DIY electric screwdriver repair

In detail: do-it-yourself electric screwdriver repair from a real master for the site my.housecope.com.

Many people probably have electric screwdrivers, battery-powered flashlights, etc. at home. in which the batteries do not pull.

My screwdriver has a fully charged battery for a couple of three screws.

Batteries in a screwdriver, cadmium in flashlights, as a rule, lead, all of them are now quite problematic to get for replacement. That will give us the conversion of devices to lithium.

1. Simplification of charging. Charging from micro usb, no need to look for where you put your own charger or where the wire from the flashlight.

2. The lithium battery is easier to find. For example, I generally took cans from an old battery from a laptop (you can find it either for free or for minimal money).

3. When replacing cadmium. There is no memory effect and you can charge at any time without waiting for a complete discharge.

4. Bigger than the standard battery capacity, often even when using a used unit. cans.

And so what we need.

1. Charge controller board, for example, on the TP4056 microcircuit. It is sold by the Chinese on Ali ebau and other sites. A clip will be sent for a dollar.

Available in two versions with and without overdischarge protection. It makes sense to use it with protection if there is no protection board in the battery itself. For 18650 batteries and the like, the protection board is usually installed on the negative terminal, if the negative is not made of metal, but of PCB glass, then this is the protection board.

The boards are similar in size. (left with protection from right without)

WARNING. For an electric screwdriver, battery protection cannot be used with a protection current of about 3A, and although the total consumption of a screwdriver is not large, inrush currents cut out the protection.

Video (click to play).

Here is a circuit board with battery protection (found on the Internet). Also in the appendix I will add documents for microcircuits.

The Chinese boards have a charge current of 1A if you want to charge from a computer port or from a weak charge, you must reduce the current to at least 0.5A. To do this, you need to replace the 1.2K resistor connected to the second leg of the TP4056 microcircuit with a larger resistor, for a current of 0.5A with approximately 2.4K resistance (the table of charging currents depending on the resistance is given in the document on the microcircuit).

I am planning on being able to charge from a computer and am replacing this resistor. Soldering and cleaning the pads.

Since it was only available with a nominal value of 2.2K, it received a charge current of 0.52A. What I considered acceptable for charging from a computer port.

2. The battery can be either bought a new one or removed, for example, from an old laptop battery.

My battery contained 6 cans connected in pairs. It is advisable to disconnect all the batteries (one of the cans was completely dead in one of the pairs) and measure the residual voltage. If there is a choice, then take banks with a large residual voltage, as a rule, and they also have more remaining capacity, although of course it is better to measure the real capacity. The battery was at 4000 mA i.e. at 2000 mA per jar, the residual capacity was noticeably 1200-1400 mA, depending on the jar.

Metal strips of contacts are welded to the batteries; they do not need to be torn off, but simply cut between the banks. It is convenient and safe to solder wires to them. The metal on the contacts of the batteries themselves is harder to solder and if you hold the soldering iron for more than a second, then there is a danger of overheating the battery, which will disable it until it burns out.

3. Wiring soldering iron tester, files, glue gun, etc.

We remove the batteries and standard charging for them.(if there is a backlight and for the flashlight it is desirable to measure the current of the LEDs on a fully charged battery)

Thinking about where to place the new battery and charging board.

Now, one of the longest stages is the finalization of the case.

To speed it up, it is better to use mechanization.

For example, Chinese cutters.

But I like the old Soviet ones better, they have better control and are less distracted. But unfortunately on sale they are more difficult to find.

We choose the extra plastic, making sure that the mini USB connector is minimally recessed.

We solder the circuit by connecting the battery and charging. And we check the operation of the charging and screwdriver, also if there are lighting LEDs, we measure the current consumption from lithium and the resistance of the damping resistor.

If the current of the lighting LEDs is very different from the current on the standard batteries, then we adjust the resistance of the balancing resistor. I soldered another resistor in parallel.

Next, degrease the body and all the parts with isopropyl alcohol or good gasoline in the shoe (ethyl alcohol does not degrease). And we fill in all the components from the hot glue gun. Excess, if that is not difficult to cut off with a knife.

After assembly, pour glue from a pistol into the holes that are intended to indicate charging.

When the glue has cooled down a little, it is easy to clean off the excess. As a result, the glue acts as a light guide and the battery is clearly visible when charging.

