nik34 sent:
Charge indicator based on the old Li-Ion battery protection board.
An easy solution for indicating the end of the charge of a LiIon or LiPo battery from a solar battery can be made from ... any dead LiIon or LiPo battery :)
They use a six-legged charge controller on a specialized mikruha DW01 (JW01, JW11, K091, G2J, G3J, S8261, NE57600, etc. analogues). The task of this controller is to disconnect the battery from the load when the battery is completely discharged and disconnect the battery from charging when it reaches 4.25V.
Here is the last effect and you can use. For my purposes, an LED that will light up when the charge is complete is quite suitable.
Here is a typical scheme for switching on this mikruha and a scheme into which it must be converted. The whole alteration consists in soldering the mosfets and soldering the LED. 
Take the red LED, it has less ignition voltage than other colors.
Now we need to connect this circuit after the traditional diode, which also traditionally steals from 0.2V (Schottky) to 0.6V from the solar panel, but it does not allow the battery to be discharged to the solar panel after dark. So, if you connect the circuit to the diode, then we get an indication of undercharging the battery by 0.6V, which is quite a lot.
Thus, the algorithm of work will be as follows: our SB, when illuminated, gives a voltage to the lipo and until the native charge controller on the battery works at a voltage of about 4.3V. As soon as the cutoff is triggered and the battery is turned off, the voltage on the diode jumps above 4.3V and our circuit, in turn, tries to protect its battery, which no longer exists and, giving a command to the same non-existent mosfet, lights the LED.
Having removed the SB from the light, the voltage on it will drop and the LED will turn off, stopping eating precious milliamps. The same solution can be used with other chargers, it is not necessary to go in cycles in the solar battery :)
You can decorate as you like, since the controller's handkerchief is miniature, no more than 3-4 mm wide, here is an example:
Our magic mikruha is on the left, two mosfets in one case on the right, they must be removed and soldered to the board in accordance with the LED circuit.
That's all, use it, it's easy.
The simplest option is shown in Figure 1. If the voltage at the B+ terminal is 9V, only the green LED will be lit, since the voltage at the base of Q1 is 1.58V, while the voltage at the emitter, equal to the voltage drop across the LED D1, in a typical case is 1.8V and Q1 is held closed. As the battery drains, the voltage across LED D2 stays pretty much the same, while the voltage at the base decreases, and at some point in time, Q1 will begin to conduct current. As a result, part of the current will branch into the red LED D1, and this proportion will increase until all the current flows into the red LED.
| Picture 1. | Basic battery voltage monitor circuit. |
For typical elements of a two-color LED, the difference in forward voltages is 0.25 V. It is this value that determines the transition region from green to red. A complete change in the color of the glow, set by the ratio of the resistances of the divider resistors R1 and R2, occurs in the voltage range
The middle of the transition region from one color to another is determined by the voltage difference between the LED and the base-emitter junction of the transistor and is approximately 1.2 V. Thus, changing B + from 7.1 V to 5.8 V will change the green glow to red.
Voltage differences will depend on specific combinations of LEDs and may not be sufficient to fully switch colors. However, the proposed circuit can still be used by including a diode in series with D2.
In Figure 2, resistor R1 has been replaced by a zener diode, resulting in a much narrower transition region. The divider no longer affects the circuit, and a complete change in the color of the glow occurs when the B + voltage changes by only 0.25 V. The transition point voltage will be 1.2 V + V Z . (Here V Z is the voltage across the zener diode, in our case it is approximately 7.2 V).
The disadvantage of such a scheme is its binding to the limited voltage scale of the zener diodes. Further complicating the situation is the fact that low-voltage zener diodes have too smooth a break in the characteristic, which does not allow you to accurately determine what the voltage V Z will be at low currents in the circuit. One solution to this problem would be to use a resistor in series with the zener diode to allow for slight adjustment by slightly increasing the junction voltage.
With the resistor values shown, the circuit draws about 1 mA of current. With high-brightness LEDs, this is sufficient for indoor use. But even this small amount of current is quite significant for a 9-volt battery, so you have to choose between drawing extra current and risking leaving the power on when you don't need it. Most likely, after the first unscheduled battery change, you will feel the benefit of this monitor.
The circuit can be converted in such a way that the transition from green to red glow occurs in the event of an increase in the input voltage. To do this, the transistor Q1 must be replaced with NPN and the emitter and collector should be swapped. And with the help of a pair of NPN and PNP transistors, you can make a windowed comparator.
Given the rather wide transition region, the circuit in Figure 1 is best suited for 9V batteries, while the circuit in Figure 2 can be adapted to other voltages.
Some batteries (usually above average quality) have a green indicator on the top (on the front panel), on the right or on the left (some call a light bulb). This "peephole" gives you an idea of the charge or discharge of your battery. In total, it has three main provisions, and it does not always glow green. Today I will tell you in detail what it is, and why it was created at all. And also we will analyze why it may not burn at all ...
To be honest, this indicator was created only to signal you about your battery, because, as a rule, their design is not collapsible, and therefore you cannot climb inside and see what they have with the electrolyte - just look at its level or measure its density. Therefore, such a "bulb" gives you a complete picture, according to which you can make a decision. However, the indicator may not always be green, as a rule, three modes are used here.
Indicator modes
This combination is very common: - green, white, black. However, some manufacturers use a combination: - green, white, red. But in essence it is one and the same. Let's go over these indications.
Green Mode - a fully charged battery, can be used in normal normal mode. This means that no charging is required.
