Is anyone going to buy the Pi Juice Hat?
It's got an integrated real time clock. I wonder if you can program it to boot up and shut down your Pi?
The Pi Juice would be ideal to use instead of battery banks.
https://www.pi-supply.com/product/pijui ... cba1185463
I looked at this a while back when I was looking for a solution which it may solve, however the main issue was battery size for my application. Looking into it now I have done a bit of learning you could basically build your own. An RTC is about £1 from china, then you just need the appropriate battery pcb for the size of the battery installation you are using - so for a 4cell li-ion setup the right charger for the job, you then need a small voltage sensor circuit to determine when the batteries have hit the discharged state.
Now additionally for wake up and shut down events, the Pi cant go from being completely off to running on its own, however arduino microcontrollers can use tiny amounts of power and do this action.
So if you have the time you could build your own, but a fair bit of coding and bug sorting which is why you pay these people £25 and wait. Does seem fairly lengthy time frame though as I would have thought if I was going to do that sort of project, I'd build one first test it and work out the code, then get it made so it can go straight out as a polished product in a shorter time frame.
With regards to a zero size one or different batteries, I would say thats a product right there. You wouldnt have one the size of a zero because of the battery, however most Li-Ion setups in things such as wireless phones etc have a small 3 pin connector which s +/-/batt temp, I'd imagine you could set a limit of battery size to plug into the unit when sold, but means you could have something the size of the Zero with a plug in battery that can be mounted remotely or used on bigger Pis with more batteries to increase battery life.