Best 18V screwdrivers
Real professional models that are suitable for any construction, repair and installation work. They can be used in batch production conditions when it is required to regularly work with a large amount of fasteners. Looking further at the description of three popular models, you can try to determine for yourself which professional cordless screwdriver is better.
Basic concepts
What the battery capacity says. Capacity, the unit of measurement for which is called ampere-hour (A / h), determines how long a tool can run on a single charge. Accordingly, a distinction is made between household instruments (with a capacity of 1.3 to 2 A / h) and professional ones with a capacity exceeding 2 A / h.
Charging speed. It is important when you need to get work done quickly. For a household instrument, and not too expensive, this characteristic varies from 2 to 12 hours. But professional models can be charged in time, or even in half an hour. Typically, these tools have lithium batteries and a pulse charger.
Battery voltage. The battery voltage can range from 3 to 36 volts. At the same time, the torque in the 14.4 V and 12 V models can be the same. In turn, the torque determines the power of the screwdriver and you might think that buying a tool with a high voltage is NOT advisable.
In fact, a 14.4 V battery is able to maintain the maximum power of the tool for a longer period and, as a result, is able to work for a longer time, by the time the drop in battery charge begins to reduce the power of the Screwdriver.
Comparison of different types of batteries:
| Li-Ion | NiMh | NiCd | |
| memory effect | No | Yes | Yes |
| storage conditions | fully charged | partially discharged | completely discharged |
| charging conditions | At any time | Only after a complete discharge | Only after a complete discharge |
| Number of charge / discharge cycles | 600 | 300.500 |
Dewalt DCD791P2
Main characteristics:
- Chuck type. Quick-clamping;
- Maximum torque, (Nm). 70;
- Battery capacity, (Ah). Five,
- Battery type. Li-Ion;
- The number of batteries included. 2.
Body and ergonomics. This model is housed in a compact plastic case with a raised rubber grip. It can be carried on a belt, which is convenient when working at height and frequent movements. The handle has a built-in LED flashlight, the brightness of which can be adjusted. Due to the increased power, the tool weighs 1.7 kg.
Engine, gearbox, battery. The screwdriver is powered by a brushless electric motor, which does NOT overheat even with intensive use. It has two speeds with smooth acceleration up to 550 and 2000 rpm. To increase the operating time, two lithium-ion batteries with a capacity of 5 Ah are used.
Keyless chuck is made entirely of high quality steel. Maximum torque of 70 Nm allows you to work with self-tapping screws of any running size.
Dewalt DCD791P2 complete set.
Functional. A tooling with a shank diameter of up to 13 mm is inserted into the screwdriver. Its power is sufficient for drilling 40 mm round holes in wood. Reverse and motor brake option available.
Pros of DeWALT DCD791P2
- Powerful and reliable electric motor.
- Full metal gear and chuck.
- Electronic speed control.
- Large battery capacity.
- Adjustable backlight brightness.
Case.
Cons of DeWALT DCD791P2
- High price.
- Perceptible weight.
Makita DF333DWAE 30 Nm
Main characteristics:
- Chuck type. Quick-clamping;
- Maximum torque, (Nm). Thirty;
- Battery capacity, (Ah). 2;
- Battery type. Li-Ion;
- The number of batteries included. 2.
Body and ergonomics. All elements of the outer shell of this screwdriver are made of durable plastic, which allowed the developers to keep within the weight of 1.1 kg. Rubber pads on the handle and the protruding parts of the body not only contribute to a secure grip, but also soften the impact in the event of a fall. There is a spring clip for wearing on a waist belt. Built-in LED lamp illuminates the work area well at night.
Engine, gearbox, battery. The screwdriver is equipped with a reliable electric motor with a good air cooling system. Powerful enough to work with screws up to 5 mm in diameter. The model has two rotational speeds with a maximum frequency of 450 and 1700 rpm for operations with fasteners and drills. Keyless chuck holds tooling with cylindrical shanks with a diameter of 0.8-10 mm.
Includes a pair of 1.5 Ah universal lithium-ion batteries with charge level indicator, which can be used with other instruments of the same brand. It takes less than an hour to charge each of them in a standard device.
Complete set Makita DF333DWAE 30 Nm.
Functional. The maximum torque is 30 Nm. It can be reduced by rotating the drum. There is a reverse option and electronic speed control.
Pros of Makita DF333DWAE 30 Nm
- High performance.
- Large torque.
- Comfortable shape.
