I want the watt hour data over time.
They jack up the voltage. Which I’m guessing that’s what the keyboard/computer use to report “charge”. If there is no current draw then it seems fine. Put a load on it and it will go down just the same. TANSYAAFL.
This WILL work, but only for circuits with extremely low drain and batteries with very, very low self-discharge rates (not NiMH batteries, for example, which have pretty high self-discharge).
Basically, let’s suppose that a Bluetooth keyboard (on average) draws 1mw at 3.0 volts and won’t work below 2.6.
When an ordinary battery crosses the 1.3v/cell threshold, it might still hold a small, but significant amount of energy that you wind up throwing away.
What they’ve done that is fairly novel, is to make a tiny, very efficient, very, very low voltage to very low voltage DC-DC boost converter. I wonder how low on voltage/current they can go to get 1.5 volts, and at what efficiency.
Watt?