I have a set of 18-volt cordless DeWalt power tools that I got about 3
years ago. Since I use them rather infrequently, I'm not getting the
lifetime out of the very expensive batteries that I would like. The
set originally had two batteries, but both have since quit working.
I have one replacement battery now, and it seems to be less able to
hold a charge as time goes on.

DeWalt apparently does not make an AC to DC converter that would be
able to power these tools with a cord. This is unfortunate because
it's a pain to have to stop work while the battery recharges. I
presume they don't offer this product because it would eat into their
very lucrative battery business... understandable.

Does anyone know if there is a third-party that makes a corded power
attachment for cordless tools?

Thanks,
Guy

--

Guy Berthiaume


"With, without,
And who'll deny,
It's what the fighting's all about."
- Roger Waters

Does anyone know if there is a third-party that makes a corded power
attachment for cordless tools?

I don't know about a third party, but Dewalt makes a product that
would suit you very well. It's about $45, which would be less than
the price of a new battery, and it will actually give you much better
performance than your current setup. See:
http://www.toolking.com/productinfo....productid=3397
(If the link doesn't work, search for Dewalt item # D21008K)
I actually own one of these products (got mine for maybe $35 on eBay),
and I've been very happy with it - highly recommended.
Andy

"Guy Berthiaume" wrote in message
...
I have a set of 18-volt cordless DeWalt power tools that I got about 3
years ago. Since I use them rather infrequently, I'm not getting the
lifetime out of the very expensive batteries that I would like. The
set originally had two batteries, but both have since quit working.
I have one replacement battery now, and it seems to be less able to
hold a charge as time goes on.

DeWalt apparently does not make an AC to DC converter that would be
able to power these tools with a cord. This is unfortunate because
it's a pain to have to stop work while the battery recharges. I
presume they don't offer this product because it would eat into their
very lucrative battery business... understandable.

Does anyone know if there is a third-party that makes a corded power
attachment for cordless tools?


Like Andy commented, a much stronger corded drill would be cheaper than an
18 volt adapter.

"Guy Berthiaume" wrote in message
...
snip
I presume they don't offer this product because it would eat into their
very lucrative battery business... understandable.

Does anyone know if there is a third-party that makes a corded power
attachment for cordless tools?

The battery business *is* very profitable and the manufacturers have locked
out 3rd parties by patenting the battery - drill interface/connection. This is
why you don't find 3rd party batteries either. They can't stop you from
getting your battery packs rebuilt, but by welding the cases together some
manufacturers make it more difficult.

I know it ain't a Dewalt but Ryobi is the only one who I'm aware of who
makes a corded 3/8" drill with a clutch. For infrequent use it may do ok.
http://www.amazon.com/Ryobi-Clutch-D.../dp/B000FKIWD2

Art

I also needed a new Dewalt battery, tho mine was a 14.4V. 89 bucks was
the best i could find, or 50 for a used one on Ebay. Then I found a
rebuilded. I got a new 2100Mh 14.4v battery core shipped to me for 39
bucks. I just have to put it in the old case and make 2 solder
connections. If you can afford the time to ship him your old battery,
he will do it for the same cost.

http://www.wcbatteryrebuilders.com/

they are is California.

On Wed, 7 Mar 2007 20:17:23 -0800, "WoodButcher"
wrote:


"Guy Berthiaume" wrote in message
.. .
snip
I presume they don't offer this product because it would eat into their
very lucrative battery business... understandable.

Does anyone know if there is a third-party that makes a corded power
attachment for cordless tools?

The battery business *is* very profitable and the manufacturers have locked
out 3rd parties by patenting the battery - drill interface/connection. This is
why you don't find 3rd party batteries either. They can't stop you from
getting your battery packs rebuilt, but by welding the cases together some
manufacturers make it more difficult.

I know it ain't a Dewalt but Ryobi is the only one who I'm aware of who
makes a corded 3/8" drill with a clutch. For infrequent use it may do ok.
http://www.amazon.com/Ryobi-Clutch-D.../dp/B000FKIWD2

Art


The problem that I have is that I have a set of DeWalt tools: Hammer
Drill, Jig Saw, Circular Saw, Reciprocating Saw, and Worklight.

It sounds like I am going to have to design my own converter. I can
take a dead battery, remove the cells, and connect it to an 18 volt
power supply. I was hoping someone had already done this, so I
wouldn't have to think about it.

