After constructing a solar panel and battery system to power a Raspberry Pi, I wanted to find a way to monitor how the battery and charger was performing. There are several ways to accomplish this task, usually involving a voltage sensor, a current sensor, or both.
A voltage-based sensor can be used to monitor the charge of the battery. Over a typical day, the battery voltage should rise as the solar panel charges the battery, and then discharge at night while the Raspberry Pi consumes power from the battery. A common technique for monitoring voltage is to use a voltage divider. If appropriate resistances are chosen for the voltage divider circuit, the drain on the battery from the sensor is negligable.
Another option is to use a current sensor. A current sensor placed off of one of the battery terminals will measure how much current is flowing into or out of the battery. Continue reading “Raspberry Pi Solar Charger Current Sensor”