Convert your electric screwdriver charging to lithium
Ways to recharge the battery at home
It should be noted that recovery is possible only for Ni-Cd batteries, which have a pronounced memory effect, due to which the capacity of the battery is lost. As a result the battery runs down quickly, and after a short break it starts working again. This problem can be solved quite easily.
- Fully charge the battery in the normal manner, ideally with a small amount of current.
- Next, fully discharge the battery by connecting a load to it. You can use an ordinary 12 volt bulb of up to 40 watts as the last one. Thus there will be a soft discharge, which will discharge not only the outer layer of the battery, but also its inner plates.
- You may perform 3 to 5 charge/discharge cycles. This will erase the memory effect and greatly increase battery capacity.
In some cases, when you can not buy new banks for the battery pack, they can be revived by pouring distilled water into them, because over time the electrolyte in the banks boils out, and they fail. Repair the battery as follows.
- Identify defective batteries by the method described above.
- Completely discharge the battery by connecting a 12 V (40 W) light bulb to the terminals.
- Disconnect the unserviceable cells (marked) from the rest.
- Remove a small piece of paper insulation from the top of the can to reveal a small grooved area. If you remove all of the paper, you will have to wrap tape around the battery.
- With the help of a thin drill 1 mm in diameter make a hole in the body of the battery, namely in the groove as shown in the photo below.
- Next, fill a syringe with distilled water and slowly pour it into the jar. In order to restore the battery the jar must be completely full.
- Wait a little while for the water to soak in well, then seal the holes with epoxy or duct tape.
- You can now solder the restored cans, placing them in their former places.
- Assemble the unit and make 3-5 cycles, including full charge and full discharge of the battery. Only after these procedures have been performed will you be able to use the tool.
DIY Lithium Battery Charger for Electric Screwdriver Batteries
In a previous article I discussed the replacement of the nickel cadmium (nickel-manganese) NiCd (NiMn) batteries of an electric screwdriver with lithium batteries. A few rules for charging batteries should be considered.
Lithium ion batteries of size 18650 can generally be charged to a voltage of 4.20V per cell with a maximum tolerance of 50 mV because higher voltage can damage the structure of the battery. The charging current of the battery can be 0,1xC to 1xC (here C-capacity). It is better to choose these values according to the datasheet. I used Samsung INR18650-30Q 3000mAh 15A batteries in my remodel of an electric screwdriver. Check the datasheet for charging current.1,5А.
The most correct way is to charge the lithium batteries in two steps by the method of CCCV (constant current, constant voltage).
First stage must provide a constant current of charge. The value of the current is 0.2-0.5С. I used a 3000 mAh battery, so the nominal charging current will be 600-1500mA. After charging the bank is at a constant voltage, the current is constantly decreasing.
Maintains the battery voltage within 4.15-4.25В. The battery is charged if the current goes down to 0.05-0.01С. Taking into account the above, we use the electronic boards from Aliexpress. CC/CV derating board with current limit on XL4015E1 chip or LM2596. Preferably the XL4015E1 board, as it is more convenient to set.
Convert Craftsman Ni-Cad screwdriver to Lithium using an 18650 flashlight
Characteristics XL4015E1. Maximum output current up to 5 A. Output Voltage: 0.8V-30V. Input voltage: 5V-32V. LM2596-based card has similar parameters, only current up to 3A.
-220\12V, 3A adapter.1pc;.The battery charger of an electric screwdriver (or power supply);.CC/CV charge board on XL4015E1 or LM2596 1pc;.connecting wires.soldering iron;.tester;.Plastic box for the charge board.1pc;.Minivoltmeter.1pc;.10-20 kΩ variable resistor (potentiometer).1pc;.Power connector for electric screwdriver battery compartment.1pc.
Assembly of the battery charger of an electric screwdriver on an adapter.
The cccv board we have already chosen above. As a power supply can be used any with the following parameters. output voltage of 18V (for the circuit 4S),current of 3A. In the first example of making a battery charger for lithium-ion batteries of an electric screwdriver I used a 12v, 3amp adapter.
I checked beforehand how much current it could deliver at rated load. Plugged a car lamp into the output and waited for half an hour. Gives out freely without overloading 1,9 A. Also measured the temperature on the heatsink of the transistor-40°C. Quite normal mode.
