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  • 18V lithium 3AH vs 24V lithium Run Time

    Has anyone done a comparison? I charged both batteries and wanted to see how long they would run my cordless vac. Both batteries ran the vac for 16 minutes before it shut down. My 18V 1.5 AH battery ran it only for 11 minutes which can be expected. If the first two batteries lasted the same would Max select power tools and batteries be needed or would there be any advantage to them. The new X3 set actually has better specs than the older Max Select tools. I am thinking of returning the Max Select kit and purchasing the X3 combo. Any thoughts or experiences with these sets are welcome. I just don't want the extra weight and size of the Max Select tools if the X3 tools perform just as well or run as long on 18 volt 3AH batteries.

  • #2
    Re: 18V lithium 3AH vs 24V lithium Run Time

    The run time is the same for the vacuum but the strokes and rpms of the maxselect saws are higher with the 24v battery I think. I own some max select tools, jigsaw, planer, and yes the caulk gun (which i think is great but i won't get into that) and the 24v battery is better on these. The vac i'm not sure, maybe is sucks harder with the 24v but I'm not sure. What i do know is that the X3 tools are freakin nice. I have the x2 and have recently got the X3 system. The performance is better than the maxselect even when you're using the 24v. The recip saw is 100% better than the maxselect or X2 version, doens't get all clogged up and cuts so much faster, its great. The smaller hammer drill is nice too, not nearly as bulky as the X2. When you say maxselect kit I'm assuming you mean the 8 pc set. That is a really good set but the new saws and smaller drill in my opinion are nicer. But I'm pretty sure the 8 pc is cheaper than the new 5 pc x3, not sure though. So I guess what I'm saying is I think th X3 is a better system than the x2 or the maxselect and if you don't mind paying a little more and you don't need the jigsaw or caulk gun then get the x3. Hope that helps

    Comment


    • #3
      Re: 18V lithium 3AH vs 24V lithium Run Time

      Originally posted by Ru&Lins_05 View Post
      The run time is the same for the vacuum but the strokes and rpms of the maxselect saws are higher with the 24v battery I think. I own some max select tools, jigsaw, planer, and yes the caulk gun (which i think is great but i won't get into that) and the 24v battery is better on these. The vac i'm not sure, maybe is sucks harder with the 24v but I'm not sure. What i do know is that the X3 tools are freakin nice. I have the x2 and have recently got the X3 system. The performance is better than the maxselect even when you're using the 24v. The recip saw is 100% better than the maxselect or X2 version, doens't get all clogged up and cuts so much faster, its great. The smaller hammer drill is nice too, not nearly as bulky as the X2. When you say maxselect kit I'm assuming you mean the 8 pc set. That is a really good set but the new saws and smaller drill in my opinion are nicer. But I'm pretty sure the 8 pc is cheaper than the new 5 pc x3, not sure though. So I guess what I'm saying is I think th X3 is a better system than the x2 or the maxselect and if you don't mind paying a little more and you don't need the jigsaw or caulk gun then get the x3. Hope that helps
      The kit I have only present one I have seen is the 3 piece 24V Max Select kit with the hammer drill, reciiprocating saw, flashlight, charger and 2 batteries for $299. I added the max select impact driver and max select circular saw at $119 each. The X3 combo is $499 with a 10% rebate from ridgid which would make it $90 cheaper than the max select tools. I will make a switch this week as I am within the 90 day period.

      The motor noise or pitch of the 18V 3.0AH and 24V 3.0AH batteries sound the same. It does have a different sound with the 18V 1.5AH battery. I also understand that it should have more power with the 24V battery with the same run time as the 18V 3.0 AH battery but it sounds the same.

      That X3 hammer drill seems smaller and lighter than the autoshift drill. I would still like to have a 24V battery and charger for the planer, radio, and vacuum if I could find a sale or clearance on the 24V Starter Kit.

      Anyone else compared the 2 different batteries in the vac. I am sure the 18V specs for the Max Select tools were done with a ni-cad and think the 18 3.0AH lithium performs like the 24V. Just my thoughts.