- Universal batteries.
- Large case made of durable plastic with compartments for tools and consumables.
- Acceptable cost.
Cons Makita DF333DWAE 30 Nm
- When working on the reverse, the chuck is loosened.
- The lamp is located close to the body, so it does not illuminate the entire working area.
BOSCH GSB 180-LI
Main characteristics:
- Chuck type. Quick-clamping;
- Maximum torque, (Nm). 54;
- Battery capacity, (Ah). 2;
- Battery type. Li-Ion;
- The number of batteries included. 2.
Body and ergonomics. The screwdriver body is made of impact-resistant plastic and has elastic pads on the handle. Successfully balanced design with a total weight of 1.64 kg, suitable for professional use. The bottom-mounted battery acts as a stand when installed vertically. LED illumination helps you navigate the work area even in poor general lighting.
Engine, gearbox, battery. The brush motor operates stably when driving screws up to 10 mm in diameter and drilling holes up to 35 mm in wood. The speed switch sets the modes with a maximum speed of 450 and 1700 rpm. Keyless chuck is capable of holding drills and bits with diameters from 1.5 to 13 mm. A pair of 2 Ah batteries for continuous operation without interruption.
BOSCH GSB 180-LI complete set.
Functional. This drill / driver is capable of working in drilling, perforated drilling and fastening tightening modes. Rotation is possible in two directions. Torque is stepped, ripens maximum at 54 Nm.
Pros of BOSCH GSB 180-LI
- High power.
- Large torque.
- Comfortable shape.
- Two batteries with charge level indication.
- Easy replacement of motor brushes.
Backlight. - Shock mode.
- Relatively low cost.
Cons of BOSCH GSB 180-LI
- Slight chuck runout.
- With intensive use, battery overload protection is often triggered.
BOSCH GSR 120-Li
Main characteristics:
- Chuck type. Quick-clamping;
- Maximum torque, (Nm). Thirty;
- Battery capacity, (Ah). 2;
- Battery type. Li-Ion;
- The number of batteries included. 2.
Body and ergonomics. The drill-driver of this brand, due to its small dimensions and the use of structural plastic, weighs only 950 g. It has a comfortable handle with a raised surface for better contact. The battery inserted into the handle does NOT interfere with work in confined spaces. The LED light illuminates the drilling area well even at night. There is a slot for attaching a strap, which makes it easy to move with the tool at height.
Engine, gearbox, battery. The power of the brushed motor is sufficient for driving in screws with a diameter of 7 mm. The keyless chuck is suitable for bits with a thickness of 1 to 10 mm. The gearbox operates in two modes with a maximum speed of 380 and 1300 rpm. A pair of compact 1.5 Ah lithium-ion batteries when used alternately to minimize downtime.
Functional. The model is designed for drilling holes and working with fasteners. The torque reaches 30 Nm and is infinitely variable by means of a rotary drum. The direction of rotation can be changed by simply moving the corresponding switch. The tool is sold with a plastic case, charger and two batteries.
BOSCH GSR 120-Li complete set.
Pros of BOSCH GSR 120-Li
- Compact size and light weight.
- Good ergonomics.
- Rapid tool change.
- Illumination of the working area.
- Adequate price.
Cons BOSCH GSR 120-Li
- Cannot be placed vertically on the base of the handle.
- The cartridge loses its grip reliability over time.
Dewalt DCD710D2 24 Nm
Main characteristics:
- Chuck type. Quick-clamping;
- Maximum torque, (Nm). 24;
- Battery capacity, (Ah). 2;
- Battery type. Li-Ion;
- The number of batteries included. 2.
Body and ergonomics. This screwdriver has a balanced design and a weight of only 1.1 kg, which is important for long professional work. Its body is made of impact-resistant plastic. The handle, thanks to its rubberized surface and comfortable shape, fits the hand with confidence. At the bottom there is a slot for attaching a strap that frees your hands when moving at height. In low light conditions, you can turn on the built-in flashlight.
Engine, gearbox, battery. The 180 W brush motor output is sufficient for drilling holes up to 20 mm in diameter in wood and up to 10 mm in metal. The reducer has two gears with smooth acceleration up to 400 and 1500 rpm. The quick-release chuck allows you to work with shanks with a diameter of 1.5 to 10 mm, spending a minimum of time on replacement.
The model is sold complete with a charger and two slider-type lithium-ion batteries with a capacity of 2 Ah each. Alternating replacement during the shift Reduces downtime.
