Battery powered device to mains

[dave7108]

My mother has a Yale external alarm which takes D type batteries. It's a PITA to get the ladders out to change them. Is there anyway to convert this to usb/12v etc

[JoshSm]

A start would be to count the batteries, 1.5V each, probably four of them giving 6V total?

You probably want it battery backed still so I'd look at a solar panel, a lithium pack and some sort of voltage regulator to get the right output voltage.

If my solar floodlights are a clue the bits aren't expensive but mine were 12V nominal voltage.

[gmaz]

Perhaps use one of these 12v power supplies with a couple of 18650 batteries, but you would need to charge it frequently. Maybe a solar panel with USB plug if the wall faces south.

https://www.aliexpress.com/item/1005007183936785.h...

https://www.aliexpress.com/item/1005010391034018.h...

[Somebody]

Battery eliminators? Something like this https://www.amazon.co.uk/dp/B0DC3BFQP9 or this https://www.amazon.co.uk/Konstsmide-5182-000-Adapt... ?