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Lipo questions

Discussion in 'Night Vision Optics and Illumination' started by Bluefrog, Feb 26, 2014.

  1. Bluefrog

    Bluefrog Busy Member

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    Got a few questions to ask

    I have got a lipo battery for my diy nv setup. I have bought a lipo safe bag to put it in when charging. Does the battery need to stay in the bag when not in use ?

    Also i know these batterys have a higher than normal chance of setting themselves on fire. Charging times ive heard range from 6hrs up to 10hrs .

    It says dont leave the battery unattended when charging / when your sleeping. So how do people charge these batterys ?

    Am i right in thinking too that the battery needs to be turned ON when charging too ?

    Thanks guys
     
  2. Andy

    Andy Administrative Staff Member Founder

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    There was a case not long a go where a gun cabinet set on fire, it was caused by a Lipo battery just sat on the shelf. I would not risk keeping a Lipo battery in the house, maybe in the garden shed or a suitable container left outdoors.
     
  3. Pidlar

    Pidlar Big Poster

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    I had a few when I had a couple of rc helicopters and had no problems. I think the main issue is the standard of the charger rather than the issues with the battery. A good quality balance charger I'd say is a must to ensure safer charging and prolonged battery life.
    All the best,Stu.
     
  4. Alex.mc

    Alex.mc Busy Member

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    The main concern with lipos is the charging. They require a particular "curve" or style of charging to be efficiently charged. Using a charger that is not specifically designed for Lipos will damage them irreparably, and could "Possibly" cause them to overheat and begin an uncontrollable internal chemical reaction (Fire!).

    However..................................... The lipos that have caught fire, are in most cases packs which are very high performance, high energy density packs that are being charged very hard or fast. That's a scenario which requires care!

    A lipo-safe bag is a great idea, but maybe you should collect all your family's mobile phones.... any Tablets or iPads.... some compact cameras.... MP3 players etc. and make sure you never leave them unattended and if you do make sure they're kept safely in the bag too? As they all have lipos in them.....
    I'm sounding flippant I know, but you should bear in mind that lipos are everywhere! They are the current battery technology. There is however a trade off here? Companies like Apple, Samsung and HTC will spend many millions making sure they have safe, reliable battery and charging systems in their products. Then they will charge you a fortune for the pleasure... but you can be fairly sure that on the whole they are okay!
    If you buy a cheap Lipo from china on ebay, then you don't have the same guarantee that it's been thoroughly tested. So.................. stick it in a lipo-safe bag! Got an old metal saucepan and lid or cast iron pot? Stick it in that and put the lid on. Job done!

    All of the batteries over the years that I've used in RC model flying, I've never left alone when charging, because they often needed serious grunt in their charge cycles, and were potentially dangerous because of their energy densities, but I wouldn't worry about a lipo in a safe bag on a slow charge.
     
  5. 1961nuffield

    1961nuffield Honorary Member

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    Location:
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    We have one for an RC car, there's a setting on the battery charger if you are leaving the battery for long term storage. The model shop I went to said the only problem they had seen, came from shorting the lipo out.

    HTH

    John
     
  6. FGYT

    FGYT Engaging Member

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    Ive got some Lipo from here in UKL not exactly expensive and use the 7.4v for 8v supply and tyhe 11.1v for a 12v supply (after talking to he owner ) with one of his chargers Im only using 850mAh size as I only power the camera and a transmitter on the gun
    full charge is only a couple of hrs

    http://www.componentshop.co.uk/batteries/radio-control/li-po-flight-packs.html

    http://www.componentshop.co.uk/1000...ipo-life-battery-packs-complete-with-psu.html

    Instruction s have charge times

    http://www.componentshop.co.uk/pdf/le-3-01.PDF
     
  7. Tadpole

    Tadpole Super Moderator Staff Member Mod/Admin

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    I have been using them for a few years with my NV & never had an issue, just be sensible :thumb: ........... :coffee:
     
    Last edited: Feb 26, 2014
  8. SteveO

    SteveO Top Poster

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    I leave my on charge overnight and now use the bag safe but then I am awake most nights anyway to attend to the battery.

    It must be switched on with the red light showing otherwise the circuit is blocked by it and the charge will not get to the cells.

    I got rid of the two pin cheapo AC adapter/charger that came with the batteries and bought a better quality 3 pin UK spec adapter.
     
