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Solar charge controller is for charge and discharge protection mode
- Jan 11, 2018 -

1, direct charge protection point voltage: direct charge also called emergency charge, is a fast charge, usually in the lower battery voltage with a high current and relatively high voltage on the battery charge, however, there is a control point, also known as protection Point is the value in the above table, when charging the battery terminal voltage is higher than these protection values, should stop direct charging. Direct charge protection point voltage is generally "overcharge protection point" voltage, battery terminal voltage charging can not be higher than the protection point, otherwise it will cause overcharge, the battery is damaged.

2, charge control point voltage: After the direct charge, the battery will normally be charge and discharge controller for a period of time, let the voltage drop, when falling to the "recovery voltage" value, will enter the state of charge. Why design is full? Is that when the direct charge is completed, there may be some individual battery "behind" (the terminal voltage is relatively low), in order to pull back these individual molecules, so that all of the battery terminal voltage uniformity, it is necessary With high voltage with moderate current recharge for a small meeting, we can see the so-called charge, that is, "balanced charge." All charge time should not be too long, usually a few minutes to ten minutes, the time is set too long but harmful. For a small system equipped with a two batteries, the charge is meaningless. Therefore, the street light controller is generally not all charge, only two stages.

3, float charge control point voltage: After the charge is completed, the battery is also allowed to stand for a period of time, so that the voltage drops naturally, when falling to the "maintenance voltage" point, it will enter the floating state, are currently used PWM (Both pulse width modulation) approach, similar to the "trickle charge" (ie, small current charge), the battery voltage is low on the charge a little, a low on the charge point, one by one to avoid the battery temperature continued to rise High, which is very good for the battery, because the battery temperature inside the battery charge and discharge greatly affected. In fact, the PWM mode is mainly designed to stabilize the battery terminal voltage, by adjusting the pulse width to reduce the battery charge current. This is a very scientific charging management system. Specifically, when the residual capacity (SOC) of the battery is> 80% at the end of the charge, the charge current must be reduced to prevent excessive outgassing (oxygen, hydrogen and sour gas) due to overcharging.

4, overdischarge protection termination voltage: This is better understood. Battery discharge can not be lower than this value, which is the national standard. Although battery manufacturers also have their own protection parameters (enterprise standard or standard), but eventually still have to move closer to the national standard. It should be noted that, for safety reasons, the general over-voltage protection of 12V battery point man-plus 0.3v temperature compensation or control circuit zero drift correction, so 12V battery over-discharge protection point voltage is: 11.10v, then 24V system over-discharge protection point voltage is 22.20V. At present, many manufacturers have used charge and discharge controller 22.2v (24v system) standards.