Remaking a Screwdriver Charge On Li Ion
Energy Storage Information Site
Each master is faced with the problem of reducing the operability of the tool, or a complete failure due to the battery. Manufacturers use nickel-cadmium batteries in 12, 14, 18 volt screwdrivers. The sequential assembly of several elements creates the desired voltage. Replacing lithium nickel-cadmium batteries increases the battery life, making the design easier. Mandatory installation of the BMS board adds reliability. Therefore, the alteration of the screwdriver on lithium batteries, mainly on the form factor 18650, is justified.
The meaning and procedure for converting screwdrivers to lithium batteries
Why do nickel-cadmium batteries fail quickly? In a garland of cans connected in series, each is distinctive. 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 desired voltage. The control system and charge balancing in individual components is not provided.
- Each Ni-Cd bank gives 1.2 V, and li-ion 18650 gives 3.6 V.
- The capacity of a lithium battery is 2 times more than a nickel-cadmium, close size.
- An overheated li-ion battery threatens to explode and catch fire, so setting charge uniformity control in banks is mandatory. BMS is not installed in nickel-cadmium batteries. the manufacturer is not interested.
- Lithium cells do not have a memory effect, unlike Ni-Cd, you can charge them at any time and for an hour.
- The screwdriver becomes much easier after the alteration of the battery on li-ion, using 18650 cans.
There are only two obstacles to remaking a screwdriver for lithium batteries. it is impossible to work with it in the negative. The capacity of the cans drops, 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 lithium battery cans and control elements in the factory container. You can also do with a flashlight by upgrading the socket for a block of 18650 elements.
Suppose you need to remodel a 12 V screwdriver using Ni-Cd cans on li-ion. If you use 3 cans, the output voltage is not enough: 3.6 x 3 = 10, 8 V. With 4 components, the power of the device will be higher: 3.6 x 4 = 14.4 V. In this case, the tool will become lighter by 182 g , its power will slightly increase, capacity is a solid plus. But when dismantling, it is necessary to leave the terminals and the native temperature sensor.
Converting a screwdriver to lithium batteries 18650 14 V
When remodeling screwdrivers of different capacities and flashlights from Ni-Cd to Li-ion, they often use 18650 form factor batteries. They easily fit into a container or socket, since instead of two or three relatives they install one lithium one. Alteration of the screwdriver battery should be carried out taking into account the characteristics of lithium batteries at 18650.
This type of energy source does not tolerate deep discharge and excessive charge. Therefore, it is necessary to use voltage control boards. Since each battery has its own character, their charge is adjusted by the balancer. The meaning of the alteration of a screwdriver with a voltage of 14.4 V is to create a device using lithium batteries to facilitate a hand tool and increase its performance. Most suitable for these purposes are lithium batteries 18650.
When selecting components, it should be noted that the starting current of the screwdriver is high, you must select the appropriate BMS for the desired number of cans and at least 30 A. To remake the screwdriver with a lithium battery, you need to stock up with a good soldering iron, non-acid flux and thick wires to make jumpers.
- 4 lithium-ion cans
- 4-bank li-ion battery controller, CF-4S30A-A is well suited. It has a built-in balancer that controls the charge of each element.
- Hot melt adhesive, TAGS solder flux, solder.
- Heat-resistant adhesive tape;
- Connection jumpers or thick wire in insulation with a cross section of at least 0.75 square, cut for bridges.
Video: Remaking a Screwdriver Charge On Li Ion
The procedure for remaking a screwdriver for 18650:
- Disassemble the housing and remove from the container a bundle of 12 Ni-Cd elements.
- Remove the garland, leaving the connector with the conclusions "" and "-". Instead of a temperature sensor, a thermocouple from the controller is installed.
- Solder the assembly, given that acid cannot be used, only neutral flux and pure solder. During the connection period, do not heat the lids. Work pointwise.
- Connect the balancing points to the controller according to the diagram. Connectors are provided on the board.
- Connect the assembly to the plus and minus terminals.
- Check the operation of the circuit. If everything works, the assembled battery, place the controller in the socket, fasten with sealant.
