Hitachi electric screwdriver convert to lithium ion

Table of Contents

Uc18yg conversion to lithium

Cordless tools are more mobile and easier to use than their corded counterparts. But do not forget about the significant disadvantage of cordless tools, it’s as you know short-lived batteries. Buying new accumulators separately is comparable in price with buying a new tool.

After four years of service, my first electric screwdriver, or rather the batteries began to lose capacity. I rebuilt my electric screwdriver from two batteries and got one working bank, but even that was not long enough. I converted my electric screwdriver to a corded screwdriver was very inconvenient. Had to buy the same, but a new 12 volt Interskol DA-12ER. The batteries in my new electric screwdriver lasted even less. As a result, two electric screwdriver in good condition and not a single battery.

Переделка батареи Hitachi EB1414s 14 4v Ni-Cd на Li-ion

On the Internet there are a lot of posts on how to solve this problem. It is proposed to convert obsolete Ni-Cd batteries into Li-ion battery type 18650. At first glance there is nothing complicated about it. You remove the old Ni-Cd batteries from the case and install the new Li-ion ones. But it was not so easy. Below is a description of what to look for when upgrading a cordless tool.

I will start with the lithium-ion 18650 batteries. Purchased on AliExpress.

Rated cell voltage 18650 3.7 volts. According to the seller, the capacity is 2600mAh, marking ICR18650 26F, size 18x65mm.

Advantages of Li-ion batteries over Ni-Cd batteries are smaller and lighter, with greater capacity, as well as the absence of the so-called memory effect. But lithium ion batteries have serious drawbacks, namely:

Negative temperatures drastically reduce capacity, which is not the case with nickel cadmium batteries. Hence the conclusion. if the tool is often used at sub-zero temperatures, changing to Li-ion will not solve the problem.

Discharge below 2,9 2,5V and overcharge above 4,2V can be critical, complete failure is possible. Consequently, you need BMS card to control the charge and discharge, if not installed, the new batteries will fail quickly.

The Internet mostly describes how to convert a 14 volt electric screwdriver. it is ideal for modernization. With four 18650 cells in series and a rated voltage of 3.7V. we get 14,8V Exactly what you need, even if fully charged plus another 2V is not terrible for the motor. And what to do with 12V tool. You have two choices, install 3 or 4 cells 18650, if three is not enough, especially with partial discharge, and if four is a lot. I chose four and in my opinion I made the right choice.

This is the so-called charge control board, discharge the battery, specifically in my case CF-4S30A-A. As can be seen from the marking, it is designed for a battery of four 18650 cans and a discharge current of up to 30A. It also has a built-in balancer, which controls the charge of each cell separately and eliminates uneven charging. For the correct operation of the board take the batteries for the assembly of the same capacity and preferably from the same batch.

In general, on sale there are a lot of BMS boards with different characteristics. I don’t recommend to take a current lower than 30A. the board will constantly go into protection, and to restore the operation of some boards need a brief supply of charging current, and for this you need to remove the battery and connect to the charger. The board we are looking at has no such flaw, you just release the trigger of the electric screwdriver and if there is no short circuit current, the board will turn itself on.

To charge the rebuilt battery, the original universal battery charger was a good fit. Interskol began outfitting its tools with universal chargers in recent years.

In the photo you can see how much voltage the BMS board charges my battery together with the standard battery charger. The battery voltage after charging is 14.95V a little higher than you need for a 12 volt electric screwdriver, but this is rather even better. My old electric screwdriver became faster and more powerful, and my fear that it would burn out after four months of use gradually disappeared. That seems to be all the basic details, you can start with the modification.

We unsolder the old banks and leave the terminals with the temperature sensor. If you remove the sensor, it will not turn on when using regular charger.

According to the schematic on the photo, solder 18650 elements in one battery. Jumpers between the banks must be made with thick wire of at least 2.5kv. The reason is that electric screwdriver currents are too high, and with a small cross section the power of the tool will drop sharply. On the network write that Li-ion batteries can not be soldered because they are afraid of overheating, and recommend to connect them by spot welding. It is possible to solder but you need stronger soldering iron not less than 60 watts. The main thing is that you have to solder quickly not to overheat the element.

It should fit into the battery case.

The wires from the board to the terminal should be flexible, as short as possible and have a cross section of at least 2.5 kV. mm.

