Power tool cells

Discussion in 'Electric Propulsion' started by pictsidhe, Apr 1, 2019.

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  1. Apr 1, 2019 #1

    pictsidhe

    pictsidhe

    pictsidhe

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    I thought others may be interested in potential cells to be used for e-flight. Battery power tools tend to come with high discahrge rate Li-ions. They seem like they could be ideal for hybrid systems. A neighbour just pawned a worx tool with me and I opened up the battery to see which cells it has:

    Worx WA3578 4Ah 20V: 10x Samsung INR18650-20R battery dated 2018
    Those cells are rated at 22A continuous discharge, 4A charge

    I also had a 2017 B&D kicking around, so:

    B&D LBXR20 1.5Ah 20V: 5x LGDAHB71765

    Those are rated at 15A continuous discharge, 4A charge. At the same weight as the Worx cells, you get 3/4 the capacity, 2/3 of the conitnuous power...

    My regular use DeWalt 1.5Ah has cells without a google-able code:

    UAI9RXA
    082526

    That's a shame, DeWalt are known for using decent cells. Maybe there is another code under the wrapper, but this pack works too nicely for me to want to disassemble further.

    If you have a li-ion power tool and would be willing to open the case and read off the cell labels, others may appreciate the information.
     
  2. Apr 1, 2019 #2

    Derswede

    Derswede

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    You can check on Amazon for their jump start packs. Similar to the Horror Freight units, those are mostly 12V at 12,000Mah LifePO battteries. jump start rating is 450A. Charging circuitry already built in.

    Derswede
     
  3. Apr 2, 2019 #3

    lr27

    lr27

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    Are these cells any cheaper than the ones you can buy as separate cells?
     
  4. Apr 2, 2019 #4

    pictsidhe

    pictsidhe

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    I haven't found any bargains so far. But having cells connected in 10's with tails may be handy for some. A few years back, the cheapest way to get then best tech was to buy DeWalt packs. It may be that there are bargains out there in Li-Ion packs. Annual sales could tip the balance, too. Knowing which packs have which cells is half the battle. I don't want to blow $50 on a pack just to see which cells it has...
    I suspect that the jump start packs may be very useful for starting, but not so good for extended use driving a prop.
     
  5. Apr 9, 2019 #5

    emir_82

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    Please don't be that cheap. If you want to go cheap but with a decent specific energy buy the Samsung 25R, they are very high power.
     
  6. Apr 9, 2019 #6

    pictsidhe

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    I had a look at possible cells a while back for a hybrid and the Samsung 25Rs were hot favourites. Good balance of power, capacity and price.

    Which brings me to to my next power tool pack:
    The Horror Fright Hercules 20V packs. I haven't opened one of these myself, but someone on else did on youtube. He found Samsung 25Rs inside. That was the 2.5Ah pack. It's very likely that the 5Ah packs have the same cells. Current price is $25 for the 2.5Ah and $40 for the 5Ah. That's a fair price for those cells. And they come built up into packs with charge balancing circuitry.
     
  7. Apr 9, 2019 #7

    Geraldc

    Geraldc

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    I am waiting for Lime scooters to get banned and buy them up for batteries.
     
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  8. Apr 9, 2019 #8

    pictsidhe

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    Thye just move them to another city. We had the Bird scooters here for a while. Too many idiot riders had them kicked out by the city.
     
  9. May 7, 2019 #9

    markaeric

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    I haven't opened up too many power tool battery packs, but the ones I have didn't have any balance circuitry other than leads coming from each cell terminal. All the balancing circuitry was in the charger itself, which makes financial sense. There is some benefit to them being in a robust enclosure, but the weight is non-negligible, and you're talking about a fair amount of battery packs to make something usable. It's not hard to make your own pack, and depending on where you source your cells, probably quite a bit cheaper too.

    And another potential source is laptop packs, though I don't know what their discharge rating tends to be like.

    Really though, if you're to be flying with these things, choose a chemistry and a reputable brand and model, and buy however many you need from the same lot.
     