Oh well, this is a hobby for me so I might as well take the time...

Thanks for your responses. At least now I know what direction to go.

Guy
--

Guy Berthiaume


"With, without,
And who'll deny,
It's what the fighting's all about."
- Roger Waters

"Guy Berthiaume" wrote in message
...
On Wed, 7 Mar 2007 20:17:23 -0800, "WoodButcher"
wrote:

snip

It sounds like I am going to have to design my own converter. I can
take a dead battery, remove the cells, and connect it to an 18 volt
power supply. I was hoping someone had already done this, so I
wouldn't have to think about it.


Think about this before you spend time and $$ on this project.
If a 115V drill pulls 6A, then your 18V drill will pull about 38A
for the same power levels. This will take at least 6ga wire to connect
your power supply to the drill. Do you want to deal with the weight
and inflexibility of this cable?

An alternative would be to design the converter/power supply to fit
into the battery case and run a regular power cord to the wall.

Art

"WoodButcher" wrote in message
. ..
Think about this before you spend time and $$ on this project.
If a 115V drill pulls 6A, then your 18V drill will pull about 38A
for the same power levels. This will take at least 6ga wire to connect
your power supply to the drill. Do you want to deal with the weight
and inflexibility of this cable?

An alternative would be to design the converter/power supply to fit
into the battery case and run a regular power cord to the wall.

Art

The problem in both cases is going to be the transformer. To handle amps
like that, it is going to be WAY to big to fit in the tool and way to
expensive to be practicle. With a transformer that big and the regulator to
handle that power, I would be surprised if you could do it for less than
$400.00 to $500.00.

CW wrote:

The problem in both cases is going to be the transformer. To handle amps
like that, it is going to be WAY to big to fit in the tool and way to
expensive to be practicle.

For this sort of application you don't need a big linear-type supply.
The motor doesn't really care about noisy power, so it would probably be
possible to fit a switching supply into there.

However, one that can provide almost 40A at 18V isn't going to be common
or cheap.

Chris

If yer close to a home depot, you can buy the ryobi packs, gut the cells
from it (they are the same size) and build yer own packs. I've even seen
replacement packs for no name drills at big lots (a US closeout retailer)
that use the same size cells. Though they are of lesser capacity and quality
than the brand named packs....
Pat

"WoodButcher" wrote in message
. ..
"Guy Berthiaume" wrote in message
...



Think about this before you spend time and $$ on this project.
If a 115V drill pulls 6A, then your 18V drill will pull about 38A
for the same power levels. This will take at least 6ga wire to connect
your power supply to the drill. Do you want to deal with the weight
and inflexibility of this cable?


And yet a 3.5 amp battery is all that is need to power the 18 volt drill.
The 18 bolt drill does not pull very many amps at all. 18 volt drills
motors so not deliver near the power of the corded 115 volt model drills.
The 18 volt drill can deliver close to the same torque by gear reduction at
the sacrifice of chuck RPM's.

On Mar 8, 8:26 pm, "WoodButcher" wrote:
Think about this before you spend time and $$ on this project.
If a 115V drill pulls 6A, then your 18V drill will pull about 38A
for the same power levels. This will take at least 6ga wire to connect
your power supply to the drill. Do you want to deal with the weight
and inflexibility of this cable?

An alternative would be to design the converter/power supply to fit
into the battery case and run a regular power cord to the wall.

Art

I find it hard to believe that a cordless battery pulls 38 amps. If
you take one apart, I doubt that they have 6 gauge wire inside. I'm
certainly not an expert, but that seems fishy. (I doubt the battery
pack can supply 38 amps )

bf wrote:
(I doubt the battery
pack can supply 38 amps )

I don't.

I used be heavily into competitive radio control car racing. We tried
to set the car up to completely drain a 2000 mAH Sub-C NiCd pack in 4
minutes + 1 lap (about 3-4 seconds). We used bus bars from cell to
cell, and ultra flexible 12 ga. wire, as the wires were only a few
inches long.

We tested packs @ 30-35 amp discharge rates using devices like this:
http://www.rctech.net/reviews/review_turbo35gfx_futureal.shtml

If the cells were matched well enough the pack would "dump", and totally
die in the space of seconds. G

No, the batteries don't, but the motor very well could. Rechargeable can put
out an amazing amount of current. No, you won't find 6 gauge wire inside.
You won't find wire at all. You will find sheetmetal straps connecting the
cells.

