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  • #16
    Re: Questions about 24V Lithium Ion Drill?

    I just have to say Disaster after reading many of your posts concerning power tools; I am in awe of your knowledge of batteries.

    You must have been an electrical engineer in a former life.

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    • #17
      Re: Questions about 24V Lithium Ion Drill?

      Originally posted by Disaster View Post
      Actually, higher voltage motors are generally more efficient, therefore they are the ones that are "less thirsty."

      The DeWalt is 36x2.4=86.4. The Ridgid is 24x3=72. All things being equal the DeWalt should run longer.
      Of course all we have focused on to this point is the battery capacity. I would suggest there is a very good chance that the DeWalt 36V motor draws more current in the stop and go environment of typical battery drill usage than the Ridgid 24V motor which will ultimately give it a shorter run time.
      The data in the linked explanation would seem to support that hypothisis.
      http://myweb.dal.ca/gillm/Assets/motorcalculations.pdf
      Last edited by roadrashray; 12-02-2007, 05:17 PM.

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      • #18
        Re: Questions about 24V Lithium Ion Drill?

        Disaster, I know the Ridgid has 72. I was saying that ... ah whatever. There is so little difference in efficiency in this voltage range it's negligible.

        Comment


        • #19
          Re: Questions about 24V Lithium Ion Drill?

          Originally posted by roadrashray View Post
          Of course all we have focused on to this point is the battery capacity. I would suggest there is a very good chance that the DeWalt 36V motor draws more current in the stop and go environment of typical battery drill usage than the Ridgid 24V motor which will ultimately give it a shorter run time.
          The data in the linked explanation would seem to support that hypothisis.
          http://myweb.dal.ca/gillm/Assets/motorcalculations.pdf
          I have to admit, that document was a little long and covered all sorts of stuff and I got impatient trying to read through that to find the particular reference you might have been referring to.

          There are all kinds of things that effect the efficiency of a motor. Here are some I can think of.

          1. Brushless vs. brushed.
          2. Motor poles, 2, 4, 6.
          3. Power ratings vs. operating range (ie. motors are more efficient at specific power levels...if you operate much lower or much higher they are less efficient...they are especially inefficient when pushed to near stall speeds.)
          4. RPM (at higher RPM's the back EMF starts robbing power.)
          5. Motor winding (Some windings are more efficient.)
          6. Bearings

          I'm sure I missed a bunch of stuff but those are most of the big ones.

          I have read enough motor comparisons and arguments that higher voltage is also more efficient, but I can't find a specific reference right now that gives a good, well argued reason for higher voltage motors to be more or less efficient.

          Here is one that doesn't draw a firm conclusion either way.

          http://www.newton.dep.anl.gov/askasc...9/eng99174.htm

          Comment


          • #20
            Re: Questions about 24V Lithium Ion Drill?

            Wow,

            So much knowledge from everyone.

            I would choose a drill based on how much power you need. I know Disaster addressed a lot of things about efficiency as well as strain and that is the biggie.

            The main problem you will run into with runtime is how much pressure or how hard you push the tool to its maximum capacity.

            For instance, if you are always boring 3-4" holes , I would look for the highest voltage drill available(Dewalt 36v). Less strain on the tool with 36volt. Which would justify the price increase.

            If you are only drilling pilot holes, a 36 volt system will not benefit someone because you are not going to take advantage of what the 36 volt drill is capable of and you will be lugging around a huge drill for no reason.
            http://www.cgiconnection.com/download

            Comment


            • #21
              Re: Questions about 24V Lithium Ion Drill?

              Originally posted by onlycordless View Post
              If you are only drilling pilot holes, a 36 volt system will not benefit someone because you are not going to take advantage of what the 36 volt drill is capable of and you will be lugging around a huge drill for no reason.
              Good advice. I rarely use my 24 volt Ridgid, preferring a much lighter Panasonic and sometimes even a 2.5# B&D. Did use the Ridgid recently when I needed to bore a hole through the wall to install another outside outlet.

