Product: Power Source: AC DC Conversion
Cordless-Tool Cord   (+41, -1)  [vote for, against]
Replace battery pack with transformer

While cordless tools are nice, they suffer the drawback that they run on batteries that first must be recharged, and second must eventually be replaced. Well, with this Idea you can postpone the second thing.

See, not EVERY time do you use a cordless tool, do you need it to be cordless! So, in those cases, you would swap the battery pack (thus not using it) with this designed-to-fit transformer pack, with cord. Plug the cord into a wall outlet, and the transformer converts 120V down to the voltage that the tool needs (because designed to fit it), and proceed as usual.

One particular thing I noticed just the other day involved drills. I have a corded drill that is pretty old, and has been strained on occasion (I saw smoke come out), and so just doesn't have the oomph that it used to have (torque, I mean). Now I also have a cordless drill with a speed-selector switch. This changes the speed or the power of the drill as needed. Not likely to smoke, therefore! I went looking for a corded drill that also had such a switch (I assume a gear-ratio adjustment, but it might instead be a motor-winding adjustment), and couldn't find one! So, suppose I could plug in a transformer pack into that cordless drill; I'd gain the long-term operation of the corded tool, along with the torque/speed switch, without having to buy an entire new tool.
-- Vernon, Dec 27 2005

(??) drill pics http://www.htc.net/~rcblum/drill/
drill pictures http://www.htc.net/~rcblum/drill/ [Bansuri, Apr 14 2006]

(?) Corded drill part http://www.amazon.c...8&v=glance&n=228013
[Renata399, Jul 14 2006]

DeWalt Transformer/Converter http://www.amazon.c...i&v=glance&n=228013
[Renata399, Jul 14 2006]

2-speed corded drill http://cdn3.volusio...s/photos/6022-2.jpg
Some years after posting this Idea, I actually found (and bought!) a 2-speed corded drill. (My old corded drill finally wore its gears out, or something.) The selector switch is the black circular thing near the business end of the drill. This model doesn't appear to be getting made any more, though. [Vernon, Mar 01 2014]

I like this idea but may i suggest you buy two batteries?
-- Antegrity, Dec 27 2005


I think this one's a winner.
-- reensure, Dec 27 2005


Brevity is wit [+].
-- normzone, Dec 27 2005


Might I suggest a bigger (possibly industrial strength)corded drill? That would be less likely to smoke.
-- andrew1, Dec 27 2005


I have worked hanging drywall where you have to set a lot of screws. I think this is a good idea but I would also believe that the complaint about cordless tools is partially the users fault.

First you have to charge the batteries. Second, you charge the batteries. Third when the first battery runs down you switch to the second and charge the first one. It's not a complicated process but lazyness often takes over and you dont charge your batteries.

I think the reason that your batteries only have a small charge in them IS BECAUSE YOU DONT CHARGE THEM. You may have to plan a couple hours ahead.

"When I get in my car there is only a little bit of gas left in the tank, so I go to my trunk and get the spare gas can, but that only gets me a couple miles. Completely pointless. I have to wait 2 hours for the tow truck to arrive so I can get going again"
-- Antegrity, Dec 27 2005


This is an appealing idea. I'd invest in this. It's easy to imagine that the product becomes the target of jokes on late night shows. I'm sure people will laugh but many of them will stop and think, "Hmmm, I could use one of those things."

Maybe a lot of people.
-- bristolz, Dec 27 2005


cool idea but wouldn't you need a different adapter for each of your tools? i have lots of cordless tools and the batteries are frustratingly non-compatible with each other, even the ones runnng on the same voltage.

not being very techy, isn't a transformer from 240volt to 12volt going to be buzzing, warm and heavy?

highly recommend spending the extra money and buying a tool with lithium batteries. they can be charged at anytime (quickly) and used mid-charge no problem.
-- rainbow, Dec 27 2005


you should have bought a corded drill ian, obviously, as should nearly everyone. as you rightly point out. or got a little man in to do the job.

the lithium batteries do however help a lot.
-- rainbow, Dec 27 2005


Great for those projects requiring full power, when a partial battery charge isn't enough. Bun.
-- Shz, Dec 27 2005


This is a classic example of how technology trends recycle simply because the old way works better.

Take for instance cell phones- they kept making them smaller until someone came up with an idea to invent a cradle that lets you connect a standard landline phone to it. And now they even have a device that enables you to connect your cell phone to your phone jack at home giving you a connection that is free of all of the hassles associated wireless- like drop outs and poor reception.

