On a sunny day (Mon, 9 Mar 2020 14:15:17 -0000 (UTC)) it happened Martin
Gregorie  wrote in :

>Has anybody tried running a Pi Zero from a single LiPO cell such as you'd
>use in a RC model aircraft or a drone? The voltage varies with charge
>from 4.2 v down to about 3.7 v
>
>I think it should work since the Pi has a regulator that drops the 5v
>supply voltage to 3.3 for internal use, but I don't know what minimum
>voltage the internal regulator needs to work correctly.
>
>FWIW, I'd prefer to avoid using a standard off-the-shelf 5v output power
>pack because:
>
>- 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.


No Pi zero here, but ebay is full of things like this:
 https://www.ebay.com/itm/274214185023
  It has a separate charging connector.
  Has a small switcher on board... 9 USD.

Was seventh hit searching ebay for 'raspberry pi battery supply'.

Single cell, not bad, a Pi zero should run a long time on 3800 mAh.

I have some bigger ebay buck and buck-boost switcher stuff from ebay.
Hard to beat their prices.

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