Put the whole circuit carefully into the case and fix it with any gasket to prevent the parts from damaging.

To fix the terminal simply put it in place and wedged it with wooden wedges. All that’s left is to reassemble the housing.

As you can see the weight of standard Ni-Cd battery is 558 grams.

The new battery weighs 376 grams, which means that the tool is now 182 grams lighter. In conclusion I want to say that it is worth this modification. the electric screwdriver is more powerful and the charge lasts much longer than with the original battery. Do it now, you will not regret it!

In this article you will learn how to inexpensively convert the battery of an electric screwdriver from Ni Cd to Li-ion batteries 18650, thereby modernizing the electric screwdriver battery, making it more powerful and increasing battery life. All steps of conversion are described in detail, so you should not have any problems, all the necessary components are listed and available.

How To Convert /Ni-Cd To Lithium Battery Conversion By Using 18650 Cells

Necessary components for modification

For the conversion were used high-current batteries 18650 with a capacity of 2500 mA / h. These batteries have already welded pins for soldering, which is very convenient and it is possible to save on battery compartments. You can order them online, they come in batches of 4 or 6. You can buy them at the links below:

hitachi, electric, screwdriver, convert, lithium

You will also need two BMS 12 boards.6V 40A, bought here:

The charger will also need to be reworked and for this you will need a voltage and current stabilization module.

You can buy a stabilizer at the link below:

At the time of modification all the components (two batteries) cost only 1100, this is much cheaper than buying a new battery for an electric screwdriver, which will contain the same Ni Cd batteries. Looking at the on the internet, I found that one battery costs from 1200, and to convert TWO batteries, I spent only 1100! All references to components can also be found at the end of the article!

Rebuilding a battery

The first thing to do is to carefully take apart the battery case and throw away the old Ni Cd batteries.

Then disconnect the battery power terminal.

You need to solder two wires to it, preferably with a large cross section. In this modification we used 4 mm² wire of about 100 mm length. In the photo above you can see the red wire, it was left so that not to mix up the polarity, to this wire it is desirable also solder a red wire, to avoid trouble and you will know exactly what it is

It is necessary to solder the minus wire to the shiny contact:

Then you have to put the brazed terminal back in the case in its place, making sure that the polarity is correct!

For fixation of the terminal you can pour hot melt glue inside the jar, it is the best way of fixation I have not found, the more so because it holds very well!

Now you can start soldering the batteries. Remove the heat shrink tubing from the batteries and bend them so that they can be soldered in series.

Next we put hot melt adhesive on the side of the battery where the contacts stick out on top and glue the BMS board as shown in the photo below. Please note that the plus and minus sides of the board and the battery are facing each other.

Then we bend the contacts of the battery on the contacts of the board and solder them, starting from the minus!

We solder a short wire to the B1 contact of the board and solder its other end to the battery connection point!

To the contact B2 we solder a short wire, the other end of which we solder to the connection point of the batteries on the opposite side!

And finally, we solder the last plus-solder contact.

Now it is left to connect the case terminals with the resulting battery, to do this solder the red wire to terminal P, and the blue, negative wire, to terminal P-.

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That’s the end of the battery redesign! It remains to fasten the fabricated battery and put in place the second part of the case. It took no more than an hour of time and, as mentioned above, 1100 bucks to rewire the two accumulators. After the tests, the screwdriver worked no worse than with the original battery and I would say much better in terms of power and the charge lasts longer. I advise everyone to rewire their old batteries! ))

Buy BMS 12 board.6V 40A Buy Samsung Batteries 18650 2500 mah 6pc.Buy Batteries Samsung 18650 2500 mah 4pcs.Buy voltage and current stabilization module Buy 3 S 25A Li-Ion 18650 BMS boards Buy Socket for connecting battery charger Buy Soldering iron

For those who do not want to remake the charger, the link below, you can buy a ready-made.

After enduring the last construction season building the formwork with this clunker, I decided that in the new season I need a normal battery.

I surfed the internet and realized a Bosch marketing ploy for my original batteries. One new battery costs the same as a new electric screwdriver with two batteries in the kit. It didn’t make sense to buy that crap for that kind of money.

The lithium-ion batteries of my electric screwdriver model were not available. New Li-ion screwdrivers were inadequately priced. Some kind of bacchanalia of sucker pricing.