But in this case there is not enough voltage. This is easy to fix, with just one penny radio component, a variable resistor (potentiometer) of 10-20 kOhm. Let’s have a look at a typical circuit of the adapter.
On the schematic there is a TL431 controlled gate, it is in the feedback circuit. Its job is to keep the output voltage stable according to the load. Through the divider of two resistors it is connected to the plus output of the adapter. We need to solder to the resistor (or remove it and solder in its place, then the voltage will be regulated to a lower side) which is connected to pin 1 of TL431 regulator and to the minus bus a variable resistor. Turn the potentiometer axis and set the desired voltage. In my case I have set it to 18V (a small margin of 16.8V for the CC/CV dropout). If you have voltage indicated on the cases of electrolytic capacitors at the output of the circuit will be higher than the new voltage they may explode. Then you have to replace them with 30% extra voltage.
Next, connect the board to the adapter to control the charge. Set the voltage of 16.8 V with the trimmer on the board. We set the current of 1,5 A with the help of another trimmer, previously connect the tester in the ammeter mode to the board’s output. Now you can connect the lithium-ion assembly of the electric screwdriver. Charging went well, current at the end of charge dropped to minimum, the battery is charged. The temperature of the adapter was in the range of 40-43°C, which is quite normal. In the long term you can drill holes in the housing of the adapter for better ventilation (especially in summer).
You can see the end of the battery charge by turning on the LED on the XL4015E1. In this example I used another board with the LM2596 because I accidentally burned out the XL4015E1 during my experiments. I advise to do better charging on XL4015E1 board.
Assembling the battery charger circuit of an electric screwdriver on a regular charger.
I had a regular charger from another electric screwdriver. It is designed to charge nickel-manganese batteries. The problem was to charge both nickel-manganese batteries and lithium-ion batteries.
It was solved very simply soldered to output wires (red plus, black minus) wires to CC/CV board. The no-load voltage at the output of the standard charger was 27 V, this is quite suitable for our charger board. Then everything is the same as with the adapter.
How to Make / Convert an Electric Screwdriver from NiCd in lithium-ion
The end of the charge, we see here by changing the color of the LED (switched from red to green).
I put the board itself CC / CV in a suitable plastic box, bringing the wires out.
The adapter modification method under the power of beginners and may be useful for other purposes, the result will get a budget unit to power various devices.
I wish you all good health and success in life and creativity!
Become an author of the site, publish your own articles, descriptions of homemade with pay-per-text. Read more here.
How a charger works
If a charger fails, it makes sense to try to repair it first. For the repair it is desirable to have a schematic diagram of the charger and a multimeter. The circuitry of many charging devices is based on the HCF4060BE chip. Its circuitry generates a float charge time interval. It has a crystal oscillator circuit and a 14 bit counter, so it is easy to implement a timer.
The principle of the charger circuit is easier to disassemble on a real example. This is what it looks like in an Interskol screwdriver:
This circuit is designed to charge 14.4 volt batteries. It has a LED indicating the connection to the network, LED2 is lit, and the charging process, LED1 is lit. As the counter U1 HCF4060BE chip or its analogs: TC4060, CD4060 are used. Rectifier is assembled on the power diodes VD1-VD4 type 1N5408. PNP transistor Q1 operates in the switching mode; its outputs are connected to the control contacts of relay S3-12A. Key operation is controlled by the controller U1.
When switching on the charger the AC voltage of 220 volt through the fuse goes to the step-down transformer, at the output of which its value is 18 volt. Then, passing through a diode bridge, it rectifies and gets to the smoothing capacitor C1 with the capacity of 330 uF. The voltage value on it is 24 volts. When the battery is connected, the contact group of the relay is in the open position. Microcircuit U1 is fed through the regulator VD6 with constant signal equal to 12 volt.
When the “Start” button SK1 is pressed, a stabilized signal through resistor R6 reaches pin 16 of the controller U1. The switch Q1 opens and through it the current flows to the relay outputs. Contacts of the device S3-12A close and the charging process begins. The diode VD8, connected in parallel with the transistor, protects it from a voltage spike, caused by switching off the relay.
