Solar charge / controller

Thread Starter


Joined Jul 10, 2008
Hi All,

I'm planning to build a solar charger / controller and I need some sugestions / advice.

The working principle is simple: A microcontroller (AtTiny25) monitors the battery voltage and switches the Solar panel with a PWM signal via a mosfet transistor. A second mosfet controls the load. If the battery is below a certain level the load is disconnected, so the battery does not run flat.

My question is concerning the PWM signal. Should I vary the duty cycle accordingly to the battery charge level? or should I shoul I mantain the duty cycle and switch on an off only?

Thanks in advance for any help