It gave me an idea to convert electric screwdriver to lithium. Li-ion banks for 3.7 V, and we need 15-16 V. We can connect four batteries in series and get 16.8 V fully charged version (4 of each).2 V per bank).

If you have a 12 volt electric screwdriver, you can connect three banks in series.

Banks i.e. individual batteries from which our battery is assembled into one big battery, I decided to take the type 18650.

These are now fashionable to use in flashlights. They’re also found in laptop batteries.

This is a battery type Sony vtc4. Capable of supplying loads (max) as much as 30 amps. Perfect for our purpose.

That’s fine, but lithium is dangerous, you can make a boom if you overcharge it.

Also our individual batteries are connected in series and over time there will be a big imbalance, t.е. some cans will overcharge and others will be severely undercharged. In consequence, such a battery will quickly fail.

To help me again come to our friends the Chinese. There’s a thing called a balancer. It monitors voltage in the process of charging at each individual bank and if it is fully charged it shuts down, and the rest continue to charge and so on until all the individual banks in our chain of batteries will not be fully charged.

This thing costs the Chinese pennies. But I got a little more serious stuff from them.

A little more expensive, but it’s worth it. The thing is that these batteries do not have any protection. In general, I also ordered a battery controller. This thing includes the balancer discussed above, as well as a whole set of protections. In particular contains: short circuit protection, overheat protection, overcurrent protection, etc.д.

  • B: battery plus;
  • B3: 1st Battery.minus and 2nd battery plus;
  • B2-: 2nd battery.minus and 3rd battery plus;
  • B1-: 3rd battery.minus and the 4th battery plus;
  • B: 4th battery.minus;
  • P: load/charger V (to the screwdriver /or to the charger );
  • P-: load/charger V- (to the screwdriver and/or to the charger).

To remove the protection (you can guess the type yourself, the seller’s instructions do not say that) you need to apply voltage to the load side, i.e.е. You can simply put the battery on a charge. The protection will be removed instantly.

Tucked everything into the original battery case, having previously removed the old nickel-cadmium cans from it. Soldered to pads. To keep them from falling out, I put some hot melt glue on them.

The received battery normally charges the regular charger, although the voltage is a little low (recommended 18V), but so far I haven’t got around to it. No need to worry about overcharging. The controller will turn the cans off on its own when fully charged.

Homemade Li-ion battery for an electric screwdriver turned out to 2.1 Ah (2100mAh). Versus the regular one.2 Ah. The new battery weighs about three times less.

Tested the product on the disassembly of the slab formwork. Just super, very happy with the result. Works great, does not saturate for a long time, draws power.

Then I ran into a little disadvantage. When you forget to set the force on the electric screwdriver (drilling mode), especially when it will be under the load, then at high loads stopping the motor, the protection goes off. I do not know if it is good or not. If you also take not balancer, and a full controller, then take a load current more, otherwise you’ll be tired of removing the protection. Or look for a controller with auto-disconnect.

My controller for the load current of 8A.

At first I used to take the second battery with me and connect it to remove the protection. Then I made a button which switches circuits to operate directly without controller and removes protection by battery voltage.

If you want you can buy large capacity jars, but be careful about the total fakes. The seller that I bought and always buy from has already checked and his stated capacity corresponds to the real one.

Mounting the lithium-ion battery

Preparing the “assembly”

Before soldering you should decide on the layout of the battery compartment. That is, arrange all the elements so that they fit comfortably in it. After that, the purchased batteries are attached with adhesive tape (PVC, tape).

Processing of contacts of mini-accumulators

They gradually oxidize. So, they need a bit of a clean up. It is lightly, using a fine-grained (sanding) sandpaper.

Soldering process tips

  • It begins with degreasing the “contact” part of the battery and a brief heating of the applied solder. It is better to tin with an easily fusible, for example, PIC-40. The soldering iron should not come into contact with the battery metal for more than 1.2 to 2 seconds. Pay special attention when soldering the positive terminal.
  • It is desirable to use copper wires, cross-section not less than 2.5 “squares”, as connection wires. They must be insulated with thermal tape.
  • All mini-accumulators are connected by jumpers according to the diagram. This is a wire or “busbar” made of strips of thin metal.
  • The final step is to connect the leads to the battery compartment terminals. In case it is difficult to stow the assembly in it, you should remove the stiffeners. They are made of plastic, so it is not difficult to get rid of them with side cutters.

