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Cordless AND Non-Cordless'able: WHY NOT?!


n00b

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The new Milwaukee light-stand and fan...running off of M18 batts AND extension-cord-able.

Why are not more (ALL) cordless tools adaptable?

Is it just impossible with the current tech?

Speaking for myself, I'd have a much easier time pulling the trigger on a tool from a line that I wasn't already "invested in" battery-wise.

Just say.

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I think it's all a business move. In the end, all companies would like consumers to be dedicated to their battery platforms. This gives them a more guaranteed return customer. For accessory items such as lights and fans I feel companies look at it as a starter item to get someone looking at their platform who doesn't have any of their current items. 

 

It would be nice to at least see large power hogs (Grinders, circ saws, etc.) to have an extension cord option. Even if they just produced an adapter that fit into the battery slot.

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It's easier to do on tools like that as they don't draw nearly as many amps than say a Super Hoe Hawg. The AC to DC adapter would be huge bulky and expensive. I think some of Milwaukee's tools are pushing 40 amps from the battery pack to the motor.

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I had an idea for an adaptor that looked like an M18 pack with a cord coming out of it (the pack obviously housing an invertor) a year or so ago and everyone acted like I was crazy.

It may be that the invertor would have to be bigger or something, but it was a good idea in theory

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Ryobi already has battery/corded tools, one is the Hybrid trimmer. They also have a hybrid fan, work light, and blower. I own a trimmer, it's a cool tool to use. Put a battery on and run around the yard doing whatnot, or plug in a cord and really go to town. I used it with the cord and it cut down a lot of thick stuff that it probably wouldn't do for very long on a battery

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I had an idea for an adaptor that looked like an M18 pack with a cord coming out of it (the pack obviously housing an invertor) a year or so ago and everyone acted like I was crazy.

It may be that the invertor would have to be bigger or something, but it was a good idea in theory

 

It seems like a pretty obvious thing to do doesn't it? I'd buy one for each cordless line I own for sure....

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Milwaukee is making one, well sort of. If you saw the new Milwaukee fan it comes with an adaptor pack designed to allow the fan to be a plug in as well as battery operated. I'm not sure if it can power bigger tools but I would imagine the output would be the same as the battery.

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Not to argue but that's just not true. All you would have to do is take a standard 18v AC to DC adapter and cram it into the tool. Add a plug end and that's it.

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Not to argue but that's just not true. All you would have to do is take a standard 18v AC to DC adapter and cram it into the tool. Add a plug end and that's it.

The only thing you would accomplish with that, is to charge the tool, or drive a weak motor (i.e fan or a very weak but big drill), as mentioned. 

 

A high power drill would need a power-supply that is as big as the tool itself to convert the 800+ watt's needed, and then you need the batteries AND maby even a charge circuit as well.

I cant really se the marked in that. Much better to just have a spare battery and a powerfull charger so you will never run out of juice. Or the old way, buy a extra corded version.

 

As PROTOOLNUT said, you need a motor that runs on AC and DC (not the biggest problem), but a drill that can handle the voltage differance. With the low voltage in the states (115V vs 230V in europe) you could maby even dream of a soulution where you take 28 very small Li-Ion cells (which is a lot of wasted space that would be needed to separate them) to get a 115V drill.

 

But then you can't use Brushless DC motor, which would be a drawback in itself.

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You need a transformer and a bridge rectifier. There could be many reasons they don't do it, depending on the voltage and size, transformers can get quite expensive. They can also get pretty heavy and bulky. So it could be price, weight, size restrictions, or they may simply want you to buy more batteries.

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I'm no engineer by any means, full disclosure, I am right out of college and had a few electrical classes based on hvac electrical components ie motors, transformers, rectifiers. If someone here has more experience with this stuff I am always willing to admit when I'm wrong lol.

I'm just curious, I'm not looking to start a fight here, this is just me trying to figure out if something will work.

Where did this 800w figure come from? 18v ÷ 800w is 44 amps.... out of a 4ah battery?

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Again, I'm not wanting to argue but...Ryobi does hybrid tools at pretty cheap prices, so I doubt it's got anything to do with the ability to make a motor run on both currents. I own their trimmer, and quite frankly the motor that's in there is probably the same as in their other cordless trimmers, the only difference is whatever they put in there to convert AC voltage to DC voltage to run off of a cord. All you need is an AC adapter, it won't charge the battery, it'll run the tool, if it's wired in right. Instead of having an AC block that you plug into the wall, you have a small adapter inside the tool, and a plug end to plug a cord into on the tool. If I was brave enough to take apart my hybrid trimmer I'd do it, and what I'd find is probably a simple adapter, transformer, selenium rectifier, diode, etc. inside wired into the power path. I've taken apart plenty of electronics and electrical devices that had DC motors and AC power, and it's all the same just different builds and different designs.

