Circuit diagram design of solar energy uninterrupted power supply equipment

Spot Remarks 2017+

Overview:
The innovation of this design is:

First, the simple and practical circuit is used to realize the stepping charging mode, that is, under sufficient sunlight, one battery charging current is greater than the charging current of the other battery, so as to charge a battery first, and then automatically charge the battery again after being charged. A battery is charged, which is equivalent to the two batteries being charged in turn, which not only makes full use of the solar energy per unit area, but also greatly increases the service life of the battery, so that the power of the solar panel can be reduced under the same load. Requirements, thereby reducing the cost of the project;
Secondly, an automatic switching system for solar energy and utility power supply is designed to make up for the shortcomings of the solar power supply for several days, and to achieve the purpose of uninterrupted home power supply.

First, the design principle and circuit analysis circuit consists of three parts: step charging circuit, solar power supply and mains power supply automatic switching circuit and street lamp control and lighting circuit, as shown in the following figure. The circuit has a simple structure, rich connotation, and the circuit works stably and reliably.
1. The stepping charging circuit is as shown in the figure below. The output lead of the solar panel is connected from the CK socket according to I=(U-E1.2)/R1.2, where I is the charging current of each branch, and U is the solar panel. The terminal voltage of the load output, E1, E2 are the voltages on the batteries E1 and E2 respectively. When the original voltages of the two batteries are the same, the charging current I1 of the battery E1 is 10 times of the charging current I2 of the battery E2; obviously, The initial speed of the charging voltage of the El battery is much larger than the initial speed of the charging voltage of the battery E2, which is equivalent to charging the battery El first by the solar panel. As the charging process continues, the voltage on the battery El is constantly increasing. Therefore, the voltage on the battery E1 gradually becomes saturated, and the charging current I1 of the battery E1 is gradually decreased. When the voltage on the battery El is charged close to the rated value, the charging current I1 of the battery E1 approaches zero. At this time, it can be considered that the charging process of the battery E1 is substantially completed.

When the solar panel charges the battery E1, it also charges the battery E2, except that the voltage of the battery E2 rises much faster than the rise of the battery El voltage. When the charging process of the battery El is substantially completed, the charging load is reduced. According to (U=E—I×r), U is the terminal voltage of the solar panel with load output, E is the voltage source voltage provided by the solar panel, I is the total current of the loop charging, and r is the solar panel Internal resistance, at this time, the terminal voltage U of the solar panel load output will rise, thereby accelerating the charging speed of the solar panel to E2, that is, accelerating the accumulation speed of the electric charge on the battery E2, after a certain period of time, the battery When the voltage on E2 is also close to the rated value, the charging current I2 of the battery E2 also approaches zero; similarly, it can be considered that the charging process of the battery E2 is basically finished. When the charging process of the two batteries is basically finished, if there is still sunlight, even though the charging current is approaching zero, when there is still a small charging current flowing, the charging process continues, but at this time the battery The speed of charge accumulation becomes extremely slow, and its purpose is not only to waste resources, but also to extend the service life of the battery.

(Please read the PDF for details)