A wired world- WOW! What will they think of next?
-- Jscotty, Dec 27 2005


I find that my cordless tools sometimes sit for weeks in the truck and the batteries always need to be re-charged before I can use them. To be able to run them on a cord while the secondary battery charges would be a big time saver and I would buy the adapter in a heartbeat if one were available. (+)
-- 2 fries shy of a happy meal, Dec 27 2005


[rainbow], those are good points. Yes, different manufacturers tend to design battery packs that don't work with other makers' stuff, so you could be half-expected to need different transformer packs from different manufacturers. (more on this below, though)

Next, yes a transformer pack is indeed heavy and warm, but battery packs are also fairly heavy, and they get warm, also (conversion of chemical energy to electricity loses a fair percentage as heat). I'm not certain that the differences are significant.

Next, to obtain lithium batteries for a particular power tool, the manufacturer usually has to offer it. Not all do.

Now, there IS a resolution to just about all of those points. This is to have a "power brick" sort of thing, which has a short cord that plugs into the wall, and a long cord that connects to the tool. Then the weight of the brick is NOT carried around, and its heat also is not in the palm of your hand. (OK, I know that most of those tools are weight-balanced assuming the battery is present. The plug-in piece would have to have a dummy wieght.) ALSO, the part that connects to the tool can be a replaceable/adaptor sort of thing, just replace the end-piece to attach to a different tool (and there would have to be a voltage-control switch on the power brick, because different tools also tend to have different voltage requirements).
-- Vernon, Dec 28 2005


Vernon, I've been thinking of the same idea, google searched, and here I am! My reason for attempting this is that I love the features of my old cordless drill and don't want to re-cell the battery packs again. It has a clutch, dual speed range, level, keyless chuck, bit holders, easy to operate reverse, and great balance. I'm going to try to stuff a 12v 3A transformer and rectifier circuit in the battery pack. Don't know if that will have the punch of a fresh pack but it's worth a try. If it doesn't work there is a budget/import tool store ,harbor freight, that sometimes has 14.4V packs on sale for less than $10 and I'll salvage the cells from that. Otherwise it's just more junk in the landfill.
-- Bansuri, Feb 01 2006


<smug mode> When I thought of this about a decade ago </smug mode>, I saw it as a large stationary transformer with a low voltage lead that plugs into the drill. It could be used with or without a battery pack attached to the drill. If one were present, it would be charging at the same time, with some electronics to prevent using the drill from causing a voltage drop large enough to interrupt the charging. When you want to go cordless, just unplug.

I assumed the only reason this wasn't standard was the increased cost of the more powerful transformer (since a working drill draws much more current than a battery being charged). The low voltage lead would also have to be fairly heavy.

However, with a decent modern drill and two batteries you can work it very hard without draining one battery before the other is fully charged. I've not bothered to replace my burned-out corded drill for this reason.
-- spidermother, Feb 01 2006


Well, it's been a while and nobody probably even looks at these old posts, but if you do I just wanted you to know that I've had success. It doesn't have as much power as a battery pack, but this is just the proof of concept version. It's a cannon printer AC adapter. There's a fuse in it that blew so I replaced it with wire, the whole thing will probably smoke soon, but in the meantime it's perfect for what I needed it for: a zero cost, light-duty, keyless chuck w/clutch drill for work. Won't get a whole lot of use but it's waaaaay better than the one that's there already. Maybe a toroidal transformer or switching power supply would work better. I don't know but I'll experiment. This is a 10 year old drill so I wouldn't be surprised if modern motors are more efficient and require less juice. Here's a link to some pictures:

I'll update if I find another way to do it.

edit: well Vernon, sorry but I couldn't post the link and the forum told me to click link and post the link but it showed up right under your post. I just don't get the whole no links thing in posts... sorry for stepping all over your area up there.
-- Bansuri, Apr 14 2006


That's awesome. I have a cordless that the battery is losing its ability to hold a charge so I'll replace that one. But I would love to make a corded attachment for those really long tough jobs that drain the battery to quick. Do you think you could contact me and tell me how you did it like I was a two year old? As we all know, I'm
-- NotTheSharpestSpoon, Apr 14 2006


[Bansuri], any Idea that has either a link or an anno added to it is presented at the top of the main Overview page, for all to have a chance to see it. It doesn't matter how old the Idea is. (My Overview is set to show 15 items in each category, instead of the default 3.) It makes some sense for an Idea that has nothing new added to it to stay "out of sight" of the Overview. Most people don't want to reread the same old stuff.

