Powering My Project

Hi,

I'm starting a project that will be housed outside. I have a large 12V solar panel that will charge a 12V Battery via a separate charge controller unit.
I'm then powering the Ardunio via a separate switching regulator (5V) to save the arduinos own voltage regulator from wasting energy converting the voltage.

Does this setup sound ok?

I also have some 12V devices that I want to control via the arduino - Which ground should they use? Before or after the regulator?

Thanks.

You better to select a point near battary "-" terminal, and connect everything else using "radial" topology, where all grounds connected at one points

Like this?

Looks o'k, to be sure check your voltage regulator drawings, if designer follows same concept or post a link.

This is the regulator I have: http://www.ebay.co.uk/itm/5V-9V-12V-24V-Voltage-Regulator-Stabilizer-Circuit-PCB-/171019556244
I have the 12V - 5V switching version.

Is it ok to power via the VIN connection? I read that power is lost as heat through the connectors? It seems to most energy efficient way to power my project from the 12V source.

What make you think that it's "switching" regulator? For me looks linear.

Is it ok to power via the VIN connection? I read that power is lost as heat through the connectors? It seems to most energy efficient way to power my project from the 12V source.

Powering via Vin you only by-passing a diode, reverse voltage protection. To by pass on-board regulator, apply external +5V to +5V input. So, to really save on power, you should search for another board, w/o regulator and serial/USB converter IC.