Hello all,

I am currently busy with a project that involves powering a micro controller from a 7V solar panel. I would like for the Micro controller to be able to switch to a back up battery pack whenever the Solar Panel doesn't provide enough output voltage to power the micro controller i.e at night preferably.

Can anyone please suggest how i can go about doing this.

Thanks.

 

Simply use two diodes!

Battery ----------->|------|MCU|--------- |<--------- Photovoltaic

Cheers

Alberto

 

Just be aware that some μCs can be damaged by a 7V power supply. Or maybe you have a regulator between the solar panel and the μC? If you use the diode solution, also note that there will be a voltage drop of up to .7V across the diode.

 

You don't need 7V. Microcontrollers are now readily available that run on 3.3V.
Use a low voltage photo-voltaic energy harvester such as LTC3105 to charge the battery. Then power the microcontroller from the battery via a 3.3V low drop-out voltage regulator.

 

Does the picture i have attatched correctly assume your proposed solution "alberto"?