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Thread ID: 142536	2016-07-19 07:43:00	Ryobi or Black & Decker?	bk T (215)	PC World Chat

Post ID	Timestamp	Content	User
1423373	2016-07-21 02:53:00	Personally I tend to follow pctech - the cheapest. Er....yes. But I bought a De Walt. Not a cheap brand. I just bought it off Trademe instead. The battery, well the batteries I searched until I found the place selling it the cheapest. So long as we are clear on that.	pctek (84)
1423374	2016-07-21 02:56:00	Voltage is far from irrelevant when it comes to BATTERY powered tools . The cells commonly used for almost all of them have similar AH ratings . To get more power you need more cells - that's simple enough . Sure you could make a 12V drill with twice as many cells in parallel and use a motor designed to use more current to take advantage of it but manufacturers chose to add more cells in series instead and go for a higher voltage . This has the added advantage that it's easier to make a DC motor spin faster by adding voltage than by any other method, 18V drills tend to offer a higher RPM which is better for drilling in most cases . Also using more current to achieve more power can be problematic requiring heavier conductors and more expensive construction . . . . . . . . . . . . Its as much marketing as anything , for the home use tools that we are talking about . I'll take my 10year old 9v drill over a cheap 12v drill any day of the week . more voltage does not mean more power . Its never that simple . simple math: P=IIR :) hey I can get more power without considering voltage , just use a bigger load (motor) C rating and motor power are what matters (and capacity, just for runtime) . Power is not determined by the no of cells in the batt . Thats physics . Theres a gearbox on all my drills, so motor speed , not such an issue .	1101 (13337)
1423375	2016-07-21 04:04:00	You are contradicting yourself. P=IIR ok, try that with 0 volts and tell me how much power you get. P also = V x A(or I if you prefer). You need to realise the values change as the voltage does. You are looking at it backwards, I'm talking about available power from a battery and you are talking about how much power is needed for a given load. However the Value of I in IIR is determined by the voltage, you can't pretend it is not. The more voltage you have the less current you require for a given load. The value of R in a electric motor is also not fixed and changes with voltage and mechanical load. If you are spinning a drill at the same speed by using gears and doing exactly the same amount of work but at two different voltages then discounting the losses through the gearbox the exact same amount of work is being done in both cases. In one case the motor is spinning faster due to a higher voltage and using less current, then being geared down more to match the lower speed of the motor running off a lower voltage. If the work load = 12W (because it's an easy number :)) and you use a 12V battery then you draw 1 amp to do that work At 18V you draw 0.6667 amps to do your 12W of work, because the motor is spinning faster and being geared down there is less load on it. If however you don't gear the motor down, you drill the hole drawing 1 amp at 18V and using 18W of power instead of 12W - the hole gets drilled faster and easier and the battery lasts the same amount of time. This is what happens in practice. Let me simplify it because you are choosing to ignore the obvious. If you have the same capacity batteries in Amp hours then the higher voltage one will have more power available. Therefore it will have the ability to do more work. As long as the battery capacity is the same then more voltage does mean more power it is exactly that simple. If you use a higher gear to achieve higher speed you will flatten the battery faster because you need more current. If you instead you use a higher voltage you will need less current so the battery will last longer for the same amount of work. Or to put it another way, your argument about a bigger load to get more power assumes unlimited current availability when in practice that's just not true. Maybe if you do connect your 12V drill to a car battery. Battery current capacity is the limiting factor on cordless tools, you can alleviate it either by adding more current capacity or by adding more voltage so that the required current is lower for the same amount of work. Either way you need more or bigger cells but the more voltage method is just easier in practical terms. Or let me take a far more practical approach. I have a Makita 14.4V drill with 1.3 A/H batteries. I also have a Ryobi 18V drill with 1.3 A/H batteries (and other higher capacity ones). The Ryobi spins faster and has a lot more torque than the Makita. In order for the 14.4 Makita to match it (which is entirely possible I'm not saying it isn't) it would have to have a larger capacity battery and a motor capable of withstanding higher currents. In practice the cheaper 18V drill is much more powerful than the older 14.4V better quality one. The Makita is still a good and very useful tool, but it does not have the same amount of power. I still prefer it for some jobs though, my Ryobi is bulky and heavy.	dugimodo (138)
1423376	2016-07-21 05:13:00	12v is all thats needed to turn a large car engine . theres a few 4x4's that have 24v power in some versions and 12 v in the other versions. the 24v versions generally have less problems with starting especially in cold temps. increasing voltage is an easy way to increase power. there is more limitations with current than with voltage. easier on switches, cables, electronic speed control and the batteries themselves. also the motors. modern trend has been smaller motors spinning higher rpm's and using a gearbox to decrease rpm and increase torque. this is especially so with starter motors. i'm surprised they havn't jumped to 24 volt for tools. there is a few things now that are 36 volt and a few in the 50v range.	tweak'e (69)
1423377	2016-07-21 05:15:00	keep in mind batteries can only output a certain current flow before temp issues come into play.	tweak'e (69)
1423378	2016-07-21 07:53:00	Also bear in mind the B&D drills the slow speed is actually too fast for putting in screws properly and the fast speed isn't really fast enough for drilling, but then I have always used trade tools either Makita or Dewalt being an ex joiner/carpenter. Milwaukee or just way too expensive here Joe	gary67 (56)
1423379	2016-07-21 18:00:00	I've bought Ryobi from Bunnings many months ago. Battery just lasts and lasts. Excellent service. Sarel	sarel (2490)
1423380	2016-07-21 19:43:00	I just bought an 18V Black and Decker drill driver (to go with my weed eater). Had it now for months' I am very pleased with it. I Use it mostly for screwing and it does well. It seems to have enough power. I like the LED light on it. And its got a holder for an extra drill bit. Aside from a very low voltage "toy" I have nto tried any others.	Digby (677)
1423381	2016-07-21 21:22:00	I've bought Ryobi from Bunnings many months ago. Battery just lasts and lasts. Excellent service. Sarel Which model did you buy, Sarel?	bk T (215)
1423382	2016-07-22 03:24:00	This got real deep, real quick. :p DeWalt are pretty decent these days. Very popular in the states. I'll stick with my Makita stuff, though. Once you're got a charger and a few batteries, the tools aren't actually too dear, and they should last well.	wratterus (105)
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