How to charge the battery of an electric screwdriver without a battery charger
Electric screwdriver battery design
The battery is the power source for cordless screwdriver models. Due to the course of physical and chemical processes (electrolysis) this element accumulates electric energy, and then outputs at their respective outputs constant voltage of the desired value. Voltage and capacity are the main parameters of any storage device. The first indicates the potential difference between the cathode and anode of the battery. The voltage is measured in volts. Capacitance determines the amount of current a battery produces in 1 hour, so it is measured in ampere hours.
In different models, the battery pack (battery) looks and is arranged in a similar way. It consists of the following structural elements:
- housing with contacts on it;
- The supplying elements (batteries);
- Temperature sensor (thermistor) circuit, which protects the unit from overheating (the range is from 50 to 600 degrees).
Not all models have thermistors. The housing is usually a plastic box, consisting of two parts. It usually has about 10 batteries inside, but sometimes more. In this case the elements are connected to each other in a chain. The free terminals of extreme batteries are connected to the terminals located on the case, which are designed for powering the electric motor of the tool and connecting it to the charging equipment. The output voltage of the battery is determined by adding this value to all the batteries connected in a single circuit.
- 2 power (.), designed for charging and discharging;
- one upper control contact connected to the thermistor;
- One contact used for charging from special charging stations, which are able to equalize the value of the charge of all the batteries contained in the unit.
Battery storage units are divided into the following types according to the type of battery:
- Nickel-metal hydride batteries (referred to as NiMh) with an output voltage of 1.2 V;
- Nickel-cadmium (labeled NiCd) also output 1.2 V;
- lithium-ion batteries (designated by the symbols Li-Ion), which have a voltage depending on the number of power cells in the battery and can be in the range of 1.2-3.6 V.
Lithium-ion batteries have a control board. In this case, a special controller monitors the operation of the cells.
An individual battery consists of the following structural elements:
- positive and negative contacts;
- electrode with a positive charge;
- the outer cover of the enclosure;
- negative electrode.
How to charge a battery without the charger
Nickel-cadmium energy storage devices are the most popular because of their affordable price, compact size, and high capacity. They can be recharged more than 1,000 times.
Safety and Precautions
When using any method of charging it is necessary to be careful and observe the precautions:
- Monitor the process. When the battery is full of energy, the procedure is stopped. Otherwise, overcharging the battery can cause its electrical elements to boil. If the temperature rises sharply, a small spark will cause the entire structure to explode.
- All parts must be properly connected to the circuit. During the assembly the technical parameters of the device are to be strictly observed, ensuring the safety of the procedure and observing the polarity. The chargers made by your own hands can completely ruin the battery, eliminating the possibility of restoring it in the future.
- The battery is charged in a short period of time with small differences in the characteristics of the modules (10-12 volts)
Types of chargers
The popularity of the screwdriver is due to the fact that it simplifies the process of screwing or unscrewing various fasteners. Characterized by mobility and small dimensions, it is indispensable for assembling furniture, dismantling equipment, roofing and other construction works. The tool owes its mobility to the batteries it contains.
The advantage of the use of batteries in the possibility of repeated use. Batteries need to be recharged from time to time by giving accumulated energy to the device. Chargers are used to restore the value of their capacity.
A screwdriver battery can be charged in two ways: with a built-in charger or with an external battery charger. Built-in battery charger allows you to charge the battery without removing it from the screwdriver. Capacity recovery circuit is located directly with the battery. While the remote involves their removal and installation in a separate device for the charge. Chargers are differentiated by the type of the battery to be regenerated. There are different types of rechargeable batteries:
The final cost of the screwdriver not least depends on the type of batteries used and the capabilities of the charger. Chargers are available in 12 volt, 14.4 volt and 18 volt. In addition, the chargers are divided by capabilities and can have:
Most battery chargers use slow charging, due to the low current. They are not equipped with a work indication and do not switch off automatically. This is more true of built-in capacity recovery devices. Chargers based on impulse circuits provide the possibility of rapid charging. They are automatically disconnected when the required voltage is reached or in the event of an emergency.