The SK1 button used works without locking. When it is released, all power is supplied via VD7, VD6 and limiting resistor R6. And also the power is fed to the LED1 through the resistor R1. The LED lights up, indicating that the charging process has begun. The timing of the chip U1 is set to one hour of operation, after which the power is removed from the transistor Q1 and, consequently, from the relay. Its contact group opens and the charging current disappears. LED1 goes out.
This charging device is equipped with an overheat protection circuit. This protection is realized with a temperature sensor. thermocouple SA1. If during the process, the temperature reaches a value greater than 45 degrees Celsius, the thermocouple is triggered, the chip receives a signal and the charge circuit is broken. Once the process is complete, the voltage across the battery terminals reaches 16.8 volts.
This way of charging is not considered intelligent, the charger can not determine in what state the battery is. Why the battery life of a cordless screwdriver will be shortened by the development of the memory effect. That is, the capacity of the battery is reduced each time after recharging.
How to convert the cordless screwdriver for work from 220 V or an external power source: instructions
Cordless screwdriver is a great helper in the home. The tool together with the master works in the house and in the garden, works in the garage or in the field. As long as the battery doesn’t run out. The number of charge-discharge cycles with a battery is limited, the battery also spoils from idleness: self-discharge destroys the cells. The battery lasts an average of 3 years, after which it must be replaced. It is possible to save the tool by converting it into a mains powered tool. Conversion can be carried out in different ways.
Pros and cons of the conversion
Unlike standard nickel batteries, lithium batteries expand the basic capabilities of an electric screwdriver. Among them:
- the ability to recharge the battery after a short work, the capacity is not reduced;
- lithium batteries will last longer because of the increased number of recharging cycles;
- it is easier to replace li-ion batteries when they run out;
- fast charging to 100% capacity in 1-3 hours instead of 10-15 hours for nickel batteries.
Nevertheless, lithium-ion batteries have a few drawbacks:
- Expensive. 250 to 500 per battery;
- They do not take well to overcharge or overdischarge, so it is better to use an automatic charger that reduces the current when the desired voltage is reached.
How to turn a cordless electric screwdriver into a cordless power tool
Cordless power tools have supplanted conventional corded power tools even in niches where it seemed impossible just a few years ago. Drills, circular saws, electric grinders, and screwdrivers, while comfortable, light, mobile, and powerful, have taken their place in the household and industrial work toolkit with the development of technology and the appearance of new batteries. But in some cases you need the reverse stroke. remaking battery-powered devices to be powered by household voltage of 220 volts. How to make a mains powered electric screwdriver and what you need to buy for this. about all of this below.
First of all, lithium is different from lithium. In short, there are Li-Ion batteries for different current output (load). In our case we just need batteries with high recoil current. As a rule, these batteries also have a higher charging current, so if you make the right charging, you can quickly charge the batteries.
I chose to use these (see “The Fuel Economy” in this manual). photo). This 18650 Sony VTC4 (or similar) 2100mAh. Bought from the Chinese here.
Excellent price/quality ratio. High current recoil and charge characteristics. The maximum load current is 30 amperes. Needless to say, such cans feel great in an electric screwdriver. Capacity 2100mAh against the standard 1100mAh (such capacity (1100mAh) usually make and factory Li-Ion batteries).
Four cans for an electric screwdriver with a voltage rating of 14 volts.4В. For a 12 volt electric screwdriver we take three cans. For a cheaper screwdriver you can get one of these HG2s.
Convert an electric screwdriver charger for lithium
If you read my previous post you might remember that after my standard electric screwdriver batteries failed and I urgently needed to keep working, I soldered together a pretty powerful converter for 8A rating and up to 15A short term load. From 24 volts to 15 volts. Two 7 Ah 12 volt batteries connected in series. I have a 14 amp electric screwdriver.4 В.
After exhausting and getting tired of the last construction season building the formwork with this thing, I decided that in the new season I needed normal batteries.
I looked around on the internet and realized the Bosch marketing ploy for my original batteries. One new battery costs as much as a new electric screwdriver with two batteries in the set. It made no sense to buy this crap for so much money.
There were no lithium-ion batteries for my electric screwdriver model. New Li-ion screwdrivers were inadequately priced. It’s like a bacchanalia of scamming suckers.
Here I had the idea myself to convert the electric screwdriver to lithium. Li-ion cans for 3.7V and we need 15-16V. We connect four batteries in series and we get 16.8 volts in a fully charged version (4 each).2 V per can).
