 cell using a three cell setting, charging a damaged cell etc...). The bottom line is that if you set your charger appropriately, and monitor the condition of your battery, you will be fine (it's not going to just combust for no good reason).

FYI... I store and charge my Lipos in an ammo box purchased for $5.00 at the local Army/Navy store...and I ALWAYS double-check my charger settings (Triton) before starting a charge.

Unbalanced prop
08-25-2005, 06:27 PM
From everything I have read, it depends a lot on the size of the battery pack. I read a thread of a guy who blew the lid off a military ammo box when he intentionaly overcharged a decent sized pack (can't remember the exact size). I also read about a guy with a small 2S pack in a sentry safe that was contained when it vented and flamed. I personally don't tightly seal any of my storage boxes. Like Utahflyer said I don't think a lipol will vent just sitting, but I don't want to create a bomb and I have a fair number of packs in each storage box. If one goes they all will.:eek:

Doug

RichTheBikeRider
08-25-2005, 07:12 PM
Nothing works better than using the batteries correctly our club has SEVERAL 60 size Electric Heli's and I've ducked as the LI-Poly of one came bouncing along the tarmac being thrown from the Heli it was in (burning like a flare). Over heating either by charging or by use is plane bad. Look at the inner workings of LI-Poly's the insulator is plastic, once melted the battery is done, if there is not enough enegry to cause a fire then it will do a slow melt Best way to prevent this is to not let it happen, don't go over the C rating (while flying) and don't rush the recharge (No. 1 on how to kill LI-Polys). I use one of the new watt meters to check the power in order to stay below the rated C of the batteries and Burning up a $500 battery is not on my list Just follow these Rules
1. Make sure there is good air movement thru the plane to cool the motor and batteries.

2. Don't fly at full power for the entire flight

3. Don't run the charge current up just because you want to get back in the air quickly.

4. If in doubt don't, let it cool.

5 Don't fly with HOT LI-Polys period.

Rich

Slent thndr
08-25-2005, 07:20 PM
Ok thanks for the advice. I plan on following all of that to the letter. But I want to have the best backup plan in case the worst does happen. Do you think a sealed Sentry safe with 1 1/2 inch thick walls would contain the blast of a 3S 1500 mAH Kokam lipo?

RichTheBikeRider
08-25-2005, 07:32 PM
Have never had one burn up just setting, and a couple of guys have had them burn up while doing something on the kitchen table (ug) safty first I keep a trash can with cat litter in the bottom, storing them in safty is good but having something around to toss them into is better.
Rich

RichTheBikeRider
08-25-2005, 07:33 PM
Oh

RichTheBikeRider
08-25-2005, 07:41 PM
Oh almost forgot, the smoke is toxic ( the batteries burn with black thick smoke ) dangeriously full of metal ions.
Rich

Slent thndr
08-27-2005, 04:31 PM
Thats good to know. Hey guys my new 3S lipo came and it is 11.50V. Does that mean its allready chargerd? Should i just top it off? In which case how does that work? My charger is the Triton.

RichTheBikeRider
08-27-2005, 05:16 PM
preaty close,never top off LI-Polys, if in doubt use the discharge cycle that came with your Triton. LI-Polys don't loose there charge like Nicads do. I fly then recharge I can then fly when I get to the field the next weekend while I charge my Nicad packs.
Rich

Utahflyer
08-27-2005, 05:44 PM
11.5 volts is the shipping voltage for a three cell. The max voltage for a Lipo is 4.2 volts per cell. Thus the “charged voltage” for a three cell lipo is 12.6 volts. If you program your triton for a three cell Lipo, it wil l cut off at 12.6. You will need to charge it before flying. Good luck.

Slent thndr
08-27-2005, 06:32 PM
ok but should i discharge it first? And so my goal is 12.6V... so i put that in as the cutoff point?

Utahflyer
08-27-2005, 06:40 PM
No. You don't need to cycle Lipos. You should wait a few charge cycles prior to charging the pack at 1c. You should charge it at .5c initially.

RichTheBikeRider
08-27-2005, 07:48 PM
Here's some info that everyone should read and understand
http://www.rcgroups.com/links/index.php?id=4544
Rich

Slent thndr
08-28-2005, 12:49 AM
I thought you were only supposed to charge them at .7C max and that you diddn't need to break them in?

Utahflyer
08-28-2005, 01:44 AM
No. You can safely charge Lipos at 1c. There is debate about the best way to prolong the life of the pack, but 1C is a standard charge rate for a Lipo pack (meaning a ~60 minute charge for a pack that's been fully discharged). .7 or .6 will certainly not hurt, except if you're impatient with your charges!

Matt Kirsch
08-28-2005, 03:26 AM
I don't know where you got that information about .7C... Can't say if the recommended charge rate has ever been that low... I think it's always been 1C.

Anyway, don't worry about all this "breaking in" mumbo-jumbo. It's more wives' tales, and that's not just my opinion. LiPolys come out of the box ready for action, at about 50% charge. Plug them into your charger (make sure you understand how to correctly set up the charger FIRST), charge them up, and they're ready for your plane.