Complete set DeWALT DCD710D2 24 Nm.
Functional. By smooth rotation of the regulator with 16 standard positions, you can set the torque up to 24 Nm. Reverse key allows one movement to change the direction of rotation of the spindle. Motor brake prevents excessive indentation of the self-tapping heads when working on soft surfaces.
Control buttons DeWALT DCD710D2 24 Nm.
Pros of DeWALT DCD710D2 24 Nm
- Reliable engine.
- High performance.
- High-quality assembly.
- Convenient shape and light weight.
- Backlight.
- Two batteries included.
- Sold with a sturdy case.
Cons DeWALT DCD710D2 24 Nm
- Sun indicator of the state of charge of the batteries.
- You have to control the tightening of the cartridge.
- High price.
Best 14.4V screwdrivers
Such devices can already be classified as professional. They are able to help make holes of various diameters, as well as fix hardware. And no longer at home, but, say, in a workshop. Or during construction work.
Metabo PowerMaxx BS 12
Main characteristics:
- Chuck type. Quick-clamping;
- Maximum torque, (Nm). 40,
- Battery capacity, (Ah). 2;
- Battery type. Li-Ion;
- The number of batteries included. 2.
Body and ergonomics. This compact model is shortened in length and weighs only 1 kg. It has a raised handle, good balancing and a wide launch key. It can be placed vertically without fear of dust entering the interior. A well-positioned light bulb at the base of the handle provides good illumination of the work area Provided with a metal hook for carrying on a belt.
Engine, gearbox, battery. The robust brush motor does NOT overheat even when drilling holes in metal up to 10 mm in diameter. The two-speed gearbox provides a spindle speed of up to 360 or 1400 rpm. Keyless chuck is designed for tooling sizes 1-10 mm.
The torque is adjustable and reaches a maximum of 40 Nm. Two 2Ah lithium-ion batteries have no memory effect and are NOT self-discharging.
Metabo PowerMaxx BS 12 complete set.
Functional. The model is equipped with a reverse, dynamic brake, spindle lock.
Pros of Metabo PowerMaxx BS 12
- Compact dimensions.
- Convenient design.
- Large torque.
- Reliable materials.
- Two powerful batteries with charge level indication.
- Case and charging station included.
Cons of Metabo PowerMaxx BS 12
- The manufacturer saved on the quality of the plastic for the suitcase.
18650 batteries. which is better
18650 batteries are manufactured by many enterprises located in Southeast Asia. When choosing products, one should pay attention to the chemical composition of the element, to the presence or absence of a built-in electronic protective unit. Additionally, the current-voltage characteristics of the battery are analyzed, which will ensure the declared performance of the tool.
Aging, storage and operating temperature range
When storing lithium-ion batteries, there is a natural degradation in performance due to the compositional configuration of the anode and cathode. Manufacturers provide a 10% reduction in capacity for each year the item is in the warehouse (subject to storage conditions). If the battery is in inappropriate conditions, then the degradation processes are accelerated. The date of manufacture and expiration date are printed on the cell body, after which the manufacturer DOES NOT guarantee the battery performance.
It is forbidden to store products in conditions of high or low temperatures, place the packaging in direct sunlight or near heating devices. When the case temperature drops below 0 ° C, the lithium-ion battery loses up to 50% of its starting capacity. It is recommended to store partially charged batteries (30-50%) with periodic recharging. When storing discharged cells, the processes of destruction of the cathode and anode are accelerated, subsequent battery recovery is impossible.
How to know which 18650 batteries are better in terms of technical characteristics
To determine the optimal battery of the 18650 series, a calculation of parameters is used in accordance with Ohm’s law. To determine the parameters, you need to know the operating voltage U and the resistance of the device R, which is measured with a test device switched to ohmmeter mode.
Protected and unprotected lithium-ion batteries
Protected batteries are marked with the Protected prefix. On the negative pole is a metal shield, under which a round-shaped board from a microprocessor is installed. The protective block is connected to the positive terminal by a separate flat cable with insulators, which runs along the battery case. The node provides short-circuit protection and prevents excessive current flow during charging. Over-discharge protection is provided, when the voltage drops, the circuit opens.
To reduce the cost of the product, the practice of refusing to install the controller, the batteries are marked Unprotected on the case. Since the protective block is excluded from the circuit, it is recommended to install batteries in devices with reduced power consumption. The user independently controls the level of charging of the batteries; to restore the capacity, a microprocessor-controlled charging unit is used.