If the memory is not universal, additional alteration is required. 12 V screwdrivers with a universal charger are assembled in the same way, but a protective connection scheme of 3×18650 3.7 V for lithium batteries is used. In the same way, a screwdriver is reworked using a battery kit of 18650 in the amount of 2 elements.
Converting a Makita screwdriver to a lithium battery
There is a Makita screwdriver with a 1.3 A / h battery and a voltage of 9.6 V. To change the power source to a lithium-ion one, you need 3 18650 components. The alteration will provide the old tool with new features: increase the duration of work on a single charge , will add power, since the operating voltage rises to 10.8 V.
For the design, you will need to use BMS, a control controller that supports the mode of operation of lithium cells within operating limits. With this breaker, the charging of each can will be uniform without exceeding 4.2 V, the lower voltage is 2.7 V. The built-in balancer is used here.
The parameters of the controller should accompany the operation of the tool when the operating current is increased to 10-20 A. A 30 V Sony VTC4 board with a capacity of 2100 A / h can ensure operation without shutting down. From 20 amperes, Sanyo UR18650NSX is suitable for receiving energy of 2600A / h. The board is needed for 3 elements, which is marked in the 3S classification. In this case, the board should have 2 contacts, plus and minus. If the findings are marked with the letters "P-", "P", "C-", they are intended for later models of screwdrivers.
A step-by-step instruction for converting a Makita screwdriver to lithium batteries looks like this.
- It is possible to disassemble the battery on glue, if on weight tap the place of connection with a hammer with a soft head. Direction of impact down to the joint along the lower part of the body.
- Take only contact plates from the old assembly, carefully disconnecting them from the battery. Sensor and disconnect must be left.
- Solder 3 elements in series using TAGS flux and insulation 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 connectors with 1.5 square wires.
- Check the operation of the circuit and assemble the housing, again putting it on the glue.
In a screwdriver with an old DC9710 charger, after the 18650 lithium battery is charged, the red LED on the panel will turn off. The charge level is monitored by the built-in controller.
The Makita DC1414 T charger is used to charge power supplies of 7.2-14.4 V. 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 12 V the charger will flash red and green. But the necessary charge is already there. The screwdriver is ready to work.
Converting a 12 V Hitachi screwdriver to 18640 lithium batteries
Features of the conversion of a 12 V Hitachi screwdriver to lithium batteries. A very compact socket for battery cells designed for finger cells. Therefore, you should prepare a place for 18650 elements. It is necessary to cut one side of the partition to fit 1 element tightly.
You need to get a flux, a flat metal connecting tape, hot melt adhesive. Install lithium batteries in a screwdriver during alteration must be through a protective controller. It should serve 3 cells 18650, voltage of 3.7 V and is designed for 20-30 amperes.
Remove the old battery from the socket, carefully disconnect the contacts in the assembly with the temperature sensor and power indicator. Strip and sign contacts. They should be brought out in one direction, connected by solder to the leads from thick wires and fill the assembly with hot glue.
Assemble an energy source with one of the controllers, designed for 3 elements. Assemble a serial circuit of 3 Li-ion elements. Connect the controller. Alteration of the lithium 12-volt battery is completed when the design is installed in the unit, is fixed, and the charge indicator lights up. After fully charged, the measurements show 12.17 volts in the external network. But this is enough for trouble-free long-term operation of the device.
Alteration of the Interskol screwdriver to 18650 lithium batteries
Sooner or later, the nickel-cadmium assembly of 15 cans fails. One or two elements are lazy, and it is already impossible to obtain the voltage at the output. Modern DS “Interskol” on lithium batteries serve much better. Alteration of a screwdriver on lithium batteries 18 volt masters mastered.
You need to purchase a protection board for 5S, 3.7 V and 40-50 A. You will need a balancing board and the energy sources themselves. 5 lithium 18650 batteries, you can leave them with factory thermistors, extending the wires. During installation, create a contact pad, insert the assembly, check operation, fix it. Assembly features wizard tips are given in detail in the video. Here is full details of the rework of the 18-volt lithium screwdriver