Modification of a Dollar Store Cordless Screwdriver.

creator: x14km2d | build: 2021-12-09 | update: 2021-12-26


Right now I’m building a rolling table for my 3D printer. This is not difficult, even if I am not a trained carpenter. I had already implemented other projects with wood and if you research a little on the Internet on what you need to pay attention, not much can happen. Tables usually need four legs not three, not even five and so on. This is not so difficult if you make an effort.


After cutting the wood to the appropriate length, I was able to pre-drill the first battens and then tighten them with the screws. After screwing in two screws by hand, it became too much of a hassle. Didn’t we have a dollar store cordless screwdriver somewhere? Yes, unfortunately it is so rarely used that the batteries have not worked properly for years, so the tool was mostly just lying around in a box collecting dust. A problem. How wonderful. I just need to install a new and more importantly a stronger battery in the cordless screwdriver and then I have solved the problem.


Material I have almost everything. I need the cordless screwdriver and a new battery that can also be recharged. Preferably with USB ports, because the previous connection is a power plug, which I no longer have. USB cables I have dozens lying around.


In order to start our conversion on our cordless screwdriver, we first have to open the casing. This is pretty simple and we only need a Phillips screwdriver for this. It then took a few seconds until I found the hidden screw under the sticker.

After we have opened something, it is always good to take a few minutes and look at everything very closely. At the bottom we can see the old batteries with the yellow tape. On the right is the black push button. In the middle we see the motor. On the left is small in black the old power plug connection for charging the cordless screwdriver. Above are three small LEDs in green, yellow and red that indicate the charging status of the cordless screwdriver.

I was able to cut off the old battery quite easily with a small side cutter. We do this on the red and black cable.

Before we solder anything, we do a dry run. What does that mean? We take crocodile clips and connect the new battery with the old circuit. With this we test if something does not burn out. Of course, you can also calculate everything theoretically, but that’s not my style.

As we can see from the photo, we see two ports here. One for USB and then another for micro USB. Overall, I find USB ports better than power plugs, because it allows me to connect them almost everywhere. Also, the battery then has more voltage (5.0v).

Since the battery screw is a model from the Dollar store, we can easily move the opening for the USB port. To do this, we mark the spot we want to cut with a waterproof pen. Then we take a small side cutter and cut a small piece on the right and left side of the plastic. Then we break out a piece with a small pair of pliers. We do this until we get to the bottom edge. Then we cut the edges clean with a modeling knife.


In between we test again and again whether everything fits so that we do not cut too much plastic from the housing.

So that we have longer cables, we solder two pieces to the existing cables. With this we can work better and do not get any problems. If, for example, a piece of housing is in the way, we can simply put the extended cable around.

To prevent the battery board from accidentally getting to another soldering point, we wrap it with Kapton tape. this prevents unwanted short circuits and cable fires.

Now we solder the red and the black cable to the battery to which the other cables have already been soldered. Please be careful not to hold the soldering iron to the battery for too long, because the battery can explode due to excessive heating.

After we soldered everything, we pack everything back into the case. The length of the new battery fits super well in the old cordless screwdriver.

Even after I screwed the last screw into the case, everything still fit. The USB port even fit so well that I didn’t have to use hot glue. So I can easily disassemble and repair everything in an emergency.

Even after I had connected the cordless screwdriver to the power for 24 hours, nothing burned out. Now I can finally turn the next screws in my trolley and no longer have to do it by hand. The next few weeks will show whether the battery can withstand greater loads or I have to buy a better cordless screwdriver online.

Function Test

I built a stand for my 3D printer and tried how well the KRAFTAKKU 3000 works. Not much stronger than before, but the battery is now intact and can be charged via USB. It’s always not enough to do really heavy work, but that’s ok, because I found out that you can use a normal drill with cordless bits. So I don’t have to buy a new cordless screwdriver, but maybe I’ll build one myself. But this is only a rough idea so far.

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