Hardware

SMA kit

Sunny Island 5048 with RS-485 piggyback communications module. Should work with all Sunny Island inverters. Connecting the RS-485 piggyback to the Sunny Island was painless (apart from having to cut power for 5 minutes) and is explained in the manual.

Raspberry Pi

Got the Model B with Ethernet port from Farnell. http://www.raspberrypi.org/ A mobile phone charger with micro-usb and an SD card with Rasbian Debian linux already installed.

USB to RS485 converter

Made sure to get a converter that used the latest FTDI chip so that it would work out the box with the RPi.