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Are there any cordless powertool systems (e.g., drills, drivers) that have a corded battery option (i.e., an adapter that fits where the battery would normally go that can be plugged in)? I've used other electrical equipment with this arrangement (e.g., video cameras), but have never seen it with power tools. If it doesn't exist, is there a practical reason why?

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Believe it or not, they do make such things. For example the Greenlee AC Adaptor for 18V Cordless Tools.

I have not heard of a "system" like that though. I suspect that's related to the fact that I've never met a pro who used or even wanted one. When battery-powered tools finally became usable, we all pledged our firstborns to whatever god made that possible and we never looked back.

Cameras, laptops, etc. can all stay in one spot for extended periods as they do their job. Power tools (at least the kind that come in cordless varieties) are in constant motion. Dealing with cords and sockets is a major time, safety, and infrastructure disadvantage.

If your tool stays in one spot enough to where you ponder an AC backup, you're often better off just buying an AC-powered tool for that job. It will: be cheaper, have more power, and be more energy efficient than jacking AC to the cordless tool.

But, if you're really jonesing to do the 60 hertz shuffle ;) and you have some electronics skills, you can rig up your own AC system, a little like this guy did -- Except I would use a proper-sized DC supply and wire it to an old battery pack (¡with the battery cells removed!) instead of hard-wiring it to the tool.

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Your answer is spot on. We pros hate being tethered to a cord unless the need is for power and lots of repeat actions in close proximity ie; chop saw or circular saw on horses. And as a result, we spend a fortune on extra batteries and chargers. I have like 8, 18volt DeWalt drills simply because it was cheaper to buy a promotion with the tool, two batteries and a charger than buy the batteries separately. –  shirlock homes Apr 29 '12 at 11:25
    
With the introduction of Lithium-Ion cordless power tools, there is absolutely no reason I can think of to be tethered to an outlet. –  ShoeMaker Apr 30 '12 at 17:07
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@ShoeMaker: You will, eventually, run out of charged batts for your cordless tool system on the job. Batts charge more slowly than they discharge when used, so the function of number of batts, number of chargers, and number of tools will always result in the available charged battery count diminishing to zero. For the average homeowner, who may drag these tools out once a month to find that both the batteries that came with his system have self-discharged to uselessness, a corded option, even if not ideal, is better than twiddling your thumbs staring at the charger. –  KeithS May 2 '12 at 18:00
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I ran a business remodeling early-mid 20th century homes for ~7 years, and my back ran out before my batteries did. I never waited on batteries. I purchased a kit with a drill, circular saw and a couple other various little things... Each item came with a battery (iirc there were 4 batteries total). I never went through more than two batteries a day, and the kit came with two chargers. Lithium-ion batteries have a decent shelf life, and even now that I don't use my tools but once every other month. I simply plan ahead that I am doing X project this weekend and drop a two batts on charge. –  ShoeMaker May 2 '12 at 19:39
    
@KeithS: I disagree. I've got 6 of the same lithium ion batteries and 3 chargers. The batteries charge in under 30 minutes. Even with only 3 batteries and 2 chargers, I can keep using my tools indefinitely if they completely discharge after only 15 minutes of use. –  Doresoom 3 hours ago
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There is a big difference between being tied to an expensive, proprietary battery pack and being tied to a 120 VAC line.

When my first battery pack for a tool dies, I dissect it and attach wires through a suitable strain-relief. I then connect the ends to an Anderson Powerpole connector, which I can then plug into a more substantial battery.

(If you do so, be sure to wire the connector according to the Amateur Radio Emergency Service standard, and you'll be able to plug it into any nearby ham radio operator's battery, if needed.)

For this reason, I favour 12 volt tools, because it is simple to find generic batteries for them -- you can even clamp them to a car battery. I don't find the additional torque of higher-voltage tools to be worth the inconvenience and expense of being tied to proprietary batteries.

I can plug into a 17 ampere-hour battery in a box with a handle, and work nearly ten times as long as I can with the 2 ampere-hour battery that came with my tool.

Another advantage is that such tools are often free! When a ~$80 battery pack goes bad, a lot of people chuck the entire tool in the rubbish bin and buy a new ~$90 tool! I "harvest" such tools and wire them to cables with Anderson Powerpole connectors for a few dollars worth of parts, and put them back in service. Or you can find "batteryless" tools at garage sales for pennies on the dollar.

Such "semi-wired" tools are far more portable than you'd think. Sure, they aren't as convenient as with the contained battery, but they can still be used remotely without running a long extension cord.

Here is a cord attached directly to a drill. I took the screws out of the case and soldered directly to the terminals that make contact with the battery. I then drilled two holes in the end and used a tie-wrap as a strain relief. This sort of mod is irreversible and permanent -- you can no longer use the OEM batteries with this drill:

Here is a cord attached directly to a drill. I took the screws out of the case and soldered directly to the terminals that make contact with the battery. I then drilled two holes in the end and used a tie-wrap as a strain relief. This sort of mod is irreversible and permanent -- you can no longer use the OEM batteries with this drill.

If your tool has an easily disassembled battery, you can modify a bad battery pack instead of the tool, preserving the use of other batteries:

If your tool has an easily disassembled battery, you can modify a bad battery pack instead of the tool, preserving the use of other batteries.

Here is a close-up of a modified battery pack. Note the strain-relief for the cord egress:

Here is a close-up of a modified battery pack. Note the strain-relief for the cord egress.

My 10 AH belt-pack is made up of NiMH "D" cells. I have these wired as two six-volt strings that can easily be connected in series, as shown here:

My 10 AH belt-pack is made up of NiMH "D" cells. I have these wired as two six-volt strings that can easily be connected in series, as shown here.

The two six-volt holders then slip into a belt holder designed for a cell phone, a very long time ago:

The two six-volt holders then slip into a belt holder designed for a cell phone, a very long time ago.

When I need lots of energy, I have a 20 AH battery housed together with a power supply for charging in an army-surplus ammo case. This will run a tool ten times longer than the OEM battery. Included is a trouble light, wired to a relay so that power fails, the light comes on. Shown also is a car battery adaptor to Anderson Power Pole connectors:

When I need lots of energy, I have a 20 AH battery housed together with a power supply for charging in an army-surplus ammo case. This will run a tool **ten times longer** than the OEM battery. Included is a trouble light, wired to a relay so that power fails, the light comes on. Shown also is a car battery adaptor to Anderson Power Pole connectors.

Here is a close-up of the egress to the ammo case. At bottom is a standard connector for a three-pin AC power cord, as used on computers and such. At the top are two pair of Anderson Power Pole connectors in a housing Anderson makes for the purpose:

Here is a close-up of the egress to the ammo case. At bottom is a standard connector for a three-pin AC power cord, as used on computers and such. At the top are two pair of Anderson Power Pole connectors in a housing Anderson makes for the purpose.

Thanks for the suggestion to post photos. I hope these are helpful!

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Do you have pictures of these mods? Post em and the answer will get more votes. –  Brock Adams May 2 '12 at 22:54
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Wow, what's that battery with 17 ampere-hours? What size and weight does it have? –  sharptooth May 4 '12 at 8:22
    
@sharptooth, they make 'em. In lead-acid they run about 14 pounds and are about the size of 2-3 bricks. In Lithium, think 13 of these, or 2 or 3 BIG laptop batteries. One reason why pictures would be impressive. –  Brock Adams May 4 '12 at 8:49
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