Using a 18V(max) solar panel, I'd like to charge a 12V lead-acid battery. I'm working from the basic inverting buck-boost circuit. My main question is, being a relatively low-power circuit, can I connect the output directly to the appropriate battery terminals, or would I need to re-invert the polarity before doing so?
It'll be monitored / driven by an Arduino. This is the inspiration: Tim Nolan's MPPT Solar Charger.
A future expansion I'm planning for this is to add a (rectified) wind turbine input as well. Obviously this would need a separate buck-boost circuit, but the question there would be: how safe would it be to connect the output of the wind buck-boost to the battery, in parallel with the solar buck-boost? I'd assume that if my software is written right, the output voltage will be the same from either side so there should be minimal problems. Please correct me if I'm wrong ... but that's a future consideration.
- My significant parts list:
- Arduino for the brains/PWM
- IR2104 MOSFET driver
- IRF540 MOSFETs
- MAX4080S Current sense
- Resistor divider
- Schottky diode for the buck-boost section
- 100uH inductor for the buck-boost section
Edit: I like Olin's simple answer, but it's not the answer to my question, as it doesn't give me any guidance with my project. Any other takers?