Alteration of the power supply unit for lithium. Assembly of the charger

Alteration of an electric screwdriver for lithium, part two, charging correctly

Last time I told how to properly redo the battery for a battery tool. I also wrote that I would tell about the features of the charge, and this time the viewer’s payment of the transducer will make the subject of the review.Who cares, I ask you to visit.

Initially, I planned to limit myself to two parts, the alteration of the battery and charger. But while preparing a review, the idea was ripening in my head for the third part of the review, more complex.And in this part I will tell you how to remake a native transformer charger, if it still works, well, or if a power transformer is still alive.

The converter scarf was ordered for quite some time in the amount of several pieces (in reserve), it was ordered specifically for this alteration, because it has some features, however, I will not run far, we will be consistent.

To begin with, I will share chargers of not three main types: 1. The simplest ones are a transformer, a diode bridge and several details. Such chargers are equipped with an ultra.bunch tool.2. Branded. In fact, the same thing, but the composition already includes simple “brains”, automatic disconnecting the charge at the end.3. “Advanced”. pulse power supply, charge controller, sometimes a charge of several batteries at the same time.

The tool from the first category rarely falls under the alteration, since it is often easier (and cheaper) to buy a new one, and the third category usually has its own difficulties in alteration. In principle, you can redo the devices of the third group, but not within the framework of the article, since there are a lot of types of such chargers and each one needs an individual approach.

This time I will redo the charger from the second group, branded, although simple. But with this alteration, it has a lot in common with the first group, therefore it will be useful for more readers.

In order to charge the battery, you need not only to connect it to the power supply, such an experiment usually does not end very well. You need to connect it to a charger. And here there is a slight misunderstanding, since quite a few people are used to calling chargers of small power supplies from which they charge their smartphones, tablets and laptops. These are not charging devices, but power supply units.

What is the difference between the charger and power supply.The power supply is intended to issue a stabilized voltage in the range of stated load currents.The charger is usually more difficult, since the output voltage depends on the load current, which in turn is limited. At the same time, in the charging device there is a terminal charge at the end, as well as sometimes protection against connecting the battery in irregular polarity.

The simplest charger is just a power supply and a resistor (sometimes an incandescent lamp, which is even better) sequentially with a battery. This scheme limits the charge current, but as you understand, it cannot do anything else.

A little more complicated when they also put a timer that turns off the charge after a certain time, but this principle quickly “kills” batteries.For example, this is done in one of the inexpensive chargers for screwdrivers (photo is not mine).

The next class is more “smart” chargers, although in fact they are not much better than the previous one.For example, here are a photo of the Bosch company charger designed to charge nicd batteries.

Alteration of an electric screwdriver for lithium, part two, charging correctly

But all these chargers seem very simple after looking at modern options for the charge of lithium batteries.

Alteration of an electric screwdriver for lithium, part two, charging correctly

Alteration of an electric screwdriver for lithium, part two, charging correctly

Of course, the last option does not quite fit into our remodeling concept, since it is desirable that our charger not only charges correctly, but also cost minimal money.

The chargers of Chinese screwdrivers are certainly not more likely to look like an example, but again, it is unlikely that anyone wants to do such a device from scratch, although this is what I plan to do in a third part, though more correctly.

Alteration of an electric screwdriver for lithium, part two, charging correctly

And so, for a start, suppose that we have a charger in our hands that simply does not fit a new type of batteries, but is good. Well, or at least he has a transformer.As I wrote above, you can even use just a resistor or light bulb, but this is “not our method”.

The conditional diagram of a typical inexpensive charger looks something like this: a transformer, a diode bridge, a thyristor and a control scheme. True, sometimes instead of a thyristor stands a relay, the current is not limited and there may be a thermal control scheme from overheating (although it does not always save.

But we need only a transformer and a diode bridge from this scheme, though we will have to add a capacitor, so we will get a certain initial unchanged part, it is marked in red and will not change further.

What difficulties can be encountered during modernization?

Before proceeding to work, it is necessary to determine the feasibility of refinement. A poor.quality or already long.operated tool is more reasonable not to redo. it is unprofitable.

