Motorhome Radioswitch from Main Battery to Leisure Battery

[canal92]

Hi new to site have some electronic knowledge but at present can't figure a way to cheaply carry out the electronics

Project A friend has a Motorhome where the Radio goes off with the engine turned off so can't sit listening to radio once parked up my idea is to have the radio wired permanently to van main battery time and Channel maintainance so channels are always where you kept them, Then to have the on/off for the radio through a two way switch on/off/on so that onsite flick the switch to habitation and then switch off or as driving then switch to main battery.
But here I am stuck as I would like to have telltale LEDs for each operation But can't think of a way to fit the LED so that it only work on the specific battery.

One thought but is it logical

Battery (A) through 10A fuse > Though an LED >Though position 1 on switch > through to the Radio but the electronic path to earth be viable as the 12v /10A going through the LED

Then Battery (B) as same

Thanks in anticipation

 

[Martaine2005]

No, that wont work..
You cannot power devices through an LED..
You may want to look at 12v illuminated switches for this project.
Something like these.

Martin

 

[canal92]

Hope this works? uploading image

Would this work or am I over-engineering

Take 28/0.30mm Wire (17A) from Leisure battery through 15A inline fuse >>>>> Then install Diode >>>Through an illuminating switch >>>> connect to the original wire to the radio
Then insert before the join between IGNition and original wire and LB wire another diode

Theory When Ignition OFF no flow of electricity to Radio >>>> so if Neon / LED switch is switched on then power to radio and for safety of drain back the Moriginal wire diode will stopany accidental connection >>> If LB accidentally left on when engine starts again Diode in the LB wire will isolate the batteries,

Am I totally wrong

 

[Martaine2005]

Yes, that looks fine. I can't see any problems with that.
You could also use a rocker switch with centre position off. Left, main battery/ign and right 2nd battery. Illuminated green for main and red for aux battery or something on the lines.
Good use of the diodes. Leave them there even if you change the switch..
Example:

Martin

 

[canal92]

what type of diode would I require

 

[Martaine2005]

Well, technically over and above the radios requirements..
But unless it is a system with amplifiers and ceiling speakers in every room etc not very big.
I would have thought 6A diodes would be over kill. So you can either try 6A or 10A diodes, or do a current test on the system.
But I would be surprised if 6A wasn't ample. Don't worry about the voltage specs, a 6A diode will probably have a 1000V rating or similar. It's just the max..
Have a look for 1KV 6A diodes to start.

Martin

 

[canal92]

would be a standard Car radio with Front stereo and rear Stereo speakers 40W per speaker approx