Li-ion balancing charger

Now the market is full of chargers. Automatic and not, with the measurement of capacity and without it. Most chargers are universal and can charge elements of any chemistry. Lithium-ion and lithium-polymer are increasingly used in different devices.
Not so long ago, I reworked a screwdriver battery for 18650 lithium-ion cells. I charge it with a smart Turnigy charger. But this charger is not for everyone.

Need to build


I made the decision to assemble a simple charger with a balance bar for lithium-ion. The charger has 3 identical independent channels. They can be charged from one element to three. If necessary, you can add any number of channels. I have three, that is, 3S or 11.1 volts.
The case for the balancing charger is the case from the burned-down D-link router. If possible, take a bigger case, it works very closely in it.
Li-ion balancing charger

One of the main components is the power supply of each channel.Their role is performed by the tablet charger boards, with a 5 volt output and a current from 1 Ampere (or you can buy on Ali Express - a 5 V 1 A switching power supply).
Li-ion balancing charger

Charge controllers are boards from China - a charge controller for a 18650 battery. For each channel, its own controller. I have a board without protection, but in this case it is not needed. You can use controller boards with connectors, I have two of them missing, removed for other projects. The price of these modules is cheap. If you are engaged in refining devices on lithium-ion and lithium-polymer, then these controllers are irreplaceable.
Li-ion balancing charger

Making balancing charger


Charge controller boards need to be soldered to the outputs of the charge boards. It is possible and separately. I soldered to thick conductors from the power cable, so the design is more rigid.
Li-ion balancing charger

On charge controller boards there are LEDs that indicate charge and end of charge. They need vypayat. Instead, they will be ordinary LEDs, different colors. They will be attached to the windows where previously the LEDs of the router blinked.
Li-ion balancing charger

By the LEDs soldered wires from the old loop of the hard drive of the computer.If there are LEDs with a common anode (plus), then it is better to apply them. I did not have such, there are applied.
Li-ion balancing charger

In place of the old LEDs, solder the cables with LEDs. In the photo I have a green LED for 3 mm. I had to replace them, they turned out to be burned, I didn’t check it before unzipping it.
Li-ion balancing charger

For the back panel, you need to cut the trim. In it we make cuts for the power switch and output connector for 4 pins. Connector removed from the old hard drive. You can use any, on the desired number of pins, with a current of 1-2 amps.
The switch removed from the old computer power supply. Fasten the cover on two screws for rigidity.
Li-ion balancing charger

The output connector is glued to epoxy glue or soda with a super glue. I pasted for speed and one and the other.
Charging board with controllers, glued to thermal glue. But before fixing, I soldered the network wires.
Li-ion balancing charger

One of the network wiring, solder to the switch. The second, directly to the second wire of the power cord.
Li-ion balancing charger

Now glue the LEDs. I glued thermo glue, and soda with super glue.
Li-ion balancing charger

We solder output jumpers.
Plus the first controller on the first leg of the output connector.Minus it on the second leg and connect with the plus of the second controller. And so on.
Li-ion balancing charger

The body is twisted and set aside.
Li-ion balancing charger

Make a wire for this charger.
Applied two pieces of wire from a computer power supply. Soldered in order from the first contact of one connector to the contact of the second.
Li-ion balancing charger

We connect the charger to the screwdriver's battery (Alteration of the screwdriver's battery to lithium). A red LED indicates an ongoing charging process. At the end of the charge, the green LED lights up. Accordingly, the icons on the case light up: Wi-Fi, second and fourth computers.
Liion balancing charger

That's the charger we got. The costs are minimal and the benefits are great.
This device can be charged on the assembly of lithium polymers, those who use the modellers in their vehicles. The main thing is to make the correct charging wire.

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