I since starting with electric power and my biggest concern has been the SAFETY of using Lipo battery packs. To date I have used A123 pack from MEC and feel this is a very safe reliable battery system. The drawback is the weight. There are some new Thunder Power V2 extreme 25C packs that I have seen advertised and this could allow the same higher current draw that I am using with the A123 cells and save 7 oz. That is a big weight savings that for competition flying is important.

My concern is that I have heard some scary stories about Lipo's going on fire in cars and houses, also the Lipos take a lot longer to charge (I'm not sure that the V2 extreme charge as slow as the older Pro-Lites). So what is the straight scoop?

Best,            Dennis

Hi Dennis,

Like you, I am very concerned with safety. I have tried to read everything I could about LiPo batteries, and I have talked to many ERC flyers that have been using LiPos for longer than my several years of experience.  I take all the precautions below and I no longer worry about any Lipo accidents. :-)

FWIW: This is my take on the safety of LiPos:

1. Lipos have become very safe to use. I am on my 200th ECL flight without any problems. And several hundred ERC flights.
      Most of the car burnings, etc. are from a few years ago when everyone was making the transition to LiPos and using the WRONG charger, or charging incorrectly, or BOTH. Many found out the hard way that they needed a special LiPo charger, their NiCad chargers did NOT work well. Also, most of the early LiPos did not have a balancer plug. This caused many of the problems that, thankfully, are no longer with us. .... Now the word has reached all but the few that never read any directions, or just don't read period! ;-)

2. The BEST safety device (after a cautious, educated mind ;-) is a good quality charger that has a built in safety feed back loop like the Thunderpower 1010 charger. This feed back loop STOPS the charge if anything is not perfect (low/high Voltage, etc).

3. Using a good balancer makes for a very safe charge with little chance of a problem. IMHO: Not using one is asking for problems.

4. There are some precautions we can take that will prevent damage if the worse happens:
     
      1. Always place your batteries on a piece of Ceramic Tile while charging. Our batteries burn like a flare.  They burn at around 2,000 F for a few seconds. This is the same temp at which the tile starts to melt. Your burning battery will "weld" itself to the tile, but it will NOT burn through it.  This is not a guess, I know it is true. Please don't ask me how I know? ;-)

       2.  Place your batteries inside a LIPOSACK or under a ceramic cover. I use the Liposack at the field and my ceramic covers at home. With luck, photos of these covers will make it to this post? .....Here is the link to the Liposack web site and the Tower link to buy one:

               http://www.liposack.com/         

                http://www3.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=Liposack&search=Go

        3. Have good ventilation where you charge. It is "very" rare to have one burn if you follow all the above steps, but if one does burn up, they put out a LOT of black, smelly SMOKE. Ideally you should charge where you can open a door to the "outside".

        4. Your goal should be to contain the burning parts, and prevent them from flying around and starting a fire. 1 and 2 above will do this. I have seen pails of sand used, Ammo Cans are also very good. BTW, my ceramic covers are small planter boxes from a Home Dept Garden center. They are perfect for our needs.

         5. I never charge any batteries in my car, even my small 11.1V 2100 mAh park flyer batteries. It just seems to me that the small convenience is out weighed by the possible mess an accident would cause, no matter how rare the event.

Again, accidents are now very rare, but a little preparation will prevent any damage to you, your friends, your car, your home, etc.  ... I think that old saying ".... an ounce of prevention ....."  says it all.  :-)

I'm sure people with more expertise than I have will give you some better input on this important subject.

Regards, 

All,

I understand about the weight being "King" in stunt, also agree that proper equipment is needed for charging/balancing (I have a TP 610C). From what has been posted charging should be done outside on a noncombustible surface, use of a Liposack sounds like a good idea.

OK now what and where do you store the batteries in at home? and for transport? Lastly, what do we need to build into our ships to protect the batteries from being bruised during use?

Best,          Dennis

Hi Dennis,

I'm glad you are asking all these safety questions, and I hope others who don't post here but listen in are taking notes on your thread. ...... I'm sure you are aware that most of my answers are directed to this larger group and that you know that I know that you know most of this stuff? 

1. Just to add to the good comments made by Kim and Alan; these batteries are very safe and the few accidents with them, from years ago, are more reflective of our 24/7 web news cycle than any meaningful statictics. I know that the burning vehicle photos from years ago were on every imaginable web site and repeated over and over again in zillions of posts! It made this one accident seem like there were thousands of vehicles burning everywhere from the "dangerous" LiPos lurking among us! ;-) .... Well it was not that bad, but you get my point.  We use gasoline every day throughout the world. It is many times more volatile and dangerous than our batteries, but we have all learned how to treat it with respect and use it safely. I think we can do the same with our batteries.
      With the above said, yes we still have to be careful, and like others have said, just follow the simple rules and all will be well. :-)

2. Home storage and Carrying batteries:

I use a clear box with a snap on lid. It holds six batteries plus my HM timer setting unit. This fits in my ECL day pack along with my stooge, lines, handle, etc. I walk to my park with this on my back and my plane in my hand and fly. :-)  I made small bubble wrap holder tubes for each battery using the small bubble wrap and clear tape. This was to be a temporary fix, but it has now worked well protecting my batteries for a year and 200 ECL flights. I also have a 3/4" foam floor, and sides,  in my plastic battery box.

