Hello all looking for some advice on a stereo I am building for my house. I have a car stereo, amplifiers and speakers, all powered by a 12 volt power supply. Everything works great, except I loose all the radio settings every time I unplug the system. I would like to add a small battery and a trickle charger to keep it charged. I was going to put it just in series with the power supply but after some reading sounds like this may be a bad idea. Looking for some input and if there is an easy way to do so. Thanks everyone.
Belkin (and almost certainly other manufacturers) have produced a UPS that outputs 12vdc for the purpose of providing uninterrupted power to their hardware, ostensibly to keep 911 service alive during power outages.
As a UPS, it has its own charging system. From what I recall upon seeing one, the output is a barrel plug, a relatively common connector, but it can be stripped off and attached in a manner suitable for your purposes.
I did a quick search for 12v ups and a few others appeared, but the correct ones share a common reference to AT&T and U-Verse, which is consistent with my exposure/experience. The first few I saw on eBay were twenty to fifty US dollars.