I’ve been messing with uninterruptible power supply issues for years and with Raspberry Pi and similar needing (only at leak of course) 3A 5v power, I’ve looked at various alternatives. Here’s a thought for motorists who are IOT enthusiasts as well..
I just solved the issue of ninterruptible power for the Raspberry Pi – purely by accident. We have a Honda that needs an EFB ( Enhanced Flooded Battery ) battery as it has auto start stop. The manufacturer fitted one of these (more expensive than run of the mill batteries). It got flattened and they don’t recover well from that – so in replacing it we fitted an AGM ( Absorbent Glass Material ) battery – better but more expensive – in our case we got a bargain – the price difference was only a tenner.
That leaves a free (and generally OK except in the cold) EFB battery (the garage was ready to bin it but I said no, it got us all the way from Spain to the Northeast of the UK but experience says it will fail in the winter cold when you least need a problem) – it simply goes a little low voltage when really cold and the car fails to start… but it will never get really cold in my office – other than that it is fine.
SO I bought a modern, efficient(ish) yet cheap 8A PWM charger that (apparently) can be left running permanently – £15 from Ebay 9 ( days+nights and counting) – and a boxed down-converter to 5v at 5a also from Ebay and that SHOULD be the end of my Raspberry Pi worries (and while I’m on – my router will handle a range of voltages around 12-14v so why not).
Time will tell, my floor is full, but there is plenty of space 18″ down under my office desk – I’ve been wondering how to make use of the space and now I have an answer.