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I want to solve a very annoying problem I've had with the last two Sony car audio receivers I've owned. The problem being that days are spent getting all the sound setting perfect to my liking, which I write down, but if the battery needs to be disconnected there's no battery backup for the receiver's memory settings, so the settings are all lost. Astonishingly they don't have this feature, even for factory sound systems, but they do have it for home clock radios and the like. I tried one of those 9V battery connectors to the lighter, supposedly just for this purpose but it didn't work.

I bought a battery pack which will hold eight 1.5V AA batteries providing 12V and it has just a Black and Red wire to connect. The receiver's power related wires are Black (ground), Yellow (constant 12V to car battery, Red to accessory 12V panel (remote which signals the receiver On/Off when the ignition key is turned and Orange for illumination.

I'll only use the battery pack and connect it before the car battery is to be disconnected and not turn the receiver on. It's just to preserve the settings in the memory. Would the correct wire connection of the battery pack be Black to ground and just splice in the Red wire into the Yellow wire going to the battery with a connector?

Thank you.

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  • sounds right, but depending where the fuse is located, , batteries need to be matched before connecting to avoid a blown 1A fuse.
    – Tony Stewart EE75
    Mar 24, 2017 at 23:32
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    Your proposed battery pack is not designed to be recharged .The prospective current from the Car battery and alternator are high .Place a diode to prevent charging to be on the safe side and as Tony Stewart stated use the fuse .If you do not need to back up for long then capacitors are an option .
    – Autistic
    Mar 24, 2017 at 23:52
  • Why are you disconnecting the battery often enough that this becomes a problem? I haven't disconnected the battery in my car in the eight years I've owned it - I will have to disconnect it sometime (soon?) to replace the battery.
    – Peter Bennett
    Mar 25, 2017 at 1:09
  • Thanks very much for the replies. The car battery would be disconnected when it dies and needs to be replaced or when the terminals need cleaning or there may be some other maintenance where it should be disconnected for safety. It doesn't happen often but just the same it's always a pain to re-set the receiver settings.
    – BretMan
    Mar 25, 2017 at 20:06
  • Correct, the backup batteries won't be rechargeable. I don't even plan to have them loaded in the pack until this disconnection situation comes up. For this to work (while the receiver is off), the battery pack will need to be a ready power source at the same time the car battery is. Then I'd disconnect the car battery and whatever power the receiver needs to maintain the memory would shift to and be drawn from the battery pack. This could be for just a few minutes or up to a few hours. So I should add a 1Amp fuse in line with the Red wire of the battery pack and I'm good to go?
    – BretMan
    Mar 25, 2017 at 20:20

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I believe you are on the right track, but going about it the wrong way. I think you need a stronger 12vdc power source to ensure you have power to your system.

In my garage I have a garage door opener with a battery backup. The battery went below spec for the garage door and the garage door let me know about it. The battery for it is a lead-acid 12vdc battery. I replaced the old battery with a fresh one and that's all she wrote. Instead of recycling the old battery, I checked to see if it would recharge and it did. This battery had two tabs on it, one for positive (+) and one for negative (-) which I attached leads to. These leads have alligator clips on them which works great for when I need a separate 12vdc battery source for whatever reason. It is also rechargeable and maintains its charge for quite some time. This small 12vdc battery is more than enough to keep power in the system to prevent exactly what you're talking about.

To use it, I connect it in series just like you'd connect jumper leads or a battery charger. Then I am able to disconnect the battery without fear of losing any presets on electronic devices within the vehicle.

You can also find these in battery backup units (UPS) which you may have your computer connected to ... they are used in a lot of different applications. Here's an example of exactly what I'm talking about:

enter image description here

I used something like this to attach to the battery leads, clipping off the end opposite the clamps and attaching connectors to them:

enter image description here

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  • That sounds like a great option although the cost is probably considerably more that what I had in mind. I have a good idea about what to do now, so thanks again. I'll try to post again after I try it out.
    – user26753
    Mar 27, 2017 at 20:58
  • It's why I used a battery I was just in the process of replacing. It's a VERY LOW BUCK option. I also had the clamps laying around from a battery tender I burnt up previously. Worked peachy.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Mar 27, 2017 at 22:30
  • The only risk you have installing this type of system, although it will maintain ICE memory settings plus likely clock and ECU settings, if you've disconnected the battery because you are doing something you'd want to protect the electrical systems from, e.g. electric welding, this would keep the circuits in the car live.
    – Steve Matthews
    Apr 17, 2019 at 10:38

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