Recharging backup battery for 5V circuits

Looking for a way to power your circuits even when the main power goes down? This circuit shows how I implemented a backup battery in my home security system.


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Be careful with batteries! They contain chemical stuff and not all battery types like to be charged by this system. In any case, don't use this circuit as a casual battery charger, because it is not meant for that. You'd be better off buying one.

Downloads

- Circuit with partlist and explanation of how it works