Types of used batteries
Ni-Cd batteries do not have any problems when charged in accelerated mode. Such batteries have a high loading capacity, low price and can safely operate at minus temperatures. Disadvantages include: memory effect, toxicity, high self-discharge rate. Therefore, before recharging this type of battery, it must be completely discharged. The battery has a high degree of self-discharge and discharges quickly, even if it is not used. At present they are practically not available due to their toxicity. Of all types have the lowest capacity.
Nickel-metal hydride is superior to NiCd in all respects. They have a lower self-discharge rate and less memory effect. They have higher capacity for the same size. They contain no toxic material, cadmium. In the price category, this type occupies a middle position, so the most common type of capacitive cells in the screwdriver is this.
How To Charge Cordless Drill Battery Without Charger
Lithium-ion ones are characterized by high capacity and low self-discharge value. These batteries do not tolerate overheating and deep discharge. In the first case, they can explode, and in the second case, they can no longer restore their capacity. They are also able to work at subzero temperatures and have no memory effect. The use of a battery charger with a microcontroller allowed to protect the battery from overcharging, thus making this type the most attractive to use. expensive than the first two types.
In addition, the main characteristic of rechargeable batteries, is their capacity. The higher this indicator. the longer the screwdriver works. Capacity unit is milliampere per hour (mA/h). The design of the battery is to connect the batteries in series and place them in a common case. For Li-Ion the voltage per cell is 3.3 volts, for NiCd and NiMH. 1.2 volts.
How to charge an electric screwdriver without a 12 volt charger
Before you can charge the battery of an electric screwdriver without a battery charger, you will need to study the instructions. Homemade charger is made taking into account the type of battery.
Specialists distinguish the following categories of electric screwdriver:
Since the battery is designed for a certain work and load, each type of tool requires an appropriate charger. The duration of the tool depends on the power of the battery. Experts distinguish the following types of batteries:
Type 2 battery, unlike the others, is compact, has more energy capacity. The tool can be charged more than 1,000 times if used properly. Charge the battery of the electric screwdriver by observing the following rules:
- Full charging of the battery. Otherwise, the energy capacity and run time of the tool will be reduced.
- Toxicity of the nickel cadmium battery (must not be dropped).
- Nickel-metal hydride battery is developed by new technology and is environmentally safe for humans. It can be recharged frequently. If the tool is not in use, then the battery is stored in a charged condition. The battery is completely discharged if the electric screwdriver is not used for a long period of time.
- The lithium-ion device has no memory effect. The battery has a high power capacity. Due to its susceptibility to low temperatures, lithium-ion batteries should not be used in winter.
To make a battery charger for an electric screwdriver with your own hands, you will need the following materials and tools:
Deciphering the indicators of the charger.
- charging cup;
- The ruined battery;
- 2 wires 15 cm long;
- soldering iron;
- a heat gun.
Use a soldering iron to unsolder the terminals of the defective battery. Marks are made with a marker on the cover of the device, where was the minus and plus. If necessary, the prepared holes are adjusted to the correct dimensions. A blade is used for this.
The next step is to run the wire through the holes. The cable is soldered to the cup, taking into account the polarity. To prevent the connector from falling apart, cardboard is inserted into the battery. The bottom cover is attached to the charging cup. The resulting construction is inserted into the adapter, and then into the battery.
To charge the device, it is possible to make a charger from the USB-source. Use a socket, USB charger, fuse (10A), connectors, paint, duct tape and tape. The electric screwdriver is disassembled into parts. The upper case is cut off from the handle with a knife.
The charger diagram for an electric screwdriver.
Make a hole on the side of the handle for the fuse. The wire is connected to the fuse and installed in the handle of the unit. To fix the fuse use glue and a hot-air gun. Wrap the housing with duct tape. The resulting design is connected to the battery connector. On the top of the electric screwdriver mount the wires. Assemble the tool with your own hands and wrap it with electrical tape. The casing is sanded and painted. The resulting device is charged.
