Fissy

I just ordered a LiPo (3-cell 1250mah) upgrade (NiCad just doesn't cut it). Just how dangerous are LiPo cells ? The warning label on these is downright frightening[X(]
What precautions do you use when charging ? Do you charge it in the middle of a 5-acre concrete parking lot, isolated from any living organism, and constantly observe through binoculars 1/2-mile away w/o blinking and the local fire department and bomb squad setup on speed-dial ?
Seriously though, what are the real world guidelines ?
If something does go wrong, do they explode like C-4 ? Do they simply melt ? Do they catch fire w/o any explosion ? What really happens ?
Thanks
P.S. Let's assume the use of an appropriate charger, power source, charge rate, etc.

Moe3754

My Feedback: (14)

http://www.helihobby.com/html/rc_hel...rs_videos.html video of one exploding look on left side to find it.

Fissy

That definitely answered my last question on "What really happens ?"
Now, where and how do you charge LiPo's and what precautions do you take (other than not purposely overcharging to satisfy your Pyro urge) ? BTW, same assumptions apply as b4.

Flygirl950

I am also getting ready to upgrade to lipos and all those warnings make me weary.

fire@forthall

Please Guys don't let the video fool you!!!!! yes they can be dangerous BUT, with that said just use cae when you charge them. Get a good charger and read all about them. I have them and love them, I have never had a problem with them and probbably goes for most everyone else just RESPECT them and you will love them.

sportygreg

My Feedback: (2)

Just charge Lipos in a non flammable container-I use a pyrex bowl.Do not leave unattended for any length of time-as soon as charger indicates full charge disconnect from charger.Any sign of swelling take off charger immediately!Do not drop lipos or discharge below 3 volts per cell-follow these basic rules and you should be OK.

marter1229

A good lipo charger and commonsense!

EZ Money

If you follow the common sense procedures when charging, handling and flying with them they are perfectly safe.

Also excercise care when soldering connectors to them to make sure you don't contact positive and negative.

Strip, solder and heat shrink one then the other. Never strip both at the same time.

Imagine trying to fly a T Rex with NICADS.

thewhizz*

Hey Fissy, check out my pic on general helicopter discussions, under the title 'my heli nearly burned the house down!' it was really serious, only for the i had to chase the dog cause he ran upstairs with a sock, did i smell the smoke. I let the battery run down too far, and it became unstable, and the photo explains the rest. you can just make out the different bits of my ex-heli! charging in a pirex bowl is better than nothing, but although they can resist the temperature of heat in an evenly heated oven, they will break with the type of heat of lipos generate, (2000 degrees) concentrated on one part of them. they have a low coeffient on expansion, but not that low, cause i broke one with heat. a pyrex bowl/tray full of sand would be ok, and stick the battery into the sand, with the contacts up. .
Murt.

rwthomas1

Mine get charged on a concrete floor with a fire extinguisher and smoke detector in the room. I am not overly concerned about the hazards of charging Lipo's. The trouble seems to come from making mistakes with them. If you never over-discharge, over-charge or drop/damage them there shouldn't be a problem. I think most ESC's have low voltage cutoffs that prevent you from over-discharging from use. A good (read expensive) computerized/automatic charger is mandatory. Trying to charge a Lipo with a standard wall-type charger is going to lead to problems. I take the human element out of it using quality electronics. The only other issue is damage. If it looks damaged, it probably is, toss the thing out. RT

Flygirl950

http://www2.towerhobbies.com/cgi-bin...&I=LXCJG7&P=ML
I just got this charger for valentines day! It charges up to 4 cell lipo batteries, how many cell lipo battery packs are usually used on a chopper like a T-rex?

cptsnoopy

please keep in mind that there is always a chance that a pack was assembled incorrectly and is just waiting for the right conditions such as a little chafing from vibration etc. Do not get comfortable with your lipos. As mentioned many times above, always treat them with respect and hopefully if your the unlucky guy in a million, you won't loose more than just a bad lipo...

jeepson33s

i have an ice charger and i believe they are simular. good charger just figure out how to use it! mine took me a while but then i just looked at the directions and that was the trick

Fissy

snoop,
That's exactly what I am referring to. We can all read the warning labels and read the instruction manuals and, if followed, the chances of major malfunction are minimal. My original question was simply how each of you, with experience, actually practices these precautions. For instance, it takes ~1+ hour to fully charge a LiPo (give or take). The instructions are to continually monitor. Do each of you sit there and stare at it the whole time or just stay in the general vicinity or within earshot of the charger's audible signals ? Also, the instructions say to charge outside of the model. Do all of you remove it from your heli each time you charge ? The manual says to place on a non-flammable container or surface well-away from anything flammable. Where do you charge ? Have you ever charged indoors ? Does everyone use a container (e.g. military ammunition box) capable of withstanding the temp. of a burning LiPo ? How far apart do you isolate it from anything else (e.g. roof, ceiling, wall, misc. objects, etc.).
BTW,
I don't mean to be an alarmist at all. This thread is not meant to decide whether we should us them or not, nor was it meant to scare. It was only meant to recommend "real world" best practices for handling a technology that seems to have a definite increase in hazerdous potential over previous technologies.[8D]

peter1b1

Yep, definitely remove from the Heli or A/C, The picture below is self explanatary, I had just checked the battery 10 minutes before, luckly my son saw smoke from my shelf and got my wife to check it out. I was using a proper LiPo charger. Luckily only cost me an A/C (crazy 8), radio transmitter and a battery drill, if it had got into the bench I could have lost the whole shed which would have been all my gear.