              Comment


              • #22
                Re: Questions about 24V Lithium Ion Drill?

                Actually it's funny you say that, I was doing some deck board pre drilling not long ago before driving the screws down. At first I was using my Makita black and white drill which is nice and light which is a really nice feature. But man is it ever SLOW! It doesn't have a super great high end RPM which is one problem. So I used it for a while and got a little tired of the slow speed. So out came Mr. 36V DC900. This might sound pretty funny for drilling small holes, but it just shot those holes something like 3 times faster than the Makita. Also when drilling vertically, the extra weigh is nice to have as it helps push it down when drilling and keeps it stable.

                So the point here is that sometimes even a big drill can be great for small jobs.

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                • #23
                  Re: Questions about 24V Lithium Ion Drill?

                  Originally posted by Sceeter W Wheels View Post
                  Actually it's funny you say that, I was doing some deck board pre drilling not long ago before driving the screws down. At first I was using my Makita black and white drill which is nice and light which is a really nice feature. But man is it ever SLOW! It doesn't have a super great high end RPM which is one problem. So I used it for a while and got a little tired of the slow speed. So out came Mr. 36V DC900. This might sound pretty funny for drilling small holes, but it just shot those holes something like 3 times faster than the Makita. Also when drilling vertically, the extra weigh is nice to have as it helps push it down when drilling and keeps it stable.

                  So the point here is that sometimes even a big drill can be great for small jobs.

                  Good point. Arguments can be made for both sides between a large and small drill.

                  There was someone on this forum who posted a comment saying that he is a small guy and can't use a big drill all day.

                  If you are drilling with your arm extended or overhead, then the difference in weight does not become helpful or even useful as with your situation of drilling vertically. Nice comparison and thanks for the info.

                  The point is, you should buy a drill for what you need it for.

                  If you are only uses 50-60% of the maximum capability of a 18V, don't pay for a 36V drill.

                  What is the RPM of your MAKITA? Makita may be slow compared to the Dewalt 36V, however, I think the RPM of the Dewalt36V and RIDGID24V are pretty close.
                  RIDGID- 1500 RPM
                  DEWALT-1400 RPM


                  Would there be a difference in drilling pilot holes(in your specific situation) between these two drills.

                  Would someone notice a difference in drilling pilot holes between a 18V and 36V with similar RPM's?

                  That may be a better test to analyze the use of a drill to someone's specific needs.
                  http://www.cgiconnection.com/download

                  Comment


                  • #24
                    Re: Questions about 24V Lithium Ion Drill?

                    Actually 36V DeWalt's top speed is 1600RPM which is a pretty decent. I'm sure compared to a Ridgid 24V or Milwaukee V28 or a regular 18V drill there would be little difference with such a small bit, that's very true. I'm just saying that although the Makita is very light, it's not a super fast drill. But I never expected it to be a tool for heavy duty use, I mostly use it for light tasks. It's so light that you could almost consider it a cordless screwdriver. Comes in very handy if you are on a ladder working overhead.

                    Originally posted by onlycordless View Post
                    If you are only uses 50-60% of the maximum capability of a 18V, don't pay for a 36V drill.

                    What is the RPM of your MAKITA? Makita may be slow compared to the Dewalt 36V, however, I think the RPM of the Dewalt36V and RIDGID24V are pretty close.
                    RIDGID- 1500 RPM
                    DEWALT-1400 RPM


                    Would there be a difference in drilling pilot holes(in your specific situation) between these two drills.

                    Would someone notice a difference in drilling pilot holes between a 18V and 36V with similar RPM's?

                    That may be a better test to analyze the use of a drill to someone's specific needs.

