Lithium-ion batteries charge indicator By Kasyan TV

Hi friends, some time ago, I published a video about car battery indicator, and I was asked to do the same indicator back for three point: seven volt lithium-ion batteries. Of course such indicators can be bought from China. There are links in the description, so this video is for those who, like working with the soldering iron and doing it themselves. Honestly, this circuit is not much different from the one that was designed for car batteries, but there are some differences. The circuit again is built on the basis of the comparator lm339, how it all works. I explained in the mentioned video.

You can learn it. If you move to the link in the description, but anyway, I will say a few words about chip operation. It includes four individual comparators in one housing. The comparator has two inputs and one output. If the voltage changes at one of the inputs, this immediately leads to a change in the output state of the comparator in the case of the lm339 chip at output, either nothing at all or equal to minus of the power supply.

Such a comparator is so-called chip with an open collector. So cathodes of the LEDs are connected to the comparator. On some inputs, it is necessary to form a stable or reference voltage as a rule, as in your diet is used for these purposes, but the fact is that we are going to monitor the voltage at a low voltage source. The Zenger diode itself must also be low voltage or more precisely. The stabilization voltage should be less than the discharged battery voltage in the case of conventional idiom ion batteries.

It is about two revolts. Therefore, it is necessary to find the Into diet for about 2.5-fold or less. Unfortunately, in my reserves, I found all these in your diet at 3.3 volts. The solution is to use the lads as a reference voltage, source for red, yellow and green LEDs. The minimum glow voltage is within 2 volts, which is what we need.

The only difference is that the LED is connected in the forward direction. Unlike the Zenger diode input, divided resistors had to be completely recalculated for a lithium battery. I made a new board which differs from the old version in its compactness. The board, in my opinion, turned out to be quite good. The installation is dance, although it is possible to make it even smaller if you use as empty components notice.

There are two jumpers marked with yellow on the board. The diode vd1 protects the chip in case. If the polarity of the connection to the battery is mixed up. As you know, the voltage of a fully charged lithium-ion battery should be around 4.1 to 4.2 volts, so the dividers are selected in a very narrow range, using resistors, with the tolerance of only 1% which guarantees high precision operation of the indicator. We have four LEDs colors could be any up to your taste to take the operation.

I connect a laboratory power supply where the voltage of a fully charged battery is set. All LEDs are own. I am gradually reducing the voltage to simulate the discharge of the battery and observe the alternate decay of the LEDs at certain voltages. This indicates the correct operation of the indicator. Such an indicator can be attached to any self-made device or used as a simple tester for lithium batteries.

How and where to use, depends only on your imagination, don't forget to rate this video and share it with friends. If it was useful, you will find all necessary information in the description, including links to buy off such indicators. Goodbye with you was Cassie on TV.

Source : Kasyan TV