Cheers guys. Bright sun today. Sunroof works beatifully.

You can clearly hear vents rotation and powerful breeze cools the car.

I'm already thinking about the On/Off switch to the trickle charger +++

If understood the ELSA scheme correctly: The HVAC unit connects the 'solar request' wire to ground when it wants to energise the relay and switch blower motor power from solar to battery (kind of when ignition is ON, but decision making can be more complicated). All other time solar request wire is in disconnected state (car is parked doing nothing, relay is de-energised) and blower motor is connected to solar element.

OK, that sounds a bit more tricky then if "solar power" is the default.
Sounds like an isolation switch would need to be in the main feed from the panel; how "meaty" is that?

>> OK, that sounds a bit more tricky then if "solar power" is the default.

Blower motor is fed by solar power when relay is not energised and car is parked. Relay can't be in energised state if car is parked as the battery will be drained that way.

>> Sounds like an isolation switch would need to be in the main feed
>> from the panel; how "meaty" is that?

Medium meaty -- 2.5 sq.mm.

It can be mechanical switch or it can be another relay. In case of relay we want the 'impulse relay' (=dual state relay). That means a relay with two steady states: A and B. You only need an impulse to switch it from position A to position B and then back again with another impulse. We don't want a classic relay that only connects to alternative position as long as constant current is applied (energised state) as we want two alternative positions A and B both available when car is parked, which means relay cannot always be in energised state (=battery drain mode).

So, a mechanical switch rated around 15A should be OK. Any idea how much the sunroof can get up to in the real world.

>> Any idea how much the sunroof can get up to in the real world.

Don't understand the question.

Power rating of facelift sunroof with 4 courses of cells is 33.6 Watt if this is what you're asking.

That will do, thanks. +++
I was probably (bad wording) asking what current it generated connected to the fans. From that I'd say it can only be a handful of Amps at most.

I'd also guess it won't be getting as high as 12V but whatever current/voltage is seen in practice won't need a massive capacity switch.
I'd guess that the main reason the cable is relatively thick is to keep the circuit resistance to a minimum.

I've got rocker switches rated at 10A/250V so that would be fine. Roughly where does the cable run and is there an obvious switch location you'd suggest?

I've just had a look at this thread, with IT's "electrickery" explained in detail: http://forum.a8parts.co.uk/showthread.php?t=5370
From that there seems to be a connection in the earth lead from the sunroof that would be ideal for looping in a "cutoff" switch, though no good for battery charging.

Blame my English as second language skill!

10A switch is more than enough.

Look at this thread and open pictures:
http://forum.a8parts.co.uk/showthread.php?t=5370

The cable where you need to install switch comes to the centre of relay baseplate. If you think of baseplate as a 3 by 3 checkerboard the wire you need arrive exactly in the middle of the baseplate.

On pictures it is red 2.5 sq.mm. cable which runs in a conduit with another ground wire which ends with yellow connector.

Please be aware that your baseplate will most probably be yellow and not red as you have facelift car.

You can install switch anywhere you want if you just extend wire in the place where you cut it for the switch.

Now you've done yours Servey I'll have to bring mine over lol

How long do you reckon it took you first time and would it be quicker 2nd time round?!