  10. May 7, 2019 #10

    TFF

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    Cells have capacity but they also have draw amp numbers. Most tools have the minimum they need to be safe. The RC world is about the high performance cells. One for performance. The other is safety. You overdraw a lipo, it will warp the cells. That is what causes the fires. Draw amps is the key to safety along with how deep you deplete them.
     
  11. May 7, 2019 #11

    pictsidhe

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    The Horror fright packs have balancing circuitry inside the packs, not in the charger. If I used them, I'd ditch the casing...
    RC cells do have very high draw rates, but they don't seem as safe power tool cells. I've heard of far more flaming RC aircraft than power tools, and there has to be a 1000 power tools for every RC aircraft... A battery fire in an electric plane is never going to end well.
    The tool cells do have varying C rates. Obviosuly, you need to pick suitable cells for your application. C rating tends to to trade against capacity. Laptop cells do not have a high C rate.
     
  12. May 7, 2019 #12

    Derswede

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    The horror freight cells are Lith Iron cells, much less likely to spontaneously combust.

    Derswede
     
  13. May 7, 2019 #13

    markaeric

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    Given their abusive environment, I'd expect nearly all power tools to use LiFePO4. I've found cells of this type that have 50 - 60A discharge rates (though kind of hard on the cell). The downside is that these have less than half the Wh/kg of some of the other lithium chemistries.
     
  14. May 7, 2019 #14

    pictsidhe

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    The Horror Fright Hercules cells are 2.5Ah Samsung 25R Li-ions. When my (li-ion) sanyo Dewalt packs die, I'm planning to gut HF packs and use them in Dewalt packs with the DW electrickery.
    The early lithium power tools used LiFePo, but all the current ones I know of use Li-ion.

    This thread is intended to be about which actual cells are found in packs, not speculation. I thought that maybe someone might find it useful.
     
  15. May 8, 2019 #15

    markaeric

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    What is the sense in going this route for cells? You can buy single S25Rs in the $4 range, but once you get to 100, you're in the low $3/cell. That Hercules pack equates to $5/cell. Sure, you get what appears to be a balancing charger circuit, but is it worth it to keep or even a good idea?
     
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  16. May 8, 2019 #16

    emir_82

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    You are right. At more of 1000 cells the price drop a lot. You also save money by not spending hundred of hours testing the cells. The balancing circuit are crap, and generally does not match a vehicle power needs. Also, you can find very cheap and good BMS with communication protocols.
    For powerwalls and things that not fly, buy cheap or search for used and free obsolete batteries. But again. The 25R price per cell is very cheap nowadays
     
  17. May 9, 2019 #17

    Norm Langlois

    Norm Langlois

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    pictsidhe I have a dead dewalt cell pack but its up north I can open it up some time after the 20th if you still are looking for that info. Its the small pack 20 volt 1.5 or 1.3 ah though.You just want to know what the cells are. Does the Ah matter for your answer.

    It seems the Ah makes a big difference to the Christmas sales offered. The low ah is what you get in a cheap sale package the, high ah costs as much as the tools.

    This is not my area of knowledge. So when there so many Dewalt power packs I have a 6ah and a 5ah . Dewalt makes a lot of power tools and at higher voltage. Just not what the home owner has laying about.
     
  18. May 10, 2019 #18

    pictsidhe

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    I have several dewalt packs with 1.5Ah cells. They are probably too small for hybrid use, but may be useful as starting batteries. The 1.5Ah pack I opened had markings that were not google-able. Not very informative. The drill it came with is rated at 460W output. That is going to be around 30A draw. More than single 25Rs will put out.
     
  19. May 10, 2019 #19

    pictsidhe

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    I just looked inside a 2016 10 cell 3ah dewalt pack: The cells are ur18650wx. Rated at 1600mAh and 25A.
     
  20. May 11, 2019 #20

    proppastie

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    all my dead packs are Nicad or Nimh.....should I bother taking them apart.....I think this thread is about modern Lipro .....correct?
     

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