Pin assignment

The connectors for connecting to the battery charger are chosen depending on its model. The two connecting cables are soldered according to the diagram.

Revitalizing an electric screwdriver. Rebuilding an electric screwdriver for 18650 lithium-ion batteries

The battery of an electric screwdriver sooner or later will get “tired” and need to be replaced. Buying a new battery is justified in a situation where the tool costs pennies. But if you have something more or less decent, or the battery is old on Ni-CD, then it definitely makes sense to change the dead 18650 batteries for new ones or completely convert the screwdriver from nickel to lithium.

Of course, like in any other case, there are some details, but if you have at least minimally straight arms, then it is not difficult to convert your electric screwdriver to lithiumium by yourself. You just need to know what to buy for the conversion and understand the basic nuances of the process. And to buy on aliexpress all for converting your electric screwdriver to lithium. elementary.

Why 18650 Li-ion? The advantages of lithium batteries are obvious:

Нестандартная переделка Hitachi на литий-ион!

1) For an electric screwdriver you need high-current 18650 batteries (ideally Sony/Murata VTC5, VTC5A, VTC6. Samsung 25R is acceptable), or less high-current batteries connected in parallel (if space allows).

2) You categorically should not use old laptop batteries and just different batteries. All 18650 batteries in the assembly should have minimal variation in capacity and other characteristics. Of course, buying a high-current 18650 battery on aliexpress is the easiest solution. Just take into account beforehand that the model name will not have anything to do with the cell inside. 4 batteries bought from the same seller in one lot may differ significantly in capacity and internal resistance. Although below is a good option for those who don’t want to solder.

Ideal. buy 18650 from a proven seller on the same avito, or order 18650 at nkon In the latter case, you will have to pay 10 euros for shipping, but the batteries will be 100% original and much cheaper than buying locally (which will reduce shipping costs to zero). I personally buy my batteries for many years at that store.

I did an article about how to choose a 18650 lithium-ion battery, if you are interested read it here

3) Connecting the batteries to the BMS board is done strictly in series: first 0V, then 4.2V, 8.4V, 12.6V, 16.8V. It will not work if the BMS is broken!

4) 18650 batteries in the assembly must be charged equally. It is best to charge each battery separately and then assemble.

5) How to Calculate How Many 18650 Lithium Batteries You Need Instead of Nickel Batteries? In general, the calculation is: 2-3 NiCd = 1 lithium, 5-6-7 NiCd = 2 lithium, 8-9-10 NiCd = 3 lithium, 11-12-13 NiCd = 4 lithium

6) Lithium batteries are very sensitive to overheating. Ideal is spot welding. Soldering works fine too. How to solder a 18650? Most importantly you need as much sting as possible. Keep the contact time of the stinger and the 18650 battery to a minimum and do not overheat the latter. Otherwise the process is no different from any other soldering. It’s best to get your hands on those old batteries you’ll be replacing.

Aliexpress promo codes for July 2020.

So, current promo codes on aliexpress for July2020. If they don’t work, see coupons and other ways in my updated list of coupons and promo codes.

Just a reminder, they add up with merchant coupons and special coupons, but not with Aliexpress coupons.

LIVE293, LIVE664, LIVE469. 250 discount (3.9) for orders from 2000

ENJOYAEPLUS. 350 off on orders of 4,000 or more for items marked Plus

BMS board

BMS (Battery Management System). Battery Management System. BMS board is extremely important when converting an electric screwdriver to lithium. Why it’s needed and how it works? It controls charging and discharging, preventing the electric screwdriver battery from overdischarging and overcharging, it has a built-in “balancer” that charges each Li-Ion battery separately in the assembly. The latter is very important! There are BMS without balancer! 3S. 12v, 4s. 14v, 5s. 18v To choose a BMS board, note that the minimum current must be 30A, otherwise it will go into protection.

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The BMS board option at the link is 2-3 dollars more expensive than some basic versions, but you get 100A instead of 30A or 40A. In my opinion this is the best BMS board from aliexpress in terms of functionality and deserves this token overpayment.

