Tag Archives: solar charge controller


Automatic solar charge controller

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Based on Michael Davis’s circuit, vina1991 built an automatic solar charge controller for a 12V battery using the 555 timer IC. It is a switching circuit controls the connections between the solar panels output and battery terminals. You can set the upper and lower thresholds for battery voltage so that the charger can automatically switch back and forth between charging and cut-off mode. When the battery terminal voltage goes below the lower limit, the charging process begins, which stops automatically when the battery voltage reaches the upper limit. The switching is performed using a relay switch.

555 Timer based automatic solar charge controller

555 Timer based automatic solar charge controller

500 Watts Solar Charge Controller

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Nathaniel VerLee’s Solar Power System Controller supports solar panels in series or parallel combinations to deliver up to 500W output, that can be used to power street lights, weather stations, sail boats, security systems, and many more applications.
Solar Power System Controller

Solar Power System Controller

The solar energy generator has a buck boost topology DC-DC converter that can either step up or step down the output voltage from the input voltage, which allows the system to operate at the panels peak efficiency known as the maximum power point. The maximum power point is tracked using a current and voltage sensor by periodically changing the input to output voltage relationship of the DC-DC converter and measuring the corresponding changes in output power the sensors. In addition to implementing Maximum Power Point Tracking, the buck boost topology allows the battery operating voltage range to be either higher, lower, or both relative to the panel input voltage depending on the solar panels used. When configured properly it can be used to harness the energy of panels up to 500W in capacity. Batteries capacities can be anywhere from 100 watt hours to a few kilo-watt hours in capacity, and the initial target battery chemistry is lithium iron phosphate due to its high cycle life and increased safety over traditional lithium cells. Other chemistries such as lead acid will also be supported in the future. The generator is composed of the following circuit blocks: a two phase buck boost DC-DC converter, a battery current sensor, a load current sensor, a battery voltage sensor, gate drivers for the converter, a C2000 micro controller, 12V, 5V, 3.3V and 1.8V rails, and a load switch.