High-current 18650 batteries for a screwdriver: types of batteries and which ones are better to choose
Regular nickel-cadmium cells installed in hand tool battery banks have a reduced resource. The use of high-current 18650 batteries for the screwdriver allows you to increase the battery life of the tool. Stable battery performance allows high torque to be maintained until fully charged.
The current efficiency of lithium-ion batteries
The current output is an additional parameter that characterizes the battery, the value is applied to the battery case, measured in A (amperes) or mA (milliamperes). Batteries with a higher parameter are called high-current ones (marked High drain) and have a reduced capacity. When choosing a battery, it is necessary to take into account the characteristics of the electric drive, an increased load on the battery leads to overheating of the structure and premature failure of the unit.
Mechanical protection for lithium-ion batteries
To prevent explosion of Li-Ion type batteries, 2 additional protection methods are used:
- A mechanical switch that breaks the power circuit when the temperature of the battery case rises. The device prevents further heating of the element, leading to deformation of the case, rupture of the shell and fire.
- A safety valve used to bleed off excess gas generated during battery operation. Together with the gaseous products, a part of the liquid electrolyte is emitted, which destroys the contact pads and electronic components of the equipment. A battery with a blown safety valve is recommended to be replaced.
Old 18650 batteries as battery cells for drills, screwdrivers
To drive the electric motor of the screwdriver, you need to use 3 elements of the 18650 standard, which are combined in a series circuit. A capacity equalization board is used to charge cells at the same time and does NOT provide the battery life stated. To increase durability, it is recommended to use the off-the-shelf 3-channel charger supplied under the designation Imax B3.
In battery banks for screwdrivers, a discharge regulator is used, which may be discarded. Control is carried out visually by means of a LED located on the side of the tool body.
Algorithm for making a homemade battery can for a screwdriver based on lithium-ion cells of the 18650 series:
- Disassemble the factory battery, install the power supply in the lower part and solder the leads to the connector, which is installed in the window on the side of the case. It is recommended to install a knife-type fuse, rated for a current of up to 10 A, the cell is placed in the 18650 power circuit.
- Route the control diodes of the charging board into separate holes. The design includes red and green lamps. Battery charging stops when green light turns on.
- Modify the charging board by replacing the resistances responsible for the current in the charging circuit with elements with an increased value. Since the microcircuits of the unit heat up during operation, it is recommended to provide for the installation of an aluminum or copper radiator. The use of a heat sink increases the reliability of the device in conditions of increased temperatures and a closed case of a battery bank.
- Install the 18650 cells into the cover, the connection pins remain unchanged. The batteries are directly connected to the working contact plates of the can and are soldered with cables to the outputs of the charging unit. Copper stranded wire is used for the connection, ensuring the safe operation of the device.
- Test battery charging and screwdriver operation.
It is allowed to assemble a battery bank from elements equipped with leads for soldering connecting wires. The elements are welded at the factory, the design allows you to assemble a jar with increased capacity. To connect the elements, a copper cable or a jumper with a cross section of at least 1.5 mm² is used.
Types of lithium-ion batteries
The industry produces several varieties of 18650 series batteries:
- Lithium-cobalt cell designed for use in devices with reduced energy consumption.
- Lithium-manganese node featuring increased power and improved stability.
- Lithium-nickel-manganese-cobalt-oxide battery with increased power and energy intensity. To further improve the performance, silicon alloying of the anode is used, but the material negatively affects the battery life. Devices are used to drive electric motors in tools or vehicles.
- Lithium-iron-phosphate battery, resistant to over-discharge and adapted to be installed instead of sulfuric acid batteries in traction drives.
- Lithium-nickel-cobalt-aluminum-oxide cell with increased power and extended service life (in comparison with lithium-cobalt type products). It is better not to use the device for screwdrivers, since the battery retained the main disadvantages of lithium-cobalt batteries.
- Lithium titanium assembly equipped with a lithium titanate crystal anode. The cathode is made of graphite, the voltage at the terminals is 2.4 V. The device supports accelerated charging modes, allows operation at low temperatures. The drop in capacity when cooled to 30 ° C does not exceed 20%. The product is NOT susceptible to thermal breakdown, but low energy consumption and increased cost inhibit the spread of lithium titanium cells.
Lithium-ion battery capacity
Battery capacity is measured in ampere hours (Ah) or milliampere hours (mAh). This characteristic determines the duration of operation at normal load until the capacitance drops to zero. These batteries have a reduced memory effect (capacity drop when recovering a partially discharged battery).
