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.

  • The yellow power wire to the radio needs 12v all the time, this keeps memory settings.
    – Moab
    Jun 2, 2020 at 1:34
  • 1
    Yes this I am aware, I would like to turn off my large power supply and have a small battery backup to maintain power but they need to be both feeding into the same wire. Which I’m not sure if it’s ok.
    – ski550doo
    Jun 2, 2020 at 2:21
  • I once used a large capacitor to temporarily maintain settings in a car radio while it was being moved. I built a wooden box with two front speakers and a pioneer car radio, and ran it from a 12 volt charger. It would immediately die if you turned the radio on, but it can be connected directly to the charger without being damaged like a batter would be. The capacitor wouldn't last very long though, so it's more of a measure which allows the radio to be moved from the garage to the house, rather than to maintain settings for a week of disconnected power. Jun 2, 2020 at 16:36

2 Answers 2


I did this years ago, and kept the power supply (12vdc) permanently switched on. The power drain was very low. Turn off the radio, and the psu keeps the memory going.

If you go to the trouble of wiring in a battery and a trickle charger, what's the point? Power stays on to something!


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.

  • Didn’t think of going this route. Would this be ok to hook in series with the power supply? I’m guessing that they would be designed for such a purpose?
    – ski550doo
    Jun 2, 2020 at 0:45

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