      Comment


      • #4
        Re: 18V lithium 3AH vs 24V lithium Run Time

        1.5 Ah battery provides half the current of 3Ah battery, so the tools would be weaker at high loads, but work at approximately same RPM under zero load.

        to get the runtime you multiply the voltage by capacity and you get energy, taking into account that at higher voltage tools will be more efficient (10-15%) because they use less current to generate same torque/power. Then you test a tool with either battery and you get the energy consumption.

        For example 18v 3Ah battery would have 54 Watt-hour energy. Of course this is not a real figure as the battery would never give up full 3 Ah, simply because it is a maximum theoretical capacity claimed by the manufacturer, battery never fully discharges, and battery never fully charges. The real energy can only be calculated using a computerized charger/discharger. This has been done for A123 batteries (Dewalt) and Sony/Konion batteries (Makita/Bosch) and Moli Energy (Milwaukee V28 / Ridgid 24v), but I haven't found 18v Li-Ion ridgid tests. Dig around on RCGroups.com.

        You also have to take into account the battery management system that disconnects the battery when per-cell voltage is too low. 18v and 24v batteries might have different cutoff voltage because they use different size/chemistry cells.

        Some tools also use DC-DC stepdown converters to bring the voltage down from 24 to 18 (Dewalt does it in their cordless vac) so the motor RPM will be the same at both voltages, hence same sound pitch. DC-DC converters waste a lot of energy as heat so you might not see any difference between a 24v and 18v battery with equal capacity in such devices.

        There are many factors, so the best way is just to test it using both batteries. If you are lazy, charge them and stick them into the incandescent light and time how long it works.

        Comment


        • #5
          Re: 18V lithium 3AH vs 24V lithium Run Time

          Be careful not to forget the light is on if you follow the light test suggested above. It is my belief that leaving lights on with NiCd batteries in them is one of the major contributors to reported battery failures.

          If you forget about it, the light can run the battery down to a voltage level where the charger fails to recognise that it is a battery.

          Because the load on the battery is low in the light, the risk of damage to the battery is very low and it can be revived back to normal. However, for most people without any other knowledge, the battery will show up 'bad' on the charger. Some people at this point might try 'jumping the battery', and this practice while seeming to resuscitate a bad battery probably results in otherwise avoidable damage.