Regarding the linking system, you did fine. Each section of a HalfBakery page is always in the same place (Idea on left, links under it, and annos on right).

Regarding your newly corded cordless drill, COOL! Well done!
-- Vernon, Apr 14 2006


Bansuri; I had this idea last fall as well. Saw these postings several months ago but just now posted a response. Send me an email if you'd like to work on it some more together or commercialize it. My contact info is in my profile on this site.
-- ottomotto35, Apr 14 2006


I had also thought about this... The biggest problem I think in this idea is that a small coil transformer cant produce enough amps or volts for good power. My Dewalt cordless drill has 18V. Small Transformers usually only go up to 12V with milli amps of output. I believe a cordless drill need upto 3.5 amps. Im not and expert by any means, so correct me if Im wrong. This may be the reason its not on the market already.
-- jcramer, May 24 2006


[jcramer], if you compare the sizes of those rechargable batteries with "wall warts", you will see that a significantly larger transformer would fit in the battery case. The assumption here is that one that does fit would also produce enough power.
-- Vernon, May 25 2006


In terms of getting a high enough output transformer: switchmode power supplies can go from 240V AC to 12, 14.4, 18, 24, etc V DC, with plenty of amps. Ran a project recently on a 14.4V switchmode supply, with continuous 10 Amps, peak 20Amps. The supply cost about $50. Looking at the circutry, I can't see why it couldn't be made smaller (cordless drill battery size), possibly including a cooling fan.

I prefer the idea of a normal (but lithium...) cordless battery drill, but where you can plug in the charger, which will run the drill and charge the battery simultaneously.
-- Custardguts, May 25 2006


I thought of this last year and started searching. I couldn't find one either mainly because they can be called all kinds of things. I finally found one for my Skil drill, item # 1214CPS. See the link high above called "Corded drill part". The transformer is SEPARATE from the drill and they use it to recharge a battery while you work. It does seem more realistic than having it in the battery. You're tethered to the wall no matter what. Whether the transformer is in your hand or sitting over at the wall doesn't really matter. The piece that snaps into the bottom of the drill is ultra light and basically hollow. It's the exact shape of a battery with the same electrical contacts for delivering the voltage. I can send real pics of this whole rig if someone wants. There is also a link to a DeWalt transformer in the battery. It looks huge.

Of course this is a good idea. The people who dog it don't see the value of it. It's like saying 'why do you want a nail gun that holds 100 nails when you can just put in 20 nails at a time?' Because sometimes you just want to blaze through projects without tending to the tool. I can run down a battery before the other one is even recharged. Sometimes you just want a deeper well of power to draw from, like a wall plug. As for drills that are already corded, they don't have a clutch. Plugging in a cordless drill gives the best of all worlds.
-- Renata399, Jul 14 2006


there are many ideas, such as this one, that are great and would really make a great product. The problem is that the batteries are an excellent source of income for these companies. I would be suprised to find a company willing to do this unless they charged enough money to recoup the costs of you, more than likely, never buying another battery.
-- tatmkr, Jul 14 2006


[Renata399], thanks for the links!

[tatmkr], cordless tools exist for a reason, and that reason will not go away any time soon. This Idea specifically indicates it is for situations where batteries are not really a better choice than a cord (plus less usage of batteries lets them last longer). So, while fewer batteries would be sold, less waste would end up needing to be recycled, too. And the companies that make batteries are not the companies that sell cordless tools. You can be sure that the tool-makers contract with the battery-makers, and could just as easily contract with transformer-makers.
-- Vernon, Jul 14 2006


This is a good one. I suggest that a possible way to accomplish this would be to have a moderate size charger connected to a smallish battery that would then power the tool. If you want to have 360 watts for work using 19 volts DC at 25% duty cycle (only drilling holes 1/4 the time) you would need a relatively cheap 5 amp charger by this scheme. A 19 amp power supply (expensive) would be required otherwise.
-- hangingchad, Jul 14 2006


Brilliant! And ironic too. [+]
-- MoreCowbell, Jul 14 2006


god bless Vernon.
-- po, Dec 24 2008


I thought that was God bless tiny tim?
-- blissmiss, Dec 24 2008


Thank you, [po].
-- Vernon, Dec 26 2008


I'm not sure that you could match the output in the same package without excessive heat buildup. It might be better to have a converter and a cord that plugs into the battery connection but without the weight the balance would be terrible.
-- WcW, Mar 01 2014


Ryobi now do tools that can switch between battery and mains power. However, I was going to post a variation.

