disadvantages
Cons are found in batteries of any type. If we speak in relation to these, then they have the following:
- Large dimensions and substantial weight;
- The presence of a pronounced memory effect.
There is another problem with nickel-cadmium batteries. The thing is that there is a high probability that soon the popularity of THESE products will come down on comments. The basic premise for this is that cadmium is a toxic material. In addition, such batteries must be disposed of in a special manner. The procedure itself is quite expensive. As for everything else, there are simply any competitors in such batteries.
By using a nickel-cadmium battery for your tool, you can ensure efficient operation in the following situations:
- Reliable operation of the device is required;
- Users want to purchase a battery with a long service life, which is able to withstand more than one thousand charge and discharge cycles;
- It is necessary that the storage life of the battery is long;
- Performing work requires the use of large charging currents;
- The work will have to be carried out in difficult operating conditions;
- Often there is a need to perform work in low temperature conditions;
- Requires a battery capable of maintaining the voltage at a stable level throughout its life.
Thus, such batteries are an excellent choice For her only for screwdrivers, but also for any power tool.
disadvantages
Batteries of this type also have disadvantages. If we talk about the most important disadvantages, then the following can be distinguished:
- They do not tolerate low temperatures;
- Their service life is shorter in comparison with nickel batteries;
- They are unpretentious to use;
- They are characterized by relative explosiveness;
- There is absolutely no way to restore them;
- The cost of such products is quite high;
- A prerequisite for their use is the use of native charging.
Nickel-cadmium
These batteries appeared over a century ago. However, despite their long history, they surpass modern types of storage batteries in a number of performance characteristics.
disadvantages
Batteries of this type are NOT without drawbacks. If we talk about the most serious, then we can list the following:
- The battery is discharged rather quickly;
- It cannot be used at temperatures below minus 10 degrees;
- The battery capacity can be restored, but no more than in half the cases;
- The battery life of this type is noticeably lower than in nickel-cadmium analogs;
- High price;
- High sensitivity to deep discharge;
- These batteries take longer to charge.
Thus, we can say that nickel-metal hydride batteries are in many ways inferior to nickel-cadmium products in terms of their performance. And although they are used in the Screwdriver, but from the user’s point of view, choosing them in favor of them is not the best solution.
Nickel metal hydride
The development of this battery was carried out in order to solve the main problems that appear when using nickel-cadmium batteries in a screwdriver. These more advanced products offer the following benefits:
- Less weight and compact size;
- Low toxicity;
- The presence of a mild memory effect;
- The presence of a higher specific capacity;
- The presence in such products of high resistance to mechanical damage.
Li-ion
Many manufacturers are actively promoting lithium-ion batteries. Such products have both advantages and certain disadvantages.
Accumulators and batteries
Energy storage information website
Alteration of the screwdriver Makita lithium battery
there is Makita a screwdriver with a 1.3 A / h battery and a voltage of 9.6 V. To change the power source on it to a lithium-ion one, you will need 3 18650 components. The alteration will provide the old tool with new capabilities: it will increase the operating time on a single charge, add power, since the operating voltage will rise to 10.8 V.
The design will require the use of a BMS, a control controller that maintains the lithium cell operating mode within operating limits. With this breaker, each cell will be charged evenly without exceeding 4.2V, lower voltage 2.7V. Built-in balancer is used here.
Controller parameters Should accompany the operation of the tool with an increase in the operating current to 10-20 A. The 30 A Sony VTC4 board, designed for a capacity of 2100 A / h, will be able to ensure operation without shutdown.Of 20 amperes, Sanyo UR18650NSX accepting energies of 2600 / h is suitable. for 3 elements, which is marked in the 3S classification. In this case, the board must have 2 contacts, plus and minus. If the pins are designated with letters R, R , FROM-, they are intended for later models of screwdrivers.
Step-by-step instructions for converting a Makita screwdriver to lithium batteries looks like this.
- You can disassemble the battery with glue if you tap the junction with a soft-headed hammer while weighing. Direction of impact downwards, in Butt on the lower part of the body.
- Take here of the old assembly only the contact plates, carefully disconnecting them from the battery. Leave the sensor and breaker.
- Solder 3 elements in series using TAGS flux and insulated jumpers. The wire cross section must be greater than 0.75 mm2.
- Assemble the circuit with the controller, and connect the power supply to the contact connectors with 1.5 square wires.
- Check the operation of the circuit and assemble the case, put it back on the glue.
In a screwdriver with an old DC9710 charger, after charging the 18650 lithium battery, the red LED on the panel will turn off. The built-in controller monitors the charge level.