I am a bit nevous about charging batteries now and agree with the comment about charging them in a container, but they need airflow to help keep them cool during charging so I don't agree with putting them in sand...

puble23

My Feedback: (1)

ok well just do your reading!

If you read up on everything you should be fine. Heres what you should do, setup a safe charging station in a place like a garge. Get a metal cooking pot or something metal with a lid. When charging place the battery inside it with your wires leading from the battery to the charger pinched under the lid. Then put a 2 1/2 pnd or 5 pnd weight ontop. That should be a safe charging setup for the battery if godforbid anything happens.

I would also recomend a LV Alarm. Becuase when these batteries go below 3.2v or 3.0v (whatever batterys instructions recomend) they can become damaged. Set your LVC on your esc as low as it goes. You land the heli as soon as the LV alarm goes off so you dont over-discharge and ruin your battery.

I believe the safe charge rate for the batteries if 1C.

Just make sure that you dont damage the batteries, drop them.

Dont just take my word for it! Read up on this stuff, read all the manuals that come with the battery. You should be fine as long as your careful.

thewhizz*

Sorry about your loss, its tough when you put alot of time into something like that.
One Guy told me another thread that the Lipo battery doesn't heat up much until it is in trouble, then it goes to 2000 degrees in about 20 seconds. I also used the correct charger, and used to check the temperature, and never noticed any heat coming from the battery, so I think sand is a good idea. metal containers can short the charger when the lead burns off the battery.
Murt

flyboy1299

My Feedback: (7)

Reply to Flygirl950-- Girl, you frighten me! Maybe I'm being over-critical but the tone of your words makes me think you are taking Li-Po's not nearly seriously enough and we don't want you ( or anybody else) to have a nasty event! Please read all you can find about Li-Po's and take it to heart! It really isn't too far fetched to say that it might save your life! I will relate two short incidents of mine that are really scary because they should have resulted in a serious fire but didn't!! In the first incident, I accidently shorted two leads on an 800mah, 7.4 pack, and immediately dropped them into my ceramic jar and slapped the lid on!! Nothing happened!! Not only that, but the pack still tests and works fine. It still flies the heli with no noticeable loss of power! In the second incident ( with the very same pack) I was connecting my new charger and didn't realize the polarity was not the same and went ahead and plugged the pack in! Having no familiarity with the charger, I looked for a lite to indicate charging was going on but didn't see one. Something made me pick up the pack and burn my hand because it was so Hot! It must have been a nano second away from smoking when I jerked the plug out of the charger. This same pack got very seriously HOT and so, again, I dropped it into my ceramic jug and plopped the lid on. I let it cool overnite and the next day the pack showed NO signs of the encounter!! Still works just fine!! Now I would not advise you to try to convince me that there is no such thing as a guardian angel, cause I'm pretty sure there is!!!!

thecheatscalc

Whew.... just wondering, what was that plane made of! if it was foam I wouldn't have expected it to burn like that, I'd guess it's wooden and covered with doped silk which just torched. ANYWAYS the real solution to the problem is to just watch it as it's charging, and check on it every twenty minutes or so. if it's still cool, good, if it's starting to get warm you should be monitoring it closely as the charger should finish any moment. IF it gets uncomfortably hot you may have a problem, you'll want to let it cool and check for problems before using again. I've had a few swell before, NOT good, but, you can tell it's swelling if the packaging looks bulged and/or the pack is squishy feeling (as if it has air in it) if you feel that, that's a BAD sign, you got to get another li-poly. There are exceptions, such as double wrapped batteries like my maxamps, it's squishy but that's the double wrapping.

basicly, use the right charger, right voltage, and right speed for charging and you should be all right, also, don't over stress the li-poly, that doesn't help either.

PS: shorting is NOT good, and can cause problems as it will de-balance the cells.

Norrmannen

Peter
Did you set cell count wrong?

Don't overdo this.
Lipos don't catch fire from too deep discharge, they can catch fire or just burst from too fast discharge and likewise from charging to too high voltage.

Properly treated lipos are not more dangerous than your cell phone lipo.

Don't discharge too hard. Surely don't charge at too high cellcount (2S battery on 3S setting).
Take care if damaged in crash, don't short circuit.

Preferably, charge only through balance plug as in this way you cannot charge to dangerously high voltage + you get a balanced pack.

Simple precautions make this nothing to worry about. I use a bag of sand on top of my batteries when charging. Sand is very efficient at putting out fires. Lipos are not supposed to heat up during charging, if they do you are doing something wrong, anyhow sand is just as efficient at cooling as air if not better.

Don't scare people of, just give good advice...