"bf" wrote in message
ps.com...
I find it hard to believe that a cordless battery pulls 38 amps. If
you take one apart, I doubt that they have 6 gauge wire inside. I'm
certainly not an expert, but that seems fishy. (I doubt the battery
pack can supply 38 amps )

"bf" wrote in message
ps.com...


I find it hard to believe that a cordless battery pulls 38 amps. If
you take one apart, I doubt that they have 6 gauge wire inside. I'm
certainly not an expert, but that seems fishy. (I doubt the battery
pack can supply 38 amps )


I don't believe it either. They would get pretty hot. The drills get their
power from gear reduction.

On Thu, 8 Mar 2007 17:26:31 -0800, "WoodButcher"
wrote:
Think about this before you spend time and $$ on this project.
If a 115V drill pulls 6A, then your 18V drill will pull about 38A
for the same power levels. This will take at least 6ga wire to connect
your power supply to the drill. Do you want to deal with the weight
and inflexibility of this cable?

An alternative would be to design the converter/power supply to fit
into the battery case and run a regular power cord to the wall.

Art


I actually didn't expect this conversation to go into the design
issues I might face. But, if you guys are willing to discuss this,
then I am more than happy to get your help.

Part of this project will be to determine the battery specs. DeWalt
has chosen not to publish specs on the batteries or the tools that use
them (at least any that I can find). I can find neither current
ratings nor horsepower ratings.

From my experimentation so far I have found the Equivalent Series
Resistance (ESR) of my remaining battery is about 0.2 ohms. This
puts the short-circuit current at about 90 Amps. Assuming a stalled
motor has an impedance of 1 ohm (a big assumption right now), then the
peak current under worst-case conditions is around 15 Amps.

Under normal load conditions, I would expect half that value. A
switching power supply with a peak output of 15 Amps and continuous
output of 8 Amps should suffice. That translates into a supply that
can handle 144 W continuous, and 270 W peak. That will be a hefty
supply. 270W is equal to about 1/3 HP.

The other issue is that most switching supplies have over-current
protection which could cause the tool to stop/start in rapid
succession if the supply can't handle the peak current demand. I
would expect that to have an adverse effect on the item being worked.

I actually have several small 18 V supplies that I can parallel for
combined output of 225 W max. This doesn't fit the exact
requirements, but it will be good enough for an experiment.

Guy


--

Guy Berthiaume


"With, without,
And who'll deny,
It's what the fighting's all about."
- Roger Waters

"Guy Berthiaume" wrote in message
...
snip
I actually didn't expect this conversation to go into the design
issues I might face. But, if you guys are willing to discuss this,
then I am more than happy to get your help.

Part of this project will be to determine the battery specs. DeWalt
has chosen not to publish specs on the batteries or the tools that use
them (at least any that I can find). I can find neither current
ratings nor horsepower ratings.

From my experimentation so far I have found the Equivalent Series
Resistance (ESR) of my remaining battery is about 0.2 ohms. This
puts the short-circuit current at about 90 Amps. Assuming a stalled
motor has an impedance of 1 ohm (a big assumption right now), then the
peak current under worst-case conditions is around 15 Amps.

Under normal load conditions, I would expect half that value. A
switching power supply with a peak output of 15 Amps and continuous
output of 8 Amps should suffice. That translates into a supply that
can handle 144 W continuous, and 270 W peak. That will be a hefty
supply. 270W is equal to about 1/3 HP.

The other issue is that most switching supplies have over-current
protection which could cause the tool to stop/start in rapid
succession if the supply can't handle the peak current demand. I
would expect that to have an adverse effect on the item being worked.

I actually have several small 18 V supplies that I can parallel for
combined output of 225 W max. This doesn't fit the exact
requirements, but it will be good enough for an experiment.

Guy

I think the motor specs would be more relevant than the battery
specs. Like you stated, the battery is capable of far more amps than
the motor would ever draw. Your plan of testing with your existing
supplies is a sound one.