Li-ion batteries, due to the presence of the controller, DO NOT allow complete discharge, which destroys the cell. The overvoltage during charging is also limited, so there is no drop in capacity. Overvoltage by 4% Reduces the capacity by half. Subsequent charging. twice more.
Lithium manganese cells
Their advantage is stable work. In addition, they are safer than lithium. cobalt. Long service life even with low resistance (increased recoil currents).
Disadvantage. they are afraid of overheating. Their capacity is lower than nickel. cobalt elements by 30% with the same dimensions.
18650 batteries. which is better
The main ones are as follows:
- Chemical composition;
- Availability of protection (electrical and mechanical)
- Current-voltage characteristics.
Lithium cobalt
These batteries have the largest charge capacity. Their disadvantages are as follows: cannot be operated in devices with a heavy load, cannot be used for quick recharging. the elements can overheat and even ignite.
High-current 18650 batteries for a screwdriver: types of batteries and which ones are better to choose
The first Li-ion battery was created in 1994 by Sony. Now they are used in all household appliances, and handheld power tools are NOT an exception. Tools equipped with nickel-cadmium elements have a reduced resource. The use of high-current 18650 batteries for the screwdriver will allow you to extend the battery life.
Types of lithium ion batteries
18650 batteries have different specifications.
The parameters are influenced by:
- Foil thickness;
- Separator thickness;
- Particle size of the active mass;
- Electrode thickness;
- Cathode material.
Cell models for high power are equipped with electrodes of the appropriate size and weight to prevent overheating. Also, the charge current is increased by adding all kinds of substances to the electrolyte.
Marked in accordance with the cathode material:
- ICR. Uses cobalt oxide for low power devices. These items have a large capacity.
- INR. nickel manganese and cobalt oxides. They guarantee increased power and energy consumption. Used to ensure the operation of engines in tools and vehicles.
- IMR is manganese oxide. Elements have high power and stability.
- NCR. oxides of nickel, cobalt and aluminum. Provide increased power and long service life. Low current output.
- IFR. iron. phosphate. provide resistance to overdischarge. Used to replace sulfuric acid batteries in traction motors.
Protected and unprotected lithium ion batteries
The presence of protection in batteries is indicated by the Protected prefix in the marking (or they write Shot circuit). Sometimes the protection is not indicated in the marking.
If there is a protection controller, then the marking looks like this: Unprotected. This is done to keep costs down. Such elements can only be put on appliances with low energy consumption. The user controls the charge level. It uses a microprocessor-controlled unit.
Aging, storage and operating temperature range
Lithium ion cells are sensitive to storage conditions. Do not store packages in direct sunlight or near heating appliances. Even worse, they tolerate temperatures below 0 degrees (with a single drop, the capacity decreases by 50%). Even if you adhere to the rules and store the elements at a temperature of 5. 15 ° C, manufacturers lay down a ten percent decrease in capacity per year from the declared.
With proper operation, excluding overloads or deep discharge, the cells can withstand up to a thousand recharges.
Old 18650 batteries as battery cells for a drill screwdriver
To replace old cans, three 18650 cells are used, assembled in series. A capacity equalization board is used for simultaneous charging. But It does not provide normal battery life. To correct this drawback, use a three-channel charger with the designation Imax B3.
The old battery banks used a discharge regulator. Now they refuse it, and the control is carried out by the LED (visually). The LED is located on the side of the screwdriver body. The dimensions of the new cells are smaller, you can put the charger in the battery pack in old banks. You just need to provide a connector for connecting to the network.
The sequence of replacing nickel-cadmium cells with lithium ion is as follows:
- Disassemble the battery and remove the old cells. At the bottom, install the power supply and pinout. A 10 A fuse should be provided.It is better to use an automobile (from imported cars).
- Display two colored LED indicators (red. charging, green. charging completed).
- Replace the resistors that regulate the charging current with more powerful ones. Install the microcircuits of the block on the radiator.
- Install the 18650 cells. Solder to the outputs of the charging unit and contact plates. Use a stranded copper wire with a cross section of at least 1.5 sq. Mm.
- Assemble, test the charging process and the operation of the screwdriver.
It is also important to know 3 nuances in getting started.
- First you need to decide on the number of cells in the battery. It is best to use 4 cells as three will only give 12.6 Volts.