Before you buy an electric screwdriver, it is advisable to pay attention to its power. If the tool will be used in household conditions, then it is possible to buy a unit with a number of 10-15 Nm. For professionals, the tool with an internal torque of no more than 130 Nm is the right choice. The purchaser should pay attention to the number of revolutions per minute. The tool, which will be used at home, should make 400-500 rpm, and the professional unit. 1200-1300 rpm.
The main indicator for the choice of an electric screwdriver is the power. The higher this index is, the longer the tool will work. The kit includes 2 batteries (one for work, the other for charging). In the construction of a homemade battery charger a KT829 transistor is used. Prepare a schematic diagram of the device in advance. To limit the charging current use a resistor with a resistance of 1 Ohm.
Through the battery the charging current is controlled by a transistor KT361. Use a collector to control the charge indicator. 1 element is responsible for the operation of the compound transistor. The charging current depends on the duration of charging. When making a homemade device, the charge threshold is taken into account. This number must be greater than the value of this parameter when charging at the maximum capacity of the battery.
Experts recommend using a transformer TP-20-14 for a homemade charger.
It can be dismantled from a black and white TV “Electronics-409”. The transformer voltage is 9 V and the current strength is 1 A. It is advisable to place the obtained device in a plastic casing of suitable dimensions.
How to charge the battery of an electric screwdriver without a charger
Cordless screwdrivers and drills have quickly entered the domestic construction tool market and are firmly entrenched there. It is noteworthy that these devices are quite problematic. First, batteries fail often, and to avoid regular breakdowns, you must initially buy expensive devices. Secondly, even more often the chargers break down, which, by the way, also cost not so cheap. The second problem, in principle, can be solved by yourself. It is enough just to understand how to charge the battery of an electric screwdriver without the charger. There are specific instructions, following which you will be able to get your electric screwdriver back in working order within a minimum of time.
Charging the electric screwdriver. Safety and precautions
Note that the following methods allow you to charge an electric screwdriver with direct current. It is necessary to constantly monitor the process and fully charge the battery. The point is that once the process is complete, the electrolytes inside the battery jars begin to boil. This contributes to a significant increase in the temperature of the battery itself. In addition, the slightest spark can cause the device to burst.
A set of materials for making your own charger
Naturally, to make the charger yourself, you will need additional materials and tools. This:
- An old, ruined battery.
- Two wires, 15 centimeters and longer.
- Charging cup.
- Heat gun.
- Soldering iron.
Most of the above you are likely to already have, so the expense of building the device will not be large. First remove the terminals from the old battery. Use a soldering iron for this. To avoid reversing the polarity, make the marks directly on the body of the device. Now you need to adjust the holes to the right size using a knife. Next, pull the wire through the prepared holes and solder to the charging cup, taking into account the polarity. The construction is still pretty fragile, so put some cardboard in the case. Fix the bottom part of the battery directly to the charging cup. You have a ready made construction. Now you can insert it into the adapter and fix it into the battery itself.
How to properly charge an electric screwdriver battery without a USB charger
To make a charger that works with a USB port you will need
- 10A fuse.
- Any USB charger.
- 220V power outlet.
- Duct tape.
- The paint.
The process of charging an electric screwdriver from USB
First we have to disassemble the tool itself. Separate the upper working part from the handle with a knife. In the handle is made a special hole, where the fuse for 10A will be installed. The wire is connected to the fuse with a soldering iron and the construction is inserted into the body of the handle. To fix the fuse, use glue and a heat gun. It is recommended that you wrap tape around the handle for greater reliability. The resulting device is inserted into the battery of the electric screwdriver. The remaining wires are mounted in the upper part of the electric screwdriver. The body is wrapped with electrical tape, painted and sanded. The detailed circuit looks as follows: The detailed process of such charging the battery of a cordless electric screwdriver is shown in this video:
Using an external power supply
This is not the most convenient option in terms of operation. In case the instrument is already old and it is too expensive to purchase additional equipment for it, it can be used. For this upgrade, the battery with the appropriate voltage is suitable. Using a powerful battery, you should provide protection for the motor. The simplest variant is a 10A fuse, installed in the power supply circuit. Do not forget that the wires, when using low voltage, should have a larger cross section than when powered from 220 V mains.
