Help with a project building a USB Power Bank that can be recharged from common disposable battery types.

Base it around an existing power bank or dedicated power bank control module. Lithium cells have very critical charge requirements and trying to charge bare cells without the correct control and protection circuitry is a recipe for disaster....

eg. Something like this, set to 2.4V for standard lithium cells:


For the varied input voltage, a "Buck-Boost" voltage converter should do the trick, connected to a USB-A socket as a 5V power source to charge the power bank.

A suitable one with the output set to 5V could take a wide range of input voltage from different battery types.

A lot will only work down to 3V or so input, so for dry cells you would need to connect 3 - 4 in series to absolutely get the last bit of energy out of them; a typical "1.5V" cell drops progressively down to about 1V as it is used up.


Some examples; a small one, possibly a quarter to half amp output:

A bit more powerful version, good for 1A probably:


There are hundred of other versions with different capabilities.

(Never accept the current ratings advertisers such as these give; most are non-technical and may use peak values that the device can stand for a few milliseconds before it fails...)