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pmer
01-15-2015, 09:00 AM
Does anyone have a cordless drill or saw with batteries that are bad or go low at inconvenient times. I was playing around with DC power supplies and got a 18 volt De Walt saw to run and cut pretty good. It has a power cord going into an old battery pack after I took the batteries out.

Has anyone tried anything like this?

cheese1566
01-15-2015, 09:25 AM
I have an old computer power supply that I rigged to be a 12 volt DC source on my workbench. I had an older 12v DeWalt drill that the batteries gave up. I disconnected the internal batteries in one of the packs and wired in a cord i can connect to the power supply. I left the batteries in just for weight to balance the drill. Works Ok for simple stuff on the workbench.

Muskyhunter1
01-15-2015, 09:28 AM
I am guessing you are changing 110V AC over to 18V DC within the power pack (battery). Basically when your battery dies you can switch to this plug in battery and you are off to the races - Right?

How'd you do it?

imashooter2
01-15-2015, 09:36 AM
If you use the tools where AC is available, why don't you just buy corded tools, save money and have a better product? If you need battery power, then buy more batteries.

A pause for the COZ
01-15-2015, 09:37 AM
I have a couple that I took the battery pac apart. Removed the dead batteries.
Soldered some wire onto the contacts and added some small battery clamps to the other end. About 8 feet of cord.

They work great running them from a 12 volt deep cycle battery. I keep one behind the seat of my truck. If out in the field and I need to drill out a rivet or some thing. I dont have to worry about the battery being dead.
Just pull up and hook up to the truck battery.

What the heck you gona do with all the dead drills around? might as well.

odfairfaxsub
01-15-2015, 10:35 AM
Interesting. I have a 12 volt craftsman I might just do this for the sake of it

cheese1566
01-15-2015, 10:47 AM
If you use the tools where AC is available, why don't you just buy corded tools, save money and have a better product? If you need battery power, then buy more batteries.

My cord has a cig lighter plug on it. When I built the power supply, I put in a cig lighter receptacle in it. I take the drill in my truck and camper during the summer and can plug it in at the campsite when primitive camping. Actually used it a few times.

plus, cost of batteries are more than drills themselves. When my 12 volt died, I picked up an 18v Makita on sale for close to what two new 12v DeWalt batteries were running.

pmer
01-15-2015, 10:59 AM
I am guessing you are changing 110V AC over to 18V DC within the power pack (battery). Basically when your battery dies you can switch to this plug in battery and you are off to the races - Right?

How'd you do it?

Yep and when the battery packs are charged back up you can remove the modified pack and use the tool normally again.

I used a 25 foot 14 gauge extension cord and DC switching power supply. The supply is too big to fit inside the battery pack.

Bzcraig
01-15-2015, 11:07 AM
Reconditioning or replacing the dead cells is pretty simple and inexpensive, lots of youtube videos on the subject.

shooter2
01-15-2015, 11:09 AM
If you use the tools where AC is available, why don't you just buy corded tools, save money and have a better product? If you need battery power, then buy more batteries.

Amen!

nicholst55
01-15-2015, 11:19 AM
Amen!

My truck has an integral power inverter and 115VAC outlet, so all I need is an extension cord and a corded tool - both of which I already own. Otherwise, I just buy either a new battery or tool, whichever is cheaper.

bangerjim
01-15-2015, 11:59 AM
It takes a 120VAC-xxDC power supply with a VERY HIGH amp rating to handle the initlal current inrush and then the loading power to make any battery op tool run correctly.

I have a BIG 20VDC supply (not a weak computer supply or wall wart!) that has a 20A output rating and it will bearly run my Mikita compound miter battery saw under any kind of load. Junked the tool and bought a corded 120VAC compound miter saw and never looked back.

NiMH and especially LiON batteries have huge inrush and sustained current capacities and are darned hard to eliminate and get your tool to even run effeciently and correctly.

Running older 12V stuff from a car battery or deep discharge battery should work, but anyone like me that went to the newer high torque 18V tools will have to seriously consider buying 18V batteries or go tto 120V corded tools which I have did on many.