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When using non-standard equipment to charge an electric screwdriver, make sure that the devices are connected correctly, that the charging mode corresponds to the technical characteristics of the battery, ensure the safety of the process.
Do I have to charge it before storing it for a long time?
If the electric screwdriver stopped charging, you can never disassemble the tool yourself, otherwise you can lose your warranty. It is best to take the broken device to a service center. Sometimes the instruction manual will tell you what to do in this situation.
Correct charging of the battery is the key to its proper operation. If you don’t ignore the rules you won’t need a new battery soon.
What voltage and current is harmless to charge the car battery
We decided to write this article when we came across one of the “service centers” on the charging of the battery. Chargers are represented by. diode bridge transformers. Even more disappointing were advices on the internet: “unscrew the banks before charging”, “find a charger supplying 16V-16.5V”, “achieve good outgassing”, “charge long with small currents”.
Charging A Drill Battery Without An “Official” Charger
We recommend to unscrew the plugs in the battery before charging (if you have them) for the owners of Chinese or grandfather’s charging. Such chargers are assembled according to the scheme “transformer plus diode bridge”. They can supply any voltage, even 20 V. Boiling when charging the electrolyte may be such that the case will burst.
Do not charge batteries you have brought in from the cold; let them warm up indoors for several hours. You also can’t charge a battery that’s too hot. Charging is safest and most efficient at room temperature.
Practically useless to charge battery discharged below 8 volts, most likely one of the batteries in it is short-circuited or polarized. A normal regulator will not fully charge a very unbalanced battery: the voltage across the current terminals will not rise above 12.5 volts to 12.6 volts. Such batteries can be cured (fully charged) only by specialists. The lagging weak banks should be charged separately at 2.4 volts with 0.1 current of the whole battery in pulsed mode.
IMPORTANT ! Working voltages of the modern battery, below which it is IMPOSSIBLE to discharge 10,8 V and above which it is IMPOSSIBLE to raise when charging 14.4 В.
The 15-16 volt voltage that most cheap Chinese chargers charge with is a strong boiling point, destroying the bubbles on the electrodes. The resulting sludge does not fall to the bottom, but remains on the plates, held by the separator envelopes. The access of the electrolyte to the active mass of the electrodes is partially blocked. Capacity and cold start current drop.
In older battery designs. boiling while charging did not have this effect. Sludge has crumbled to the bottom. to its allotted place.
At 16V charging voltage, if you do not unscrew the battery caps and do not let the gases escape, the battery will simply inflate or crack its case. There is no need to unscrew the covers for normal charging voltage. In some batteries they simply do not exist.
IMPORTANT! Battery malfunction can be detected by the charging process. A dead battery is no longer capable of accepting charge currents above 1 to 2 Amps. A sign of a battery that has died from severe sulfation is the following: even at low charging currents the voltage immediately rises to a maximum of 14.4 volts. By the battery voltage (12.7-13 V) it looks like it is fully charged. Worthlessness is indicated by the test with a fork or a car starter. the voltage on the terminals immediately drops, the engine does not start. This sulfation is most likely irreversible and the battery should be recycled.
IMPORTANT! Do not charge with a current higher than 1/10th of its capacity, also too small currents lower than 1/20th are useless. For standard 60 Ah batteries the normal charging currents are from 3A to 6A (7 to 9 Ampere when charging in “current feed pause” mode). In a battery the charging current will start chemical reactions. The reactions depend on the amount of active mass on the plates and its thickness, the electrode area, the temperature range, the undesirable process of electrolysis of water. A too low current will not charge the entire bulking volume of the electrode but only the very top layer. After that the voltage will rise to 14V or more signaling the end of the charge. The electrolysis of the water will begin. Continuing to charge such a battery with a low current is impossible, as there will be passivation of electrodes. the plates will lose their ability to accept normal charging currents at all. If the charging current in the battery is too high, unwanted chemical reactions will occur, which in addition will be too violent and destructive. If the current charge is too high for a particular battery, because of the “extra current” begins abundant release of hydrogen and oxygen from the electrolyte. boiling, “gurgling” in the jars. Bubbling destroys the layer of the filler, and free oxygen oxidizes the lead in the plus plates, turning them into a soft easily destroyed by vibration lead oxide “spongy lead”. In a good battery, when you stop applying current, the boiling should stop immediately.
