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Charging a battery pack from a solar panel? Answered

A  part of my culminating project to graduate from my technical school involves a simple circuit. I want to have a solar panel charge a 7.2v battery pack. This will then output to a female USB port for charging mobile devices. I have majority of my circuit figured out. However, I am not sure how I can effectively regulate the charging of the battery. I know I need a solar panel that outputs higher voltage than the battery, and a Diode in between to prevent backflow into the panels. However, How would I prevent overcharging?

3 Replies

steveastrouk (author)2012-10-18

Use a charge control IC. For further credit, use a MPPT IC.

Stephen Woodward did a rather clever discrete circuit years ago in Electronic Design IIRC.

If this is for a final project, it would be unfair to give you much more information.

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dkop1 (author)steveastrouk2012-10-18

True, it would be rather Unfair. Thank you for the info!

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steveastrouk (author)dkop12012-10-19

Do some more research, and by all means, we'll critique it and help - but start with the research.....

With the right charger topology, your panel can be lower voltage than your battery.....

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