If I worked out of a truck, I would seriously consider an inverter to give good AC power to run quality high-powered corded tools. Much better than battery tools that die in the middle of a job!

If you are in the market for new cordless tools, check out the 18V LiON Bosch line! I have 4 of them and those batteries just never dies. And LiON's hold their charge for an extremelly long time and recharge in about an hour. I just hated the NiCAD and NiMN batteries that develop memories and drain themselves automatically. Every time I reached for a tool, the battery was dead or low charge. Not good. I wasted more money rebuilding NiCAD/NiMH packs than I paid for the new superior Bosch technology.

banger

MtGun44
01-15-2015, 01:50 PM
I am not a fan of battery tools, but there are places where it is a big hassle to get power (like down
by the creek when working on my bridge) - lugging out the generator or rigging a bunch of long
extension cords - where they makes sense.

I am in the middle of rebuilding a couple of packs for a drill my Dad left me, seems to be a good
Craftsman drill, but batts are all shot. Picked up some brand new packs for some defunct drill
online cheap and pulled them apart, packed up the cells but haven't had time to solder them
together yet. Not too hard, really.

Bill

SOFMatchstaff
01-15-2015, 03:24 PM
I did this years ago with an old B&D, hard wired it to a set of clips and hooked it to the truck battery. Later set it up to run off the trailer light recepticle so it was handier at the tailgate when assembling target stands and other stuff on the range.

Still use it occasionally when building scenarios for a match. I also buy the cheap battery packs at Harbor frieght , break them down and use the cells to keep my batch of older Streamlights working.

pmer
01-15-2015, 03:49 PM
I've never rebuilt any packs but have bought some generic NI CAD packs for a 14.4 volt DeWalt drill. They worked pretty good.

I started this project for a friend at church that runs a construction crew. They like the big worm gear driven Skill saws for the big cutting jobs but also like to run around with cordless 18 volt DeWalt saws. They are battery hogs compared to drills. The batteries regardless of there chemical makeup have great start up current and you do have to match the power supply to the startup current that the tool will draw.

I first tried a 3 amp variable voltage power supply but it was too small and a 6 amp but it was too small too. They both would start and run a variable speed drill but little to no load though. I picked up an old school 24 volt power supply with big capacitors and a step down transformer, it weighs about 50 lbs. I found that a 6'' circular saw was drawing about 18 amps while cutting 2 x 10s with it, pushing hard it had more power than with a battery pack. And then matched it to a switching power supply because they are smaller and cheaper than a step down set up.

The Dewalt LithIon packs have load protection and a low voltage shut off built into them. I had to bypass that circuitry because the switching power supply has that built in to it along with a cooling fan too. So he has it now, it will be fun to see if holds up to their use.

Plate plinker
01-15-2015, 07:04 PM
If you use the tools where AC is available, why don't you just buy corded tools, save money and have a better product? If you need battery power, then buy more batteries.
Because we are reloaders!
reloaders = cheapskates
Why buy when you can cobble?

cheese1566
01-15-2015, 07:36 PM
Because we are reloaders!
reloaders = cheapskates
Why buy when you can cobble?

right on brother!

we could easily buy bullets and not cast...we could easily buy ammo and not reload...but where is the fun in that!!!

I made up the drill because:
1. I already had it
2. Wasn't sinking money into it because I upgraded to a heavy duty 18 volt
3. The power supply was already made for tinkering and testing on the workbench. Plus, we use it to air up air mattresses with our 12 volt camping inflator at the house.
4. The old drill was sitting useless under the bench. Couldn't sell for anything and didn't want to toss it.
5. I have a few corded drills in the tool bin when heavy duty long running is needed.

firefly1957
01-15-2015, 09:40 PM
I added a old 12V drill to my case trimmer under a load it draws 5 amps you need a good power supply or a battery to run them .