Alteration of another screwdriver. Now the battery can be charged without removing it from the screwdriver.

The battery is removable. (After the alteration, a micro USB connector and a charge indicator appeared on it)

A set of cadmium batteries and contacts were attached directly to the batteries.

With the help of hot melt glue I made a clip of contacts.

I placed the charger in the back and soldered all the components.

Redesigning the flashlight with a lead battery and charging from the mains took even less time since nothing had to be undermined.

Looking through the boxes with various junk the other day, I came across an Einhell bavaria bas 3,6 electric screwdriver.

As pictured, only model 3.6.

The battery on it ordered to live for a long time, so it was thrown down and was not used. Not to say that it is a convenient and necessary thing, but hands itched to restore it.

As batteries, there are three 1.2V batteries, with a capacity of only 800 mAh. We throw them out right away, already mentally trying on an 18650 can in their place, and preferably two.

At first I thought to install them directly into the handle, but the inner diameter did not allow it to be done.

Well, let's do with one, since a recent measurement of the capacity gave the result of 1850 mAh.

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Then the question arose of fixing the battery, I wanted to leave it removable and quick-change, a holder ordered from China came to the rescue, although it was for 3 elements, but this is not a problem.

We mark, cut, try on.

Not bad already, continue fitting. We solder the wires, simultaneously filling everything with glue.

The battery is installed, it's time to think about charging it. For this purpose, we will use the module on the TP4056, I did not take a photo, but there is nothing special there - we try it on in place, solder the wires and fill it with the same glue from the pistol.

The connector did not come out very beautiful, but this does not in any way affect the functionality and strength, and thanks to the glue, the charge indication is now clearly visible - the glue around the connector is highlighted.

This is what the electric screwdriver looks like now.

Bottom line: operability is restored, the battery has become quickly replaceable, any power supply unit with a wire is suitable for charging.

Well, as a bonus, the removable part can be used as a charger for 18650 batteries.

I did it slowly in a couple of hours, took pictures on Xiaomi Redmi Note 3

the key point in all such posts is to find an electric screwdriver, a screwdriver, an American shuttle in your trash.

Lived up to the time when imported junk falls under the joke "finalize with a file"

funny, I'm at work on the contrary, threw out the lithium and put 3 nickels. I have been using it for the second year

Tell me where did you get good banks?

Gutted laptop batteries

All 6 cans do not die in them at once =)

These batteries can be easily bought for a penny at any electronics repair service.

I took so quite usable 18650 at 30r / pc))

Yes, it so happened that we gave away a couple of laptops with live batteries

Well, here's the xs. Screwdriver - normal. And this?

Yes, I am so skeptical about this thing. I have a Zubr screw. You know, it works fine. I don’t know any problems with him. Apart from the moment when Akum sits down. A boy friend has a Makita screw. Small, lithium in a pen. Replaceable blocks, but not visible. In the sense that the block does not stick out from below, as the magazine enters the pistol. He collects cabinets. Also, he says, he does not know grief. But, as in a laminated (pressed chipboard with a coating) to drive screws into a container, this is one thing, but like into a coating. Sometimes it is necessary to tighten it with a screwdriver. Straight, make a lot of effort. How this screwdriver will go there, screw it in - I do not know. And install the doors? Screw the box to the wall. There material and aerated concrete, and brick, and stupid concrete in monolithic. What is there to twist to her? Sometimes work with a mixer, sometimes drill. Probably, these screwdrivers for other tasks. Disassemble the technique.

There is a discharge indicator on the charge controller, otherwise by eye)

Yes, I was probably wrong about the discharge indicator. But this is not critical to me.

In terms of functionality and dimensions, the cordless screwdriver is in the middle between a conventional screwdriver and a screwdriver. Due to its lightness and compactness, this electric screwdriver works quickly with different fasteners compared to a manual screwdriver. It is used for the assembly of furniture, repair and maintenance of various equipment. Plus, the tool can be made by hand.

The cordless screwdriver is used for screwing and unscrewing various fasteners into non-solid materials, for example, made of wood. The screwdriver battery is built into the handle, so the tool is small. The device can be used where there is no need to drill and tighten the fasteners too much, to work in narrow places and openings in which a screwdriver cannot fit.

The rechargeable screwdriver is used in the assembly of furniture, installation of windows, repair of household and computer equipment, maintenance of cars, when performing small household work.

The tool is characterized by parameters that you need to know about: