How to choose the photovoltaic panel on the solar street lamp?

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In addition to the size of the battery, the solar panels determine how much power they can charge in a day. So the right choice and matching of solar panels is also very important, the following to give you some instructions on the selection of solar panels.

In addition to the size of the battery, the solar panels determine how much power they can charge in a day. So the right choice and matching of solar panels is also very important, the following to give you some instructions on the selection of solar panels.

 

1, the solar panel must choose the correct open-circuit voltage and working voltage

If the choice is PWM solar street lamp controller, to 12V storage and charging, the open circuit voltage of the solar panel is generally about 20V, the working voltage is generally 17.5V. When charging a 24V battery, the open circuit voltage and operating voltage of the solar panel are twice that of 12V.

 

If the MPPT solar regulator is selected, the open circuit voltage of the solar panel cannot exceed the highest input voltage of the controller.

 

  1. Solar panel power selection

Solar panel power selection, according to the formula below

P = Q * h/U * factor 1 / factor 2 / factor 3 * Vp

 

Explanation:

Q-- Load power

H-- load day service time

U-- system voltage

ξ1-- Number of solar panel comprehensive loss systems, take 1.05

ξ2-- Control circuit efficiency, 0.85

ξ3-- battery charging and discharging efficiency, 0.85

Vp- Working voltage of solar panel

 

  1. Solar panel type, divided into single crystal and polycrystal

Single-crystal solar panels are more efficient, with less attenuation, but are a little more expensive, while polycrystalline solar panels are less efficient, but cheaper

 

  1. External dimension of solar panels

A lot of dimensions, must be based on their own street lamp installation environment to determine what size is more appropriate, generally speaking, the power of the same case, choose a smaller size is more appropriate.

 

This solar regulator belongs to the basic type, support directly connect the solar panel to the battery charging, and support automatic power off, realize the automatic charging control of the battery. At the same time, the controller also supports the button control load, and the phone charging function, quite practical.

 

It is found that a Hetai LCD driver chip is used for the screen display and an unmarked chip is used for the whole machine control. Internal use of 34063 step-down chip for step-down, and TI LM258 operational amplifier for current sampling and amplification. Through the MOS tube to control the battery charge and discharge and load output, five MOS tube models are polished, suitable for the occasion of low requirements.

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