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Lipo Batteries - A Warning

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  • Lipo Batteries - A Warning

    Had an incident yesterday that was a sober warning aout Lipo Batteries.

    I've standardised on using 5000mah Lipos for subs, so I can swap from boat to boat..............these are what I've been using....

    Image result for zippy flightmax 5000mah 3s1p 25c

    ...........Zippy Flightmax 25C 11.1V versions of the above, works perfectly with my 12V sub systems.

    I store these in my attic work room, in a tin box away from heat etc., and only fully charge them when using or testing the subs.

    I've seen enough scary vids of these things going on fire, so seeing one of them was developing a bit of swelling, I decided to dispose of it.

    As I was bringing it downstairs, perhaps I squeezed it, but it went on fire, igniting within a second and setting off the house fire alarms. Luckily I dropped it before it burned through my fingers, but it did a fair bit of damage to the carpets. Managed to kick it into a tiled bathroom where I could get some water onto it. The top two floors of the house were completely encased in noxious smoke for about 10 minutes.

    Here's some of the damage...............around 600 bucks of new carpet will be needed.

    Click image for larger version  Name:	IMG_1750 (800x600).jpg Views:	1 Size:	317.3 KB ID:	127320

    And here's the remains of the little b*****d........................

    Click image for larger version  Name:	IMG_1751 (800x600).jpg Views:	1 Size:	297.7 KB ID:	127321

    Look, we've enough things in the world to scare the crap out of us, so I don't want to be alarmist, but I admit this left me shaken, the number of 'what ifs' are frightening. Needless to say, Mrs. Boattrainman was a bit p****d off!

    Not sure what more I could do to keep safe, but I'll be keeping my spare fire extinguisher nearer the work room from now on.

    All's well that end's well, no one got hurt, except for a slightly burnt thumb.

    The Boattrainman
    Last edited by The Boattrainman; 08-15-2018, 03:59 PM.
    ''We're after men, and I wish to God I was with them........!''

  • #2
    Sobering. Thanks for the reminder -- these are pin-pulled hand grenades if not cared for properly.

    "... well, that takes care of Jorgenson's theory!"


    • #3
      I use Zippy LiPo as well........I will give it a little more respect now.
      If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.


      • #4
        I'm checking for swelling - and checking the batteries too!


        • #5
          Most lipos will puff, if I binned every lipo pack that swells i’d go through them like smarties.

          You were unlucky. Sadly lipos are highly flammable if the plates short- many think it’s the lithium causing the flames, but there’s only about 2% lithium in the pack, the electrolyte is the chief culprit that burns. A lot of effort is going into creating a solid electrolyte for lithium batteries, but they’re not there yet. Manufacturing is reaching the limit of lithium battery technology in current forms, which apparently hasn’t altered greatly since the batteries were first introduced to the market in the early 1990’s by Sony. When they do perfect a solid electrolyte, manufacturers will be able to use more lithium in the batteries, which will hugely increase capacity, believed to be up to ten times what is available today.

          With present tech, increased capacity has been achieved by moving the plates closer together, but this makes the battery more vulnerable to shorting if it’s physically damaged. Remember the furore over the Samsung Note 7, with new phones combusting in handbags and pockets? That lead to a total recall and cost Samsung billions, and the problem was down to a very high density battery, combined with insufficient delicacy when assembling the phone.

          Physically tougher lipos can be found in the cylindrical 18650 cells (the first four numbers dictate the dimension in mm e.g.18mm diameter by 65mm long) These are made in very high volume for use in laptops, electric cars (e.g. Tesla) and the good thing is, they’’re a standard size. Capacity wise they tend to top out at around 3.5Ah , some have better c ratings than others mind you. Higher capacity batteries are available in larger sizes, but the choice is lower and the price higher, because they’re not made in such high volume. So for instance you can get 26650, and Tesla have developed a new battery with Panasonic for their Model 3 car, 2170, which has high capacity and c rating for its size.

