I work offshore. For last 10 years have tended to leave car in garage for 4 weeks unused as wife can't be bothered driving whatever we have had and just uses her own. Have always plugged in a simple battery conditioner of the type that trickle charges through the cigarette lighter/internal 12V supply. Last time departing was first time I had had the car since purchase to do this for various reasons.

Anyway on using the internal centre console socket when I switched on there was a noticeable hum from somewhere forward of windscreen centre so left it off. Eventually found out from dealer that this was me back feeding some module that didn't like it and that if you ever want to do this then use the boot power point only.

Only now home and with other issues with the car have I found out that it has affected the Alpine unit upsetting many of the settings I had in it and loosing the speech yet again. All has had to be reset and appears to be working okay but beware. Nothing is ever simple is it!

Handy to know Al thanks. I'm the same as you, and use a trickle charger.

I have trickle chargers on both the Esprit and Elise which are connected to the battery terminals permanently and they have inline connectors that I pull apart to disconnect when taking the cars out.

Just a quick question, Ive tried to plug my battery conditioner in to the Evora tonight, using the handbrake 12v (have now noticed I should use the boot) but the charger wasn't working. Does the internal 12v socket not have power to it when the ignition is off? And the boot one does?

Will try the boot one when I get home

Ok update.

It appears to charge the battery from both ports, but if plugged into the handbrake one, it still allows certain things to work, such as the fan/aircon which makes a distinct humming noise. Al I'd imagine this is what you were hearing..

I've left it plugged into the boot

It happens to mine too. The trickle charger looses the presets on my Sony. Very odd.

The 12v socket behind the handbrake is only live when the ignition is switched on.

I have a simple Halfords trickle charger on both the Esprit and the Elise and one part of the cable which is fused is permanently connected to the battery and the lead to the plug in charger is fed out through the slotted vents on the engine cover so that when connected and switched on I can close the engine covers therefore no need to disconnect the boot light on the Esprit.

I have trickle chargers on both the Esprit and Elise which are connected to the battery terminals permanently and they have inline connectors that I pull apart to disconnect when taking the cars out.

Exactly how mines set up. 100% solid connection to the battery, seconds to connect and loads better than clips or having to trust the push fit of a lighter socket.

The 12v socket behind the handbrake is only live when the ignition is switched on.

Definately not the case in my one...