It is the corners of our LiPos that need protecting. This is their weakest point. If they get bumped by a hard object in their corner, even gently, it will break the integrity of the case and pushes the extremely thin sheets inside together and allows them to touch each other. This does not result in a burn of the battery, it just PUFFS up a little (about 1/8") because of the internal gases produced and it is now useless and should be set aside in a safe area for 30 min. then disposed of.  Packing the batteries in some form of foam while storing, transporting, etc. is a simple, and important precaution.

The ideal is a metal RC TX case, or an inexpensive, strong plastic pistol case. They have foam in them already and can hold our batteries in a very safe manner, custom packed like a camera is. I carry my ERC batteries in one of these. .... Here is a link:

http://www3.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=TX+case&search=Go

3. Foam in Plane

For anyone who makes consistently safe landings, mounting the batteries with the FEMALE Velcro on the bottom of the battery and the MALE Velcro in the plane is more than enough padding for the battery. Even when strapped down snugly with the Velcro holding strap there is still enough padding left. Try to use thin, very light duty Velcro (like the red, double sided stuff used to wrap cables together) for this battery mounting. This stuff is more than enough to keep the battery from shifting in flight or during a small bounce landing (not yours Dennis, but for the rest of us who still bounce some times ;-). This also allows the battery to be easily removed. Please DON'T use strong Velcro here, you will curse it every time you struggle to get your battery out. I make my battery tray out of 1/64 ply with 1/8" balsa glued on top of it. This gives a slight cushion to the battery. At least I delude myself into thinking it does. 
       Use medium strong Velcro for the holding strap.  In flight the batteries are subject to much lighter forces than they get in ERC and there have never been any problems that I have seen or heard of.
      Someone mentioned protecting the front of the battery in case of a crash. Like you, I don't build for a crash, BUT in this case it is very easy to put some Styrofoam in front of the battery. I have about 3/4" of it +1/8" balsa in my plane just in case. Cheap, easy, light, my kind of solution. 

SIDE BAR, protecting LiPos in a ECL trainer?

Last year Kim mentioned that if we used ECL for CL training, or early pattern training, that the batteries would get expensive because they do not "crash" well.  .... I totally agree with Kim!  If we are using the typical CL trainer plane, Ringmaster, Clown, or others the batteries would always be at risk. .....But, I think a purpose built, FOAM, high wing, pusher, motor on top like a SE seaplane ECL trainer (think Multiplexes great pusher ERC foam motorglider converted to ECL :-) may be the perfect tool for the job. The timer can be set for 2 min flights. etc, etc. ....  But then, there is really no one coming into the hobby that needs training so this may be a solution looking for a problem to solve? 

A few little things that are easy, and help a lot:

1. Get one of the little cell test units from Sin City Jets. These little postage stamp size meters plug into the balancer plug on your battery. They tell you the V level of each cell. If you have left your batteries set for several weeks, this unit will tell you the level of each cell to tell you if you need to top off your batteries. It is also a good indicator of how your batteries are doing, showing how close each cell is to perfect. It is a good alert to a problem. I use it about every 20 flights.  You will also need to order one of their adaptor plugs so you can use it on different battery brands.  Here is the link:       http://sincityjets.com/

2. We all get distracted at the field, so I am a big fan of KIS systems to idiot proof my equipment to save it from the "idiot" pilot.  ..... You may want to use some method to mark your batteries right after you use them. ....I use a red rubber band. ..... This will prevent you from destroying one by mistaking it for a fresh one and putting it up for it's 2nd, suicide mission, flight. This will also help you when you get home to charge your batteries if you have not used them all, etc. I have also numbered all my batteries so I can use them in a rotation so they all get = use.

Yikes Dennis, this was going to be one of my succinct answers! Honest

Regards, 

Rudy and All,

I know that bringing out negative issues is not what we like to talk about, but I think the discussion has shed light on what we as a E_CL group need to teach new comers. Rudy, your comments are laid out just the way we need to present information here. We need to keep providing the complete picture and not short cut the descriptions, this at times means repeating things that the regulars already know as we get to the point.