Ready assemblies of 18650 batteries

For those who do not want to solder, you can buy prewelded 18650 assemblies for screwdrivers on aliexpress! S. number of batteries in series (voltage increase), P. number of batteries in parallel (capacity increase). So, for a basic 12V screwdriver you must buy 3S1P or 3S2P (increase the capacity), for 18-20V screwdriver. 5S1P / 5S2P (a lot of capacity). Read the description of the battery models below

I am 100% sure there will not be any VTC6 at the link, but even the ones you have allow you to count on normal operation, the reviews are good.

Power indicator

A simple and useful thing that shows the battery charge.

Mini spot-welding machine

If you have no desire to solder or make your own spot-welding machine from microwave guts, then you can be helped by this tool. Despite its extremely compact size, it works perfectly and can be a great help. Especially in situations where you have to weld somewhere where it is not convenient to carry a full unit.

Tape for welding 18650 batteries

If buying pre-built battery assemblies doesn’t interest you, then you will definitely need a battery connection strip. Of course, you can also buy it locally. But if you are still waiting for the same BMS board from eBay, it makes sense to order there and everything else and save time on shopping.

CC/CV charging module

And this CC\CV module is for those who want to convert their electric screwdriver to lithium. The old charger won’t charge and you’ll need a small unit. If you have a multimeter, you can adjust it. If spending a couple of bucks is not a problem, you can get the best possible display of all parameters, from voltage to current and buy a version with a display.

Power supply for the charger

Note! Li-ion assembly must be charged strictly with a lithium battery charger! The nickel battery charger will not work! To buy the right charger unit, you need to multiply the number of batteries in your assembly by 4.2. Т.е. 1х188650. 4.2v, 2. 8.4v, 3- 12.6v and so on. There are a lot of different power supplies on aliexpress, just type power supply 4 into your search.2v (or some other necessary voltage)

18650 Battery Holder

Not the most important part of your assembly. To avoid shaking the batteries can be kolhozhozhit some options from foam rubber and heat shrink. But if you want it neat and tidy. there’s nothing better than these holders.

Silicone wire

And of course you also need a wire. And, let’s face it, a good piece of good-quality, soft silicone wire comes in handy even without the electric screwdriver being rebuilt or repaired.

And there you have it. At aliexpress there is absolutely everything you may need to replace an old electric screwdriver 18650 batteries with a new one or to switch your electric screwdriver from nickel to lithium-ion batteries.

By the way, there at aliexpress you can buy a lot of good cordless tools (selection one and two) and nozzles for screwdrivers.

If you work with an electric screwdriver or any other tool, you will probably need a good headlamp. Now on aliexpress there is an opportunity to buy a really inexpensive and good model: with built-in charger, good brightness and color temperature light, a magnet in the end (ideal for work under the hood). If interested, here’s my full review and comparison of the Sofirn SP40

And below, in the “about the author” section, there are many other useful picks.

Conversion of a Hitachi Electric Screwdriver to Lithium Batteries

Nickel-cadmium batteries are not convenient because of their “memory effect” that is why it is reasonable and profitable to switch to lithium-ion batteries.

Preparation: selection of necessary devices, elements

Battery pack that has lost its performance must be disassembled. The halves of the housing can be held together with glue and/or screws, locks. To separate the glued seam it is gently tapped with a rubber mallet, so that the halves of the plastic case separated from each other, but not cracked. The elements are removed from the opened casing and assembled into a “cassette”. The contact pad is carefully separated and will need to be attached to the new lithium batteries.

A new Li-Ion battery for a Hitachi electric screwdriver requires the purchase of additional accessories, with the following things to consider:

  • The new batteries should be similar to the old ones in size and voltage.
  • It is more reasonable to choose batteries that are already equipped with nickel plates, so as not to spend time on soldering.
  • The lithium-ion battery needs a BMS board (Battery Management System). It evenly distributes energy between the banks, protects the device from sudden voltage glitches, shuts it down if the charging time is exceeded, or the batteries are discharged to almost zero. To protect against overheating, a thermal detector is connected to the board.
  • You will need a power insulated wire of suitable thickness to connect the cassette to the contact pad.

Rebuilding a screwdriver battery for lithium. A practical example of high energy.

Happy Old New Year to all! Please don’t throw any hoops, but this is another example of a screwdriver battery rework. Nothing new or revolutionary here, just an example of how the highest battery capacity can be achieved. In my particular case, just a demonstration example.