MaryB
01-15-2015, 11:15 PM
If you do rebuild a battery pack do NOT use LiON in place of Nicad or NIMH or you might get to witness a battery explosion and fire! I have rebuilt several packs for my older drills but really need to go to LiON tools.

bangerjim
01-16-2015, 12:39 AM
Yes the chargers for LiON are entirely different than the others. DO NOT try it.

sjbrdn
01-16-2015, 12:53 AM
Half of what you guys are talking about is over my simple head. As a professional contractor, I primarily use the DeWalt cordless systems and I find that the battery packs have a longer life with regular use. I completely discharge each battery before recharging and alternate so all batteries get regular use. My father-in-law has the same tool set I have and his are always dead because he never uses them. He has had to replace his batteries because of non-use more often than I have with regular use. If you use the cordless tools regularly or need them because power is not available, I think cordless tools are great. But, for the average home owner who just uses them a few times a year, I think they're a bad investment.

timberhawk
01-16-2015, 01:29 PM
I've been rebuilding battery packs for years. It used to be pretty hard to find sub c cells and good rechargeable batteries to rebuild with.
Now hobby stores and electronic stores sell all types of rechargeable batteries made to rebuild battery packs for model cars and such. They work great in power tool rebuilds because they're high capacity for longer run times.
But, as stated above, you've got to swap out comparable batteries (NiMH, NiCad, LiON, etc.) or you will create a potentially dangerous situation.

bangerjim
01-16-2015, 03:11 PM
Half of what you guys are talking about is over my simple head. As a professional contractor, I primarily use the DeWalt cordless systems and I find that the battery packs have a longer life with regular use. I completely discharge each battery before recharging and alternate so all batteries get regular use. My father-in-law has the same tool set I have and his are always dead because he never uses them. He has had to replace his batteries because of non-use more often than I have with regular use. If you use the cordless tools regularly or need them because power is not available, I think cordless tools are great. But, for the average home owner who just uses them a few times a year, I think they're a bad investment.

That is exactly the reason LiON systems are superior. They hold their charge for a VERY long time without loosing power, recharge quickly, and weigh only ounces rather than pounds like the older batteries do. I gave away 5 DeWalt 12/18v drills we used because the batteries were a PITA. I checked with a local battery recycler and by far the largest number of batteries they get in are the DeWalt 12/18 volt NiCad. Tons of them.

You have to totally drain a NiCad battery pack each time you use it or it could/will develop a memory and will not take a full charge after a while. I have "zapped" many a NiCad battery in my life trying to "burn the shorts" out of them. Works maybe 40% of the time. Most are trash after they start loosing charging power.

Then came the NiMH technology that drains itself (!) during idle times to prevent the memory thing, But if you let it sit for a period of time (perhaps weeks), next time you grab it, it's dead............from it's own internal designed draining.

If you are seriously thinking about new cordless tools, you really want to consider the LiON technology. Powerful, lightweight, fast charge, holds a charge for almost forever (!) At least it seems like it. My original Lexus hybrid SUV has LiON batteries and after 6 years they are still going strong. And that is in AZ summer heat. And Lexus gives a 10 year warranty on the battery. The new Lexus seems to have even more power!

wv109323
01-17-2015, 12:31 AM
I have a Craftsman 19.2 volts battery pack that just died. Where is the best place to buy Ni-CD batteries for that application.

pmer
02-09-2015, 03:54 PM
I have a Craftsman 19.2 volts battery pack that just died. Where is the best place to buy Ni-CD batteries for that application.

Here could be a place for generic Craftsman batteries.

http://www.batteryship.com/htmlos/htmlos.cgi/43354.1.142952650816236865

Its been a little while did anyone try to get a power supply running for a cordless tool? I have some video of mine cutting, I'll try and post it when I get to the house.

bangerjim
02-09-2015, 07:46 PM
Here could be a place for generic Craftsman batteries.

http://www.batteryship.com/htmlos/htmlos.cgi/43354.1.142952650816236865

Its been a little while did anyone try to get a power supply running for a cordless tool? I have some video of mine cutting, I'll try and post it when I get to the house.

