micro_builder

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i know no-one wants to sit and read all this, but if you dont want to burn your house or car down, its worth reading. please do yourself a huge favor: if you're new to lipos, READ ALL OF THIS! a lot of people have had a lot of expensive damage to their house and other belongings because they didnt know the safety requirements of lipos. it may take a few minutes to read, but its a heck of a lot better than the alternative.

i have attatched two pictures, the first is what will happen if the follwing information is not taken seriously. the 2nd pic is what a ballooned cell will look like. if you've got an AA or other micro RTF that doesnt seem to take a charge and doesnt fly because a loss of power, check the cell. if it looks like the pic, put it in salt water.

Here are a few MANDATORY guidelines for charging/using LiPos (Lithium Polymer Batteries).

1. whether you're flying an AA, piccoZ/havoc, or any other of the micro RTFs, never use any charger other than what comes with the plane/helicopter - and always read the instructions. if you're modding things to the extent of removing the lipo from the plane, always keep the lipo in a fire proof container. if you're knowledgable enough to use your own dedicated lipo charger, always make sure you have the charge rate at the correct setting. never charge a lipo with a charger meant for NiCD or NiMH batteries!!!

2. NEVER charge the batteries unattended. This is the number one reason for houses and cars being burned to a crisp by lithium fires.

3. Use a safe surface to charge your batteries on so that if they burst into flame no damage will occur. Vented fire safes, pyrex dishes with sand in the bottom, fireplaces, plant pots, are all good options.

4. DO NOT CHARGE AT MORE THAN 1C unless specifically authorized by the pack vendor. I have personally had a fire in my home because of violating this rule.

5. DO NOT puncture the cell, ever. If a cell balloons quickly place it in a fire safe place, especially if you were charging it when it ballooned. After you have let the cell sit in the fire safe place for at least 2 hours. submerge the cell in saltwater to "kill" the cell overnight, it will then be safe to dispose of properly.

6. If you crash with your lithium cells they may be damaged such that they are shorted inside. The cells may look just fine. If you crash in ANY way carefully remove the battery pack from the aircraft and watch it carefully for at least the next 20 min. Several fires have been caused by damaged cells being thrown in the car and then the cells catch fire later and destroys the car completely.

7. Charge your batteries in a open ventilated area. If a battery does rupture or explode hazardous fumes and material will spew from the battery.

8. Keep a bucket of sand nearby when you are flying or charging batteries. This is a cost effective way to extinguish fires. This is very cheap and absolutly necessary.

9. It can happen to you, do not think to yourself that “it won't happen to me� as soon as you do that it you'll be trying to rescue your kids from your burning house or car. I'm very serious about this.

Now that we have covered that important topic let's move on to lighter matters:

2. Lithium What?
Lithium Polymer batteries are used in many electronic devices. Cell Phone, Laptops, PDA's, Hearing Aids just to name a few. Most, if not all, lithium polymer batteries are not designed for RC use, we use them in different applications than they were designed for. The reason we use Lithium cells is that they are significantly lighter than comparable NiCad or NiMH batteries, which makes our planes fly longer and better.

3. Voltage and Cell Count:
LiPolys act differently than NiCad or NiMH batteries do when charging and discharging. Lithium batteries are fully charged when each cell has a voltage of 4.2 volts. They are fully discharged when each cell has a voltage of 3.0 volts. It is important not to exceed both the high voltage of 4.2 volts and the low voltage of 3.0 volts. Exceeding these limits can harm the battery.

4. Naming conventions explained.
How fast a battery can discharge is it's maximum current capacity. Current is generally rated in C's for the battery. C is how long it takes to discharge the battery in fractions of an hour. For instance 1 C discharges the battery in 1/1 hours or 1 hour. 2 C discharges the battery in ½ or half an hour. All RC batteries are rated in milli Amp hours. If a battery is rated at 2000 mAh and you discharge it at 2000mA (or 2 amps, 1 amp = 1000mA) it will be completely discharged in one hour. The C rating of the battery is thus based on its capacity. A 2000mAh cell discharged a 2 amps is being discharged at 1C (2000mA x 1), a 2000mAh cell discharged at 6 amps is being discharged at 3C( 2000mA x 3). All batteries have limitations on how fast they can discharge.

5. Which battery should you buy?
One great way to find out what the best battery is, is to look at graphs of the batteries performance. Looking at how low the voltage of the cell drops at various amperages will give you a metric to compare that battery to similar size/weight batteries.
If graphs aren't your thing then simply look at what other people are using in successful setups that are similar to your application. If a lot of people are reporting long flight times and lots of power from airplane X, with power system Y, and battery Z and you do the same, then if your setup is similar the same battery will probably work well for you.
It pays to learn something about Watts, Volts, and Amps. Understanding these concepts is beyond the scope of this document, but can serve you well in not only figuring out what battery is best but also in your electric aircraft hobby.

