New iPad type radio, how to use when stopped?

[Oliver Mg]

This is the frustrating thing about "at a distance help". I don't own a modern one (and likely never will) but if I did, this would be something I would have to sort out pronto, and being well into electrics, I could and would. But, I don't have my hands on one, so here I'm working blind.

However, I'm guessing the actual "radio" is buried away somewhere, unlike your more usual "pull it out of the dash" earlier arrangement (where this mod is easy). If this is the case then there are likely a couple of options. Assuming you have a basic multimeter (and know how to use it) and that you can find the "radio" unit, then it should be a fairly simple case of finding which wire goes "dead" when you turn the key off. Then you would cut that wire, safely insulate the "feed" side, and on the other bit (that goes to the radio), connect a wire straight to the battery, via a fuse, say 10 Amp, close to the battery end.

Another option might be to find the fuse that feeds the radio. Then find the "feed wire" that feeds that fuse, cut that and do the same. Or, if it's a standard blade fuse, one could remove the fuse, find out (with your meter) which of the two terminals the fuse "plugs into" is live (with the ignition on of course) and, using a bit of wire with a "Lucar" spade connector attached, plug it into the other terminal (which is the one that connects to the radio unit), then, connect that to a nearby permanently live feed. Note, often fuse panels have a couple of unused terminals, which may be permanently live (use you meter) and one of those could be used. Again, you should put a fuse in that new bit of wire, an "inline" type from a motor accessory shop is fine.

One point though. I understand from what I have been told (I don't and won't own a modern fully "electronic controlled" vehicle) that on such vehicles the "brain" is a sensitive thing. Like, I have heard that if you need to jump start one, you need to follow certain procedures (rather than just simply hooking up the jump leads). So, if anything I have suggested above does owt funny to your cars "brain", please don't blame me <wink> This is just one of the reasons why I prefer earlier vehicles = I understand them !! (and don't need a dealership's computer diagnostic thing to fix them !!)

I'm working on this too (2012 diesel Berlingo) .. I want the Radio/Sound system, Cigarette lighter power socket, USB power sockets and Interior Lighting to work at night, like a regular campervan with a leisure battery.  Due to previously having no manual, (which Haynes have just issued Jan2017 and is on order from Ebay) and the complexities of computer-controlled electrics, I'm taking my time over this project. I fit one or two items at a time, ponder on any possible bad side effects and try it out for a few days/months ! So Far, no problems.  - I have found below the offside rear window a loom with a 12v (live when ignition on/engine runs) power connector under the plastic side cover which would feed a cig socket in later/higher spec vehicles.
I made a simple isolated extension loom that plugs into this little socket. This 12v feed first goes through a diode to prevent any volts, from my fiddling, feeding back into the car's computer-control system. Next is the + terminal of a 12v 22Ah golf cart battery tucked into a perfectly sized cubbyhole in the bodywork. Blocks of foam ensure the gel-battery stays fixed in position, on its side in this cubbyhole. From this battery via a 10A fused I wired an isolating switch, 12v LCD volts display, twin 5v USB outlets and a Cigarette lighter 12v socket. When the ignition/engine is on my 22Ah battery charges at the correct voltage and powers my sockets whether the engine is off or on. On the opposite side of the boot interior is another identical cubbyhole waiting for an additional battery if required. Next I need to figure out a simple changeover switch for the radio as you mentioned, but mine is planned to run the Radio/Audio system off my 22Ah battery.  To safeguard the car computer system another isolating diode may be required to feed the radio 12v from my 22Ah battery via a changeover switch. When I get the new Haynes manual this fog may clear. It may not even be possible. Wadya recon ? I may post some photos if anyone is interested.