          Comment


          • #6
            Re: 18V lithium 3AH vs 24V lithium Run Time

            Originally posted by Tennesseepowerstroke View Post
            Has anyone done a comparison? I charged both batteries and wanted to see how long they would run my cordless vac. Both batteries ran the vac for 16 minutes before it shut down. My 18V 1.5 AH battery ran it only for 11 minutes which can be expected. If the first two batteries lasted the same would Max select power tools and batteries be needed or would there be any advantage to them. The new X3 set actually has better specs than the older Max Select tools. I am thinking of returning the Max Select kit and purchasing the X3 combo. Any thoughts or experiences with these sets are welcome. I just don't want the extra weight and size of the Max Select tools if the X3 tools perform just as well or run as long on 18 volt 3AH batteries.
            Yes, we do comparisons with power tools every day by using them in very arduous conditions. Battery capacity specifications, no load or light load run times, power tool specs are nice discussion points, however I will suggest that the most accurate test of a tools value is how it performs when used in true working conditions over a long period of time.
            We have over 70 cordless power tools driven by battery systems ranging from 9.6V, 12V, 14.4V, 18V, to 24V utilizing NiCad and LI technology. We use and abuse them hard every day in rain, snow, plaster, concrete and filthy rotted wood debri. We work with them in temperatures below freezing and above 100 degrees. We abuse them by using them to the point of overheating and then going further until the casings become so hot they will burn your hand. We run batteries until they are discharged to zero. We don't do any of those things malisciously. They are just the challenges that tools used in professional applications face every day. The job must be done regardless of weather, availability of fresh batteries or the risk of possible damage to the tool.
            We started with the Makita 9.6V Nicad system which was a very adaquate performer and would still be using them for some purposes except after we switched to the DeWalt 14.4 tools we had a chance to sell our entire inventory of Makita 9.6 and decided to do it to eliminate the number of batteries and chargers we needed to equip our crews with. We still have a couple of DeWalt 14.4V drills and they are used every day and one of them is ten years old. They are very adaquate performers for 95% of the drilling tasks our crews encounter daily. Yes, for 4" hole saw applications or for a
            3/4" auger in to pressure treated we will reach for the Ridgid 24V drill, but the DeWalt 14.4V drill and NiCad battery combination is like the energizer bunny, ten years old and still going strong. I know some electrical contractors who have been using the Panasonic 14.4 drills for over ten years and would not accept any replacements because those drills have proven to be the most dependable performers over the years when used every day.
            We started using Ridgid power tools two years ago primarily due to the potential cost savings related to the LSA which includes the batteries. We started with a 24V set which included the Hammer drill, recip saw, circ saw and light. As we developed confidence regarding Ridgid cordless tool durability we added several MaxSelect tools including the impact, portable planer, and jig saw. When the 18V LI compact drill was introduced we tried one of them and found them to be one of the best balanced, most controlable most usefull drills we have ever used. The Ridgid cordless tools have performed very well in very tough conditions and we continued to add them to our inventory until we currently own over sixty of them in all voltage sizes and applications. We also have several Ridgid corded tools including a
            12" sliding miter, a compressor, and a contractor table saw.
            We have never conducted battery tests or any of the other esoteric measures discussed by some in this forum. I read about them in Tools on Line and some of the other tests conducted by various publications. Those are interesting to read and compare to our experiances. We don't always agree with their results. It's important to remember that the battery is only one component of a tool "system". When we plug a battery into a drill and pull the trigger many other factors come into play that determine how usefull that tool will be the first day and ten years into the future. Just to list a few, the motor needs to be built to run efficiently to make maximum use of the current it is drawing from the battery. The motor must be durable enough to continue to function when it has ingested plaster dust, snow and all the other contaminents encoutered on a job site. The motor must be durable enough to to not melt down when worked so hard the case becomes to hot to touch. The motor must be mounted solidly enough so that when the drill is dropped ten feet onto a concrete floor it will stay together. I won't belabor the point, however it is important for the "power tool system" to have high quality motors, chucks, bearings, trigger controls, cases and other components in order to be a usefull tool. It is not always the most powerfull, or fastest, or lightest or greatest run time tool that is the best "on the job" tool.
            The truth is that a battery operated power tool starts to deteriorate the very first time we use it. The batteries begin declining in efficiency, the bearings start to wear, the motor brushes begin getting dirty, and the lubricants start to break down. I suggest that simple non performance battery tests of a new battery is not a very good measurment of how a battery power tool will perform every day and over time on the job site. I have never heard contractors rate their tools on the basis of battery tests. We talk in terms of power, durability, and capability of the tool on the job not on a test bench.
            Our experiance would indicate that there is a place for both NiCad and LI batts in power tools. For most applications voltages above 18 are not necessary and weight, durability and balance would seem to be the more important considerations. We have had no experiance with the Nano technology however reports indicate it will be a viable addition to the mix.
            In closing I suggest that less focus on the battery specs and more focus on tool system capability is the correct way of evaluating tool usefulness.
            .....Ray

            Comment


            • #7
              Re: 18V lithium 3AH vs 24V lithium Run Time

              Originally posted by DRC-Wartex View Post
              1.5 Ah battery provides half the current of 3Ah battery, so the tools would be weaker at high loads, but work at approximately same RPM under zero load.

              to get the runtime you multiply the voltage by capacity and you get energy, taking into account that at higher voltage tools will be more efficient (10-15%) because they use less current to generate same torque/power. Then you test a tool with either battery and you get the energy consumption.

              For example 18v 3Ah battery would have 54 Watt-hour energy. Of course this is not a real figure as the battery would never give up full 3 Ah, simply because it is a maximum theoretical capacity claimed by the manufacturer, battery never fully discharges, and battery never fully charges. The real energy can only be calculated using a computerized charger/discharger. This has been done for A123 batteries (Dewalt) and Sony/Konion batteries (Makita/Bosch) and Moli Energy (Milwaukee V28 / Ridgid 24v), but I haven't found 18v Li-Ion ridgid tests. Dig around on RCGroups.com.

              You also have to take into account the battery management system that disconnects the battery when per-cell voltage is too low. 18v and 24v batteries might have different cutoff voltage because they use different size/chemistry cells.

