Hi guys, I have a specific LED clock that I'd like to use built into my custom wooden case. The clock operates on 4x standard AAA batteries, or USB power via the supplied wall wart. The batteries will continue to run the clock if the USB supply is removed. However, using a set of Energizer Advanced batteries, with the clock on constant display and the USB supply removed, the batteries last 2 days. The clock does not say (in the very limited instructions) to use rechargeable batteries, so I am going to assume that the default is the USB power, and it will switch to batteries if the power is removed, but does not actually charge the batteries. Since Eva is a power nazi and regularly shuts off the power to our computers at the wall, I want this (specific) clock to be capable of running on batteries alone for up to 24hrs at a time, and more than just a couple of times . 12hrs would be the general maximum, but a bit of headroom would be nice. I guess I could use a different clock, but most clocks with battery backup don't display when the power is removed, just keep the time settings, and this particular clock is perfect for my needs so I'd really like to use this specific clock, not a different clock, anyway. My thoughts are to use a power bank as an inline UPS kinda thingy, so running the clock 24/7 from the power bank and charging it simultaneously when the power is on. I'm pretty sure most power banks are not designed for this kind of constant use though, even if (and I'm pretty sure they don't?) they can charge and discharge at the same time. Obviously I don't want to spend a fortune on a proper UPS, so I'm hoping I can roll my own. Any thoughts?