          These cylindrical batteries have a strong case like the more traditional Nimh and Nicad packs. They find less favour in the modelling community partly because of extra weight, which is a big deal for performance use, especially in aircraft, but also partly becuase many modellers are unaware of the alternatives.

          Lithium iron phosphate is an alternative chemistry. These are far more stable than lipo, but have a lower energy density. They have a higher upfront cost, but a longer cycle life, so work out the cheapest battery technology long term. A123 had the finest LiFe batteries, the sad demise of that company demonstrates the best tech doesn’t always win, but you can still buy their batteries. They have excellent C ratings, as they were designed for electric cars from the outset.
          Last edited by Subculture; 08-16-2018, 04:39 AM.
          DIVE IN! Go on, go on, go on, go on, GO ON!


          • #6
            Don May gave a very informative talk on Lipo batteries at the Carmel Funrun. I learned that if the battery has swelled to cut the leads off, one at a time, and dunk the battery in a bucket of water. In a few days the water should neutralize the battery so it can be disposed of. Also, always balance charge the battery and discharge it so it is at no more than 60-70% charge for storage.


            • #7
              I rang a buddy of mine who's into electric model planes, he had a dozens of Lipos in his work room last time I dropped in.

              He concurs that Lipo puffing is relatively common, he doesn't bin them either until they are seriously swelled, plus he keeps them checked for consistency across each cell and he stores them all at 70/80% of charge, and follows all other good practices.

              I agree I was unlucky, as I said nothing to be getting too alarmist over, but the exception proves the rule and as I'm working above where I live (no separate work room off the main house), I'll be keeping a closer eye on them, can't take the risk of the house going up (even if it's unlikely).

              I've looked at alternatives, 'hard case' Lipos, the ones based on Graphene, but they all seem to have problems.

              I don't need too many Lipos, three max, as my surface runners use Nicads/Live Steam etc, so I've resigned to keeping three going and replacing them once there's an issue (maybe every year/eighteen months).

              ''We're after men, and I wish to God I was with them........!''


              • #8
                I bought a couple of LiPo bags. I use them for storage and one for charging (after a run).
                Rob, I am pretty sure you take care of your things so this explosion really has me thinking.
                If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.


                • #9
                  Worth remembering that these days, if you buy and use the following, they probably use lithium power packs-

                  Laptop or tablet computer
                  Cordless tools
                  Cordless vacuum cleaner
                  Electric car
                  Digital camera

                  In fact pretty much anything now being made with a rechargeable battery tends to be lithium.
                  DIVE IN! Go on, go on, go on, go on, GO ON!


                  • #10
                    The LiPo storage bags are a great idea, as are charging boxes. I've got so many of those things sitting around the shop and storage bay... if they went up at once, you'd see the fireworks across the gulf...


                    • #11
                      Thanks for all the good advice, and just to confirm how 'anal' I am about this stuff, here is the storage case for my charger and leads, so they don't get damaged.

                      Click image for larger version

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                      I've ordered some fire retardent Lipo storage/charge bags.

                      The only concern here is the location of my workroom. As it is, my insurance company are dealing with this as a small claim (i.e, under 1,000 euros), no loss adjuster et.c, they will sort the claim on the basis of photos, estimate of damage anda claim form.

                      I've no doubt that if the damage had been in low to multiple thousands, or if the Fire Services had to be called, questions would be asked about what I'm doing with such potentially combustible materials in the house. I've been dealing with insurance companies though my day job for the last few years, and the amount of twisting and turning they do to reduce or even cancel claims is mind boggling.

                      I'm envious of the builders with a separate workroom or small building to work from.

                      Then again, I'll be working on a 'live steam' engine for my new project over the winter, while the boiler is fully certified, I'll have another potentially exposive item in the attic!!!!


                      Last edited by The Boattrainman; 08-17-2018, 11:54 AM.
                      ''We're after men, and I wish to God I was with them........!''


                      • #12
                        A simple ceramic or glass pot is as good as any for storage.
                        DIVE IN! Go on, go on, go on, go on, GO ON!