Read my post #12 above.

bangerjim

pmer
02-09-2015, 08:29 PM
Read my post #12 above.

bangerjim

Hi Jim, I googled an 18 volt cordless Mikita mitter saw. I'm not sure if I found what you had but if it used a 3.3 AH battery, I'm not sure why a 20 Amp DC power supply set to about 19.5 volts would not get that saw to cut wood. 390 watts of available power to the motor in the saw should have done it. Especially if you had a solid 120 VAC going into the supply.

I'm having trouble getting video going I might have to use a link. It's on youtube (I think) Still trying to get video.

bangerjim
02-09-2015, 08:54 PM
It did run and did cut soft pine wood. I don't normally cut soft pine. It really struggled thru walnut, oak, and mahogany! The in rush power is very high from a battery pack. Sustained cutting in very hard dry woods just did not "cut it" in my book. An underpowered saw is a dangerous saw. It is NOT used portable, and in fact is bolted down in my shop.

But it was so awkward and cumbersome to have that huge power supply to run a small saw! I just went out and bought a 120V corded quality compound miter saw (NOT HF!) and dumped the Makita. Not worth the hassle, wiring, adaptors for the battery compartment and remembering to turn the stupid PS on and off when I wanted to cut wood! You just cannot beat corded tools when talking saws and high current usages.

If one wants to build jury-rigged power supplies for cordless tools, more "power" to 'ya! Been there-done that. I will stick with corded tools for hard, heavy work. And use LiON drills only for portable use. I have thrown away a LOT (!) of 12 and 18 volt DeWalt tools in recent years.

It is sure nice to know when you grab a power tool (corded or LiON) it will run and run a long time!

banger

pmer
02-10-2015, 01:29 AM
https://www.youtube.com/watch?v=b8NkW1OB8hs

Okay so I think it can be viewed in action now. I filled a coffee can of saw dust with it so far to be used for casting. I was test stalling an 18 volt drill with a auger style drill bit and the drill seemed to stall at close to same pushing force with batteries or the DC pow. supp. I can cut some oak and see if there is much difference. Common sense would tell me that a more dense wood would have to be cut slower than a soft wood when using a battery too. (at least by how this Dewalt acts, it has seen use)

I didn't build it to over power the tool, I'm sure a person could hit it with a 24 volt battery charger/vehicle starter and it would cut like a beast till it melted. But I think it could be a nice back up to help finish a project or if you have an odd name cordless tool that is hard to get batteries for. It does make the tool more versatile being able to go from DC to AC and back again.

popper
02-10-2015, 10:24 AM
Unless you really need the 'portable' powder, go with corded stuff. Do your soldering FAST when repairing batt packs, the solder temp is hard on them - commercial packs are spot welded. I've fixed a few, had some repaired commercially, not worth the price. If one cell goes to zero charge, recharging will short it out - you can 'slowly' trickle charge to safely recover - both Nicad & NiMh. SuperCap are the best but really expensive. Multiphase computer controlled motors are neat also, wish they were 3 volt.

timberhawk
02-10-2015, 03:58 PM
It did run and did cut soft pine wood. I don't normally cut soft pine. It really struggled thru walnut, oak, and mahogany! The in rush power is very high from a battery pack. Sustained cutting in very hard dry woods just did not "cut it" in my book. An underpowered saw is a dangerous saw. It is NOT used portable, and in fact is bolted down in my shop.

But it was so awkward and cumbersome to have that huge power supply to run a small saw! I just went out and bought a 120V corded quality compound miter saw (NOT HF!) and dumped the Makita. Not worth the hassle, wiring, adaptors for the battery compartment and remembering to turn the stupid PS on and off when I wanted to cut wood! You just cannot beat corded tools when talking saws and high current usages.

If one wants to build jury-rigged power supplies for cordless tools, more "power" to 'ya! Been there-done that. I will stick with corded tools for hard, heavy work. And use LiON drills only for portable use. I have thrown away a LOT (!) of 12 and 18 volt DeWalt tools in recent years.

