I have 6 station lamps rated at 12v that I run off a 9v battery. I would like to solar power these and have them automatically switch on at dusk.

Can anyone tell me the best way to achieve this, for example modify a garden light in some way or obtain a circuit diagram and build from scratch.

This ought to be an off the shelf product for garden railways ?

You can quite easily modify the LED output of a cheap single solar powered lamp but the solar panel is very small and usually just trickle charges a small 1.2v cell or 2.

There are separate installation kits like this one from: Conrad

This gives a bigger solar panel plus night/day function and a switchable movement detector so you could have them coming on only when a train (or cat) passes....

I'm sure Maplin do similar.

This is what I plan to wire up to an old car battery or a Sealed Lead Acid Battery(SLA)out in
the garden hooked up to a string of LED Christmas lights in my buildings when I build them.
Reckon it should keep the lights going 24/7 that way so no need for fancy on/off switches etc.
Still on the wish list though along with a ton of other stuff.



Charger:- http://www.jaycar.co.uk/productView.asp?ID=MB3501&form=CAT2&SUBCATID=1004#12

SLA battery:- http://www.jaycar.co.uk/productView.asp?ID=SB2485&form=CAT2&SUBCATID=997#12

This is what I am using. Some simple diagrams, rules and equations for sparkless types like me.

http://www.reuk.co.uk/buy-9V-250MA-SOLAR-PANEL.htm

I don't think I am the first to say this, but you can add a light sensor to the circuit. I personally don't know how to wire that in, but I know that the sensor detects X amount of light, and when it goes below a certain point, it triggers a switch which turns on the light. Got it, because I confused my self just now.

to truly see what I am talking about, go to the store, and buy a cheap solar light, then take it apart. After looking at something long enough, someone usually figures it out.

Tell us what you find when done!

Having thought about this a bit more (won't do that thinking stuff much any more, I got one hell of a headache from doing it ) I have found a method to do the on/off thing.
It involves an LDR (Light Dependent Resistor).
Here is a circuit using a relay as the on/off switch but you could use a transistor to do the same thing.
http://electroschematics.com/5899/diy-ldr-switch-circuits

All I have to now is make some cheap easy buildings to put the lighting in but that is another story.