I have a motorhome and tow my car behind. Since I have to leave the car in accessory mode so the steering wheel is unlocked, the battery doesn't last a long time.
I want to run a DS line from the motorhome hookup (fused at motorhome) to the battery in a car to utilize the motorhomes charging. I plan to fuse at the car battery. Really would like to add a diode to prevent the car battery from backfeeding into the motorhome.
All batteries are flooded lead acid, 12V. Since there is a good possibility of backfeed when starting (diesel draws a lot of power to start), I'm not sure what size of a diode I should use or even where I could purchase one.
I live about 40 miles North of Toronto Canada.
Any suggestions on where to get or improve the circuit would be greatly appreciated.