6. Dealing with temperature.
Lithium batteries like heat, but not too much. In the winter time, try to keep your batteries from the cold as much as possible. Leave them in the car while your flying, or keep them in your cargo pants... etc. At the same time don't let them heat up too much. Try to keep your batteries from reaching 160F after use. This will prolong the life of the cells. A good way to measure temperature is a handheld IR meter, they can be found for around $50.00 at most hobby shops.

there, that wasnt so bad now, was it? please do ask any questions, the more you know about lipos, the more safe you and your planes, house, car, and everything else will be.

nick

just for the record, most of this is not my information, but its better than i could've written. most of the info in the text was meant for larger cells, not our micro RTFs. that being said however, if you're modding your lipo powered RTF, all the above info still pertains to you. our little lipos dont pack nearly the punch as the big 2, 3, and higher cell packs, but they can still cause damage. i've been using lipos for 2 years now and have never had a cell vent or flame up on me, and thats because i know the right and wrong way to use these cells. please be safe!

googledperson

Great Job! we need one of these! this should be stickied

ArmedZagi

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That first pic is pretty spectacular....

Neurotex

A much needed sticky!
If lawyers get into this and manufacturers are sued it could lead
to the end of lipo's being sold to the public. Even if that's not the
case it could cause a spike in prices and force hobby shops not
to even bother selling them for fear of legal action.
A must read- thanks for posting the info.

FERNDALE AIR FORCE

The Lawyers are half way here. I have a 2s lipo coming from tower and on the packing list is a lipo warning page. So, for those of you that are buying lipos after tomorrow the price will stay the same, for now, but you'll be getting a safety sheet. Tim

micro_builder

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yeah i thought this was overdue, i'm kind of surprised all the RC forums dont have something like this right off the batt. i did send a PM to one of the moderators though asking to put it up as a sticky, so i'm sure it'll be up soon.

i had edited the text a bit so it was a bit more user friendly to completely new people. the lipo jargon can be kinda confusing at times. i also figured that if someone here was getting into the hobby enough to be investing money in their own lipos and chargers, they've probably got a good idea of the safety precautions so the text didnt cover much of that aspect. might not be a bad thing to cover though.

i do worry about the future of lipos in the hands of people who are unfamiliar with them. it does only take one accident to have a big problem on your hands, and only a few lawsuits to make the toy companies start rethinking the use of lipos in off the shelf RTFs. i dont think we'll have to worry about losing lipos completely though, everyday technology like cell phones and laptop computers rely on them far too much to go back to big heavy nimh. good thing!

nick

BriGuy76

Thanks for taking the time to compose this! I just bought a LiPo powered plane and had no idea that these batteries where this unstable. I work in the electronics field as an Engineering Tech and did not even know this. Granted I never used this technology battery. At any rate thanks again for this info, I actually feel better about what I bought since I'll now know how to maintain it properly and safely!

andrewtexas123

WOW, i just jot back from taking a picooz apart and i was cuting aroud the lipo battery i THINK i saw smoke and throw it on the ground and stood back. Damn that was scary. I waited a min or to and then picked it up looked at it from a little ways away and did not see any thing and i throw it out the window. I am scared now i am going to wait till the morning to go retreave it. Should i be scared?


Thanks Andrew!

micro_builder

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best thing you can do is get a glass of water, put a few tablespoons worth of salt in it, mix it well, the put the cell in the salt water over night. after that, you can throw it away safely. if you punctured the cell with a very small hole, it would vent fumes slowly and probably wouldnt swell or burst and once its done venting the cell is basically dead, but you're still best off submerging it in salt water.

the picco has a small lipo, so its not as much of a danger, but this is the sort of thing that unknowing folks need to be aware of. i'd be willing to bet 90% of lipo accidents with our micro RTFs is this exact sort of thing (how many folks have stuck a pin or nail or other sharp object in the nose to change the CG?).

lipos can be dangerous if not used properly, but used correctly they can be as safe as a normal battery. like i mentioned before, i've used lipos for about 2 years now and have never had an incident other than one or two cells swelling. so, dunk the cell in salt water and it'll be fine.

nick

heli_Rod

What is the proper way to dispose of these batteries?

Rod

micro_builder

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Rod,
depends on how nature-oriented you are i suppose. you can toss them in the garbage, but then they end up in a landfill somewhere, so i bring all my used/dead batteries to a battery recycling center - once i'm certain they're completely dead, of course.

nick

FERNDALE AIR FORCE

OK, I agree that a lipo sticky should be on the forum. I thought that we had beat this horse to death until I read andrews post. He's been here for a while, and if he doesn't know the consequences of bad lipo handling then we need the sticky. I'm now using 2 cell lipos and am completely confident that if I cut one, fire is next. Tim

andrewtexas123

This deserves a sticky!

andrewtexas123

Well i decided not to gowith all of this salt and water stuff i kicked it around out side nothin happend so i looked at is closly and i cut the top of the cell.

micro_builder

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not trying to be rude, but that is just completely unsafe. you simply can not tell the condition of a lipo cell by kicking it around and looking closely at it. i'd say you got very lucky by nothing happening when you cut the top of the cell - if it still had some kick left in it, you'd be dealing with some burn issues right now. lithium burns fast and very hot, and all it takes is contact with oxygen to get a fire from it. it only takes a minute to mix salt and water together, a minute that could save you and your family a lot of problems.

using a voltmeter to test the cells voltage is the only way to know if the cell is completely dead. if the meter reads zero, then its safe, if it reads anything other than that, do NOT puncture it. even if the cell is completely dead, its still best to just leave it alone and dispose of it, lithium is toxic, so you dont want to be playing with the contents of the cell.

please, do not take any short cuts with these batteries, and always take the needed precautions. this may all sound a bit extreme, but this is just one of those cases where its much better to be safe than sorry. have your dad or mom read the info on the first post as well, so they know too.

nick

andrewtexas123

lol, too late... I throw it away and got a new piccoz!

