I'm installing a new radio in my 2006 Ford motorhome. The radio has two power wires, a red primary power wire that comes on with the key to turn on the radio, and a yellow wire that is hot all the time to provide power to retain the memories and settings. The problem is I disconnect my chassis battery when storing the RV for more than a week. I don't want to have to reprogram everything in the radio when this happens.
There is also a house battery on board. It will occasionally be disconnected for maintenance or storage, but less often than the chassis battery. Both are 12v batteries. The house battery is 400ah of lithum iron chemistry. The motorhome comes from the factory with a toggle switch to power the radio from either the chassis battery or the house battery. This switch toggles the primary power and the memory power wire.
My proposed change would be to send power from both batteries through diodes so that the memory wire is automatically power from either battery, regardless of the state of any of the switches. The memory wire typically draws 200 microamps, but it also surges to around 500ma when the radio is powering down (i.e. the key is turned off and the red wire no longer supplies power).
Do you see any potential problems with this? I know there will be a 1.2v drop across the diode, I think that will be fine. FYI the radio is a Sony XAV-AX150. I will of course put a small fuse on each wire as it leaves the battery.
Thanks.
There is also a house battery on board. It will occasionally be disconnected for maintenance or storage, but less often than the chassis battery. Both are 12v batteries. The house battery is 400ah of lithum iron chemistry. The motorhome comes from the factory with a toggle switch to power the radio from either the chassis battery or the house battery. This switch toggles the primary power and the memory power wire.
My proposed change would be to send power from both batteries through diodes so that the memory wire is automatically power from either battery, regardless of the state of any of the switches. The memory wire typically draws 200 microamps, but it also surges to around 500ma when the radio is powering down (i.e. the key is turned off and the red wire no longer supplies power).
Do you see any potential problems with this? I know there will be a 1.2v drop across the diode, I think that will be fine. FYI the radio is a Sony XAV-AX150. I will of course put a small fuse on each wire as it leaves the battery.
Thanks.