              Some tools also use DC-DC stepdown converters to bring the voltage down from 24 to 18 (Dewalt does it in their cordless vac) so the motor RPM will be the same at both voltages, hence same sound pitch. DC-DC converters waste a lot of energy as heat so you might not see any difference between a 24v and 18v battery with equal capacity in such devices.

              There are many factors, so the best way is just to test it using both batteries. If you are lazy, charge them and stick them into the incandescent light and time how long it works.
              The Ridgid rep told me the tool determines the power and this is why the specs are better for the new X3 tools than the Max Select tools. She said this is why the X3 has more power. This makes sense to me. I took the Max Select combo back and purchased the X3 5 piece combo set which has a $50 rebate. The tools definitely feel better in your hands. They are smaller and lighter but who knows if they are better built.

              I'm not lazy but don't have the free time to see how long a flashlight will burn with an 18V battery. My 18 year old 9.6V Makita batteries will still power my Makita flashlight for over 2 hours.

              Comment


              • #8
                Re: 18V lithium 3AH vs 24V lithium Run Time

                roadrashray, the original question was pertaining the runtime of a 24v battery in a dual voltage tool.

                To put it simply, energy of a 18v Li-ion battery is 50.4 watt-hours and 24v is 69.6 w-h, which gives us about 38% longer runtime. I can bet you $500 that my figure is within 5% accurate. And no matter how you twist it, how old your drill is or how hard you drive it etc etc, that factor will always stay the same as long as both batteries are used in the same tool, if there is no voltage conversion.

                You already posted your essay once, and you are obviously hinting at me when talking about "some people", it seems you rather enjoy the sound of your keyboard. All your jobsite experience is fluff. It only reflects habits of a particular group, and based on your ravings, I can tell that you simply don't use your tools properly if you drive them to a point where they overheat and overdischarge batteries, no matter what your excuse is. Abusing tools is not a way to measure their performance. You can have 2 identical drills and one may fail in half the time compared to the other one if abused, and that tells you nothing. Minor defect in tool materials will prove to be fatal under extreme loads and insignificant under normal loads. If your Ridgid works to a point where motor smokes and Makita shuts off when you exceed manufacturer specs, that doesn't make Ridgid a better tool. That just means less thought was put into the safety of Ridgid (or whatever brand, don't mean to pick on Ridgid) tool. It's all perceptional.

                Power tool use varies so greatly from person to person and from job to job that the there is no way to calculate accurate metrics based solely on some construction workers' hearsay.

                After many many years of "testing" on construction sites, there are always some crews who swear by Bosch, and some that love Makita and wouldn't touch anything else and so on. One would think we would single out the best performers, but yet will still have such a large variety.

                All of them are governed by laws of physics, and tool performance can be calculated and projected into a real world. Best indicator for manufacturer is service center activity and lab tests. This is why they specify accessories and tool capabilities in the manual, so that you can get the best performance and determine the best tool for the job.

                There is only so much you can improve in a DC motor (which has been improved for over 150 years) or a MOSFET (ooo, big words) or gearbox, but there is a lot more you can do in the battery department. So when it comes to performance, battery plays a dominant role. If you take 2 drills of ANY manufacturer, and load them at the same RPM with the same work with identical batteries, your performance difference will be negligent. If you repeatedly bash your tools into the concrete and fill motors with dirt and one stays in one piece longer then the other, well, that just means you are a lucky dumbass. I renovated houses and framed many walls and there is not a mark on my Milwaukee nailgun, and I drove A LOT of nails with it. And I've seen people who pull the drill out of the box and in 20 minutes chuck is plugged up with drywall dust and tar is all over the body, doesn't make them a "pro" in any way. You seem to dwell on the idea that if the tool is overheated, driven hard, dirty and abused and it stands up it makes it a good tool. It only makes it long-lasting. But in terms of how much work you get done with this tool per hour, that is a totally different story.

                Cordless tools are used in many other industries and in some applications, battery energy and weight will play the primary role, and torque, speed and gimmicks such as LED or trigger smoothness and bit holders will play a secondary role, such as aerospace. In metalworking speed plays a big role, and in concrete work - mechanical reliability.

                I'm not saying that jobsite tests are bad, I'm just saying they are grossly inaccurate and personal, so whatever performance you percieve on the jobsite is only valid for your particular work habit and your job types.