A switching supply is definitely the way to go. An off line switcher
running at several hundred KHz will have magnetics which are much
smaller and lighter than the cells of your current battery pack. Your
over-current concerns can be addressed by simply designing it to go
into a constant current mode instead of shutting down and restarting.
I also wouldn't bother with PFC. A non-isolated design will be more
compact and less costly than an isolated one and the drill/saw/whatnots
are usually insulated sufficiently to avoid shock, but this is a safety issue
and is your call. And finally, given the application, the ripple spec can
be relaxed or even eliminated as the motor(s) receive PWM current
supplied by the VSR electronics anyway. If your design for the
converter allows the voltage to fall to zero 120 times per second this
would be probably be unnoticeable to the user.

Art

Guy Berthiaume wrote:

I actually didn't expect this conversation to go into the design
issues I might face. But, if you guys are willing to discuss this,
then I am more than happy to get your help.

Part of this project will be to determine the battery specs. DeWalt
has chosen not to publish specs on the batteries or the tools that use
them (at least any that I can find). I can find neither current
ratings nor horsepower ratings.

It looks like the DeWalt 18V drill currently shown on their web site is
listed at "510 Unit Watts Out"??? 510W / 18V = 28.333 Amp.

http://www.dewalt.com/us/products/to...roductID=15104

--
Jack Novak
Buffalo, NY - USA

Guy Berthiaume wrote:
It sounds like I am going to have to design my own converter. I can
take a dead battery, remove the cells, and connect it to an 18 volt
power supply. I was hoping someone had already done this, so I
wouldn't have to think about it.

I just came across an article on the web about battery to corded
conversion and immediately thought of this post. Here's the link:
http://www.instructables.com/id/ECYS...DWXW6?ALLSTEPS

I heard about it through
http://makezine.com/blog/

On Wed, 7 Mar 2007 20:17:23 -0800, "WoodButcher"
wrote:


"Guy Berthiaume" wrote in message
.. .
snip
I presume they don't offer this product because it would eat into their
very lucrative battery business... understandable.

Does anyone know if there is a third-party that makes a corded power
attachment for cordless tools?

The battery business *is* very profitable and the manufacturers have locked
out 3rd parties by patenting the battery - drill interface/connection. This is
why you don't find 3rd party batteries either. They can't stop you from
getting your battery packs rebuilt, but by welding the cases together some
manufacturers make it more difficult.

I know it ain't a Dewalt but Ryobi is the only one who I'm aware of who
makes a corded 3/8" drill with a clutch. For infrequent use it may do ok.
http://www.amazon.com/Ryobi-Clutch-D.../dp/B000FKIWD2

Art


My younger received a similar Ryobi drill/driver as a wedding gift
(from someone who knew she has a "fix-it" personality).

It serves well for basic home handy-person use. I wouldn't recommend
it for installing a deck or a room of drywall, but it works OK for
hanging curtain hardware and the like.

John

On Thu, 08 Mar 2007 01:40:13 GMT, Guy Berthiaume
wrote:


DeWalt apparently does not make an AC to DC converter that would be
able to power these tools with a cord. This is unfortunate because
it's a pain to have to stop work while the battery recharges. I
presume they don't offer this product because it would eat into their
very lucrative battery business... understandable.

I don't know why you say its *understandable*.

Its damn sleazy. They should make the batteries available for a
reasonable price.

That's why he said it's understandable. "Damn sleazy" is a common business
model.
Free greed, it's the American way.

wrote in message
...
On Thu, 08 Mar 2007 01:40:13 GMT, Guy Berthiaume
wrote:


DeWalt apparently does not make an AC to DC converter that would be
able to power these tools with a cord. This is unfortunate because
it's a pain to have to stop work while the battery recharges. I
presume they don't offer this product because it would eat into their
very lucrative battery business... understandable.

I don't know why you say its *understandable*.

Its damn sleazy. They should make the batteries available for a
reasonable price.

On Fri, 09 Mar 2007 20:25:58 GMT, "CW" wrote:

That's why he said it's understandable. "Damn sleazy" is a common business
model.
Free greed, it's the American way.


Just so you understand, I mean that I understand their profit motive.

Myself, I wouldn't go so far as to call it sleazy because I have no
way to know what issues they face in manufacturing these batteries,
but I wouldn't be surprised if they have an "embarassing" profit
margin.

Guy

--

Guy Berthiaume


"With, without,
And who'll deny,
It's what the fighting's all about."
- Roger Waters