Hello, dear readers and DIY !
Surely many of you have devices powered by 18650 batteries. Recently, they are used in flashlights, toys, laptops and other devices.
In this article, the author of the YouTube channel “Sorin – DIY Electrical Nerd” will tell you how to make one of the simplest chargers for this type of battery.
Materials needed for homemade products.
– 18650 Li-ion batteries
– TP4056 – battery charge controller
– 18650 battery compartment < br> – Charger for smartphone
– Magnetic cable Micro USB Type C
– Wires, copper wire, double-sided tape
– Solder, rosin, textolite, plywood, ferric chloride, sandpaper.
Tools used by the author.
– Soldering station
– Multimeter, USB tester
– “Third hand” with illumination
– Screwdriver with a set of bits
– Pliers, pliers, ruler, permanent marker.
It's clear that Li-ion 18650 batteries can be bought. However, if you are planning to replace an old laptop battery, then do not throw it away.
The charging and discharging processes of these batteries are controlled by a special controller that not only monitors their condition, but also counts the charge-discharge cycles. It can reject even a good battery.
As a result, it is possible to extract several quite working batteries from it.
The assembly disassembled by the author is made according to the 2s3p scheme. First, the plastic case is disassembled, the temperature sensor is separated, and the controller wires leading to the batteries are soldered.
When separating a pair of cell elements, first you need to cut the tape connecting the negative pins.
Then the batteries are bent to the sides, freeing up access to the tape connecting the positive terminals. Now it can be cut without the risk of being short-circuited. The remains of the tape are carefully removed with pliers.
The battery contacts are cleaned with sandpaper .
Now we need to weed out the faulty batteries by checking the voltage on them with a multimeter. It must be at least 2.7V. For the author, all batteries have a voltage of about 4 volts, and this is even if they have not been charged for several months.
To create a charger you will need several 18650 battery holders and a battery control board. The author will make a charger for 4 batteries, and each one needs its own TP4056 controller.
Resistor R3 is installed on the controller board, which is responsible for the battery charging current. This resistor can be replaced by setting the correct current. It is also possible to install a trimmer, and manually adjust the current depending on the type of battery. The nominal charge current can be found based on the model of the used 18650 Li-ion battery.
The wiring diagram of all elements is extremely simple. The inputs of all controllers are connected in parallel. Since each board has a microUSB connector on board, you can connect a charger from a smartphone to any of them.
housed holders and controllers. All that remains is to connect all the elements with wires according to the diagram.
If you want to get a better quality product, it is advisable to make a printed circuit board.
The author cut out a piece of fiberglass, and marked on its surface the centers of all holes in the controllers and for the holder pins.
Then the author drills all the holes with a thin 0.8 mm drill, placing a plate under the future board. Holes are countersunk on the reverse side.
Now you need to clean the copper coating, degrease it, and draw tracks nail polish or permanent marker.
Of course, if you have a laser printer, you can print the circuit and transfer it to the board using an iron.
Etching of the board is performed in the classical way – in an aqueous solution of ferric chloride. It won't take very long.
After etching, the board needs to be rinsed and the varnish removed from the soldering points with a knife or sandpaper.
The controllers do not have legs, so the master will connect them to the PCB using copper wire jumpers. He first removed the varnish insulation from it.
The wire is fixed in “Third hand”, and its end is soldered to the board.
The wire is cut so that a pin 5-7 in length remains mm.
Holders are installed in their places. It is extremely important to observe polarity – controllers are not equipped with reverse polarity protection, and burn out instantly.
It remains to bite off the excess wire and solder the controllers.
On the bottom side of the board you need to make jumpers that provide power to the controllers. The author did not take this into account when laying the board.
The previously cut plywood board is just suitable as a base. The board is fixed on the board with double-sided tape.
The power source will be a smartphone charger connected to the board with a Micro USB cable .
The author uses a low-power 1A unit, which will allow you to quickly charge only one battery as you can see on the graph, the current during charging reaches just 1A.
And yes, under no circumstances turn on such devices on carpet or other flammable materials, as the author does!
First he discharged the battery to 2.8V.
By connecting a USB tester, the author measures the charge current of one battery.
As expected, the controller regulates the current at different charging stages according to the schedule.
When a single battery is charged, a blue LED on the respective controller lights up.
To charge all batteries at the same time, you need to use a smartphone charger with a current of 3-4A.
And here is an omnivorous professional charger, for those who prefers the finished product.
Thank the author for his recommendations on how to make a simple charger for 18650 batteries.
Good mood, good health, and interesting ideas to everyone!
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Author's video can be found here.
Hello, dear readers and DIY !