The price of the necessary materials and the efforts spent will be 2/3 of the cost of the equipment itself.It is more rational to buy a new electric screwdriver or drill. It is worth considering other points:

• Lithium batteries of the 18650 standard (only they are suitable as a replacement) have a length of 6.5 cm and diameter 1.8 cm. Sitting nest for Ni-CD is not suitable for Li-Ion. Place batteries in the battery housing. In this case, you will need to independently perform the installation of wires and a protective chip.
• At the output of Li-Ion voltage is 3.6th century. This parameter of Ni-CD is 1.2 century. New batteries can simply be incompatible with equipment.
• Lithium-ion batteries will not withstand the reloading voltage of more than 4.2 V and discharge up to 2.7th century. Work in this mode will very quickly disable battery elements, so installing the protective board is required.
• A native charger (attached to equipment for work from Ni-CD) in 8 out of 10 cases cannot be used for Li-ion. You need to buy a new one. If there is no purchase plans, then you still need to redo the charger of an electric screwdriver for work from lithium batteries, which can also have its difficulties.

Alteration of the instrument of all inconvenience cannot be excluded.

The new lithium battery shows poor performance when used at low temperatures. We must weigh all the pros and cons, starting work.

Pros and cons of modernization of electrical screwdriver

One minus is already indicated-a rapid decrease in the capacity of elements at ambient temperatures below 7-100C. There is one more-the price of batteries, but unlike NI-CD elements lithium-ion batteries are much more durable. Nickel-cadmium battery chemically unpredictable. Upon failure of one battery, the remaining will not give the desired voltage for the operation of the equipment.

• The capacity of lithium-ion batteries is 2 times greater than that of nickel-cadmium parameters;
• No “memory effect” of the charge. Charging can be carried out with any category of element, at any time.
• Standard 18650 will facilitate the weight of the structure. It will be easier and easier to work.

Do not forget about the need to install a protective fee (overheating, the Li-ion element explodes, can provoke a fire) during the work.

Methods for connecting battery elements

A block that accumulates energy can be collected in different ways. There are three types of assembly:

It is necessary to solder as soon as possible, so you need a powerful soldering iron by about 100 watts. Lithium batteries are afraid of overheating, so they cannot be heated for a long time, high temperature leads to damage. In the absence of experience, it is worth resorting to the services of a professional.

The technique of connecting elements into the unit using spot welding is considered the best. A master who has a special welding machine has better handle work.

Special cassettes are considered not very reliable. The received contacts have a significant transition resistance, which at a high current will begin to quickly collapse.

The elements are connected sequentially, then the voltage is summarized, and the size of the container does not change. Consistently connected batteries not everyone fails at the same time, because in some cases, one working jar can be restored from two batteries of electric screwdriver by choosing serviceable. But it must be borne in mind that it will not last long. Therefore, experts advise to resort to such repair in rare cases.

Charger for an electric screwdriver converted under lithium

Another crazy handles 🙂 Caution, traffic! Many pictures! And many letters 🙂 If anyone remembers, I have long reduced the battery of my electric screwdriver for lithium. But with normal charging, everything pulled for him. Yes, and now it is necessary to charge it more than once every few days, and once a month 🙂 When it was not lazy, he set to charge from a laboratory BP with a restriction of voltage and current, when it was lazy, he stuck into an old native charger, which is completely for lithium at all not calculated and gave out something about 18 volts and under three amperes. Hope placed on the protection board inside the battery. But still the thought of normal charging did not leave me. And even a power supply with a voltage and current regulator for a long time:. PSA. www.Aliexpress.COM/Item/Power-SupPly-Module-110V-220V-TO-DC-24V-6A-DC-SWITCHING-SUPPLY-BOARD/32827334983.HTML. regulator. www.Aliexpress.COM/item/DC-DC-DOWN-DOWN-CONSTANTANT-VOLTAGE-CURrent-SUPPLY-MOULE-Drop-Shipping/3278753675.HTML chose with a margin of power and with the calculation to give a 20-24 volts to the regulator and limit up to 16 on it.7 volt and up to 1 ampere. Looking ahead. with a PSU, a small bummer was waiting for me, but more on this will be further in the review.

