I'm trying to build a wireless/mobile monitor. The monitor will be included in a wheeled cart, so I have some limited storage available in the cavity behind the monitor, but not much. The cart itself will not have access to power most of the time. The monitor will be showing the screen of a computer located at a fixed point in the room. I'm looking for something that can run off of a small battery for about 6-8 hours during the day. The cart can be plugged in to recharge overnight.
I've started with this item as the display:
And one of these for the wireless signaling:
And this setup already works well when I can plug them into a wall outlet. Now I just need the power packs. I was hoping to use these:
Based on the draws from the display and receiver, that should provide enough power to go about 10.5 hours, so it will meet my 8 hour goal even after it's had some wear.
Unfortunately, I can't get it to work. The power pack will charge a phone, but it won't stay active when the display and receiver are connected; it just shuts off after a few seconds, before the devices can even turn on. I feel like the power pack is expecting a special charging signal from them that these devices are not providing, because they have no batteries of their own, but I don't really know what's going on.
So that's my question: what is going on here? I also hope to learn what I need to know to find a battery pack (or hack the one I have, if possible, and this can include soldering the battery to a different board) that will work for this concept.