Why not have the charger built into the tool? That way, you can run the tool on mains when convenient, and the battery charges while you work. When you need to go cordless, just unplug the main lead from the tool. This would eliminate the need for a separate battery charger (though one could be provided, so that you can charge several battery packs at once, as an option).
-- MaxwellBuchanan, Aug 06 2019


[+] As anyone whom is employed in work involving current battery tools knows. Especially 95% into a job.
-- wjt, Aug 07 2019


[MaxwellBuchanan]; I have had some battery-powered devices that do that, but not power tools. IIRC, a Phillips razor (typically touted as "dual power") and an LED flood- light. Oh, also my computer.
-- neutrinos_shadow, Aug 07 2019


//Oh, also my computer.// Now that, [ns], is a damned fine example. Although I'd warrant your computer relies on an adaptor, rather than a direct connection to the mains, to recharge its batteries. With the smallth and lightth of switched-mode convertors, there's no reason not to have them built into the device.
-- MaxwellBuchanan, Aug 07 2019


Yes, all of them use a "wall-wart" or bigger/fancier transformer; and yes, the clever little "switch at zero volts" units could easily be put into all sorts of battery-powered things.
Aside: it took [Vernon] until 2000-something to find a 2- speed corded drill?! My dad had one from 1970-something (or possibly older) that only recently gave up (umm, may have been my fault...).
-- neutrinos_shadow, Aug 07 2019


Powering a battery-powered tool from the wall is possible, but problematic, your power adapter becomes an absolute monster. Bosch have an 18V grinder that operates up to 800W, which would mean a 50 Amp supply, and that's without spikes. Somewhere in the order of 10x laptop power bricks, bulky and expensive.

Alternatively, most corded power tools are made with universal motors - they're comutated, they don't care if you feed them with AC or DC so just drag 10* car batteries around with you and you should be good all day. I think AvE did a video running a circular saw on DC.

*20 in europe
-- bs0u0155, Aug 07 2019


Eventually we will ditch the cord. There is just so much space to fill with the right formula of energy.
-- wjt, Aug 09 2019


What [Ian Tindale] said fourteen years ago.
-- pertinax, Aug 09 2019


You mean all that stuff about being spied on by trained pigeons, and being confused about how many legs he should have, and the little yellow pixies that come in the night and steal his dreams ?
-- 8th of 7, Aug 09 2019


*Especially* the pixies.
-- pertinax, Aug 09 2019


Needed holes can be in very inconvenient places. Cordless is better. Advancement is exponential especially if it has economic drive. Power cells will just get better and better until they are so good, no advancement is necessary.

I still like the idea for now because it can be done now.
-- wjt, Aug 10 2019


Isn't it annoying when you type up a bunch of stuff in reply to stuff that was said earlier in the conversation, because you'll forget what you wanted to reply to and what you wanted to say if you read on before writing, only to discover when you read the later-said stuff that someone else has already said several of the things you've written up? I'm not going to delete the redundant stuff from this anno, so that you all can be annoyed with me.

[rainbow]: // not being very techy, isn't a transformer from 240volt to 12volt going to be buzzing, warm and heavy? //

[Vernon]: // Now, there IS a resolution to just about all of those points. This is to have a "power brick" sort of thing, which has a short cord that plugs into the wall, and a long cord that connects to the tool. Then the weight of the brick is NOT carried around, and its heat also is not in the palm of your hand. //

[spidermother]: // a large stationary transformer with a low voltage lead that plugs into the drill //

The problem with that is that drills probably take quite high peak currents, maybe in the tens of amps. A power supply for that will be large (like a computer power supply), but that's fine if it's stationary. (The battery charger can be smaller because it charges the battery at a continuous low current.) The real problem might be the cable. To safely carry a higher current without melting, a wire needs to be wider, and therefore less flexible.

[spidermother]: // I assumed the only reason this wasn't standard was the increased cost of the more powerful transformer (since a working drill draws much more current than a battery being charged). The low voltage lead would also have to be fairly heavy. //

Oh—looks like that was already said. Anyway, a better method might be to run mains AC straight to the motor. I think most drills (before the new brushless-motored ones at least) use universal motors, because those have high power density. Universal motors are so called because they can run on either AC or DC. I know you can run most corded power tools off of car batteries for this reason. The motor might have to be designed specially for this, but it means that you can make a drill that can run off of either batteries or a plain AC cord with no power adapter. You might, depending on the motor, be able to modify, and get to work, a dead battery pack to have a mains cord coming out of it instead of cells inside it.

