Temperature compensation for solar charge controllers — Why is it important?

Importance of Temperature Compensation

Temperature compensation for solar charge controllers is essential because the voltage output of solar panels and the charging current of batteries vary significantly with temperature changes. Most solar panels have a maximum power point (MPP) voltage that shifts with temperature, which can result in a 0.5-1.5% change in voltage for every degree Celsius change in temperature. Similarly, battery banks experience a 0.2-0.5% change in charging current for every degree Celsius change in temperature. If not compensated for, these temperature-related changes can cause the charge controller to overcharge or undercharge the batteries, leading to reduced battery lifespan and system efficiency.

Techniques for Temperature Compensation

To implement temperature compensation for solar charge controllers, you can use a thermistor or a temperature sensor connected to the charge controller. Some charge controllers, especially MPPT models, have built-in temperature compensation algorithms that can adjust the charging parameters based on the temperature readings from the connected sensor. When setting up temperature compensation, ensure that the thermistor or temperature sensor is installed in a location that accurately reflects the temperature of the solar panels or the battery bank. Typically, a thermistor with a resistance range of 10-100 kΩ is used for temperature compensation, and the charge controller should be programmed to adjust the charging parameters based on the temperature readings.