phil0054

Thank you very much for that clarification. I assumed that if DeWalt was going to log usage through their batteries, they would have realized this and created logs that could be serialized or identified by the type of tool used. Otherwise, you are correct, they would not get useful information. I also thought that the recycled batteries would be the easiest to retrieve. Otherwise, how would DeWalt retrieve the data? I would guess that the only data available would be from failed tools that would reflect the 2% of extreme abusers and 1% of manufacturing defects. This would obviously skew the data. Perhaps this is exactly why DeWalt made their business decisions the way they did. I hope they never stop producing the 18v NiCd series until the other stuff can outperform on the extreme end. Thank you again. JP

VERY interesting thing about the intelligent battery packs: Instant source of useful usage feedback for engineering optimization and customer needs. Rather slick, but also rather underhanded, like big brother watching every time I use my tools, not cool. They know we will recycle their batteries, all they have to do is collect them and upload the usage data. Bottom line is, I pay a premium for tools that perform to the max. Motor burns out? Replace the motor. It is worth the performance! And I have put my drills through mixing mud, driving 4" deck screws, hanging sheetrock, framing with screws, drilling through stucco with 4" hole saws, hammering into concrete, and running light and heavy electrical using spades and augers, with very little time spent in first or second gear. In fact, I usually only use those gears when the battery is nearly dead and I just need to finish sinking a screw. I have only ever replaced one drill, the transmission failed and would not switch back to high gear (I should have never put it into first gear!). My other two 18v drills are starting to show the need for new brushes--after more than 10 years of abuse! If anything, DeWalt should be NEVER sacrifice max performance. People are simple and usually make quick associations like High Voltage=More Power. And in the minds of most users, More Power=More capabilities and for longer times. Not stalling out because some self preservation circuit decided the load was too much. Forcing an employee or user to switch to a lower gear creates a common situation: Plenty of times, a slower bit speed will actually significantly reduce its cutting efficiency, which means that using a slower gear to ramp up the torque will actually require to drill to work harder and longer, and it will mean the employee will not be able to get as much done. Good explanation of capacity vs power, which are indeed two different things, but they are equivalent in the sense that the power output of a motor times its efficiency can never exceed the capacity of the batteries, in fact the output times its efficiency is EQUAL to the capacity of the battery. Honestly, I think DeWalt is gearing up for hybrid ultracap/battery sources that will require intelligent switching. the advantage will be higher max performance (if the motor can HANDLE it), quicker charging and no battery cycle limits. I love my cordless tools, and the only way I'd upgrade to the 36v or even the 20v line is if max performance is improved. I'm not as concerned with battery life, that's what multi port chargers and extra batteries are for. I detest waiting for my tools to perform. And until the corded tools lose their status as the benchmark for performance, then performance should be the metric.