In addition, he counted all the fasteners for bolts (stainless steel) and screws, which also had long been stuck on Ali. I took several diameters at once. from M1 to M3 🙂 bolts. www.Aliexpress.COM/item/500PCS-LOT-DIN7985-Stainless-STEEL-304-M2-PhILLIPS-PAN-ROD-HEAD-SCREW-KIT-M2X4-5/32765362652.HTML and the same seller have many other sizes of screws. www.Aliexpress.COM/Item/400pcs-M2-Cross-Pan-GEAD-SELF-TApping-Screws-Black-Oxide-Kit-M2-4-5-6/32580525848.html and the same seller also has other sizes. Have come in handy more than once 🙂

This is what the native charging of an electric screwdriver and the battery looked:

The battery was inserted into it upside down:

Inside the nest there are three contacts. two power supply and one for the heat.guide inside the battery: (here the contacts are already pulled out)

In charging a transformer and a fee with a simple analogue electronics:

The power supply with the regulator was not imposed in the native charging building, so the case had to be done new. At first there was a thought to make a “cap” separately with contacts, dressing on the battery, and separately the charging itself. But then I thought that this did not give any win, only extra wires would be confused underfoot. And I decided to repeat the design of my native charge. BP with a regulator inside, and immediately in the housing of the Battery Nest.

Recently, everything I am going to do, I have been modeling first. Especially such things that should be combined with ready.made ones. for example with the battery of an electric screwdriver. And so that in modeling the case there was something to start from, I started with the model of the “leg” of the battery. Its shape is simple, only a caliper was enough to remove all sizes, the very first printed model perfectly combined with the original: well, or it seemed to me so 🙂 After that, I started modeling the nest, based on the already made model model. I printed the nest. the foot printed earlier enters perfectly:

But the leg of the real battery somehow does not really feel in the printed nest: I recheck all sizes-everything is true, but the contacts do not get a little, it dangles a bit and generally sits in generally crookedly. In the end, I looked around that the leg, it turns out, is narrowing up not by all the faces. Flat front line goes evenly, without narrowing. I reprinted the leg and the nest, and everything fell into place, then it fell into place 🙂 Then, a little more slightly changed and printed the nest, picking up the exact size. over, several times it was inattentive. in the model I changed one size. external, and after the press I looked at another. the internal. And he was surprised that somehow nothing was changing 🙂

After the trial two legs and four nests, I was completely pleased with the result. Added the upper surface, stiffener ribs and mounts with contacts to the nest: and moved to the next stage. modeling of the case itself. Immediately decided that the case would be from the upper and lower halves, only it was necessary to decide how to place BP and regulator inside. To do this, I spent half a day and made their models. And began to virtually apply them to each other and to the nest in different versions. In the end, he stopped on such a layout:

Well, when the layout is understandable, then the size of the case becomes more or less understandable, so you can proceed to its final drawing. Started with the top cover. Nothing complicated. expand the upper plane to the size of the case, raise the walls, add racks for fastening the stabilizer. To small vertical elements-racks, for example, for 3D printing it is better to add ribs to enhance. And to the base of all vertical elements. especially thin, for example, walls. it is useful to add chamfers so that the area of ​​the base increases, this will give additional strength. I did not forget about cooling. on the upper side made two rows of narrow slots, just above the radiators of the regulator. He twisted the corners of the case, and near the nest twisted more difficult. purely for design 🙂 added holes for two indicator LEDs. And made the edge around the perimeter. In the lower half there will be a retaliatory edge so that half will slightly enter each other. It turned out like this: I try on the regulator and a board with contacts: the other side, with inserted LEDs:

By the way, I also made a contact model separately 🙂 Later I also added a small neckline to the network cord and mounting for tightening two halves of the housings:

With the lower half of the case, everything was even easier. to copy the outline of the upper half, stretch the walls, add racks for BP, fastening the halves, ventilation holes and the retaliatory edge: try on the BP: and you can see how everything feels in height: all yourself is wonderful Feels 🙂

The choice of controller

With all its advantages, lithium-ion elements are sensitive to:

It is difficult to control these parameters for several hours that will be required to replenish the battery energy. Therefore, these functions are assigned to the PCB system (Power Control Board) or SOF (functioning system). It is a small board, which is often built into the battery housing (because of this, the length of the element of the size of 18650 is slightly higher than the promised 65 mm). This system stops the charge when the desired voltage reaches and turns off the battery when discharged to the set level. Such elements have a Protected marking on the case. If the marking is absent or the unprotected is directly indicated, then the battery is not equipped with such a system and you will have to control the charge parameters manually or put this function to the external device.