 

 

A motor that runs off of 18v, like those inside our tools, wouldn't need anything more than a standard AC adapter. You plug the adapter into the wall, then stick the wires onto the terminals on the tool. There's no battery to be charged, the adapter would run the tool. Power is power, and if it's the same power that's generated by an 18v battery...say an 18v @ 4 amps...which is possible with an AC adapter, then there's no issue. Take a look around your house, at your electronics. You're gonna find block AC adapters everywhere. Read the specs on them. Voltage in, voltage out, and amps (or milliamps). Read the specs on a battery...voltage out and amps (or milliamps). Same thing folks, the only thing you need to worry about with an AC adapter is proper polarity.

 

 

Not trying to argue, not trying to be difficult. Just stating fact. AC voltage is AC voltage, DC voltage is DC voltage, there's no magical equations here, no magical miracles happening inside the tool. If you could find an AC adapter that has 18v @ 4 amps, you could run your power tools with no issues by stripping the wires on the adapter and soldering them to the battery terminals inside the tool. I've done stuff like this before

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You need a transformer and a bridge rectifier. There could be many reasons they don't do it, depending on the voltage and size, transformers can get quite expensive. They can also get pretty heavy and bulky. So it could be price, weight, size restrictions, or they may simply want you to buy more batteries.

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Thats true, but only if you go the "old way" without any electronics. So called linear power supply. Today, almost all electronics uses a SMPS (Switched mode power supply), which is a lot more complicated and smaller/cheaper. Mainly becouse it changes the frequency from 60HZ to tens of thousands of hertz. Which makes the transformer and capacitors needed, a lot smaller for the same power.

Even if its ten times lighter than the simple linear stuff though, it is still a lot of power needed, and to get it on compact high power equipment is still a stretch.

I'm no engineer by any means, full disclosure, I am right out of college and had a few electrical classes based on hvac electrical components ie motors, transformers, rectifiers. If someone here has more experience with this stuff I am always willing to admit when I'm wrong lol.

I'm just curious, I'm not looking to start a fight here, this is just me trying to figure out if something will work.

Where did this 800w figure come from? 18v ÷ 800w is 44 amps.... out of a 4ah battery?

Sent from my SGH-T999L using Tapatalk

The 800w figure was a estimate, made from the specs given on some of the more powerfull drills. Both Makita (DHP481 at least) and dewalt does give the specs on their drills output ratings. Their best offers is both rated for 650W output, which roughly translate into 800W ish input. (given a very efficient controller and motor)

44 amp is not THAT much for two Li-ion cells in parallell (5x2 cells).

Again, I'm not wanting to argue but...Ryobi does hybrid tools at pretty cheap prices, so I doubt it's got anything to do with the ability to make a motor run on both currents. I own their trimmer, and quite frankly the motor that's in there is probably the same as in their other cordless trimmers, the only difference is whatever they put in there to convert AC voltage to DC voltage to run off of a cord. All you need is an AC adapter, it won't charge the battery, it'll run the tool, if it's wired in right. Instead of having an AC block that you plug into the wall, you have a small adapter inside the tool, and a plug end to plug a cord into on the tool. If I was brave enough to take apart my hybrid trimmer I'd do it, and what I'd find is probably a simple adapter, transformer, selenium rectifier, diode, etc. inside wired into the power path. I've taken apart plenty of electronics and electrical devices that had DC motors and AC power, and it's all the same just different builds and different designs.

A motor that runs off of 18v, like those inside our tools, wouldn't need anything more than a standard AC adapter. You plug the adapter into the wall, then stick the wires onto the terminals on the tool. There's no battery to be charged, the adapter would run the tool. Power is power, and if it's the same power that's generated by an 18v battery...say an 18v @ 4 amps...which is possible with an AC adapter, then there's no issue. Take a look around your house, at your electronics. You're gonna find block AC adapters everywhere. Read the specs on them. Voltage in, voltage out, and amps (or milliamps). Read the specs on a battery...voltage out and amps (or milliamps). Same thing folks, the only thing you need to worry about with an AC adapter is proper polarity.

Not trying to argue, not trying to be difficult. Just stating fact. AC voltage is AC voltage, DC voltage is DC voltage, there's no magical equations here, no magical miracles happening inside the tool. If you could find an AC adapter that has 18v @ 4 amps, you could run your power tools with no issues by stripping the wires on the adapter and soldering them to the battery terminals inside the tool. I've done stuff like this before

No problem. I dont try to argue too much.

Even though there are some missconseptions, they are not the point, , so I'm not going to argue on them (also, don't want to heat the debate or offend anyone) :)

I'm not saying that there are anything "magical" about the power coming from the battery. And that you cant run it from wall-current.

Thats not our point. We are saying that you can't without tranforming down the voltage, and for thar, you need a power supply. I.E an adapter, which you mentioned. Your example with a weak adapter on 4A would not work for the high power situations. Not even close. (as stated higher up in this post, you should have around ten times that) A trimmer might be an example on a low power unit, but I have never opened them up for examination.

The point I'm trying to make, is that drills, saws and a lot of other power eqipment needs a lot of power. Small adapters you find around the house is way to weak.

I actually have a bit of experience of hooking up drill motors to different projects/experience. Measured current also was in tens of amps. And a 15A power supply could not start a medium sized drill. It's overcurrent protection kicked in (which was around 20A).

Also, sorry for my bad english. It's not used that often, and a phone is not the most sutiable platform to write. XD

Though it is very well possible to use a large power-adapter/powersupply that you hang on the wall, and then use a thick cable. It's impractical, but works. :)

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I really would like this idea to work, but there are some issues. Here is a somewhat long winded answer.

 

What would be nice is an adapter that plugs into the cordless tool battery port that can use a 120V power supply. This adapter would need to have a higher current rating than the most demanding power tool. Let’s use the Milwaukee angle grinder for example. I could not find power specs for the M18, but the comparable 7.5Amp corded 4 ½” version runs at 10,000 rpm (M18 does 8500 according to HD) with a max wattage output of 825W. 120V x 7.5A = 900W. Close to the 825W, power loss in the system, rounding up on amperage rating, etc.

So for arguments sake, let’s say the cordless version puts out the same power as the corded. 900W/18V=50A. A little more conservative than DR99’s statement that some Milwaukee tools push 40A. An 18V 900W power supply is a large bench top unit that costs a lot more than batteries.  If we went with the 40A, it would still be a 720W power supply that I wouldn’t want hanging off the end of my drill. You might be able to use a bench top power supply and run a cord from that, but by the time you have that setup, your batteries will be charged.

 

Batteries can put out high power for short periods of time. The specs for batteries are voltage and amp-hours (Ah). An 18V battery with a 4Ah battery can run at 40A for .1 Hour (6 minutes).

 

Now, why is there dual/hybrid lights and fans? They are low power and could probably run for days, while the grinder is going to die relatively quickly under continuous use. The Ryobi led light is 20W. An 18V 1.2A adapter (20W/18V=1.11A) is about the size of a cell phone charger and could easily be integrated into the internal system. Making an adapter that could work with lower demanding tools is a possibility, but you would have to be careful not to use it on a power hungry tool cause you could start a fire. At least melt the adapter plastic. What company would put out a universal adapter that could start a fire if plugged into the wrong tool. They would have to make a separate port or prongs and at that point it’s not worth it.

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Greenlee makes an adapter.

http://www.amazon.com/Greenlee-EAC18120-120-Volt-Adapter-Cordless/dp/B004I0Q5PC

This looks like it's interchangeable with makita batteries.

 

This was my idea exactly! Looks like someone else thought of it first…..damnit!

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Greenlee makes an adapter.http://www.amazon.com/Greenlee-EAC18120-120-Volt-Adapter-Cordless/dp/B004I0Q5PC

This looks like it's interchangeable with makita batteries.

yupp they are still interesting products to test. I'm not sure it could deliver the full goods. (I'am a bit sceptical, from the last discussion on the same matter) But then, even half power would be a good job.

Aaaand of course that if it will power most makita tools. The DHP481 wont start without the 3'd connector which I guess is some kind of connection with the controller. So a physical fit is only one of the problems on high-power makita tools.

But yeah, it's not a full sulution to the problem, becouse you need to replace it with the batteries and you cant drive it from both sources, unless you change it out. Or you would double the space.

And since Makita batteries charge more or less as quick as you can use them, I don't see the whole point?

Sorry guys, Im a bit sceptical becouse it's smaller than any other power-adapters I have seen with that kind of needed power for powerfull stuff.

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