The ZeroLiPO module doesn't work very well with this power-hungry display. Adding a big capacitor across the power helped somewhat, but you can still see problems when the display has a lot of white to show.

For now I'm just powering the whole thing from a 1S LiPO battery directly, without any boost converter or other circuit. That works well, due to reasons described in this project log, and I'm actually quite happy with this. However, there is no overdischarge protection, and I need to manually switch the power off after the raspberry pi shuts down – there should be a better way to do it.

So I started looking around for a ready module for that – what can I say, I'm lazy – and was quite surprised that I couldn't find anything like that. OK, fine, I will just have to build my own. I looked around a bit for similar projects to steal from, and found this one: http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/raspberry-pi/on-off-power-controller – it's a very nice schematic, and it only uses one GPIO pin to both signal the pi to shutdown, and see when it finished. I might still make this, because it's generally useful, but for now I have a better idea.

That project log I linked, it's for a project that exactly fits my needs. And that project is available to buy on Tindie. It's a battery, a charger, a touch pad button for switching it on and off, and I2C for battery monitoring and low power shutdown. It does everything I need. I will probably try to put a smaller battery in it, so that it fits the size of the pi zero better, but that's it.