                    Comment


                    • #25
                      Re: Questions about 24V Lithium Ion Drill?

                      don't buy into Dewalts UWO sales pitch. they changed the rating on all of their tools when they could no longer match the torque rating of other tools. Funny how the torque rating is good for everyone else to measure power including car companies. dewalt has a 3 speed transmission for exactly that reason so the drill runs slower to produce more torque!!!
                      have you also noticed that the Nano and regular xrp drill have the same power at 420 uwo , so what does the extra $120 give you.

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                      • #26
                        Re: Questions about 24V Lithium Ion Drill?

                        Originally posted by itfc447 View Post
                        don't buy into Dewalts UWO sales pitch.
                        Call it "sales pitch" but power IS what matters and UWO is power. Archimedes said, "Give me a long enough lever and I can lift the world." He should have added....Veryyyy slowwwwly. Torque, without power equals slowwwwww speed. Gearing a drill down for torque is moronic and only used to SELL drills with "high torque." It is better to have a drill with torque at working speeds. It is unfortunate that more companies don't use the power rating. It is more useful.

                        DeWalts drill is very good. More drills should make the kind of power DeWalt does with 18 volts.

                        As far as power and Lithium Ion goes, there isn't any reason to expect more power out of Lithium Ion. What you should expect is longer battery storage and life and "flatter" power.

                        Comment


                        • #27
                          Re: Questions about 24V Lithium Ion Drill?

                          double post
                          Last edited by Velosapien; 12-10-2007, 09:55 AM.

                          Comment


                          • #28
                            Re: Questions about 24V Lithium Ion Drill?

                            Originally posted by itfc447 View Post
                            don't buy into Dewalts UWO sales pitch. they changed the rating on all of their tools when they could no longer match the torque rating of other tools. Funny how the torque rating is good for everyone else to measure power including car companies. dewalt has a 3 speed transmission for exactly that reason so the drill runs slower to produce more torque!!!
                            have you also noticed that the Nano and regular xrp drill have the same power at 420 uwo , so what does the extra $120 give you.
                            Have you ever actually looked at their drill specifications closely? They use a 3 speed gearbox to give a 3rd high speed gear running at about 1600 - 2000 depending on the model. That increases the blow per minute rate. The other two gears are the standard 450rpm/1450 rpm similar to that found on all other drills. That's why Dewalt is usually the leader when it comes to hammerdrilling cordless drills. Their slowest gear is 450rpm which is faster that than the slowest gear on most other drills. The Makita LXT drill for example has roughly the same torque in the lowest gear as the Dewalt yet spins at a sluggish 300rpm! The Dewalt has more power since it can roughly match that torque at a 50% higher speed

                            Maximum torque is much different on an electric motor than a gas one. Electric motors hit their peak torque in a spike for a fraction of a second just as they stall and begin to overheat and burn out. A drill with a rated at 600in lbs can't actually sustain that for any usable period of time. Not to mention drills are already reaching the maximum practical torque at which they can be handled with out miving into impact driver territory. The torque game can only go so far before you start snapping wrists.

                            Tools have typically been measured in watts all around the world, including by Dewalt. Only in the US have they typically been measured in torque. Problem with that is the torque measurement gives absoutely no hint on how the tool performs. Even a 9.6v drill can have 700 in-lbs of torque. It just needs to be geared slow enough. If you take a look at reviews and comparisons of drills you'll immedaiately notice theres are dramatic performance differences on drills with similar torque ratings. The UWO rating, while still not ideal in my opinion is a much better reflection on what a tool can give you under real usable power.

                            Comment


                            • #29
                              Re: Questions about 24V Lithium Ion Drill?

