Re: Backup power supply

Computer Nerd Kev <not@telling.you.invalid> wrote:

Andriy D <usenet@dolik.dev> wrote:

The Natural Philosopher <tnp@invalid.invalid> wrote:

On 14/03/2024 07:57, Andriy D wrote:

This is exactly my concern - I want this think up&running 24/7/365 and I don't want
it to burn my house down :)
I guess this is where you'd say 'risk' and 'price' are in a inverse relationship ;)
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It is entirely possible to trickle charge a lithium cell at uber low
risk, Essentially you want to current limit the supply at at one tenth
of the hourly capacity so e,g a 2200mAh celll would need to be charged
at no more than 220mA, and voltage limit the charge at 4.2V.

Majority of the schemes I've found so far suggest use of NiMH cells as
they are less 'combustive'.

 
Indeed, but if the power requirements are low (a Pi Zero without any
power-hungry USB/HDMI connections) then supercaps might be an easier
option. Since then you don't need to worry about over-charging,
which will still wear out NiMH, even if it doesn't then burn your
house down.

I had this thought as well, as all I need is to have enough power to
cover for a few seconds of a power outage or gracefully shutdown RPi if
it's longer than that. Thanks for that link!

--

Cheers,
\aID