That, of course, won't work for the newer brushless drills, which have other advantages (more consistent torque, maybe higher efficiency), but that's good, because it means brushed technology will remain competitive, which is good for competition.

[spidermother]: // I saw it as a large stationary transformer with a low voltage lead that plugs into the drill. It could be used with or without a battery pack attached to the drill. If one were present, it would be charging at the same time, with some electronics to prevent using the drill from causing a voltage drop large enough to interrupt the charging. When you want to go cordless, just unplug. //

[Custardguts]: // I prefer the idea of a normal (but lithium...) cordless battery drill, but where you can plug in the charger, which will run the drill and charge the battery simultaneously. //

The problem I see there is that the charging circuitry would have to be integrated into the battery, whereas, with current drills, the battery is just some cells connected to the terminals, with a temperature sensor connected to another terminal, and all of the charge control is done by the charger, which you only need one of and which can more easily have vents. The power supply would have to provide enough voltage on the low-voltage power cord for the drill motor, and the battery would have to convert that to the voltage it needs for charging (from somewhat lower to slightly higher than the supply voltage, assuming the power supply and battery are both supposed to give the motor the same voltage). This would increase the size, cost, and heat generation of the battery pack, while you'd still have a stationary power device that's already much more expensive than the current battery charger due to the increased current requirement.

On the other hand, you could use the battery as a buffer, so that the power supply doesn't have to supply as much current and can be cheaper. But then the battery would probably generate even more heat (in the cells rather than in the charge controller), because it's now supplying those peaks.

[MaxwellBuchanan]: // Why not have the charger built into the tool? That way, you can run the tool on mains when convenient, and the battery charges while you work. When you need to go cordless, just unplug the main lead from the tool. This would eliminate the need for a separate battery charger (though one could be provided, so that you can charge several battery packs at once, as an option). //

That's a better way. Why didn't I think of that two paragraphs ago? On the other hand, that probably means the heat would be generated in the drill's handgrip, right in the middle of your gripping hand. But on the gripping hand, the drill already has active ventilation!

[bs0u0155]: // Powering a battery-powered tool from the wall is possible, but problematic, your power adapter becomes an absolute monster. Bosch have an 18V grinder that operates up to 800W, which would mean a 50 Amp supply, and that's without spikes. Somewhere in the order of 10x laptop power bricks, bulky and expensive. //

*sigh*

Does anybody have an idea that they can post to solve the problem described at the top of this anno?
-- notexactly, Aug 11 2019


//Does anybody have an idea that they can post to solve the problem described at the top of this anno?//

which was

//Isn't it annoying when you type up a bunch of stuff in reply to stuff that was said earlier in the conversation, because you'll forget what you wanted to reply to and what you wanted to say if you read on before writing, only to discover when you read the later-said stuff that someone else has already said several of the things you've written up? I'm not going to delete the redundant stuff from this anno, so that you all can be annoyed with me.//

Yes. Used to drive me nuts. I'd spend so much time googling words I didn't know in people's annos that by the time I had re-joined the stream I'd have to start googling again and many times life just butts in so many times in a row that days go by.

Now I open a second window for my annotation while reading an idea I want to comment on, then cntrl c annos of others, cntrl v to the anno page between // // marks so I won't forget, and go back to reading again so that I can erase redundancies before I post.

Then I refresh and scroll to the bottom of the posting again because sometimes, Damn you people are fast on the draw.
-- 2 fries shy of a happy meal, Aug 11 2019


I typically click [annotate] and do that in the same window/tab, as the other annotations are still visible there while writing. Scrolling up and down and finding my place again is a bit annoying, but only slightly. The reason that that doesn't entirely solve the problem for me is that, when I read something I want to reply to, I typically think of the wording of my reply very soon. So, if I were to just collect the quotations to reply to, and then write my stuff when I'm completely done reading, I would have forgotten that wonderful wording I came up with. I think I need something that points out to me that a given point I'm currently reading has already been replied to, below. But that sounds like a difficult AI problem.

// Then I refresh and scroll to the bottom of the posting again //

I don't often have that happen, even though I sometimes post long annotations that take up to a couple of hours to write, probably just because I'm often a bit behind on the recent list and therefore annotating ideas that aren't as active.
-- notexactly, Aug 12 2019


//solve the problem described// Don't worry, it all gets ironed out in prototyping.....unless marketing gets involved.
-- wjt, Aug 13 2019



random, halfbakery