                              Originally posted by Velosapien View Post
                              Have you ever actually looked at their drill specifications closely? They use a 3 speed gearbox to give a 3rd high speed gear running at about 1600 - 2000 depending on the model. That increases the blow per minute rate. The other two gears are the standard 450rpm/1450 rpm similar to that found on all other drills. That's why Dewalt is usually the leader when it comes to hammerdrilling cordless drills. Their slowest gear is 450rpm which is faster that than the slowest gear on most other drills. The Makita LXT drill for example has roughly the same torque in the lowest gear as the Dewalt yet spins at a sluggish 300rpm! The Dewalt has more power since it can roughly match that torque at a 50% higher speed

                              Maximum torque is much different on an electric motor than a gas one. Electric motors hit their peak torque in a spike for a fraction of a second just as they stall and begin to overheat and burn out. A drill with a rated at 600in lbs can't actually sustain that for any usable period of time. Not to mention drills are already reaching the maximum practical torque at which they can be handled with out miving into impact driver territory. The torque game can only go so far before you start snapping wrists.

                              Tools have typically been measured in watts all around the world, including by Dewalt. Only in the US have they typically been measured in torque. Problem with that is the torque measurement gives absoutely no hint on how the tool performs. Even a 9.6v drill can have 700 in-lbs of torque. It just needs to be geared slow enough. If you take a look at reviews and comparisons of drills you'll immedaiately notice theres are dramatic performance differences on drills with similar torque ratings. The UWO rating, while still not ideal in my opinion is a much better reflection on what a tool can give you under real usable power.
                              On many of these threads we have a tendency to get off into the minutia of the manufacturers specifications of tools. They all put their own spin on RPM(no pun intended), torque, amps, battery materials, four pole motors, etc, etc. While all this stuff has some amount of meaning, in my opinion the most important criteria is the usability of the tool. I particularly like the tool reviews where they not only conduct standardized tests of how many 1/2 inch holes drilled in so much time and such stuff but they take the tools out on the jobsite and talk about "how usable it is." I find that the most important information because it doesn't matter how much power a tool delivers if it is to heavy to lift, or the trigger control is so poor it is unusable or materials of such poor quality it spends most of its life in a repair facility.
                              The best cordless drill I've ever used was the Panasonic 12V LI drill because it was beautifully balanced, had very usable power, venier like trigger control and the LI batteries provided phenominal runtime when every one else only offered Nicad.
                              At the other end of the spectrum I remember the first 18V drill I used which was a Ryobi. The trigger was an off on-switch which made all that power impossible to control, it didn't have a electric brake which also contributed to it's unusability as one couldn't stop over or underdriving screws. The drill and batteries overheated rapidly which brought the project to a stop or in my case brought out the old 12V drill to continue the job. I don't mean to pick on Ryobi as this was an early model 18V drill and I'm confident they have made great strides with later models. The point is, this tool generated tremendous power and had impressive specifications but it was virtually unusable on the jobsite.
                              That is why when I see all the hype around new products I wait for awhile to hear from the professionals who use them every day and how they really work in the "world of work". When there was all the hue and cry on this forum about the Ridgid 18V LI compact drill only having 1 1/2 amp batteries instead of the advertised 3 amp and some were all exercised that it's weight was a few onces more than the Makita or Hitachi I wasn't impressed. That's because I had been using the drill on the job every day for several months and had found it to be the most usable drill since the venerable 12V Panasonic. The weight might not be the lightest however the balance is excellent, the batteries might not be 3amp, however I have never experianced battery problems either due to short charge life or heating or any other limitations. It might have a few inches less torque than the 18V Milwaukee, however the trigger control is so precise it is a dream to use on tight access overhead screws. So although some of the "numbers" might not look as good as other drills in the real world of work it is a very good tool.

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                              • #30
                                Re: Questions about 24V Lithium Ion Drill?

                                I am in your corner Ray. I try to keep the number crunching to the Accountants. If you really want to how a tool performs do as I do. If its going to be an expensive purchase rent a tool from each of the contenders for a few days and run it through its paces. As, everyone of us has different needs and body builds its important to purchase a tool that fits you. It may cost you an extra $50 but ultimately you will have the tool that best suits YOU!



                                My 2 cents for what its worth

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