A common thing about electric motors: They produce 90% of their torque from 0 rpm and reach their peak operating rpm very quickly. You started to hit the nail when you talked about power being equivalent to the amount of work that can be done. The only thing that can change from one model or brand to another is the efficiency of the motor and switching system. No matter what RPM is used, a more efficient drive system (including friction from transmission and bearings) will be able to do more work for the same battery capacity. Another simple way of looking at this is relative battery capacity vs. max usage. I could say compare two drills with the same battery, but one has a smaller motor. Obviously the one with the smaller motor will outlast, and potentially drive more small diameter screws, thus increasing utility. Dont be confused by higher voltage numbers. What really counts with batteries is the capacity in watts or Amp-hours. Now, the other way to compare two drills is to think of two drills with the same size motor connected to two different sized batteries. Obviously the one with the biggest capacity will last the longest. Well, the biggest NiCd battery is 2.4Ah, where the LiIon battery has a 3.0Ah capacity. Regardless of the voltage, the 3Ah battery will outperform the other battery. Combine a bigger battery with a smaller motor and you get a drill that lasts a lot longer for most tasks. The only thing lost is extreme performance. Wit the complaints about the 36v drill getting stuck. Torque relates directly to whether or not a drill will stall out under a large bit or power through it. This was one complaint with the 36v drill! Lasts all day but stalls out more easily than the 18v. Therefore, all we need to make good comparisons are Torque, max RPM and Battery power in Amps. Anybody can decide what is more important for their own usage, extreme torque or lots of speed or long lasting power. It just so happened to be that the 18v NiCd drill has the highest RPM and the highest torque numbers. What does this mean from a usage point? It means that the motor is likely capable of drawing more power and battery life is not as long, but you can get more done during that discharge period and less likely to stall the drill. The reason I brought up driving in 4" deck screws in top gear is because under high torque low RPM situations, losses from internal friction of the transmission can be significant. This means that driving in a fastener at high speed takes less power than it does at low speed. A similar example is driving a nail into wood. Pounding one in with slow speed swings takes forever, but one very fast hit can sink the nail in one shot. Its just to illustrate the difference between kinetic and static friction. Honestly, I don't know if DeWalt introduced the UWO to bamboozle the competition or the customer. Who would buy a high voltage setup if the 18v can generate more torque? Is it just a marketing gimmick or is it to attempt to show useful power. In purely engineering or scientific arenas, anytime you see the word unit in a measurement it means literally, per unit. If we dissect Unit Watt Output , I'd have to guess it has to do with a unitless or unmentioned measure of 'utility' per watt of power put through the motor. Again, the 36v motor generates less torque and uses less power, therefore the same capacity battery will last longer. And, since most operations such as drilling small holes or driving short screws do not require max torque or power, a lower power output could be considered an easy tradeoff for much more 'utility' overall. Divide that utility by the watts put in and you have UWO. Then the only decision left is to decide the gearing required to turn the maximum recommended bit at the optimal speed for that bit. Bits are designed for a maximum efficiency at a specific RPM. Larger bits generally do not have to turn as fast, so spinning the bit at max rpm does not always work well. But this brings up a different compromise: the different needs for drilling vs. driving. Driving has two extremes: long and skinny or long and fat. 4" deck screws can be driven at max speed because the higher speed drops friction enough to make it so the motor can muscle it in (at least deWalt 18v drills can!). Larger diameter screws such as 1/2" lag bolts can easily require more torque than the motor generates at the shaft, so a transmission is used to amplify the torque. But in either case, max torque is needed from the motor. Drilling is altogether different. Once you pull the trigger, the motor jumps to max rpm and burns energy whether you are drilling or not. This is one source of power loss. But, when drilling with small bits, the max torque needed never reaches capacity, and energy is wasted, unless the switching is sophisticated enough to reduce current but not voltage, keep the rpms up while matching torque needed for the job. On the other hand, large diameter bits need to match most efficient rpm for the bit with enough torque from the motor to turn the bit under binding conditions. This is where top of the line models should shine, IMHO. That 36v drill should be capable of generating at least 50% more torque than the 18v drill. Not because I want to see a dead or overheated battery, but because the standard is still a corded drill for torque. There should be no drop in energy density between an 18v and a 36v battery, but the 36v should be able to dump that juice faster for more extreme performance, and have better power management for low power applications. Its a lot like a car with a very high performance engine. Just because it has 1000hp and 1000 ft-lb of torque, doesn't mean it can't also be efficient (think turbo 4's and 6's vs large displacement engines). It just depends on your usage, but having the performance available when you want or need it, can make or break customer loyalty.

After reading all of these posts, I decided to research the numbers listed in the european sites. I am very curious about the 36v tools because energy is energy. Transmission gearing does not matter. Torque is affected by gearing, but not power. Mechanical power and its equivalent, electrical power, is a combination of torque and time, volts and amps. So, we have a tradeoff between voltage and efficient energy storage, and current and motor efficiency. Higher voltage makes more intense magnetic fields, but it also creates electrical resistance and heat buildup, which kills motor efficiency and wastes battery power. In a nutshell, I found that both the NiCd and LiIon 18v drills were rated at 55Nm. interestingly, the reviews for the 36v drill were glowing over battery life, but curiously, the max torque was rated at only 42Nm! The 18v drills spin faster in all three gears. Return to the principles that with equivalent power, high speed=low torque. Well, the 36v drill is both lower torque and lower speed, which means that the power consumed is significantly lower (or the motor is LESS efficient, which I doubt). No wonder the battery lasts all day. At this point, unless I discover that the 36v torque rating was an error, I'll stick with my 18v. Using a 1" spade bit I bore a hole into an end grain Ash dunnage board, and when I hit a hole I corssdrilled, the drill ripped itself out of my grip and busted half my thumb nail off! Now, I'm STILL curious to do a heads up comparison. I also used to drive 4" deck screws in on 3rd gear, all the time! Truth is, speed helps eliminate static friction which is higher than dynamic friction, between the wood and the fastener. I also believe the transmission does not have to reduce the motor speed in 3rd gear, which is probably why my tranny is still going strong . I REALLY love the metal chuck with the free-spinning ring! When I want to do something ultra-precise, I can guide the front of the drill with excellent control by holding onto that ring. I've used the other kind, and I'm not very impressed. An option for 5/8" chuck would be kewl, as I have come across many old large size pits that are bigger than 1/2". Kewl, but not necessary. If anybody is driven enough, you CAN create a mini dyno to check max torque using basic materials.