As the control component of solar street lights (solar garden lights), the solar controller plays an irreplaceable role in the solar street light system. Like the human brain or a computer processor, it's small in size but plays a crucial role. Therefore, choosing a high-quality controller is crucial. The following briefly explains several key considerations when selecting a controller:
Trip Protection Voltage
Some users have found that after a period of operation, especially after several consecutive rainy days, their solar street lights may not light up for several days or even several days. The battery voltage is normal, and neither the controller nor the light source appear to be faulty. This issue has puzzled many maintenance personnel. It turns out the problem lies in the voltage level for the "trip protection" function. The higher this value is, the longer the recovery time after an undervoltage condition increases, resulting in prolonged periods of malfunction.
A high-quality controller should allow customers to customize the trip protection voltage based on their configuration. However, it's important to note that the battery panel configuration must be reasonable. If the daily charge level of the battery panel can't keep up with the nightly discharge level, the battery will often be in deep discharge over time, significantly shortening its lifespan. Therefore, the battery panel configuration must maximize margin. The larger the battery panel configuration, the lower the voltage at which the protection circuit is triggered can be set, minimizing the risk of battery damage.
Constant Current Output
Due to the inherent characteristics of LED light sources, constant current or current limiting is necessary. This either ensures normal operation or reduces lifespan. Common LED lights rely on a separate driver to achieve constant current, but this driver consumes considerable power. Therefore, efforts are underway to integrate the constant current control within the controller, which not only simplifies installation but also reduces power consumption.
Output Time Period
Ordinary controllers can only be set to turn off the light after a certain number of hours, such as 4 or 8 hours, which doesn't meet the needs of many customers. A high-quality controller should offer flexible time period settings, with configurable time for each period, multiple on and off modes, and, ideally, independent control of each channel.
LED Light Output Power Adjustment
Among solar-powered lighting fixtures, LEDs are best suited for achieving variable output power through pulse width modulation. By limiting the pulse width or current, the duty cycle of the LED light's overall output can be adjusted. For example, a 30W LED light with six 1W LEDs in a string of five can be configured for nighttime power dissipation. For example, the power can be adjusted to 15W in the late evening and 24W in the early morning, with the current locked. This ensures full-night lighting while saving on solar panels and batteries. Long-term testing has shown that pulse width modulation generates significantly less heat, extending the lifespan of the LED.
Heat Dissipation
To reduce costs, many controllers fail to consider heat dissipation. Consequently, when the load current or charging current is high, heat builds up, increasing the internal resistance of the controller's field-effect transistors (FETs), significantly reducing charging efficiency. Overheating can also significantly shorten the lifespan of the FETs, even leading to burnout. This is especially true in the summer, when outdoor temperatures are high. Therefore, a good heat sink is essential for the controller. Iron or plastic casings cannot meet summer heat dissipation requirements, so aluminum is the preferred material for controller hardware.
MCT Charging Mode
Conventional solar controllers use a three-stage charging method similar to that of mains chargers: constant current, constant voltage, and float charge. Because the mains grid has unlimited energy, failure to use constant current charging can directly lead to battery explosion and damage. However, solar street light systems have limited panel power, so continuing to use the constant current charging method used by mains controllers is unscientific. If the current generated by the panel exceeds the current limit of the controller's first stage, charging efficiency will decrease. The MCT charging method tracks the maximum current of the solar panel to avoid waste. By monitoring the battery voltage and calculating a temperature compensation value, a pulsed trickle charge is applied when the battery voltage approaches its peak value. This not only fully charges the battery but also prevents overcharging.
Waterproof and Moisture-Proof Performance
Coastal users will be most aware that a non-waterproof controller can corrode its circuit boards after about six months. For ease of maintenance, most customers place the controller on the base of the light pole. However, many light pole manufacturers' bases are poorly sealed, allowing rainwater to enter during rain. A controller that is not completely waterproof is likely to corrode due to water ingress. Excessive water ingress can instantly cause a short circuit in the controller circuit. It's also important to wrap the wiring connectors with waterproof tape, as ordinary insulating tape cannot protect the connection points from water ingress.
Temperature Compensation Function
This is an often overlooked feature, but it's crucial and essential. Batteries have a unique negative temperature characteristic: their voltage increases at low temperatures and decreases at high temperatures. The controller monitors the battery voltage in real time during charging. Generally, a 12V battery is protected at around 14.5V to prevent overcharging and damage. Without a temperature-compensated controller, the controller's real-time battery voltage readings can vary significantly depending on the temperature, leading to serious consequences such as undercharging in low-temperature environments and overcharging in high-temperature environments.
Post time: Sep-30-2025