Solar panels belong to photovoltaic (PV) power generation equipment (the key component being semiconductor devices). When exposed to direct sunlight, they generate current through the Compton effect. Due to the inherent characteristics and limitations of materials and light sources, the generated current has an unpredictable curve. If this current is directly fed into the battery or directly supplied to the load, it can easily damage the battery and load, severely reducing their lifespan. Therefore, we must first feed the current into the solar controller, using a series of dedicated integrated circuits for intelligent adjustment and adding multi-stage battery charging protection. Simultaneously, we use our unique controller system, the "Adaptive Three-Stage Charging Mode," to ensure the operational safety and lifespan of the battery and load. When supplying power to the load, the battery current is also first injected into the solar controller. After the solar controller has undergone its adjustment, the current is then sent to the load. The purposes of this are: firstly, to stabilize the charging and discharging current; secondly, to ensure that the battery is not overcharged or over-discharged; and thirdly, to perform a series of detection and protection checks on the load and battery. If you want to use equipment that requires AC power, you must add an inverter before the load to convert it to AC power.
characteristic
All models and specifications of our manufactured solar power controllers feature an adaptive three-stage charging mode controlled by digital circuit design. The solar power controllers also have functions such as gas evolution adjustment, overvoltage and overcurrent protection. The controllers can effectively ensure that the solar power supply and distribution system operates more safely, more stably and for a longer period of time.
1. Controller-integrated three-stage charging method
The deterioration of battery characteristics, besides normal lifespan embrittlement, is mainly due to two reasons: first, excessively high charging voltage leading to internal gas evolution and water shortage; second, excessively low charging voltage or insufficient charging leading to plate thiocyanate formation. Therefore, battery charging must be performed with over-limit protection. The intelligent system operates in three stages (constant current and voltage limiting, constant current source current reduction, and trickle charging, see Figure 1). The controller automatically sets the charging time for each stage according to the difference between new and old batteries, automatically charging with the corresponding charging method to prevent battery power supply failures. The controller can achieve safe, efficient, and full-capacity charging.
2. Controller charging maintenance
When the controller detects that the battery voltage exceeds the final charging voltage, the battery will release radon and O2, triggering the valve to release gas. Excessive gas release will eventually cause dehydration damage to the lithium battery electrolyte. Furthermore, even if the battery reaches the final charging voltage, it is unlikely to be fully charged, therefore the charging current cannot be interrupted. At this point, the controller, through its built-in sensor, automatically adjusts based on the operating temperature. The controller gradually reduces the charging current to trickle charging, aiming to keep the final charging voltage below the limit. This effectively controls the oxygen cycle and hydrogen evolution processes within the battery, minimizing the risk of battery degradation and embrittlement.
3. Controller charging and discharging maintenance
Even without charge/discharge protection, rechargeable batteries can be damaged. When the voltage reaches the set minimum charge/discharge voltage, the controller will automatically disconnect the load to prevent the battery from being overcharged or over-discharged. The load will only be reconnected when the solar panels charge the battery to the controller's set recharge voltage.
4. Controller gas evolution adjustment
If a battery fails to undergo gas evolution reaction for an extended period, acid stratification will occur inside the battery, leading to battery capacity degradation. Therefore, we can use digital circuit design to periodically disable the controller's charging protection function, allowing the battery to experience overvoltage gas evolution at set times. This prevents acid stratification, reduces battery capacity degradation and memory effect, and extends battery life.
5. Controller overvoltage protection
A 47V zinc oxide varistor is connected in series at the charging voltage input terminal. When the voltage reaches 47V, it will be penetrated, causing a short circuit fault between the positive and negative terminals of the input swing (this will not damage the solar panel) and prevent high voltage damage to the controller and battery due to unexpected conditions.
6. Controller overcurrent protection
A fuse is connected in series in the control circuit of the battery, and the controller can reasonably provide overcurrent protection for the battery.
