I'm trying to build a portable Mini-ITX PC. I want it to have similar power capabilities to a laptop. That is, the ability to plug or unplug it from the power main without it losing power and shutting down. Additionally, I want it to be possible to change the battery while the power main is connected, also without shutting down. And before anyone asks, I do not want a laptop, or any box that I can't easily open and replace/upgrade the parts.
Now, I've already found a decent Lithium-ion battery that has 12v 5.5mm DC as both input and output. In theory, I can connect it in a chain with a DC adapter. But, besides the risk of killing the battery with constant recharge and discharge, it would be impossible to unplug it in that state without losing power.
I'm therefore looking for a component to which I can plug both the battery and the power main (or a suitable DC adapter), and it would only use the battery if the power main is unplugged. Then, I can simply use a splitter for the main power, so that it both charges the battery, and powers the PC.
I did find a load-sharing YPWR board from mini-box, but it seems to use both power sources at the same time, if both are connected. I want something similar, that would prioritize using the power main, and not discharge the battery when the power main is present.
I'm also open to other solutions, or combinations of components, of course.