Why not offer a CORDED battery replacement?
If the battery poops out, you could continue to use the tool with a cord -
much like you can with a cell phone.
The working parts business of battery charger that comes with the tool is
smaller than the battery itself, and could easily be fitted in a case the
size of the battery.
In the alternative, why doesn't some clever entrepreneur concoct the device
to sell as an after-market product? Certainly non-OEM battery replacements
are available; why not power-cord replacements for the battery?
Heck, I've got some old batteries lying about, I might just try building a
small DC power supply to fit in the scooped-out innards of one.
Just thinking out loud.
On Fri, 04 Dec 2009 04:15:35 -0800, ransley wrote:
I'm sure they all have it sewn up so that nobody can make anything to fit
in the battery slot of their tools without their blessing :-(
re. running from charger, I doubt the charger has enough guts to provide
the power to seriously run the tool (they'll be designed to charge the
battery at a far lower rate than it can actually deliver), but a suitable
PSU could be built to fit in the space of most batteries...
My Firestorm came with 2 batteries. What's wrong with just swapping out
the battery? My other battery will be recharged by the time I need it.
If you need more than that, get an electric (corded) drill. I have a 1/2
inch plug in for heavy jobs.
Quote: "Heck, I've got some old batteries lying about, I might just
try building a
small DC power supply to fit in the scooped-out innards of one."
Been thinking the same!
An excellent basic idea; although I wish batteries were 'Universal'!
And yes a power supply MIGHT be built into a dud battery case to power
a cordless; although it would have to supply a much higher current
capacity than that for just recharging a typical cordless battery,
continuously, over a few hours!
Welcome any comments on the Calcs. below.
Also see my previous post about setting up two old truck batteries to
power our 24 volt computer UPSs. And extending that to our main work
bench. Our good neighbour mentioned recently that he's thinking of
replacing his four transport truck batteries again; before, or during
this winter. So although we have three of his previous ones they'd do
fine. We also have an heavy old-timer 26 volt DC battery charger
supply than can be modified etc.
If the 24 volt proves too high for a couple of the older 12/14 volt
cordless drill with dud batteries and dud chargers am thinking of a 12
volt tap (to keep it simple) or a voltage regulator circuit to step
down to say 18 volts.
To date experiments seem to show that several of these older 12 volt
cordless work fine on anything from 10 to 18 volts; although how much
torque they'd have at 10 volts not yet checked.
The idea being that the now useless cordless drills be used at the
bench; we have some other newer cordless with good batteries and
chargers that still work for outside/portable work. Typically a
replacement Bosch charger was $70+, two new batteries around $50 each,
total $170 plus shipping etc. for a Bosch set (including carrying
case) originally bought for $150! Answer go out and buy new! Price
planned obsolescence? We didn't buy another Bosch however!
Calcs: Typical cordless drill takes say 60 watts? That's 12 volts at 5
amps = 60 watts. Or maybe 100 watts, that's around 8 or 9 amps. If a
typical cordless battery is 2.5 ampere hour it will last about 2.5/ 5
to 2.5/8 = 0.5 to 0.3 hours ( 12 to 30 minutes say) running time? So
somewhere around 5 to 10 amps (at 12 to 18 volts) sounds about right?
Obviously a good idea brewing? And even if a typical cordless required
say 150 watts that's still only 1.2 amps at 'mains supply voltage of
120 volts' .So lightweight lamp cord (18AWG) could be used for an AC
wall plug-in part of it!. Certainly a lot bigger than a Wall-wart but
sounds technically feasible?
Oh btw; tried running a cordless without any battery on DC from a
small supply such as those supplied to power a CB radio. The PS was
rated at around 3 amps.
And it worked OK, without load on the drill. And proper polarity +/-
Also tried same voltage AC (Approx. 12 volts RMS) and while the drill
rotated and would reverse it obviuosly didn't like it; probably the
speed controll/trgger not designed for AC! Same results with three
cordless of different manufacturers.