A few coincidences of compatible things happened, and I thought, why not combine them? All the more curious as to what will come out of this. So, I have a LiitoKala Lii-500, used batteries from laptops, a screwdriver with old and original batteries, and two old batteries from a screwdriver of unknown brand. But, with a similar connection socket and increased in depth. A quick check showed that it is possible to accommodate up to 16 18650 batteries without much difficulty in the enlarged battery. That is, make 3S5P or 4S4P. My screwdriver needs 12 volts, so I need five paralleled batteries, in series with two more similar batteries. After testing the used batteries I got three 7 Ah batteries each. Of course, there must be complete galvanic isolation of the batteries with the connection of their leads to the connector installed for this purpose. A decoupling is necessary to connect the screwdriver battery to the battery charger LiitoKala Lii-500. When the charge is complete, a mating plug (dad) is inserted into the connector with jumpers that connect all three batteries. I will not go deep into it, if it is not clear to someone, I will explain in more detail. One not so nice moment is that the batteries are so exactly matched to the depth of the case that it was possible to solder the conductive stripe only to the plus contact and solder the minus to the sides of the batteries. However, you can see everything in the photo. Of course, it was not possible to install any electronic gadgets, and they are not needed. High-current batteries are not needed in my case, because the output of five parallel batteries is already very high. However, if you put new modern batteries in this construction, the power reserve will be unprecedented. The screwdriver also came with its original charger. In principle it is not necessary, however, may be useful for a small recharging time in case of need, and already at home to add LiitoKala Lii-500. By the way, the case is also not native, I had to cut the plastic to fit. However, everything is clear in the photo.

I added a photo of the connector with fuses:

I add a voltage meter on alex323 tip to modify the battery

The point and order of converting screwdrivers to lithium batteries

Why nickel-cadmium batteries fail quickly? In a daisy chain connected cans each is special. The chemical process is individual, the charge in closed systems is different. In case of a malfunction in one bank, the design does not give the right voltage. There is no charge control and balancing system in the individual components.

  • Each Ni-Cd bank gives 1.2 V, and li-ion 18650 gives 3.6 V.
  • The lithium battery has twice the capacity of the nickel-cadmium battery, close in size.
  • Overheated li-ion battery threatens an explosion and combustion, that is why the installation of the charge uniformity control in the banks is obligatory. Nickel cadmium batteries don’t have BMS because the manufacturer is not interested.
  • Lithium cells have no memory effect, unlike Ni-Cd, you can charge them at any time and within an hour.
  • The electric screwdriver becomes much lighter after converting the battery to li-ion, using 18650 batteries.

There are only two obstacles to converting an electric screwdriver for lithium batteries. it cannot be operated in minus temperatures. The capacity of the batteries drops starting from as low as 10 0 C. Lithium batteries are expensive.

Knowing what input voltage the electric screwdriver requires, the modification of the charger is made, taking into account the placement of the lithium battery cells and the control elements in the factory container. You can also do the same with a flashlight by upgrading the socket for a block of 18650 cells.

Suppose you need to convert a 12V electric screwdriver that uses Ni-Cd banks to li-ion. If you use 3 banks, the output voltage is insufficient: 3.6 x 3 = 10, 8 V. With 4 components the capacity will be higher: 3.6 x 4 = 14.4V. The tool will become lighter by 182 g, slightly increasing its power, capacity. all this is just a plus. But it is necessary to leave the terminals and the native temperature sensor when disassembling.

Grounds and difficulties of modification

Advantages and disadvantages of Li-ion

First of all, note that the old nickel-cadmium batteries are quite reliable, inexpensive and can operate at low temperatures, withstanding a large number of charge-discharge cycles. But they have the disadvantage of gradually losing capacity if you charge them before they are fully discharged (the so called “memory effect”).

The need to convert an electric screwdriver to lithium 18650 batteries is due to a number of advantages of the latter, the main ones being:

Battery size 18650

However, the newer lithium batteries also have the disadvantage that their parameters worsen when fully discharged. At voltages over 4.2 and under 2.7 volts, they “feel” not very comfortable. That’s why during production these products are equipped with built-in controllers that protect them from short circuits, overvoltages and deep discharges.