                Comment


                • #9
                  Re: 18V lithium 3AH vs 24V lithium Run Time

                  Originally posted by DRC-Wartex View Post
                  If you repeatedly bash your tools into the concrete and fill motors with dirt and one stays in one piece longer then the other, well, that just means you are a lucky dumbass.
                  First, wow lets keep the forum friendly huh? Second, Reputation is a big part of the tool industry and when someone you trust tells you, "I don't use DeWalt b/c..." you think second about buying that exact tool, you don't ask, gee i wonder if he babied his tools or even if he took care of them. I agree that tests are important to look into and are interesting, but if the battery makes the drill run long enough to get jobs done then great! If the chuck fails or the gears grind under a tough load I don't think its a saftey mechanism, its just a sucky tool.
                  Last edited by Ru&Lins_05; 01-13-2009, 12:37 AM.

                  Comment


                  • #10
                    Re: 18V lithium 3AH vs 24V lithium Run Time

                    Originally posted by Ru&Lins_05 View Post
                    The run time is the same for the vacuum but the strokes and rpms of the maxselect saws are higher with the 24v battery I think. I own some max select tools, jigsaw, planer, and yes the caulk gun (which i think is great but i won't get into that) and the 24v battery is better on these. The vac i'm not sure, maybe is sucks harder with the 24v but I'm not sure. What i do know is that the X3 tools are freakin nice. I have the x2 and have recently got the X3 system. The performance is better than the maxselect even when you're using the 24v. The recip saw is 100% better than the maxselect or X2 version, doens't get all clogged up and cuts so much faster, its great. The smaller hammer drill is nice too, not nearly as bulky as the X2. When you say maxselect kit I'm assuming you mean the 8 pc set. That is a really good set but the new saws and smaller drill in my opinion are nicer. But I'm pretty sure the 8 pc is cheaper than the new 5 pc x3, not sure though. So I guess what I'm saying is I think th X3 is a better system than the x2 or the maxselect and if you don't mind paying a little more and you don't need the jigsaw or caulk gun then get the x3. Hope that helps
                    I returned the 24v combo and purchased the X3 combo set. These tools [drill and batteries] are much smaller and lighter. According to Ridgid tech support they will outperform the 24 volt tools. This may or may not be correct. I do know I tried the 24v and 18v freshly charged batteries in the vac again. The 24v cut off at 15 minutes this time and 1 of the 18v batteries lasted 20 minutes with the other lasting 21 minutes [3.0 AH]. With the specs for the X2 tools with 18V batteries being better than specs for the MaxSelect with a 24V batteries it made my choice an easy one. Reliability could be better or worse than the MaxSelect tools but with a back up Autoshift drill and the LSA I will be ok. The X2 Hammer Drill is smaller than the Autoshift drill and the trigger is more ergonomicaly designed.

                    Comment


                    • #11
                      Re: 18V lithium 3AH vs 24V lithium Run Time

                      Originally posted by DRC-Wartex View Post
                      1.5 Ah battery provides half the current of 3Ah battery, so the tools would be weaker at high loads, but work at approximately same RPM under zero load.

                      to get the runtime you multiply the voltage by capacity and you get energy, taking into account that at higher voltage tools will be more efficient (10-15%) because they use less current to generate same torque/power. Then you test a tool with either battery and you get the energy consumption.

                      For example 18v 3Ah battery would have 54 Watt-hour energy. Of course this is not a real figure as the battery would never give up full 3 Ah, simply because it is a maximum theoretical capacity claimed by the manufacturer, battery never fully discharges, and battery never fully charges. The real energy can only be calculated using a computerized charger/discharger. This has been done for A123 batteries (Dewalt) and Sony/Konion batteries (Makita/Bosch) and Moli Energy (Milwaukee V28 / Ridgid 24v), but I haven't found 18v Li-Ion ridgid tests. Dig around on RCGroups.com.

                      You also have to take into account the battery management system that disconnects the battery when per-cell voltage is too low. 18v and 24v batteries might have different cutoff voltage because they use different size/chemistry cells.

                      Some tools also use DC-DC stepdown converters to bring the voltage down from 24 to 18 (Dewalt does it in their cordless vac) so the motor RPM will be the same at both voltages, hence same sound pitch. DC-DC converters waste a lot of energy as heat so you might not see any difference between a 24v and 18v battery with equal capacity in such devices.