If you have a 12-volt electric screwdriver, you can connect three cans in series.
Banks that is, individual batteries from which is going to be our battery in one big battery, I decided to take a type 18650.
These are now fashionable to use in flashlights. These are also found as part of laptop batteries.
This is a Sony vtc4 type battery. Capable of supplying a maximum of 30 Amps. Perfect for our purpose.
Everything would be fine, but lithium is a dangerous thing, you can make a boom if you overcharge.
Our batteries are connected in series and there will be a big imbalance in time.е. some cans will overcharge and others will be undercharged. In consequence, such a battery will quickly fail.
To help me again came our friends from China. There is such a thing called a balancer. controls the voltage during charging at each individual bank and in case of its full charge disconnects it, and the rest continue to charge and so on until all the individual banks in our series battery chain will not be fully charged.
This thing costs pennies from the Chinese. But I got a little more serious stuff from them.
It’s a little bit more expensive, but it’s worth it. The thing about these batteries is that they don’t have any protection. In general, I also ordered a battery controller. This thing includes the balancer mentioned above as well as a whole set of protections. Particularly it contains: short circuit protection, overheat protection, overcurrent protection, etc.д.
Battery and Charger Conversion (Nicd to Lithium) Compact Cordless Drill | RYOBI BD-120
- B: Battery plus;
- B3: 1st battery.minus and 2nd battery plus;
- B2-: 2nd battery.B3: 1st battery minus and 3rd battery plus;
- B1-: 3rd battery.minus and 4th battery plus;
- B: 4th battery.minus;
- P: load/charge V (to the screwdriver /or to the charger );
- P-: load/charge V- (to the screwdriver and/or to the charger).
After piecing everything together, I tried the electric screwdriver in action and oh well, nothing works. What the heck, did the Chinese sold me a fake, but no they were not to blame. The thing turned out that during the assembly process, I must have shorted something somewhere, in general, it triggered the protection, completely disconnecting the battery from the load.
To remove the protection (guess the type yourself, it’s not in the seller’s instructions) you need to apply voltage on the load side, t.е. can just put the battery on the charge. Protection is removed instantly.
Tucked everything into the regular battery case, taking out the old nickel cadmium banks first. Soldered to the contact pads. To keep them from falling out, filled the case with thermal adhesive.
Battery charger charges the battery normally, although the voltage is small (recommended 18V), but I have not got around to it yet. No need to worry about recharging. The controller will shut down the battery itself when it is fully charged.
Homemade Li-ion battery for an electric screwdriver turned out to 2.1 Ah (2100mAh). Versus the stock capacity of 1.2 Ah. The new battery weighs three times less.
Tested the product on the disassembly of the slab formwork. Just super, very happy with the result. Works great, doesn’t sit down for long, pulls powerfully.
Then I had a little disadvantage. When you forget to set the force on the electric screwdriver (drilling mode), especially when it tips up, then at high loads stopping the motor, triggered protection. I do not know if this is good or not. If you also take not balancer but full controller, then take a larger current load, otherwise you will be tired of removing the protection. Or look for a controller with autodischarge.
My controller for the load current of 8A.
At first I took the second battery with me, connecting to it removed the protection. Then I made a button which switches circuit to work directly without controller and at the same time removes protection with the help of battery voltage.
If you want you can buy cans for a larger capacity, but be careful in this plan are solid fakes. The seller from whom I bought and constantly buy I have already checked and his declared capacity corresponds to the real one.
Conversion of electric screwdriver to lithium batteries
This issue is worth focusing on. For the electric screwdriver user, the installation of lithium-ion batteries opens up some previously inaccessible “features”:
- 1. the batteries can be recharged after a short period of work, this will not reduce their capacity;
- 2. batteries will last for a greater number of charge-discharge cycles. When they run out, they can be easily replaced.
- 3 Charging will be many times faster (about 1-3 hours, compared to 13-15 hours for nickel cadmium).
- 1 Li-ion batteries are more expensive. You’ll have to pay 250 to 500 for one.
- 2 The next disadvantage is their fastidiousness to charging. they do not tolerate neither overcharging nor overdischarging and, frankly speaking, it is better to charge them with a “smart” charger which, when a certain voltage is reached, reduces the current supplied to the batteries.