No need to confuse PCB (SOF) with the BMS system. Battle Management System or PCM. Power Charge Module. This system is intended for elementary control of the battery charge included in the battery according to the consistent scheme. The elements from which the battery is compiled have a certain spread of the parameters, so a situation is possible when part of the elements is already charged, and the other part still needs to be charged. Obviously, this mode is unfavorable for batteries. This problem is designed to solve BMS (“Balancir”). And in the case under consideration, this system cannot be dispensed with.

Typical BMS switch scheme is shown in the figure. Upon reaching nominal parameters, the element is shunted by the internal key, the remaining batteries continue to charge.

For different manufacturers, the marking may vary somewhat (instead of “B-” there is a designation “0V”, instead of the serial number of the battery-the total voltage at the connection point). You can purchase a finished device on the Internet on well.known trading floors. You need to choose the following parameters:

And, of course, it is necessary to measure the dimensions of the board with the available installation place.

Security measures when working with batteries

When assembling the battery, it should be remembered that the currents during the operation of an electric screwdriver can reach 11-12 amperes, so the area of ​​the contact of the connecting tires between the elements should be maximum. Therefore, the option of connecting with spot welding, often offered on the Internet, is not the best. It is better to solder the shinka over the entire area of ​​the battery contact. At the same time, it must be understood that the elements are very sensitive to overheating, so you need to solder quickly and confidently, using acid fluxes. the batteries are not made of copper or brass. It is advisable to use heat volumes, in the role of which pliers can act and t.P.

It is necessary to ensure that splashes of acid during soldering do not fall on other surfaces, because this will subsequently lead to corrosion in these places. The rations must be thoroughly washed.

How are the “native” battery in electrical screwdrivers

The batteries of screws have a fairly simple device. There are several batteries in the screwdriver itself, which are interconnected. They are created for short.lived work, as they consist of simple elements.

The reasons for the failure of the old batteries

There are a lot of reasons for the failure of old batteries. In order to avoid them, it will be necessary to carry out safety precautions and rules for working with electronic devices and batteries. You also need to comply with storage conditions.

Popular reasons for the failure of old power sources.

Pros and cons of installation of lithium batteries

Lithium-ion models of batteries have a number of their features. It is certainly worth trying to make such a variety yourself, since they are better than native batteries. advantages than disadvantages.

The positive aspects of lithium-ion models:

• increased electricity density by 1 mass;
• Self.discharge is practically absent. This means that with prolonged storage, the device will not lose its former capacity and it will be enough to conduct a training cycle for such a variety;
• There is no memory effect. This means that the battery does not have an unpleasant ability to “remember” the last charging cycle. The battery can be charged at any convenient moment, regardless of the remaining amount of charging;
• Creating your own lithium.based battery is not an expensive event. It will require some elements that are inexpensive and in addition to the manufacture of batteries will be useful in other household issues;
• Power sources can work out a long service life if proper care for them;
• ion batteries can work from one charge longer than other models.
• lithium-ion models are “afraid” of deep discharge. The pluses of devices indicate the ability to infect them at any time and with any charging. There is one exception, it is impossible to allow the full discharge of the battery, this leads to the loss of energy capacity and failure;
• It will be possible to create a power source on their own only in more or less knowledgeable people;
• The danger carries overheating. Because of it, the device will fail along with the battery.

The disadvantages are quite blurry and can relate to many modern batteries. Therefore, the conclusion must be done independently.

What tools will be needed to redo the screwdriver for a 12 volt lithium battery

To remake batteries for lithium-ion batteries, you will need such tools as:

• a soldering device with a capacity of more than 40 watts with some consumables, including an acid flux;
• Repair tools such as screwdrivers, pliers, scalpel, hammer, nippers, knife.
• In some cases, an insulation tape may be required;
• It is also mandatory when using a welding machine to use a specialized protective mask.