                      There are many factors, so the best way is just to test it using both batteries. If you are lazy, charge them and stick them into the incandescent light and time how long it works.
                      You are probably correct with voltage [24v] being stepped down to 18V for the cordless vac. The pitch is the same with both batteries. I'm not lazy but I know it would take a long time to drain a battery with the flashlight. My 18 year old 9.6v Makita batteries still power the flashlight for over 2 hours.

                      Comment


                      • #12
                        Re: 18V lithium 3AH vs 24V lithium Run Time

                        Originally posted by roadrashray View Post
                        Yes, we do comparisons with power tools every day by using them in very arduous conditions. Battery capacity specifications, no load or light load run times, power tool specs are nice discussion points, however I will suggest that the most accurate test of a tools value is how it performs when used in true working conditions over a long period of time.
                        We have over 70 cordless power tools driven by battery systems ranging from 9.6V, 12V, 14.4V, 18V, to 24V utilizing NiCad and LI technology. We use and abuse them hard every day in rain, snow, plaster, concrete and filthy rotted wood debri. We work with them in temperatures below freezing and above 100 degrees. We abuse them by using them to the point of overheating and then going further until the casings become so hot they will burn your hand. We run batteries until they are discharged to zero. We don't do any of those things malisciously. They are just the challenges that tools used in professional applications face every day. The job must be done regardless of weather, availability of fresh batteries or the risk of possible damage to the tool.
                        We started with the Makita 9.6V Nicad system which was a very adaquate performer and would still be using them for some purposes except after we switched to the DeWalt 14.4 tools we had a chance to sell our entire inventory of Makita 9.6 and decided to do it to eliminate the number of batteries and chargers we needed to equip our crews with. We still have a couple of DeWalt 14.4V drills and they are used every day and one of them is ten years old. They are very adaquate performers for 95% of the drilling tasks our crews encounter daily. Yes, for 4" hole saw applications or for a
                        3/4" auger in to pressure treated we will reach for the Ridgid 24V drill, but the DeWalt 14.4V drill and NiCad battery combination is like the energizer bunny, ten years old and still going strong. I know some electrical contractors who have been using the Panasonic 14.4 drills for over ten years and would not accept any replacements because those drills have proven to be the most dependable performers over the years when used every day.
                        We started using Ridgid power tools two years ago primarily due to the potential cost savings related to the LSA which includes the batteries. We started with a 24V set which included the Hammer drill, recip saw, circ saw and light. As we developed confidence regarding Ridgid cordless tool durability we added several MaxSelect tools including the impact, portable planer, and jig saw. When the 18V LI compact drill was introduced we tried one of them and found them to be one of the best balanced, most controlable most usefull drills we have ever used. The Ridgid cordless tools have performed very well in very tough conditions and we continued to add them to our inventory until we currently own over sixty of them in all voltage sizes and applications. We also have several Ridgid corded tools including a
                        12" sliding miter, a compressor, and a contractor table saw.
                        We have never conducted battery tests or any of the other esoteric measures discussed by some in this forum. I read about them in Tools on Line and some of the other tests conducted by various publications. Those are interesting to read and compare to our experiances. We don't always agree with their results. It's important to remember that the battery is only one component of a tool "system". When we plug a battery into a drill and pull the trigger many other factors come into play that determine how usefull that tool will be the first day and ten years into the future. Just to list a few, the motor needs to be built to run efficiently to make maximum use of the current it is drawing from the battery. The motor must be durable enough to continue to function when it has ingested plaster dust, snow and all the other contaminents encoutered on a job site. The motor must be durable enough to to not melt down when worked so hard the case becomes to hot to touch. The motor must be mounted solidly enough so that when the drill is dropped ten feet onto a concrete floor it will stay together. I won't belabor the point, however it is important for the "power tool system" to have high quality motors, chucks, bearings, trigger controls, cases and other components in order to be a usefull tool. It is not always the most powerfull, or fastest, or lightest or greatest run time tool that is the best "on the job" tool.
                        The truth is that a battery operated power tool starts to deteriorate the very first time we use it. The batteries begin declining in efficiency, the bearings start to wear, the motor brushes begin getting dirty, and the lubricants start to break down. I suggest that simple non performance battery tests of a new battery is not a very good measurment of how a battery power tool will perform every day and over time on the job site. I have never heard contractors rate their tools on the basis of battery tests. We talk in terms of power, durability, and capability of the tool on the job not on a test bench.
                        Our experiance would indicate that there is a place for both NiCad and LI batts in power tools. For most applications voltages above 18 are not necessary and weight, durability and balance would seem to be the more important considerations. We have had no experiance with the Nano technology however reports indicate it will be a viable addition to the mix.
                        In closing I suggest that less focus on the battery specs and more focus on tool system capability is the correct way of evaluating tool usefulness.
                        .....Ray
                        I believe the X3 is a more capable system. That is why I asked the question about battery comparison. They could be wrong, but Ridgids website specs are better for the 18V system. I had a few concerns about the MaxSelect tools. Weight being #1. Then the circular saw kept stalling cutting treated lumber. I will find out if the X3 circular saw does this. I think the orbital action of the reciprocating saw can only be a positive addition. I also picked up the 4 piece combo kit for the radio, batteries and the Autoshift drill for a back up. I will get rid of the Makita and keep the Autoshift in the RV. It might have been these particular 24V batteries, but 18V batteries that run longer in a tool at close to half the weight, smaller size and can be found everywhere clinched the deal for me.

