I've been checking all the questions and can find many similar ones, but unfortunately none that addresses my problem. I ended up reading many interesting questions and answers (including e.g. this one Can i connect Power source (like usb charger) parallel connection with power bank output for keep Uninterruptible power supply (UPS))
I however already have a few PowerBanks mainly something like this. I would like to use one of them as a ups, but my problem is it does not seem to charge when it is charging. Is that a "feature" of the battery, or is it to "protect" me from wearing the battery down? How difficult/dangerous would it be to disable that feature? Could i just go ahead and get the power directly from the end-poles of the batteries bypassing all circuitry, or that would be dangerous?
Last, I have a second brand of powerbank, this one. Here things are even more complecated, as the battery requires me to press a button for it to start charging... Is this standard?
I have seen it be done, since I have found that there are similar power banks out there that can fact provide while charging e.g., with other power banks, e.g. http://raspi-ups.appspot.com/en/index.jsp. It also seems to be an "ok"-ish thing to do (https://www.quora.com/Is-it-okay-to-charge-your-phone-through-a-power-bank-while-the-power-bank-itself-is-being-charged)