Alteration of an electric screwdriver on Li-Ion without BMS

Many masters have a battery electric screwdriver in the service. Over time, the battery degrades and holds less and less a charge. Battery wear is very much affected by autonomous work. Constant recharge does not help. In this situation, the “re.launch” of the battery helps with the same elements. The most commonly used elements in the batteries of electric screwdriver, this is the type of “SC”. But the most valuable of the master is with your own hands.We will redo the electric screwdriver with a battery for 14.4 Volta. In screwdrivers, the motor is often used for a wide range of supply voltage. So in this case you can use only three Li-ion cells of format 18650. I will not use control. The category of elements will be seen in the work. As soon as the self.tapping screw is not twisted, for example, it’s time to put it on charging.

Alteration of an electric screwdriver on Li-Ion without a BMS board

First we analyze our battery. There are 12 elements inside it. 10 pieces in one row and 2 in the second row. The second row of elements is welded to the contact group welded. Leave a couple of elements with a contact group, we dispose of the rest.

Now you need to solder the wires for further work. Contacts turned out to be from the material that cannot be filled, so we solder the wires to the elements. Minus to the body of the element, and plus directly to the plus patch. Old elements play the role of support in the work do not participate.

I will use lithium-ion batteries of format 18650. Elements BU. High-current elements are needed for refinement. I “changed” my elements in a thermal shrink from Sanyo, the old one was pretty battered. Checked the residual capacity of IMAX.We connect the batteries sequentially and solder the elements of the head. The battery is almost ready.

Now we will provide comfortable exercises. You need to install a connector for four contacts. I applied the connector from the old motherboard to the number of contacts I need. I took the return part from the old computer power supply.

Cut the hole under the connector. Pour the connector with epoxy glue or super glue with soda. We also solder the wires.

Sold the wires to the elements. The wire from the first contact of the connector to plus battery. The wire from the second contact of the connector to the plus of the second element, it is also the minus of the first element and so on. Since I will charge a “smart” charger, you need to make a balancing wire.

As a connector for connecting to a charger, I will use the wire from a computer power supply. The wire through which the floppy discod. Cut all the keys from the connector and it is perfect for the charger. Squeezes simply. Red wire to the first contact of the battery connector. Black wire to the second contact of the battery connector and t. D.

We connect to the charger and do not forget about power wires. We have a balancing post. Install balancing on the charger and wait for a full charge.

Alteration of an electric screwdriver for lithium, part two, charging correctly

Last time I told how to properly redo the battery for a battery tool. I also wrote that I would tell about the features of the charge, and this time the viewer’s payment of the transducer will make the subject of the review. Who cares, I ask you to visit.

Initially, I planned to limit myself to two parts, the alteration of the battery and charger. But while preparing a review, the idea was ripening in my head for the third part of the review, more complex. And in this part I will tell you how to remake a native transformer charger, if it still works, well, or if a power transformer is still alive.

The converter scarf was ordered for quite some time in the amount of several pieces (in reserve), it was ordered specifically for this alteration, because it has some features, however, I will not run far, beem is consistent.

To begin with, I will share chargers of not three main types: 1. The simplest ones are a transformer, a diode bridge and several details. Such chargers are equipped with an ultra.bunch tool. 2. Branded. In fact, the same thing, but the composition already includes simple “brains”, automatic disconnecting the charge at the end. 3. “Advanced”. pulse power supply, charge controller, sometimes a charge of undeski batteries at the same time.

The tool from the first category rarely falls under the alteration, since it is often easier (and cheaper) to buy a new one, and the third category usually has its own difficulties in alteration. In principle, you can redo the devices of the third group, but not within the framework of the article, since there are a lot of types of such chargers and each one needs an individual approach.

This time I will redo the charger from the second group, branded, although simple. But with this alteration, it has a lot in common with the first group, therefore it will be useful for more readers.

In order to charge the battery, you need not only to connect it to the power supply, such an experiment usually does not end very well. You need to connect it to a charger. And here there is a slight misunderstanding, since quite a few people are used to calling chargers of small power supplies from which they charge their smartphones, tablets and laptops. These are not charging devices, but power supply units.

What is the difference between the charger and power supply. The power supply is intended to issue a stabilized voltage in the range of stated load currents. The charger is usually more difficult, since the output voltage depends on the load current, which in turn is limited. At the same time, in the charging device there is a terminal charge at the end, as well as sometimes protection against connecting the battery in irregular polarity.

The simplest charger is just a power supply and a resistor (sometimes an incandescent lamp, which is even better) sequentially with a battery. This scheme limits the charge current, but as you understand, it cannot do anything else.