Please note! their integrated electronic regulator switches them off automatically if the mains supply is interrupted or if the battery of the electric screwdriver is outside the working tool compartment. Another disadvantage of converting an electric screwdriver battery to lithium is that the new batteries are not adapted to function at low temperatures

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However, all of these disadvantages are more than offset by the previously discussed advantages

Another disadvantage of converting the battery of an electric screwdriver to lithium is the inadaptability of new batteries to function at low temperatures. However, all these disadvantages are more than offset by the previously discussed advantages.

Problematic areas

To implement the above benefits will need to solve a number of issues arising from the conversion of the battery of an electric screwdriver to li-ion, namely:

  • Working dimensions of the new product, determined by its designation (diameter. 18 mm, length. 65 mm) do not match the dimensions of the elements to be replaced;
  • Full replacement of batteries is possible only if you modify the battery compartment, allowing you to put the controller board and the harness of connecting wires;
  • When remaking must also take into account the difference in voltage of each element of the prefabricated source, consisting of several batteries (1.2 volts for nickel-cadmium vs. 3.7 volts for Li-ion).

Important! Bearing this in mind, you should try in advance to adjust the total voltage of several new cells to its old value (the figure below shows nickel-cadmium batteries). Nickel-cadmium cells

Nickel-cadmium cells

In some cases it is impossible to achieve coincidence of supply voltages at all, what makes me refuse from alterations or look for other, suitable by this parameter products

It is important to respect the measure and calculate the economic feasibility of switching to Li-ion 18650 (otherwise the modernization can be more expensive than the tool itself)

Converting an electric screwdriver to lithium. Part 1

Not so long ago I started to remake my electric screwdriver for Li-ion. The topic is not new and probably many have already successfully implemented it, but my work in this direction has just begun. Of course Google knows everything and my searches brought me the following result:

  • The battery power should not be inferior to the original
  • Capacity respectively, too, should not be inferior to the original (well, as it would be battery life)
  • A balancer for the cans is desirable
  • Battery status monitor (a voltmeter is not good enough, I don’t want to think what the voltage is, I need a indicator with 3 LEDs or something like that)
  • Charging must be done correctly
  • And finally, disconnecting the battery from the charger at the end of the charge without human intervention.

Now I will give you all the material I dug up for this venture (all authors I know will of course be listed) and try to give all references to necessary parts or additional materials. And at the end I will share my own crafts (although this will most likely be in a separate article, because at the time of this writing, the work is still in full swing).

Connecting the batteries.

Several solutions are used to connect the batteries:

Cassette, very simple and accessible, but categorically not recommended for high currents, since it has a high contact resistance.2. Soldering. It has the right to life, I do it myself sometimes, but this method has nuances.At least know how to solder. And be able to solder correctly, and most importantly. quickly.In addition, you need to have a proper soldering iron.Soldering is done in the following way: We grind a place of contact, we cover this place with flux (I use F3), we take a tinned wire (it is better not so big section, 0.75mm.sq enough), put a lot of solder on the soldering iron sting, touch the wire and together with it press to the battery contact. Either put the wire to the soldering point and touch the soldering iron with a big drop of solder to the place between the wire and the battery.But as I wrote above, the method has nuances, you need a powerful soldering iron with a massive stinger. The battery has a large heat capacity and with a light tip it is trivial to cool it to such a temperature that the solder “freezes”, sometimes together with the tip (depending on the soldering iron). You will end up spending a long time trying to heat the point of contact and you will end up overheating the battery.Therefore take an old soldering iron with a big copper nib, preferably well heated, then heated will be only the soldering point and after the heat is just distributed and the total temperature will not be very high.The problem is with the minus lead of the battery, there is usually no problem with soldering the plus lead, it’s lighter, but I don’t recommend to overheat it much either.In any case, if you have no experience in soldering, I do not recommend this method.3. The most correct way is spot welding, instantly, without overheating. But the welding machine must be properly adjusted not to make a through hole in the bottom of the battery, so it is better to turn to professionals. You can get your battery welded at the market for a small fee.

Alternatively, some online stores offer a service (or rather variants of lots, with and without paddles) for welding contact paddles, it is not very expensive, but much safer than soldering.

In the photo you can see that there is a cloth insulator between the petal and the battery case. This is important because without it, you can overheat the petal and it will melt the battery insulation, I think the consequences are clear.