I was totally new to E_CL about 6 months ago and even though I have flown CL for over 30 yrs and understood how these planes work, finding E_CL information and sorting though the numerous options took a lot of time. With the help of several people on this board I developed a package that works well. As I worked though the process I repeated the complete setup description in numerous posts solely for the benefit of those who might be looking to start with E_CL and want a starting point. We need to make it easy for people to get started in E_CL, granted once you get the basics a whole lot of stuff makes sense but we need to allow them to get there quickly.

Now as I look to move forward to fly E_CL in competition I am working to refine the package. The A123 3s2p 10V battery with the AXI 2820/8 motor works very well but it is heavy. The good news here is that most of the weight is positioned near the CG and doesn't hurt that much. I know some guys that are flying Old Time Stunt that have added weight boxes at the CG and every time they get a more powerful engine they add more prop and up the weight. These guys are top flyer's and when the wind blows it's very hard to beat them, but the key is the old bar bell idea of were the weight is positioned (short version - weight on the ends i.e. front or rear of fuse, is bad and slows control response and stability).

That said if you can save 4 oz by changing battery pack it is worth a close look. I still like the XXXX/8 motors since they are lighter and can pull lots of amps. Matching the battery to take advantage of this is what I'm now trying to do and having a safe way of using the Lipo's will do this.

Best,          Dennis

Hi Keith, if everything fails with travelling, I can buy here the same type of battery as you need and bring them to france by car 

I will take also all tools ... simple

Keith,

Why not ship via Fed X 9or others) several packs and he could bring them. Thats got to be less expensive than buying new ones unless money is no concern.

Now that the mfg'ers have the chargers sorted out, to keep the pack balanced and not overcharge, the remaining safety problem with Li Poly batteries is the fact that they can fail internally at almost any time.  The failure rate is very low, although Sony had a major problems with what was apparently one production batch.  But they can very occasionally fail and catch fire while flying, while charging, or even just sitting there.  Couple that with the fact that people get complacent when they don't have problems, and there is a real potential for a once in a lifetime disaster.  If nothing bad happens for a long time it is easy to forget to do some of the safety practices.

Well I will reiterate. I leave my laptop out all the time. Yes there is a finite chance that something might happen. But that is also true with a lot of things in the house (gas, electricity.....). I am sure that driving to work is the most dangerous thing I do on a daily basis (probably also for the lipo's, since they are in the car with me.

I don't mean to minimize your concerns. But how many Lipo distributers have you heard that have burned down? I don't over-worry about my lipos. But I try to handle them (charge, carrying them around) with care, but not fear. I always look at what is happening when I charge them, but I do charge them in the basement.

Keith,
It is a good idea to get the charge to the ~40% to 50% level. That's how they are shipped from the distributer. Might as well lower the energy level and it is claimed they last longer in that state --than if they are fully charged or more discharged. Also if you pack them in your luggage, you can't be sure about the temperature they might be subjected to. You don't want fully charged batteries to get too cold (from what I understand).

Thanks to all for the info and good suggestions. I will indeed do some more homework on the fireproof container thing. This is really a good forum, so keep it up guys!

Keith R

Keith,

Sorry for the delay in getting back to you.

You said:

"Basically, as things stand now, I could stick the batteries in the flight case and get away with it."

Well I guess if you did get away with it then that would be OK. BUT!!!

You may wish to read the following documents:


http://www.markhopkins.co.uk/docs/liionshipping2.pdf


http://www.ulbi.com/documents/whitepapers/Ultralife_Batteries_Lithium_Battery_Transportation_Regulations.pdf


Here is the wording diect from the SAA web site:

********************************************************

9.3 ITEMS UNACCEPTABLE AS BAGGAGE
9.3.1 You must not include in your Baggage

9.3.1.1 Items which do not constitute Baggage as defined in Article 1;

9.3.1.2 Items which are likely to endanger the aircraft or persons or property on board the aircraft, such as those specified in the International Civil Aviation Organization (ICAO) Technical Instructions for the Safe Transport of Dangerous Goods by Air and the International Air Transport Association (IATA) Dangerous Goods Regulations, and in our regulations (further information is available from us on request);

9.3.1.3 Items the carriage of which is prohibited by the applicable laws, regulations or orders of any state to be flown from or to;
***********************************************************************************


When I travelled to Spain I did just as you are contemplating. I put the batteries in my checked luggage and there was never a word said. Of course they did not look at my checked baggage. Paul Walker is shipping his batteries ahead of time.

Generally we exceed the 2gm limit per battery if we use more than a 3S2P 2200 pack.

So you can try to get away with it but the potential $27,500 per non-disclosed battery fine might cause you to blink once or twice   

Your batteries can travel at any voltage. If you were to store them for a period of time, they should be drawn down to 3.8  volts/cell for optimum life.

Have a great trip and say hi to Loren for me.


Kim.