Martin Gregorie  wrote:
> - They're are rather bulkier than a bare LiPO and, if possible, I'd like
> to get a Pi zero plus the battery into the space behind a Pimoroni
> HyperPixel - 4.0, which is 86mm x 56.5mm
>
> - Almost all power packs only have a single mini USB connection for both
> charging and power output, so it would need a additional wiring and at
> least an external socket plus plug to avoid the need to unplug it from
> the Pi to charge it - adding more bulk and fiddling.

You don't want to power it directly from the lithium cell - you need a
cutoff circuit to prevent overcharge and overdischarge.  The cutoff is often
integrated into a 5V stepup chip, so there's no point using the bare cell
even if it would work.

However you can buy the power board from a power bank without the
batteries.  If you search ebay or better Aliexpress for 'power bank pcb'
there's lots of them of varying form factors.  For example, a selection:
https://www.ebay.co.uk/itm/5V-1A-2A-2-1A-Power-Bank-Charger-Module-Battery-USB-
LED-Boost-Step-Up-PCB-Board/283407817785

(shipping from China might take a while at the moment)

Theo

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