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  • #31
    New Batteries?

    Right. Intrigued by this Lithium Battery witch hunt, I consulted my triton charger hand book. When I oponed the box, the first thing that dropped out was a sheet of A4 with Important warning concerning the use of li-ion and li-poly cells Stating that The Li-io/Li-poly chemistry is a very volatile mixture. Misuse can quickly result in Li-ion/Li-poly cells getting hot, exploding, or igniting, which could lead to serious damage or personal injury. When I got the charger out, there was a sticker on it saying exactly the same thing. When I oponed the instruction manual, which details how to charge the types of batt that the triton can charge- Nicad, Nimh, Li-ion, Li-poly, SLA etc, under the Li-ion/Li-poly section, it says right at the top, in bold Important warning concerning the use of li-ion and li-poly cells Stating that The Li-io/Li-poly chemistry is a very volatile mixture. Misuse can quickly result in Li-ion/Li-poly cells getting hot, exploding, or igniting, which could lead to serious damage or personal injury.

    I get the impression the triton manufacturers are trying to tell me something. I then spoke to some folks at Sussex Model Centre. The conclusion was the same. Whether or not the explode when you look at the, as some ppl seem to be claiming, it is clear that they are more dangerous than the other battery types, and whilst we all strive to be as careful as possible with our batteries anyway, extra care should be taken when using these.

    As a bare minimum, ensure all your li-ion/li-poly batts have obtained UL1642 approval (quality of construction) and I would say you also want to ensure it has a built-in protection circuit. When draining this things quickly, and charging them, there is a much much greater risk of them exploding than there is with Nicads or Nimhs and so on.

    As with most things like this, ensuring you use the safest and best practise (and I would be dubious as to whether or not use in a fighting root is safe practise) then there shouldnt be a problem.

    Happy new year,

    Eddy

    Comment


    • #32
      New Batteries?

      Li-Ions certainly need to be treated with care - however the suggestion from Ewan was that merely falling off a pallet would cause them to blow up !

      There is no doubt that you should not abuse Li-Ion cells, what you gain in weight must be paid for in respect. They should only be charged using a proper Li-Ion charger for example, but then that is the case with all batteries - we would never think of putting a NiCad on an SLA charger so its common sense that you wouldnt put a Li-Ion on a NiCad charger !

      Yes you need to be careful, read the instructions and know what youre doing - but that doesnt make them inherently dangerous. A NiCad pack in the hands of someone who doesnt know what theyre doing is pretty dangerous !

      So long as you follow the instructions and best practice, there is no reason why a Li-Ion pack shouldnt be as reliable as a NiCad or NiMH, which I think is what Eddy is saying - so long as you play by the rules, youre fine.

      ..... bottom line is they are NOT going to blow up if they fall on the floor !

      Ed
      http://www.stormrobot.comhttp://www.stormrobot.com

      Comment


      • #33
        New Batteries?

        True, and as one of my friends whos into RC boat races will tell you, a lot of NiCad packs have entered the water without a boat during events.

        On some occasions even more than inside a boat.

        Comment


        • #34
          New Batteries?

          I was simply saying before, that if they fell off a pallet etc, AND it shortcircuited, Like what happened in my laptop accident, that then bad things could happen. But I do aggree that for fuse protected Li-Ions, the chance of them shortcircuiting is VERY low.
          I think that Li-Ions may come into use someday for robots, but the technology needs to evolve to cater for high current needs etc.
          THE END

          Comment


          • #35
            New Batteries?

            The reason In my opinion why Li-pos are slightly more lightly to get damaged is that they do not have a super though outer shell like a ni-mh/ni-cd/sla etc. The shell on them is some thin foil type thing. This helps to keep the weight down but does not make them as secure.

            Li-po technolegy has come along way. The first came with soft bendable tabs now the tabs are pcbs. They first came with no safety warnings now they do. It was like when ni-cds came out first. People did not know how to treat them correctly hence alot of fires. Now people know how to treat Ni-cds we see alot less fires.

            In my opinion Li-pos are where Ni-mhs were about 3-4years ago. Now look at Ni-mhs. The new Gp 3300cells have almost the same current handelling capabilities as the 2400mah Ni-cds. Things are constently advancing.

            But as i said it is possible to use them but I dont have to money to use them nor do most people.

            As for if a li-po gets punchered. Well its simple you get a bucket of water and add salt then chuck the battery into the bucket for 1-2days then just throw it in the trash.

            Every battery is dangerous. I got a 3rd degree burn from a 700mah 4.8v Ni-cd battery when it shorted. In featherweights now people are using 24 and 36v 2400mah ni-cds the short circuit current is much higher. We have to respect batteries. If you dont you will get hurt. As they say if you play with fire you will get burnt. If we treat all our batteries nicely we will never have a peoblem. If you dont then you do so at your own risk. One of the antweight guys who is an electronic engineer told me he got a really bad burn from a AAA alkaline. Most of us would class this as a safe thing as it never crosses our mind what they can do.

            Regards
            Ian Mc Donald

            Comment


            • #36
              New Batteries?

              Well, heres examples of both sides of the arguement:

              http://www.rcstuff.us/battery/lipo/lipo_DNA.htmlhttp://www.rcstuff.us/battery/lipo/lipo_DNA.html

              http://www.robotwars101.org/~robotwars1/phpBB/viewtopic.php?mode=viewtopic&topic=94&forum=1&star t=330http://www.robotwars101.org/~robotwa...iewtopic&topic =94&forum=1&start=330 (3rd post down)

              We need some industrial standards to refer to.

              Comment


              • #37
                New Batteries?

                Wow someone actually remembers them posts, I thought that they got totally ignored. lol

                But yes the battery can be pierced, crushed, heated and hit but it dont tell you if they connected it up to try it lol because if its connected it might be a whole different story.