The Makita DC1414 T charger is used to charge 7.2-14.4 V power sources. While charging, the red light is on. But when charging a lithium battery, its voltage does NOT fit into the standards of salt products, and after 12V, the charger will flash red and green. But the required charging is already there. The screwdriver is ready to work.
Alteration of the screwdriver Hitachi 12V for 18640 lithium batteries
Features of alteration of a screwdriver Hitachi 12V for lithium batteries. The very compact battery compartment is designed for finger cells. Therefore, you should prepare a place for 18650 cells. It is necessary to cut one side into the partitions in order to tightly place 1 element.
You need to get a gumboil, a flat metal connecting tape, hot glue. It is necessary to install lithium batteries in a screwdriver during rework through a protective controller. It should service 3 18650 cells, 3.7V and rated for 20-30 amps.
Remove the old battery from the socket, carefully disconnect the contacts in the assembly with the temperature sensor and the power indicator. Clean up and sign contacts. They should be brought out to one side, connected with solder to the leads from thick wires and filled with hot melt glue on the assembly.
Assemble a power source with one of the 3 cell controllers. Build a serial circuit of 3 Li-ion cells. Connect the controller. The conversion of the 12-volt lithium battery is completed when the structure is installed in the unit, secured, and the charging indicator lights up. After fully charging, the measurements show 12.17 volts in the external network. But this is enough for trouble-free long-term operation of the device.
Conversion of a screwdriver to lithium batteries 18650
Every craftsman is faced with the problem of reduced tool performance, or complete failure due to the battery. Manufacturers use nickel-cadmium batteries in 12-volt, 14-volt, 18-volt screwdrivers. The sequential assembly of several elements creates the desired voltage. Replacing nickel-cadmium batteries with lithium batteries extends battery life by making the design lighter. Mandatory BMS board installation adds reliability. Therefore, the conversion of a screwdriver to lithium batteries, mainly to the 18650 form factor, is justified.
Conversion of a screwdriver to lithium batteries 18650 14 V
When converting screwdrivers of different power and flashlights from Ni-Cd to Li-ion, batteries of the form factor 18650 are more often used. They easily fit into a container or a nest, since instead of two or three relatives, one lithium is installed. Alteration of the screwdriver battery should be carried out taking into account the peculiarities of lithium 18650 batteries.
This kind of energy source does not tolerate deep discharge and unnecessary charge. Hence, it is necessary to use voltage control boards. Since each battery has its own character, their charge is adjusted by a balancer. The point of reworking a screwdriver with a voltage of 14.4 V lies in the creation of a device with the introduction of lithium batteries to facilitate the hand tool and increase its performance. Lithium 18650 batteries are most suitable for THESE purposes.
When selecting components, it should be taken into account that the starting current of the screwdriver is high, you must select the Corresponding BMS for the required number of cans and not less than 30 A. To convert the charging of the screwdriver to a lithium battery, you must stock up on a good soldering iron, and not acid flux and thick wires to make jumpers.
- Lithium-ion cans in the amount of 4 pcs.
- 4-cell li-ion battery controller, CF-4S30A-A works well. It has a built-in balancer that controls the charge of each element.
- Hot melt glue, flux for soldering TAGS, solder.
- Heat-resistant adhesive tape;
- Jumpers or thick insulated wire with a cross-section of at least 0.75 squares, cut for bridges.
The procedure for reworking a screwdriver for 18650:
- Disassemble the case and remove a bundle of 12 Ni-Cd cells from the container.
- Remove the garland, leave the connector with leads and. Instead of a thermal sensor, a thermocouple from the controller will be installed.
- Solder the assembly, Considering that you cannot use acid, only neutral flux and pure solder. During the connection period, the lid must not be heated. Work pointwise.
- Connect balancing points to the controller according to the diagram. The board has connectors.
- Connect assembly with plus and minus pins.
- Check the functionality of the circuit. If everything works, Assemble the battery, place the controller in the socket, secure with a sealant.
If the charger is NOT universal, additional alteration will be required. Screwdrivers for 12 V with a universal charger are assembled in the same way, but a protective connection circuit 3×18650 3.7 V for lithium batteries is used. In the same way, a screwdriver is being reworked with the introduction of a set of 18650 batteries in the amount of 2 parts.
The meaning and procedure for converting screwdrivers to lithium batteries
Why do nickel-cadmium batteries fail quickly? Each garland of cans connected in series is special. The chemical process is individual, the charge in closed systems is different. If there is a malfunction in one bank, the design does not provide the required voltage. The control system and charge balancing in SEPARATE components is not provided.
- Each Ni-Cd bank provides 1.2V, and the Li-ion 18650.3.6V.