It is also harmful to store the battery at a constant low charging current. If you charge an already charged battery. the positive plates will oxidize and the water will “boil off” from the electrolyte. The result is a battery with corroding electrodes, loose jumpers, and a high self-discharge rate.
The process of charging the battery should be controlled visually, watching the electrolyte does not “boil”, which usually happens at voltages above 14.4V; and with the help of a multimeter, measuring the voltage and current of charge. Cheap antimony batteries always boil. Also there will be bubbles when charging a sulfated battery. Low-power charger (1-2 Ampere current) will not charge even a 60Ah battery. It will definitely raise the NRT of the battery to 12.7V, but it will add a lot of health problems to the battery. In the case of more powerful chargers there is a problem of “excessive current” and rapidly increasing voltage, leading to destructive for the battery electrolysis of water. It’s optimal to charge the battery even with “grandfather’s” charger plugged into the socket with the help of the timer in the drip charging mode: after a short period of current supply (10-30 sec) turn the charger off for a while (10 sec), then on again and then off again. This is how most of the rules for charging a battery are followed. The charge is carried out with a strong current, the voltage does not rise prematurely; at the moment of disconnecting the charger the battery “assimilates” the chemical processes of the charge received, the voltage does not rise too rapidly, the water “boiling” process does not occur. You can connect the charge through an electronic on/off timer for the socket, or you can feed the charge through a homemade multivibrator “blinker. The simplest blinker is made from a turn signal relay. There are diagrams on the internet. The on and off time is set by experimenting with the charger and battery characteristics.
It is best to charge the battery with a modern “smart” charger that has “brains” inside. processor. Such charger is capable of selecting currents and voltages of charging and can control them.
Find out the charging time of your battery
The 12 volt battery of a car is charged when its voltage and current values do not change for 2 hours. Saving settings for 1 hour is sufficient for full operation. This usually occurs at 16.3 (±0.1) volts.
Charging lithium polymer batteries
Lipo 3.8 V batteries can be charged with the devices that come with them, or with chargers like the Imax B6.
Batteries are charged at 20 to 100% of their nominal capacity. Lower values are preferable for the battery. The main question is what voltage a charged battery shows? Once 70-80% is reached, charging begins at a constant voltage and decreasing current.
Special devices for Lipo 3.8 V signals the end of charging when 70-80% of capacity is reached. Further density setting provides more infrequent charging, but reduces the life of the battery as a whole.
When charging a 3.8 volt lithium polymer battery, the charger should read 4.2 volts. It will take slightly longer to charge at 4.1 volts, but the battery will last much longer.
How to charge without a native charger?
If you have chosen the solution of charging the device by car charger, you must first set the minimum value on the device. The battery is removed, determine its polarity (find the “plus” and “minus”). After that connect the charger terminals directly to it. If it is impossible, the knot is improved, for which plates or clips are used. Charge the battery for about 15-20 minutes and turn it off as soon as it has become warm. Usually a short charge time is sufficient in this case. As for the charging current, it should be between 0.5 and 0.1 depending on the capacity of the battery itself in ampere/hours.
An 18 volt battery with a capacity of 2 Ah needs a battery charger with an 18 volt charging current and 200 mA per hour. It is preferable that the charger values are about 8 times less. To supply current it is necessary to use special crocodiles, hanging them on the current-carrying plates of the battery connector. It is important that the charger itself has a jack for charging.
If the charger is built into the battery, you can charge it with an adapter that lowers the voltage. In this case, you can pick up a universal charger in the store. If not, you will need to either repair your current charger or look for an analog battery charger. It is important to use a battery charger with current control function, charging the battery for a few hours.
It is preferable to secure the alligators by means of metal wires so that the contact is sufficient. The voltage should match the battery pack. Only place such a battery on charge when there is residual charge. If the parameters of the devices do not match, but have slight differences, in some cases short-term charging is possible. But, as a rule, it leads to a rapid breakdown of the battery.