Converting EB1414S battery of DS14DVF3 electric screwdriver into Li-Ion one and reduce current in Hitachi UC18YG charger

The EB1414S battery conversion of the electric Hitachi DS14DVF3 screwdriver for Li-Ion lithium batteries and, respectively, the Li-Ion battery conversion and current reduction in the charger Hitachi UC18YG.

Remove the dead Ni-Cd batteries from the EB-1414S and solder the 18650 Li-Ion batteries (5 pcs x 4.2V = 21V).

Why 21V and not like Ni-Cd 12pcs x 1.44V=17.28V and you need about 4pcs Li-Ion x 4.2V = 16.8V max? Because the quality of the circuit and the screwdriver motor is high, and it perfectly holds the voltage increased by 21%, and power respectively by 47%, the more starting current is limited by the circuit and the regulator turns (the button when lightly pressed gives a slow speed, and with a strong high).

In the battery charger change the ZD2 regulator for BZX55C20 (20V), and change the variable resistor VR1 (there’s one with a yellow cross) to a constant 300 kOhm, as a result the charger will charge the battery current of 400mA, showing a red LED charging to 21V (up to 21V recharges the battery by dripping, reduced current, as it should Li-Ion).

After modification, check the voltage at the terminals of the battery charger without the battery, it is 20.6 21.0 V (jumps once per second). If voltage is higher than 21V, it’s better to choose ZD2 regulator for slightly lower voltage. When installing a dead battery check the charging current with R15 resistor 0.1Ohm resistor (measuring for current), at a charging current of 0.4A the voltage across it will be 40 milliVolts (0.04V).

  • Li-Ion battery is two times lighter than Ni-Cd and has more torque, by 47%.
  • Capacity. If you usually have Ni-Cd 1500mAh for one day, then the same Li-Ion 2200mAh will last a day and a half.
  • As a result of charging with a small current of 0.4A lifetime of the Li-Ion battery will be 4-5 years, which is twice as long as it was on the former native 2.6A fast charge Ni-Cd (2-3 years) overheat cutoff! of the battery each time you charge it.
  • The red indicator at the end of the charge does not go out, and the charger itself is quite warm from the bottom, even without the battery (in standby mode it is better not to leave it on, so as not to eat the power).
  • Longer charging time 2200mAh Li-Ion battery, current 0.4A for about 6 hours.
  • Naturally, in freezing temperatures Li-Ion batteries lose their ability to work much faster and harder than Ni-Cd batteries, but the cost of new Ni-Cd 1500mAh batteries is higher than the cost of recharging.
  • There is no balancer in the battery circuit for lithium batteries so there is no overcharge above 4.2V, so you need to put the same capacity batteries in the ac.

Not recommended: Even a little overdischarge Li-Ion batteries (that is, when you lose power electric screwdriver (discharge) is strictly prohibited to kill the converted Li-Ion battery in the trash (to finish the job to the end), but in reality because of his laziness or race to sit the battery to zero. If time is tight, it is more important to charge the battery at least a little and finish the construction issue already without killing the battery. After all, Li-Ion batteries are more prone to loss of capacity with severe discharges (Below 3.6V per ac, but here x 5 pcs = 18V).

It is important to sign everything converted bright marker, 21V Li-Ion, for example 2200mAh, it is also strictly forbidden to SAVE IN HOLE, so as not to stick in other chargers and did not burn anything.

It is also important to take the principle: work with a screwdriver, and be sure to put the ac.

Where to get 5 pcs of Li-Ion batteries 4.2V ?

  • A neighbor’s battery from an old broken laptop.
  • You can go to any laptop shop and ask the master dead laptop batteries: (there are usually even 6 pcs 18650, new ones are about 2200mAh, and for 5 years, usually a couple of 18650 dies, and 4 pcs of them do not lose capacity below 1300 mAh). Test the batteries with the BT-C3100 V2.2 according to capacity and internal resistance, the more capacity and the less resistance the better ac. In a screwdriver battery, it is more important to pick the same capacity lithium batteries. If the internal resistance of the Li-Ion battery is above 500 milliOhms, and the 5 pieces are above 2500 milliOhms (2.5 ohm), then they will not pull the screwdriver.
  • Buy from China on aliexpress (but not the Chinese rubbish 4200mAh-6000mAh, actually 800mAh).) you can use real Panasonic branded NCR18650B 3400mAh with cashback on the program They will actually last more than twice as long as the original EB1414S. 1500 mAh.

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