Yes the input to charge pump is an external energy source ....The energy to recharge a battery must come from an external source.
Hello,In your initial question, I thought you were proposing powering the charge pump from the battery being charged thereby making a perpetual motion machine which violates the laws of thermodynamics.
Are you proposing charging the battery using an externally powered charge-pump only when the battery voltage is below 1V? If so, what is magic about 1V? Shouldn't the end-of-charge condition for the battery be more like 4v?
What is the role of the charge pump? Is it in addition to a conventional charger? Or is it supposed to replace it?