- We collect the 18650 battery, you need to pay attention to the capacity and discharge current. When the battery is operating, the current consumption is in the range of 5 or 10 amperes, but if you sharply press the power button, it can jump up to 25.This means that the maximum discharge current should be about 30 amperes on an 18650 battery.
- You should also pay attention to the controller. Its characteristics should be equal to the rated voltage and discharge current. For a 14.4V battery, the controller is the optimum voltage. The operating current must be several times less than the maximum permissible.
3 pros and 5 cons of rework for a screwdriver
- The energy density of the elements will be better than that of nickel-cadmium. This means that the screwdriver will retain its original weight, even slightly lighter, while the output voltage remains within the normal range.
- Lithium batteries charge much faster than others. It only takes one time to charge them safely.
- Lithium-ion batteries have a memory effect. From this we can conclude that there is no need to completely discharge them before installing them on the charger.
- If you install a lithium battery, you will have to carefully monitor it: when charging. above 4.2 Volts, it cannot be charged, and discharged by less than 2.7 Volts. Otherwise, the battery will simply fail.
- 18650 cans are used as lithium cells. They differ in size from nickel-cadmium. In addition, you will have to find a place for the charge controller of the discharge of the wires. And all this should somehow fit into the body Screwdriver.
- The charger for cadmium batteries may NOT be suitable for rework. You may have to additionally look for a universal charger.
- It will NOT work outdoors in winter, as the lithium battery does not tolerate negative temperatures well.
- Li-ion battery costs more than cadmium.
Answers:
- B) It is advisable to take the Chinese KEEPPOWER batteries. Samsung does not release models with protection.
- A) The correct output readings are 5 Volts and a current from 0.5 to 1 of the nominal capacity of the battery itself.
- A) 10. 25 are ideal indicators. Do not place the battery in any other environment.
- A) Two stages. first with a voltage of 0.2-1, and then with a high constant.
- A) Only one. A high voltage is immediately applied to the element. The rest of the stages are missing.
The problem with a NiCd battery installed in a screwdriver is that it needs to be used constantly. If the battery is completely discharged or is not used for a long time, then the crystallization process will begin in it, and the battery will soon fail altogether.
It costs a lot of money to replace the battery as batteries that fit a screwdriver are expensive.
For these reasons, the owners of screwdrivers slightly alter the battery in order to connect lithium cells to it. But before starting such work, you need to think about whether it is necessary to make such an alteration and whether it is advisable at all.
Definition An 18650 battery is a 3.7V battery.
What are the best 18650 batteries for a flashlight, screwdriver
- When purchasing 18650 batteries for flashlight with protection, which manufacturer is preferable?
- What indicators should chargers give for 18650?
A) The output is 5 volts and the current is from 0.5 to 1 of the nominal capacity of the battery itself.
B) The output is 10 Volts and the current is from 1 to 3 of the nominal capacity of the battery itself.
- In what temperature range is it desirable to store the battery?
A) 10. 25 are ideal indicators. Do not carry the battery in extremely cold or hot places. B) At a temperature of 20. 45 degrees.
- How many stages does a lithium battery go through??
- How many charging steps are there in a lithium battery that takes less than an hour to charge?
How to avoid 4 mistakes when assembling 18650 charging
To properly connect lithium cells to the battery, you will need to follow the instructions exactly:
-
We disassemble the battery case. In the 14.4 model, you can find 12 1.2 Volt nickel-cadmium batteries. Here we immediately get rid of this coupling. we bite off with pliers. As a result, you get only a connector with “plus” and “minus”.
Body
Chargers for 18650 batteries
The 18650 battery will have to use the correct charger. At the output, it will give out 5 volts and a current from 0.5 to 1 of the nominal capacity of the battery itself. If the lithium cells support 2600 mAh, then a current of 1.3-2.6 amperes should be used to charge it.
The lithium battery charger charges the battery in several stages:
- First, a voltage of 0.2-1 is applied to the battery.
- Further, charging already takes place at a constant voltage.
If the charger has a pulse mode, it will significantly speed up the charging time.
In the event that the battery contains graphite, then the voltage does not have to exceed 4.3 Volts per cell. If this indicator is exceeded, then the energy density will increase, and the oxidative process will go.
There are lithium batteries that take less than an hour to charge. The second stage is not provided in them. the current is immediately supplied to 80% and after that it is put into operation. It is normal for a lithium type battery.