- Lithium battery capacity is 2 times that of nickel-cadmium battery, similar size.
- An overheated li-ion battery threatens an explosion and fire, therefore, the installation of monitoring the uniformity of the charge in the banks is mandatory. Nickel-cadmium batteries DO NOT use BMS. The manufacturer is NOT interested.
- Lithium cells have a memory effect, unlike Ni-Cd, they can be charged at any time and within an hour.
- The screwdriver becomes much easier after converting the battery to li-ion, with the introduction of 18650 cells.
There are only two obstacles to converting a screwdriver for lithium batteries. It is impossible to work with it at minus. The capacity of cans decreases, starting from a decrease already from 10 0 C. Lithium batteries are expensive.
Knowing what input voltage is required for the screwdriver, the charger is reworked, taking into account the placement of the lithium battery cells and control elements in the factory container. You can also do with a flashlight by upgrading the socket for a block of 18650 cells.
Let’s say you need to rework a 12 V screwdriver using Ni-Cd cans on li-ion. If you use 3 banks, the output voltage is not enough 3.6 x 3 = 10.8 V. With 4 components, the power of the device will be higher than 3.6 x 4 = 14.4 V. This will make the instrument 182 g lighter, a little its power and capacity will increase. Solid pluses. But when dismantling, you must leave the terminals and the native thermal sensor.
DIY screwdriver alteration
Consider the option with a remote power supply.
We build in a ready-made power supply
To do this, you need to purchase a ready-made block with suitable characteristics and dimensions. There is enough such good on the radio market.
Take the body with you and go to the fitting. When the required power supply is purchased. Carefully separate it from the case.
By placing a screwdriver in the battery box. All components Must be securely fastened.
If necessary, extend the wires between the control board and the transformer. If the circuit touches the metal parts of the transformer during operation. A short circuit will occur.
Since the space in the case allows. Spreading the board and transformer for better cooling. Whichever quality power supply you choose. The load will be high and overheating is possible.
It will not be superfluous to fix additional radiators on the power control microcircuits. Operate the screwdriver for a long time, unplug it and touch the radio parts on the control board.
You yourself will understand which elements need heat dissipation. Holes for air circulation can be made in the housing.
Do-it-yourself alteration of the power supply unit will not take much time, and the cost of the purchased module is incomparable with restoring the battery’s performance.
Battery Disadvantages
- Needs regular recharging. Sooner or later, batteries will use up their cycle life.
- The cheaper the tool, the faster the rework time will come.
There is nothing wrong with that, but you should be aware of the fact that the manufacturer saves as much as you do. Therefore, the most expensive unit (and this is the battery) will be the cheapest when bundled.
As a result, we get an excellent tool with a serviceable motor and NOT a worn gearbox, which does not work due to a poor-quality battery.
There is an option to purchase a new set of batteries, or replace faulty batteries in the unit. However, this is a budget event. The cost is comparable to buying a new screwdriver.
Second option. Using a spare or old battery from the car (if you have one). But the starter battery is heavy, and the use of such a tandem is not very comfortable.
Battery case power supply
Mobility is preserved, you are limited only by the length of the network cable. The only problem. How a sufficiently powerful transformer is squeezed into a small case.
Remember Ohm’s law again, and understand that a powerful 220 volt electric motor can be compact.
Using a car battery charger
The principle is the same as with the introduction of a computer power supply. You need to purchase an old charger for the starter batteries. The modern fashion for compact impulse chargers has left analog linear devices with manual control of voltage and charge current behind board. Therefore, such a device can be purchased on the automotive market for a symbolic cost.
Charger MAX INTER
It’s good if the voltage can be adjusted smoothly. In this case, your makeshift power supply will fit any screwdriver.
Converting it to a power tool is reduced to connecting the input of the electric motor to the power terminals of the charger.
Making a homemade power supply
If you are familiar with the principles of building electrical circuits. You can make your own power supply. Scheme giving general concepts. In the illustration.
The transformer can be picked up from an old tube TV, or other household appliances. Power for 220 volts 250-350W. The main thing is the power supply. Donors should not be impulsive.
The voltage on the secondary winding is 24-30 volts. The secondary winding is made from a wire of the corresponding section.
However, if the current of the output winding is not less than 15 amperes (see transformer specification). Is there nothing to worry about.
After losses on the diode bridge (1-1.5 V on the diode), you will get the required output value.
If you have an electrical engineering degree. Let’s make the calculation ourselves. Or in a practical way: by connecting a 220 volt 100W incandescent lamp as a load, measuring the output voltage. E
If it exceeds the needs of a screwdriver. Reduce the number of turns of the secondary winding of the transformer.