A little more complicated when they also put a timer that turns off the charge after a certain time, but this principle quickly “kills” batteries. For example, this is done in one of the inexpensive chargers for screwdrivers (photo is not mine).

The next class is more “smart” chargers, although in fact they are not much better than the previous one. For example, here are a photo of the Bosch company charger designed to charge nicd batteries.

But all these chargers seem very simple after looking at modern options for the charge of lithium batteries.

Of course, the last option does not quite fit into our remodeling concept, since it is desirable that our charger not only charges correctly, but also cost minimal money.

The chargers of Chinese screwdrivers are certainly not more likely to look like an example, but again, it is unlikely that anyone wants to do such a device from scratch, although this is what I plan to do in a third part, though more correctly.

And so, for a start, suppose that we have a charger in our hands that simply does not fit a new type of batteries, but is good. Well, or at least he has a transformer. As I wrote above, you can even use just a resistor or light bulb, but this is “not our method”.

The conditional diagram of a typical inexpensive charger looks something like this: a transformer, a diode bridge, a thyristor and a control scheme. True, sometimes instead of a thyristor stands a relay, the current is not limited and there may be a thermal control scheme from overheating (although it does not always save.

But we need only a transformer and a diode bridge from this scheme, though we will have to add a capacitor, so we will get a certain initial unchanged part, it is marked in red and will not change further.

The diode bridge is usually on the board and, if necessary, it can be used (if it is working). T.e. By and large, you can fall out of the board all radio elements, leaving only four diodes and terminals for connecting the battery, and use the board itself as a basis. The cathode of the diodes is marked with a strip, the point where two outputs are connected by the strip are connected. plus, respectively, the connection point of “not thundered” conclusions. minus. The transformer is connected to two other points of the connection.

True, opening the charger you can see such a picture (do not pay attention to the absence of a transformer): in this case you will have to fall out everything.

And how many batteries buy?

Charged 18650 battery gives out 4.2 volts. Divide the voltage from which the electric screwdriver works by 4.2 and round the larger direction (for a 12-volt electrical screwdriver. 3 batteries).

After that, carefully open the battery compartment. It will contain a battery collected from nickel-cadmium batteries.

The upper batteries are attached to the contact group of the battery compartment of the electric screwdriver by the method of point welding. You can disconnect the batteries from the terminals with a knife, if this does not come out. have a bite of the contact platform coming from the terminal to the battery above the welding location. Put out the extracted battery in the point intended for this.

Assembly.

The project implies a quick removal of batteries (so that at the end of work, it was possible to easily put them on a stationary charger, for example, Nitecore i4 (on the website https: // sdelaysam-svoimirukami.ru also has articles on how to assemble a budget charger for these batteries)), so holders 2 x 18650 were used.

To achieve the desired voltage. it is necessary to connect the batteries sequentially (with this connection, the plus of the battery is connected with the minus of the subsequent). Since I used 2 holders, they must be interconnected for current exchange

The initial wires of the Holders were too thin, because of which they could have losses for heating, in order to avoid this, they were soldered to wires of larger diameter, taking into account the new location of the batteries.

For an approximate indication of the battery charge level, a 12V LED was used, connected sequentially with a current.limiting resistor for 1 kOhm.

The power of the LED must be removed parallel to the power supply of electric screwdriver. To do this, to the thick wires of the plus and minus of the battery block, wires of a smaller section are soldered.

The wires of a larger section must be soldered to the terminals of the battery block of an electric screwdriver, in my case they are put to a separate plate, and after that, we return the plate to a regular position, if desired, fixing with glue.

To observe the LED in the body of the battery compartment, you need to make a hole (a warmed nail is good for this).

Since the LED performs the indicator, and not the lighting device, you can fix it in the hole, applying thermocles to it (due to this, the glow will become softer). Photo of an electric screwdriver after processing.

Please note that for the correct operation of the batteries in the sequential connection, they must be “married”, in other words, they must be taken from one batch, one container and model. Subject to this rule, they will be discharged at the same time. To check the battery charge and prevent them from changing them. use the LED (the smaller the charge, the more dull light it radiates. Without proper training, this is not so simple, so be sure to check the voltage on the batteries with a voltmeter).