                        Your results or opinions may vary. More opinions welcome.
                        Last edited by Tennesseepowerstroke; 01-26-2009, 12:58 PM. Reason: grammar

                        Comment


                        • #13
                          Re: 18V lithium 3AH vs 24V lithium Run Time

                          Originally posted by DRC-Wartex View Post
                          1.5 Ah battery provides half the current of 3Ah battery, so the tools would be weaker at high loads, but work at approximately same RPM under zero load.

                          to get the runtime you multiply the voltage by capacity and you get energy, taking into account that at higher voltage tools will be more efficient (10-15%) because they use less current to generate same torque/power. Then you test a tool with either battery and you get the energy consumption.

                          For example 18v 3Ah battery would have 54 Watt-hour energy. Of course this is not a real figure as the battery would never give up full 3 Ah, simply because it is a maximum theoretical capacity claimed by the manufacturer, battery never fully discharges, and battery never fully charges. The real energy can only be calculated using a computerized charger/discharger. This has been done for A123 batteries (Dewalt) and Sony/Konion batteries (Makita/Bosch) and Moli Energy (Milwaukee V28 / Ridgid 24v), but I haven't found 18v Li-Ion ridgid tests. Dig around on RCGroups.com.

                          You also have to take into account the battery management system that disconnects the battery when per-cell voltage is too low. 18v and 24v batteries might have different cutoff voltage because they use different size/chemistry cells.

                          Some tools also use DC-DC stepdown converters to bring the voltage down from 24 to 18 (Dewalt does it in their cordless vac) so the motor RPM will be the same at both voltages, hence same sound pitch. DC-DC converters waste a lot of energy as heat so you might not see any difference between a 24v and 18v battery with equal capacity in such devices.

                          There are many factors, so the best way is just to test it using both batteries. If you are lazy, charge them and stick them into the incandescent light and time how long it works.
                          DRC-Wartex

                          A Ridgid rep did confirm that the MaxSelect tools have a switch to step the 24 volts down to 18 volts. Makes me wonder if there is even a single advantage of any kind to the 24V MaxSelect tools.

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                          • #14
                            Re: 18V lithium 3AH vs 24V lithium Run Time

                            I find that hard to believe when the rpms and performance are way different now that I have the 24v. The 24v batt. makes them run much better. Ridgig even has different rpm ratings based on batt. used. The 18v max select circ saw was nearly useless on 18v.

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                            • #15
                              Re: 18V lithium 3AH vs 24V lithium Run Time

                              Originally posted by Andrew M. View Post
                              I find that hard to believe when the rpms and performance are way different now that I have the 24v. The 24v batt. makes them run much better. Ridgig even has different rpm ratings based on batt. used. The 18v max select circ saw was nearly useless on 18v.
                              What do you find hard to believe. Go to their website and read the specs. Are you comparing the 24V lithium to the old 18V nicad or the new 18V 3.0 AH lithium?

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