Hi Poncho I bought the SCA 1200 amp unit from super cheap auto 9 months ago for $115 on special.
http://www.supercheapauto.com.au/onl...ecommendations
I use it to power an Orion XT12g Dob, not had any problems with it yet.
Longest usage of had was around 6 hours and it still reported half charged after the session.
A few months back they had the SCA1900 on special for $115.