                Ive now seen this warning posted :

                -------------------------------------------------------------------------------- ------------------

                WARNING
                Safety precautions for Lithium Polymer and NiCd cells/packs

                1. Never fast-charge any battery type unattended.
                2. Never charge LiPo cells/packs at any rate unattended.
                3. Only charge LiPo cells/packs with a charger designed specifically for lithium polymer chemistry.
                4. LiPo cells can ignite because of unmatched cell capacity or voltage, cell damage, charger failure, incorrect charger settings and other factors.
                5. Always use the correct charging voltage. LiPo cells/packs may ignite if connected to a charger supplying more than 6 volts per cell.
                6. Always assure the charger is working properly.
                7. Always charge LiPo cells/packs where no harm can result, no matter what happens.
                8. Never charge a cell/pack in a model. A hot pack may ignite wood, foam or plastic.
                9. Never charge a cell/pack inside a motor vehicle, or in a vehicle€™s engine compartment.
                10. Never charge a cell/pack on a wooden workbench, or on any flammable material.
                11. If a cell/pack is involved in a crash:

                a. Remove the cell/pack from the model.
                b. Carefully inspect the cell/pack for shorts in the wiring or connections. If in doubt, cut all wires from the cell/pack.
                c. Disassemble the pack.
                d. Inspect cells for dents, cracks and splits. Dispose of damaged cells (see below).

                12. Dispose of cells/packs as follows:

                a. Discharge: with the cell/pack in a safe area, connect a moderate resistance across the terminals until the cell/pack is discharged. CAUTION: cell/pack may be hot!
                b. Discard:

                - NiMH: place in regular trash.
                - NiCd: recycle (cadmium is toxic).
                - LiPo: puncture plastic envelope, immerse in salt water for several hours, place in regular trash.

                13. Handle all cells/packs with care, as they can deliver high currents if shorted. Shorting by a ring, for example, will remove a finger.
                14. Always store cells/packs in a secure location where they cannot be shorted or handled by children.
                15. When constructing a pack, use only cells of the same capacity (mAh).

                -------------------------------------------------------------------------------- -----------------

                And you might also find that there is also now safety guard electronics to prevent overvoltage when charging LiPo packs with a current-regulated LiPo charger just incase you accidentally apply a too-high voltage or charge for too long which you can see from the video and pictures on RCStuff.us causes a scary firework show

                https://www.fmadirect.com/site/Detail.htm?item=1779&section=28https://www.fmadirect.com/site/Detai...779&section=28
                http://www.rcstuff.us/battery/lipo/lipo_DNA.htmlhttp://www.rcstuff.us/battery/lipo/lipo_DNA.html
                http://www.robotwars101.org/~robotwars1/phpBB/viewtopic.php?mode=viewtopic&topic=94&forum=1&star t=330http://www.robotwars101.org/~robotwa...iewtopic&topic =94&forum=1&start=330

                Chris - http://www.featherweights.org/forum Im So Evil Im Worshipped By The Devil

                Comment


                • #38
                  New Batteries?

                  Ed - It is true that lots of portable consumer devices such as MP3 Players, PDAs and Mobile phones do use Li-on/Li-po technology and they are indeed classed as non spillable. But they are certainly more volatile than most other battery types, and there have been quite a few fire/explosion incidents - especially in mobile phones:

                  http://www.theregister.co.uk/content/68/33828.htmlhttp://www.theregister.co.uk/content/68/33828.html
                  http://www.theregister.co.uk/content/68/33879.htmlhttp://www.theregister.co.uk/content/68/33879.html
                  http://www.theregister.co.uk/content/68/33990.htmlhttp://www.theregister.co.uk/content/68/33990.html

                  It seems that overcharge,internal failure and short circuit are more likley to cause a li-po/li-on battery to fail, rather than impact.

                  As far as robot use goes they should be fine, if they do happen to explode or catch fire, better if it happens in an R/C metal box than while in your hand pressed against the side of your head!

                  Ewan - If your laptop hit the floor hard enough to damage the battery, id be more concerned about the state of the hard drive.


                  Dominic

                  http://www.ukrobotics.comhttp://www.ukrobotics.com

                  Comment


                  • #39
                    New Batteries?

                    Yep, the Lap top got off abit bad aswell...
                    A month at a repair service did the job
                    Cheers, Ewan

                    Comment


                    • #40
                      New Batteries?

                      Does anyone know anything about silicone lead batteries? i am thinking of getting them but need to know if they can be charged on my Supernova. These are the batteries I am considering http://www.overlander.co.uk/detail.asp?categoryid=55&ID=354http://www.overlander.co.uk/detail.a...ryid=55&ID=354

                      Joe Townsend
                      Team Cut Corners

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                      • #41
                        New Batteries?

                        I think youll find these are ni-mh batteries with a silicon wire lead for connection.

                        Richard

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                        • #42
                          New Batteries?

                          OK thanks, i feel a bit think now.

                          Comment


                          • #43
                            New Batteries?

                            Yeah Joseph, just normal NiMh packs mate, they can be charged from ur supernova. I was looking into those batteries to use in our new bot. I dont know really, look ok, cheap and decent, just there a new company, so personaly im sticking with GP and Sanyo, but dont get me wrong, KAN might be a decent company that make good batteries, i dont know.

                            Mr Stu

                            Comment


                            • #44
                              New Batteries?

                              They are! They have been used for a long time in aeroplanes and have a very simular rating to the Other 3000mah Ni-mhs around

                              Regards
                              Ian Mc Donald

                              Comment


                              • #45
                                New Batteries?

                                Thanks anyway but Ive decided to go with NiCads, NiMh cant give the currents I require.

                                Joseph Townsend

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