for the folks on a budget you can buy a cheap solar controller on ebay:
http://www.ebay.co.uk/itm/Solar-Charge-Controller-20A-Panel-Battery-Regulator-Safe-Protection-High-Quality-/121399443448?pt=LH_DefaultDomain_3&hash=item1c43f87ff8
& then connect this to a 12v Solenoid & screw it all to an old bit of ply or ali' if your posh.....
You connect the wires & for under £20 it should work not as good as a £500 unit but then you can fit 4 more panels with the £400 you just saved & that will charge better then the £500 unit anyway right?
I get it I know the boffin's love all the hi-tech stuff but I just like old school over kill that works....
My set up cost me £1200.00 for the panels & £80.00 for the controller & a day to stick the panels on the roof & wire up the batteries.....
The 4 200amp hour batteries cost £100 each trade.....
We run a fridge freezer, washing machine with dryer, HDTV, popcorn machine, lap top, I-pad, phone chargers, cooker hood, 2kw inverter that stays on 24/7 & so far I have not had that beeping sound from the inverter that we all hate so much.....