Features of choosing a screwdriver battery
The problem of which type of battery is best for screwdrivers cannot be resolved unambiguously. The most important selection factors:
- Cost accounting;
- Operating conditions;
- The desired characteristics;
- Ecological problems.
For rare home use, when it is necessary to work or store in low temperatures, an unambiguous choice of nickel-cadmium inexpensive batteries, which are usually completed with budget household models of screwdrivers.
For regular professional work in positive temperatures and rooms, it is preferable to choose Li-Ion batteries. They have the best combination of characteristics and charge faster. However, over time, their parameters deteriorate. Most of the latest professional screwdrivers are equipped with lithium-ion batteries to increase power and reduce the weight and size of the equipment.
Lithium-ion batteries
The mass production of lithium-ion batteries was started in 1991 by Sony Corporation. Due to their advantage, they have practically supplanted other types of batteries in the production of smartphones, tablets, laptops and won a significant share of the market for batteries for power tools. The following positive characteristics of Li-Ion cells should be noted:
- Increased specific capacity at the level of 110-230 V x h / kg
- Self-discharge reduced to 3-5% per month;
- Complete absence of memory problems;
- Excellent environmental friendliness;
- No problems with disposal;
- Reduced by almost 40% weight;
- Compactness;
- Accelerated charging.
However, due to a number of shortcomings, they could not completely replace nickel-cadmium batteries. Key problems with Li-Ion batteries:
- High price;
- Accelerated discharge at negative temperatures;
- Danger of complete discharge and overcharge;
- Shorter service life;
- Explosion hazard on impact.
Due to the decay actions of lithium, the service time is limited even without operation.
This explains these three main types of screwdriver batteries:
Which battery is best for a screwdriver
Convenient, mobile cordless power tool has long entered our life, making it more comfortable. Cordless screwdrivers have become especially in demand, rather than those requiring an electrical connection. They are essential for professionals, increasing the productivity and quality of their work. The use of such screwdrivers in everyday life is also constantly expanding, thanks to the facilitated and accelerated solution of numerous problems. The most important element that determines the quality, reliability and performance of a mobile power tool is its battery. And the question of which battery is better for a screwdriver becomes decisive when choosing it.
- Screwdriver battery characteristics
- The main types and parameters of batteries used in screwdrivers
- Nickel-cadmium batteries
- Nickel-metal hydride batteries
- Lithium-ion batteries
- Lithium polymer batteries
- Lithium Polymer Battery Precautions
- Features of choosing a screwdriver battery
- Useful
Lithium Polymer Battery Precautions
When using lithium polymer batteries, safety precautions must be strictly followed. To charge the device, only a “smart” charger is used, which performs certain functions:
- Monitors voltage within the maximum allowable 4.2 V;
- Maintains the required parameters of the charging current at the maximum;
- Equalizes and controls the voltage in each battery cell separately;
- Multifunction devices are also capable of keeping an eye on temperature and charging time limits.
In this case, the battery must be discharged under control, otherwise a voltage drop in each cell below 3.2 V will lead to a rapid loss of device capacity and a decrease in operating cycles. In addition, at lower rates, a short circuit may occur, which will provoke the device to warm up and lead to the likelihood of an explosion.
Temperature also plays an important role in the use of lithium polymer batteries. It is not recommended to allow the temperature of the device to rise above 60 ° C during discharging. This can lead to spontaneous combustion, and subsequently to an explosion of the product.
It is not recommended to charge the battery at home in order to avoid the negative consequences of overheating the battery. It is best to store lithium-polymer products at temperatures from 5 to 28 o C. During the period when the screwdriver is not used, the battery still ages, so there is no need to purchase the device for future use. When buying, you should carefully study the date of manufacture, because over time, batteries lose their capacity even during storage.
The main types and parameters of batteries used in screwdrivers
Power, duration of autonomous use, torque, reliability and durability of a screwdriver is largely determined by the type and specific characteristics of the installed battery. There are four main types of batteries used for modern power tools:
- Nickel-cadmium type conventionally designated Ni-Cd;
- Improved nickel-metal hydride batteries, which correspond to the Ni-MH symbol;
- Modern lithium-ion models, otherwise referred to as Li-Ion;
- Lithium polymer batteries, or LIPO.
Often the battery type designation is present in the model name of the screwdriver. And, I read on the Bosch GSR10.8-2LI Professional power tool, it can be said with confidence about the use of a lithium-ion battery, and in the Metabo BS12NiCd model there is a nickel-cadmium battery. But in some cases, for example, Rostec ASh1812-2B, the presence of a nickel-cadmium battery can only be determined by the device’s passport.
