I have a 2013 XF (2.0-T) that I'm in the process of installing a nice dashcam setup. Not wanting to drain the battery down in parking mode over several days, I've built and am installing a nice LiFePO4 40AH battery in the rear. There's an associated charger to go with that - it pulls power from the main battery in the boot ONLY when the ignition lead has +12V ... That way it only charges when the car is running. It also has a solar-panel input, so it can take a modicum of power while parked - should be enough to keep the battery well-charged if it's sunny.

So far so good. I've installed the exact same setup in my wife's Kia Sportage and my 94 Supra. Works swimmingly.

Now I need a fuse or wire in the rear area that only has +12V when the car is on. Metering the rear fuse-box though, every damn fuse has +12V all the time. Same for the passenger footwell fuse-box. The engine compartment fuses though, the power-socket and cigarette lighter fuses are ignition-only, so that's good, but YUCK, pulling a wire from the engine compartment all the way to the boot.

Does anyone know of a reasonably-accessible source of ignition-only +12V in the boot area ?

For those interested, the details of the setup are :

Blackvue 900x-2ch-plus
Kanruis DC-DC charger - 30W solar panel - 20x Headway 38120 batteries per backup battery
Daly 30A BMS

The charger needs 16V-25V for the solar input, but the panel only has USB and 14.4V output. It was easy enough to open up and solder a power-connector pigtail right onto the panel inputs. Poof, 25V right there. First two battery pics below.


Batteries under construction

Batteries complete

Solar panel mod - access to direct panel 25V output

 

Bumping ... I'm thinking to possibly dig for the fuel pump wiring for ignition on signal ?

any hints ?

 

Somewhere in the back is a grey plug used for the towbar wiring, there should be an ignition in that plug.(not certain which side).

 

Ah excellent, thanks. I'll poke around.

 

The other thing that I used to use when fitting gps trackers is a voltage sensing relay, start the car the voltage rises & turns a permanent live to a switched feed! Turn the car off & it drops out.

Like this....https://www.in-carpc.co.uk/product/v...-sense-module/

Or this on ebay..https://www.ebay.co.uk/itm/144433582...RoCzUMQAvD_BwE