@harvey_slash Search google images for "constant current source". Most of those circuits will provide a constant current until the battery reaches some certain value. Unfortunately, most of them aren't designed with that in mind, so they won't tell you what that value is. But you ought to be able to work it out.
What components do I need to build a regulated power supply with an input voltage of 220V AC and outputs of 3V, 6V, 9V, 12V? Assuming max. current of 1A in each outputs.
I understand that's an underestimated topic in EE, also if (ultra)(very)low power equipment is fancy today, but for a home project I'd just buy a wall adapter
six capacitors from ATX psus running straight from the rectified grid
And once I wanted to design a super high power audio amp and since transformers are $$$ I was thinking to make something out of discrete components running directly from the grid, but luckily I soon found out it was not such a great idea
mainly because they don't make 15kW loudspeakers, where \$15kW=\frac{(350V)^2}{8\Omega}\$
@VladimirCravero I guess you are officially one of the grumpy old farts on EE.SE that everybody is annoyed with, because they always say what you can't do.
Welcome to the league of EE.SE's grumpy old farts.
We need an official plaque for that
@VladimirCravero Fuse? Amp range? Expensive meter that has a fused amp range.