Nickel-metal hydride batteries
Nickel-metal hydride batteries, created in the eighties of the last century, were designed to eliminate the toxicity problem of nickel-cadmium batteries. They really solve environmental issues and are easy to dispose of. Additional advantages are the reduced weight and dimensions of such batteries by a third, increased capacity in the range of 60-70 V h / kg, and a noticeable reduction in memory problems. However, NiMH cells could not push out nickel-cadmium batteries.
The reasons blocking the widespread adoption of nickel-metal hydride batteries are the following disadvantages:
- The number of working cycles reduced to 500;
- High price;
- Incomplete elimination of the memory effect;
- Self-discharge within 7-10%;
- Lack of resistance to low temperatures.
Therefore, their use is limited. Nickel-metal hydride batteries also require full discharge during operation.
Screwdriver battery specifications
The main characteristics that determine the performance of a power tool battery include:
- Capacity, which determines the duration of autonomous operation and is measured in A / h;
- Voltage in volts (V) affecting power and torque;
- Charging speed in hours, ensuring ease of use;
- The allowable number of charging cycles affecting durability;
- Self-discharge level in percent month.
For household screwdrivers, batteries with a capacity of 1.3 to 2 A / h are usually used. Professional models have more stringent requirements for operating time, and batteries with a capacity of less than two amperes / hour are not used for them.
In a power tool, rechargeable batteries with a voltage of 3.6-36 V are usually installed. often, these are values from the range 24, 18, 14, 4, 12 V, multiples of 1.2 V. Voltage over 36 V is usually not used for safety reasons, since the required insulation will affect the weight, size, complexity and reliability of the model. For new Li-Ion batteries, the multiplicity is 3.6 V, which allows you to reduce the number of batteries and reduce the size of the compartment.
For household models, the charging speed is within 2-12 hours, and for professional screwdrivers 0.5-1 time. Modern models with Li-Ion batteries are equipped with pulse chargers that speed up the process.
The number of allowable charging cycles, battery life, self-discharge level, operating features directly depend on the type of battery. Let’s take a closer look at which 18650 batteries are better for a screwdriver.
Nickel-cadmium batteries
Nickel-cadmium batteries were created in the 19th century, but their modern design appeared in the forties of the last century. Despite the development of more modern battery options, they continue to be widely used for cordless power tools, due to their key advantage. a combination of low cost with a large current generated and increased durability, reaching about 1000 charge cycles. At the same time, they charge quickly enough, and are not afraid of low temperatures and overcharging.
However, there are serious disadvantages in nickel-cadmium batteries:
- Memory problem;
- Considerable weight and dimensions;
- The presence of highly toxic materials in the structure;
- Increased complexity of disposal;
- Self-discharge at the level of ten percent per month;
- Low values of specific energy consumption of about 45-65 W x hour / kg.
The key problem, called the memory effect, is that if the battery starts charging at a certain level of charge, then the total capacity decreases by this value.
Therefore, many models with nickel-cadmium batteries are equipped with two sets of batteries, for example, Stern CD06-168 B. Despite the large number of operating cycles, the service life of Ni-Cd batteries due to degradation of the contact material usually does NOT exceed 6 years. Long-term storage of such a battery must be done in a completely discharged state.
The second main drawback of THESE batteries is the high toxicity of cadmium, so such cells are produced only in three countries.
Lithium polymer batteries
The cordless instrument is easy to use and does NOT generally depend on an electrical outlet nearby. For the effective use of the screwdriver, a rechargeable battery is required. Depending on the composition, the properties of the battery differ and represent different characteristics during operation.
On the market you can find a large selection of batteries for construction tools, including the latest development in the form of a lithium polymer device. The battery of the latest generation works on the principle of its predecessor. the lithium-ion battery. The difference is the use of a gel-like substance instead of a liquid electrolyte.
Lithium polymer batteries have several advantages:
- Less explosive than lithium-ion batteries;
- Do not have a memory effect, which means they do NOT require a complete discharge;
- Show resistance to external mechanical stress and vibration.
Despite the significant advantages, rechargeable batteries for screwdrivers are still endowed with some disadvantages:
- Poor tolerance to low temperatures;
- Short service life. about 2-3 years;
- Low number of work cycles. no more than 500;
- Increased requirements for operating conditions.
Construction tools using lithium-polymer batteries are quite rare, which is justified by the high cost of the device technology.