  9. terry1001

    terry1001 Major Poster

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    Most of the cells used here are probably Li ion rather than LiPo but each needs to be charged in a specific way so only a charger for that type of battery should be used. A charging bag is a good idea but even so it should not be left on charge ince the charging cycle is finished. A good quality charger is also well worthwhile, I use a Nitecore i4 which automatically detects the battery type and charges accordingly, it will actually charge a mixture of different types at the same time.<br>As has been said the problems srise when batteries are charged too fast, for too long or when they are shorted or otherwise discharged at a high rate. This can also apply to any rechargeable battery, even your AAA ones if they are abused. The best way forward is to apply common sense to batteries, they do contain a lot of energy when fully charged and should be treated with respect.<br>The battery packs with on/off awitches will normally need to be switched ON in order to charge, the switch isolates both leads. It is worth putting these in a charging bag and charging them slowly, most of the chargers supplied will only provide a low current so, while they work, should be ok, never try using a car battery charger or any other charger which is not designed to work with this type of battery.
     
  10. Alex.mc

    Alex.mc Busy Member

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    It's the Lithium in the batteries which can fuel a thermal runaway when shorted. The energy release if shorted can be huge, and when the reaction gets going it's difficult to stop. This will not happen with normal use.

    Cells that spontaneously combust, are internal failures that cause a short. Badly made batteries is usually the answer there.

    When they first arrived on the model flying scene, there were a number of people who lost there cars up in flames at the flying fields! It was manily caused by inappropriate charging techniques or just plain wrong chargers! And the fact that people put them in the boot, or bonnet or inside their cars to charge like they did with Nicads and Nimhs. It was early days though and the manufacturers were competing to land-grab a chunk of the market, and the cell build and chemistries weren't what they are now.
    Nicads used to explode on occasion in the earlys days as well!

    Things are much better now. Most quality packs have protection built in, even to the single cell level such as a lot of the 18650 cells.


    I got shouted at once for walking across a petrol station on my mobile phone! The signs are still up at most! I did some research when I got home. very few petrol stations go up in flames at all. Most are caused by deliberate arson, people crashing into the pumps, and other obvious forms of ignition. The numbers caused by unknown circumstances are very few indeed, something like 2 worldwide in the last 10 years! And in those few cases no one was using a mobile phone!
    If you think about it, you drive into a petrol station in your car, which can sometimes gain a static charge which shocks you when you touch it? Then you have a hot engine close to the ground, and a far hotter catalytic converter, let alone the possibly red hot turbocharger, not to mention the high tension spark plugs and coils, and then you step out with your steel tipped shoes and your nylon clothing(lol!) and then wave a nozzle around with fuel often spilling out of it........

    It's a modern day myth that has saturated popular culture, that a spark from your phone could possibly make a petrol station catch fire! When did your mobile phone last spark at you????

    Lipos are defineably safe, by virtue of the fact that billions of them are in use daily in mobile phones and other gadgets. We operate at the edge of this, so it pays to be sensible, but don't lose any sleep over it if you are sensible about using them.
     
  11. weebster

    weebster Posting Addict

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    I think the mobile and petrol station saga was more to do with the mobile interfering with the pump read out if you were talking on it at the time.....seem to recall the same fiasco with cb radio,myth was if you keyed the mike on the cb when filling up the pump didn't record the amount of fuel going in,whether it did work or not I have no idea.
     
  12. Bluefrog

    Bluefrog Busy Member

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    Thanks for all the advice guys .... first charge went well yesterday. Am keeping it in the bag at all times and have a fire extinguisher close by just in case
     
  13. David M

    David M Donator

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    I have used Li-poly batteries in R/C models since they became readily available and charge them using a quality Pro-Prodigy balancer charger (about £30). I charge them in the front room of an evening whilst with them. Most can be charged at 1C (i.e a 1300mAh battery can be safely charged at a rate of 1300mA) but I use a rate that tends to take about 3 hours. Lipos get damaged very easily if you over discharge them beyond 3.0v a cell and will puff and lose capacity, a good guidline is to only use 70% of their capacity before recharging, so try and measure what your equipment draws from them and work out how much run time you can have. The only time I've ever heard of a Lipo going up in flames was when a mate forgot to disconnect the battery from his R/C helicopter and he had the shock of his life when smoke billowed from his garage a few days later when it had over-discharged.

    When my batteries are finished, I enjoy standing them against a wall and shooting them with my airgun. The pellet passes straight through and causes a delayed reaction in making them ignite, they fizz and flame like a firework, I then take the remains to the safe disposal place at the local tip.......:up:
     

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