White indicator - he tells us about the low electrolyte level. In unattended, this also happens, most likely, the battery was often recharged, and a gaseous electrolyte was released through a special valve. You need to disassemble and add distilled water.
Black or red indicator - this tells us about the discharge of our battery, and the indicator is critical, mandatory recharging is required! It is important! Leaving the battery uncharged for a long time can damage it.
As you can see, these colors give certain signals to the owner, look in occasionally and then your battery will last a long time. I also want to note that this indicator does not have any light bulbs in its structure at all, the next paragraph will turn your idea around ...
About a light bulb - not a light bulb
I wanted to write this information from above, but this way it turns out more intrigue. In the structure of this sensor, no light bulbs are used at all - nor ordinary incandescent (low-voltage) - as many people think, neither LED, nor any other.
Here the structure is different. . In fact, this is an ordinary hydrometer, only built into the battery case. It automatically measures the density of the electrolyte, and at different values it pops up - one or another ball, which is projected through a magnifying glass tube and a magnifying glass into a special window. It should be noted that the balls float up, as it were, along special grooves that are made in the shape of a pyramid - this is important! REMEMBER!
If the battery is charged, then a green ball pops up, and you see it in the window. If it is discharged, then either red floats in, or none at all, so you see blackness. But if there is no electrolyte, then the end of the pyramid seems to be exposed - you see its end in the window, many confuse it with white.
The use of electricians in the battery would not be justified - even if the light bulb were low-voltage, it would still suck out some of the energy from the battery (and in winter, oh, how not necessary). YES, and if it burns out, the owner will start to get nervous.
Now a detailed video, maybe someone did not understand about the pyramid ...
Why does it not light up even after being fully charged?
A very common question, many still think that this is a light bulb and after charging it should light up! As we have already discussed, this is not at all the case. And it is quite possible that when fully charged, the green indicator will not come out! WHY?
YES, it's simple:
- The green ball can just "stick" on these "little skids". It is worth shaking the battery, and it will take its place. It happens very often.
- Dirt from the plates got in, over time the plates begin to crumble, the electrolyte becomes cloudy, it has particles of lead, so it prevents the indicator from transmitting information normally.
- The battery is really out of order, this cannot be ruled out either, even with long charges it does not take density.
Can this indicator be removed?
On most batteries, yes, this window is unscrewed similar to a cork - but it will have to be twisted with force, it can even be broken, my friends twisted it with thin-tipped pliers, and small “holes” were made in the window for hooking. In general - a "collective farm", but theoretically you can remove it! It is also worth remembering that if you unscrewed it, then the airless space inside was violated, it is quite possible that a gaseous composition will come out - “explosive gas” or “HHO”. Then you will need to add distilled water. So always think, but you need to disassemble the battery!
I’m actually finishing the article, the information is clear and to the point, I think it was useful to you, read our AUTOBLOG.
Not all cars have an indicator that displays the battery charge level. The motorist must independently monitor this indicator, periodically checking it with a voltmeter, after disconnecting the battery from the machine's electrical network. However, a simple electronic device will allow you to get approximate figures without leaving the cabin.
The choice of circuit and components
Finished construction
Structurally, a self-made battery charge control indicator consists of an electronic unit, on the body of which there are three LEDs: red, blue and green. The choice of color may be different - it is important that when one of them is activated, the information received is correctly interpreted.
Due to the small size of the device, you can use an ordinary prototyping board. The optimal scheme of the device is preselected. You can find several models, but the most common and therefore workable version of the battery charge indicator is shown in the figure.
Diagram of the board and its components
Before installing the components, it is necessary to arrange them on the printed circuit board according to the diagram. Only then can you cut it to the desired size. It is important that the indicator has a minimum size. If you plan to install it in a housing, you should take into account its internal dimensions.
This circuit is designed to control the operation of a car battery with a mains voltage of 6 to 14 V. For other values of this parameter, the characteristics of the components should be changed. Their list is shown in the table.
- 20.09.2014
A trigger is a device with two stable equilibrium states designed to record and store information. The flip-flop is capable of storing 1 bit of data. The symbol of the trigger has the form of a rectangle, inside which the letter T is written. Input signals are connected to the image of the rectangle on the left. The designations of signal inputs are written on an additional field in the left part of the rectangle. …
- 23.11.2017
Thermocouple (thermoelectric converter) is a device used in industry, scientific research, medicine, and automation systems. Mainly used for temperature measurement. The principle of operation is based on the Seebeck effect or, in other words, the thermoelectric effect. There is a contact potential difference between the connected conductors; if the joints of conductors connected in a ring are at the same temperature, the sum of such differences ...
- 17.01.2019
The TEA5767 IC manufactured by NXP is used to design low-voltage FM radio tuners. The TEA5767 has internal IF extraction and demodulation of the received signal, which allows you to get by with a minimum set of external components. Technical parameters TEA5767: Supply voltage from 2.5 to 5 V Current consumption at Upit = 5 V 12.8 mA Sensitivity 2 …
- 20.09.2014
The brand of ferromagnetic material, the type and type of magnetic circuit is selected depending on the purpose of the component, operating frequency, requirements for electromagnetic interference, and so on. In accordance with GOST 20249-80, the magnetic circuits of transformers and chokes operating at a frequency of 50 Hz are made of electrical steel grades 1511, 1521, 3411, 3412 with a thickness of 0.2 ... 0.5 mm. The use of magnetic circuits from ...