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What is average current drawn dy the drill

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  • What is average current drawn dy the drill

    Hello,
    I just bought Dewalt DC930 14.4V drill, and shocked by pity battery life.
    Just out of curiosity, I measured current at full speed rotation with NO load.
    It is around 8-10 AMPS !!!!!

    Geee..... 14.4 *10 = 140 watts just for free run?
    No wonder the battery doesn't run longer than 20 min.
    Based on 1.5 a/h battery capacity, this thing demad 6.6C (6.6* capacity = 10) discharge current capability? This is bogus.

    Now I am wondering, is it just my drill and it better go back to store, or it is normal?
    Can anyone measure free running current at max RPM on 14.4 dewalt drill, please?

    Thanks

  • #2
    Re: What is average current drawn dy the drill

    Maybe you should spend more time looking for a job....

    Comment


    • #3
      Re: What is average current drawn by the drill

      I did not measure any drills,

      but if you take 140 watts and put that in a 120 volt drill that is 1.16 amps

      Dwd110k 3/8in. Vsr Drill Kit, Keyless chuck pistol grip 3/8" drill, 7.0 Amp motor delivers high performance, 3/8" all-metal ratcheting keyless chuck, 0-2,500 rpm variable speed with reverse http://www.google.com/products/catal...740&sa=title#p
      comparing it to the 3/8 corded unit it pulls or says a 7.0 amp motor, so I would not think that would unreasonable, for free run.
      (now my guess is there not in the same class power wise, (in that my guess is the cordless is less RPM, but I bet the drain is a lot on a heavy load, (I know I have had smoke coming out of my 18 volt unit before), any time one reduces the voltage you up the amps, to get the same power,

      The DC930R 14.4 Volt XRP 1/2" drill/driver uses a DEWALT built high power, high efficiency motor to deliver 335 unit watts out of power for maximum performance in all drilling and fastening applications. http://www.toolking.com/dewalt-dc930...LAID=430268138
      aparently "unit watts out" is a fairly new measurement,

      (from this site, http://www.toolsofthetrade.net/indus...ticleID=501481 it apears that the "Unit watts Out", is simualr to drawbar horse power in a a tractor, the engine has more rated power but the amount of power that gets to the wheels is called draw bar Horse power, so the actuly draw on the motor is most likely much higher, (as stated by the last post in this thread, http://www.ridgidforum.com/forum/showthread.php?t=8684)
      (on the corded drills the watts out and the rated watts is about 2/3 from the dewalt web site, saying the effecently is simular), so the actuly draw on the battries could be up to 500 watts, or near 35 amps, the "335 unit watts out" apears to be the precieved power of the chuck at varous speeds, so the free run would be about a 1/3 to a 1/4 than the full load amps, I do not really know, but it seems reasonable to me the draw could / would in that area.

      On heavy run use the battries do not last that long, 20 mins sounds fairly good, to me, I have had some applications were I have used up a good battery in a few mins, and other applications where it lasts for hours.
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      Comment


      • #4
        Re: What is average current drawn dy the drill

        Originally posted by dc930 View Post
        Hello,
        I just bought Dewalt DC930 14.4V drill, and shocked by pity battery life.
        Just out of curiosity, I measured current at full speed rotation with NO load.
        It is around 8-10 AMPS !!!!!

        Geee..... 14.4 *10 = 140 watts just for free run?
        No wonder the battery doesn't run longer than 20 min.
        Based on 1.5 a/h battery capacity, this thing demad 6.6C (6.6* capacity = 10) discharge current capability? This is bogus.

        Now I am wondering, is it just my drill and it better go back to store, or it is normal?
        Can anyone measure free running current at max RPM on 14.4 dewalt drill, please?

        Thanks
        Typical 35-45A with a 1" spade bit, up to 60A in stall. I also think you measured your current wrong. What did you use and how did you measure it?

        Comment


        • #5
          Re: What is average current drawn dy the drill

          Actually I just stick my DVM between the drill and the battery.

          Some one mentioned 60 AMP in stall, this is short condition, and the current will be limited by internal baterry and motor impedance.

          Still 60 amps is impossible. 60 amps will melt 14 gage wire.

          Coming back to my original question, I found another similar drill from my friend, and it does show the same current draw at free run. So, there is "nothing wrong" with the drill.

          Except it is designed to kill the battery.

          As I said any cells designed to be discharged at sertain current. I do not have spec for dewalt 1.5 a/h NiCd battery but it is typically not exceed 2-3C (2-3 time of capacity or 1.5 in this case)

          Comment

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