I would like to use a 4.2V(voltage varies from 3.6v up to 4.2v) Li battery to power a Pi - for this it seems like I would need a DC-DC boost converter.

From what I found, all of those seem to create very high, unregulated voltages. I would imagine that a phone that can act as a USB host has such a circuit and allows peripheral USB devices to use 5v when connected, however I am not sure how that is done.

I could use one of the generic boost converters, and then connect a drop-down regulator, however that seems inefficient - is there a better solution?

  • I'm not sure why you think something like ebay.co.uk/itm/271515919466 won't work.
    – joan
    Aug 6, 2014 at 19:59
  • @joan well, with that one in particular the 600mA is a bit low, but that is the general device that I am looking for. Aug 6, 2014 at 20:05
  • It was the first I came across. I realise the form factor and amperage aren't suitable. I'd be happy to attach a similar device to my Pi.
    – joan
    Aug 6, 2014 at 20:21

2 Answers 2


You could build a boost converter using a TPS61030 boost converter from TI or you could use this product that uses it.

Personally I would be nervous using a cheap converter from ebay to power my RPi.


That is a sensitive matter, cause you need both a battery charger and (generally) a buck/boost converter - due to the varying voltages of the battery. I recently found this Aliexpress UPS (https://pt.aliexpress.com/item/1005002519021541.html) that does both, beautifully.

Have been testing it for couple of days without hiccups. In my case I am using 6 li-po (2 parallel 3 series) and my load is: Pi 4, 7" HDMI screen and a miliohmmeter, using a total of 65W from the battery at peaks (during measurements).

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