Automotive Radio memory retention with the battery disconnected

[rmc1218]

I have a classic car and I don't want the battery hooked up all the time, for safety. Does anyone know if there's a power device I can splice into the stereo "memory retention" wire that will supply power to the memory while the vehicle battery is disconnected and charge up again while the vehicle electrical system is reconnected?

 

[kanewolf]

There are devices that will plug into the standard cigarette lighter and provide radio power via a 9v battery. I don't know how long they will hold a radio. It sounds like you would want weeks maybe. https/www.amazon.com/CTA-Tools-3002-Computer-Memory/dp/B000GKD5Q0

 

[americanaudiophile]

You may be able to run a parallel memory retention wire to the battery and attach a clip to it. Attach the clip before you remove the hot from the battery.
If you install a battery cut off switch you can just leave the extra wire attached to the battery terminal before the switch.