It is sure nice to know when you grab a power tool (corded or LiON) it will run and run a long time!

banger

I agree with everything you said. Battery operated tools have their nitch, but not for every use. Sometimes you have to have the corded tools.

We do a lot of work in the back woods at deer leases and the back pasture. My DeWalt 18 volt impact screw driver, 1/2" hammer drill and cordless saw get a lot of use and are very handy and convenient.

When we need more power for larger stuff, I have a 1600 Watt inverter that will run the big corded drills and saws. Just more of a hassle to hook them up and you have to keep the truck running to not run the battery down with the inverter.

Each tool has it's strong points and weak points and each of use has to decide which tool is right for the job at hand.

I rebuild the battery packs because I'm a tinkerer and it gives me a lot of satisfaction to fix something instead of throwing it away or recycling it.

bangerjim
02-10-2015, 04:12 PM
https://www.youtube.com/watch?v=b8NkW1OB8hs

Okay so I think it can be viewed in action now. I filled a coffee can of saw dust with it so far to be used for casting. I was test stalling an 18 volt drill with a auger style drill bit and the drill seemed to stall at close to same pushing force with batteries or the DC pow. supp. I can cut some oak and see if there is much difference. Common sense would tell me that a more dense wood would have to be cut slower than a soft wood when using a battery too. (at least by how this Dewalt acts, it has seen use)

I didn't build it to over power the tool, I'm sure a person could hit it with a 24 volt battery charger/vehicle starter and it would cut like a beast till it melted. But I think it could be a nice back up to help finish a project or if you have an odd name cordless tool that is hard to get batteries for. It does make the tool more versatile being able to go from DC to AC and back again.


Yes it does cut, but my Bosch 18v LiON saw will cut thru oak 3x faster than that and not stall. And do it many dozens of times B4 needing a 1 hour recharge. That sluggish cutting is why I threw away all the Dewalt stuff I had and went with Bosch LiON everything for cordless we use in the shops. I have never had a Bosch LiON battery go dead on us while doing a job. And that was a LOT of board feet of cutting and hundreds of 3/8-1/2" holes!

Repairing old NiCAD or NIMH packs is, as said above, generally a waste of $$ and time in my book. I have done it many many time in earlier days. And I have the spot welding equipment to make up the packs. Soldering can ruin the cells if you are not careful. And some cell tabs will not "tin" at all (Cd plated?).....they are made for spot welding only.

At a local recycler, the largest quantiy of bad batteriy packs are yellow - DeWalt! And they also get in lots of old yellow drills too. Old drills (deWalt, Skill, Ryobi, Craftsman are the most common) populate the used tool and junk stores in piles. (mine went to the dump)

There are those on here that say they have re-built drill packs and are satisfied with the performance. I have also done that and have been totally disgusted in the performance and short life gained and the $$ involved. It is all in what you expect from a tool.

My opinion: Save your money and buy a new LiON system. You will never regret it!!!!!

pmer
02-10-2015, 09:58 PM
I didn't really want to turn this thread into bashing one brand over the other. I can understand comparisons of the DC power supply to a "corded" tool because of my blue wire going into the battery pack. But any comparison IMO ends there because the cordless saw is still running on direct current. The 15 amp AC motor in a "corded" saw out classes these little DC motors.

DC power supplies come in many shapes and sizes. You're using one when you plug your cell phone in to charge it. Some DC motors are so big they would be too heavy to be hauled in a pickup. Since power plants generate power in ALTERNATING CURRENT a DC power supply is needed to run it. (converting alternating current to direct current)

So to me it doesn't matter what color the saw is or how great its batteries are, there is a DC power supply that will spin its motor under unload.

I've used tools that were powered from air to corded and cordless. I'll grab a cordless tool 90% percent of the time because they are so convenient, even in a shop setting cordless tools are used to great effect.

I'm not hard selling you on a brand of tool or trashing another brand. Just saying there is another option for power. My guess is that this idea would be better suited to the occasional user that knows how spendy batteries are and might not have a fully charged one to finish a project and can't or don't want to wait to charge their battery. I've been there myself. I think I could help someone get this going if they chose.