Crash_Airlines

I'm new to lipos and I'm trying to learn more about them for the safety of me and my house. The link below made it sound like they shouldn't be charged in temps of over 113. I live in hot Arizona, and I was wondering if it's still safe to charge and store my lipos in the garage during summer when we can sometimes get up to over 116 degrees? I don't want to store them inhouse where its cooler with the airconditioning because of the potential fire hazard lipos seem to pose. I currently have been charging and storing lipos in my garage. I put each lipo in the hollow section of a cement building block on my cement garage floor, and then I have a cement brick that is 12 inches wide by 12 inches wide by 2 inches thick that I cover the holes of the cement block where the lipos are in. I leave a little space for wires and air. I store and charge the lipos this way in my garage, and was wondering if that's OK when the Arizona heat reaches over 116 in the summer months?

Also, can Lipos actually explode, or do they just have the potential to go on fire? Are the Lipos mainly dangerous just when charging, or can they be just as dangerous sitting around idle? Like I said, I'm new to Lipos and I'm not sure what mainly causes them to start on fire and I just want to make sure I do my part to prevent it. The charger I got with my CX2 seems to stop charging automatically, so I wouldn't think overcharging would be a problem if my charger is working properly.

[link]http://home.comcast.net/~truerc/Data_sheet/Lipoly_Safety_Warning.htm[/link]

}---O---{

Thanks for the valuable reading material!

Dave ESPI

A good read. thanks

I've got LIPOs and am still kind of leary about keeping them around. They are "Safe" provided you handle them with respect, and don't beat them up. With all the super crashes and flips and flying/ skidding loose battery packs I've had with years of high speed on-road pan-car racing, I would almost want to put a lipo in a bullet proof fire-proof protection case or safe in the car, and when gravity and weight is not an issue, GREAT ! protect them packs !


Flying though..... that adds weights and defeats the bennifit of Lipo.

LIPO= High output, lightweight GO JUICE !

just " THINK" before putting something somewhere unattended, and always inspect your stuff routinely, and accidents can all but be eleminated.

Oh, and I have 4 saltwater reef aquarium tanks, so having salty water and sand on hand at all times is an added bonus... LOL

micro_builder

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those are good questions! honestly, i'm not 100% sure about the charging temps, so i wont even comment on it. there is a battery forum here on RCU though, i'm sure they could give a proper answer.

lipos do explode, to an extent. usually they swell up with fumes inside the metal casing, once the pressure is high enough, the metal cant hold it in and the cell bursts. its this releasing of pressure, combined with either nasty chemical fumes, or flames, that cause all the problems.

the majority of lipo accidents happen during charging, its the most dangerous time when using lipos. there have been reported cases of lipos just going up in smoke with no apparent reason, but there probably is a reason for it, it just might not be obvious. any damage occured to a cell cause cause swelling or venting, if the cell gets dented, bent, dropped or crashed, it can cause problems internally that cant be seen on the outside. if the cell looks at all damaged, or if the cell was in a plane and the plane crashed, keep the cell in a fire safe place for a day or two, just to be safe, and once its sat for a while, if you try charging it, do it in a fire safe place and dont leave it unattended.

for all the safety issues there might be with lipos, they are still safe if used properly. read up on them as much as possible and learn all you can, and never assume a cell is ok and never think "it'll never happen to me"

i hope Murphys Law isnt listening to me right now....

Dave ESPI,
i did a lot of RC car'ing back in the day, still enjoy a drive now and then. i've always used the good old NiMH and NiCD packs, but after i got my RC18MT with the brushless system, i couldnt help but try a 2 cell 1500mah lipo pack. the performance was quite amazing to say the least, but for as easily as those tiny cars can loose control, i only ran it a few times. some high density foam might be good protection though.

nick

Crash_Airlines

Thanks for the added info.

alrogers84

also, dont try to test the MaH with just a voltmeter... testing the current is ok, but i guess you have to hok it up to the motor to test the MaH.. im not an electrical genius and almost blew myself my... basically tying to test the mah, and not understanding the funky instructions on the sheet for the tester, i touched the two leads to the battery and it went "fizzle, poof" and thick white smoke emerged from the murky depths of the cell.. then i threw in my ammo can, it was hot as crap though.. they dont tell you that in the safety sheet.. but then again i was playing in unknown territory... next time ill trust the label on the battery..

coleholley

Nice thread and here's some more pictures I found.