Lithium ion canteen...

[Externet]

Hi. How whacko would this be to use as a simplistic external 'canteen' supply for a digital camera that uses 2xAA cells that not last much ?


Currently am using the right portion only to supply the camera and has worked very well for 4 years, and I transfer the 18650 to recharge on its standalone charger.
Was thinking on doing the charging via the same camera plug instead, which would place both Si diodes counterparalleled is series to (+)

 

[Externet]

Arithmetics do not fit perfect.
5.0V supply - 0.7V drop yields 4.3V for charging
If the cell is 3.7V charged, minus 0.7V drop feeds 3.0V to camera.

(Had to split the post in two portions as got message of being too large)