I think there's a couple of reasons, a crummy reason and a good
Crummy reason: Because it is very much part of their product strategy
that when the batteries quit taking a charge a couple of years after
purchase, *you buy a whole new tool*. There used to be companies that
made affordable tools that lasted a homeowner's lifetime...where are
they now? Gone, their brands walking among us like zombies,
artificially animated by holding companies and investment funds. The
smart money is in planned obsolescence.
Good reason: take this DeWalt that turns up on a random Google search:
Blurb says it's a 510 Watt motor (it's rare to see Wattage quoted for
cordless tools, but let's take this as typical) so that 18 V battery
pack is putting out 28 Amps. The leftover power bricks you've got
lying around from old cellphones put out *milli*-amps. Sure you can
build or buy a 28 Amp 18 V power supply, but it ain't gonna fit in to
the hollowed-out battery case, and you'll need booster cables to
connect it to the tool.
Its a great idea but physics gets in the way. :(
Take a look at a Malibu light 12v 300W power supply......its a brick.
I doubt that a AC/DC power supply with enough poop to power a drill
will fit in the comparable battery space.
So I think you;d be stuck "making" the low voltage DC "elsewhere" &
supplying to the tool via a cord.
Any appreciable power at lower volts require HIGH amps. High amps
require BIG conductors to minimize voltage drop.
The whole battery thing works because of the asymmetric charge /
discharge times & amperage demands.
btw I rigged up something like this to run my 12v Makita drill/drivers
off my car battery but I had to use HEAVY cables (like good sized
jumper cables). Working with them was like dragging a snake around
with me. My light weight easy to use cordless drills were now less
mobile than a corded 120v drill. :(
Good thing I made it out of stuff on hand & didn't buy the materials.
I think it is (was) a great idea.........but I couldn't get to work
I think that will get rectified!
Main thing is how to safely get the voltage down from 115 to the 12 to
18 volts or so to operate the previously battery operated drill.
OR; use the truck battery arrangement at the work-bench as previously
Years ago, an electronics teacher I had, told a story about
one of the many pranks electronics geeks will play on each
other. I'm guilty of quite a few but the prank the teacher
told about was brilliant. There is always some smart ass
who tells the new guy to go get an AC battery off the shelf
in the back. Well, it was pulled on a new guy who was fresh
out of tech school and of course knew everything. Well, he
was told that AC batteries were a new item and that there
was one on the shelf. The skeptical young man went to the
back and sure enough, there, on the shelf was an item labeled
AC battery. He took it back into the shop and handed it to
the senior tech while saying that they were pulling his leg.
The prankster told the newbie to watch this. When the battery
was connected to an oscilloscope, it displayed a nice little
1.5 volts peak to peak sine wave. The guys in the shop had
installed a little battery powered oscillator inside the empty
casing of a D cell. The old regular D cells were basically a
zinc can with a carbon rod connected to the + contact and
they were relatively easy to open up and clean out.
Let's see some of the pranks I would pull. In one shop where
I worked, our workbenches had a master switch that we would
flip on when we sat down to start our day of toil. #1, paint
the guy's soldering iron with liquid flux then coat it with
gun powder. #2, Take a bunch of 12volt miniature lamps and
hook them to the 120volt power so that the sun came out when
the victim flipped the master switch on his bench. #3, Swap
the contents of the tuner wash and freeze spray cans. I would
pull a vacuum on an empty can then connect them together with
the plastic extension tubes and transfer the disparate content.
The victim would get an unexpected result when trying to clean
or cool something. #4, The old add a handful of extra hardware
to the tray holding a disassembled item trick. There are many
more pranks that a bunch of warped, bored, creative people
would pull on each other.
About the spray cans, the freeze spray is expensive and canned air for
blowing the dust out of computers is cheap, especially by the case.
Just hold the can upside down and you have freeze spray. I also hook
them together when a can of paint somehow lost most of it's pressure.
Hook up a canned air can (upright) to the paint can and pressurize it again.
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