Dude, you're going to worry yourself to death... LiPolys are not that dangerous if you treat them properly, and take proper precautions. Don't hit them with a baseball bat. Don't cross the wires. Pay attention when you're charging them. They won't spontaneously explode or burst into flames just sitting there. The cells need to have sustained some sort of damage, and pretty severe damage at that, to fail to the point where they catch fire.

...and no more of this "exploding," "hand grenade" crap, okay? LiPolys do not EXPLODE in and of themselves. Yes they do burn quickly, but it's not really an explosion.

Slent thndr
08-28-2005, 03:35 AM
They 'deflagrate' then. Definition: cause to burn rapidly and with great intensity. But I have heared stories about them deflagrating on their (corectly set up) first charges and stuff. In one case that happened, left a 3 ft crater on the desk, and spreyed toxic liquid all over the room. Luckely she had a fire extinguisher near by or it would have ended worse.

I have also heared of 6 ft (intense) flames coming out of them. Granted there was some fuzzyness about wether he set it right on that one. His friend gave it to him, and he charged it, then realized that it might have allready been charged. It then blew up on the disscharge. So yah 98% of lipo accidents are becuase of human error, but still its good to be safe. Thanks for the info though.

I flew it how it was tonight (no time to charge it) at about 11.5V. Of course it wasn't performing all that well but such is to be expected right? Or are they supposed to provide the same power at half charge?

RichTheBikeRider
08-28-2005, 04:26 AM
Amps x Volts=Watts, Watts are what drive the prop
10A x 11.5 =115 Watts. maximum is say 125 watts thats about 8% off so if we ball park the RPM's where down about 800-1000 RPM, With outrunners you can over prop them RPMs drop and batteries get HOT, Dosn't bother Ni-Cads but sure does LI-Polys. I'm gonna fly my old astro 40 pattern plane tomorrow its got 20 3000 Ni-cads.Charge'em up and go fly.
oh and check tour full charge voltage and motor RPM and did you read the instructions on the cut-off Voltage on your controler it should be set to 9 volts at lest for LI-Polys.
Rich

Slent thndr
08-28-2005, 05:00 AM
Ok thanks. No I diddn't read the whole thing but I allready have the ESC programed for the 3S setting. I think its 8V though. I hear that that 2.6 or 2.5V/Cell is fine. And thats the highest setting anyway.

And how do you know its running at 10A? I know the batt is 1500 mAH and is rated at 8C. But just because the batt can send that much doesn't mean that the esc is pulling that much right?

RichTheBikeRider
08-28-2005, 05:47 AM
Astro and several other manufactures make inline Volt,amp,watt meters you insert it between the battery and the controler. I have one that has a serial connection and came with software that will plot and print graphs so you can compare changes you make there is a flight unit out there but I haven't seen it,these are all bench units.
Rich

Slent thndr
08-28-2005, 03:24 PM
Was just doing the first charge (a little less than 1C). The first time it stopped after 1 Sec and said it was done lol. Then i tried again, stopped after just 444 mAH. I know that the batt was pretty run down too but mabye not all the way. I had the temp set at 10 degrees above room temp, which would mean 84 degrees. What is wrong? After charge the voltage is still only 11.75V. The charger, although new, is working fine I think on my NiMhs.

Utahflyer
08-28-2005, 05:58 PM
Is it a Triton charger? Try it without the thermal probe and just keep an eye on it. It soulnds like the probe is cutting off the charge. Either that, or set the cutoff temp to a higher value.

Slent thndr
08-28-2005, 06:36 PM
ok i will try. yes it is the triton.

RichTheBikeRider
08-28-2005, 09:23 PM
OK heres the info If you have the delux Triton set the tempature to 110 risky beyond that, Everyone seams to agree
with 3S or more if your battery has a balancer use it like at home (example Thunder Power tp-205)charge batteries out of the model and in a flame proff container (several guys are using small bread boxes )if in doubt go to www.fkyingcirkus.com (http://www.fkyingcirkus.com) and search dangerious batteries you will see whats left of a Ford Explorer. Read the manual that came with the charger or go to there web site and download it.
Rich

Slent thndr
08-29-2005, 12:40 AM
There is a deluxe version? I dont know about that but i did buy an optional temp sensor. I charged it without the sensor and it did fine. I think the sensor is ether junk or is defective because it terminates prematurly with all my batts even when set to 130 degrees. So without the sensor everything works dandy. I just dont have that extra layer or safty. Oh well.

Ok so the fully charged V of a 3S lipo should be 12.6 (which it reached by the way).

what about for a 8 Cell NiCd or NiMh
or a 6 Cell NiCd or NiMh?

Utahflyer
08-29-2005, 12:52 AM
Not real sure about Nicd or nimh, but I'm glad to hear you got your lipo where it should be. I wouldn't worry too much about not having the thermal probe. Many people feel it is completely unnecessary.

Utahflyer
08-29-2005, 01:03 AM
1

Slent thndr
08-29-2005, 02:12 AM
Yeah the probe just adds more oprotunity for glitches. And I think Matt K did a fine job at stating his (helpfull) opionons.