Specifically the little boards in the photo.
First question: can I harvest the board from a small lithium cell and pop it onto a larger lithium cell? (I'll be using it in a very low-current application, I just want a bigger cell)
Second question: once the board is attached, can I charge the lithium cell directly from 5V relying on the overcharge protection, or should I still use a buck regulator?
Thanks!

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