I bought a isdt sc-608 charger just to try out because they are tiny and I was wanting to save space in my GT12 pit box.
I've now bought another 2 of them for my off road pit box, they are great little chargers, the 608 will charge at 8amps and they make two slightly bigger chargers that can charge at 14 and 20 amps.
Got to say that I was surprised at how good/accurate they have been, updated firmware is available from isdt every so often which is nice too see.
http://www.isdt.co
http://www.isdt.co/sc-608.html
http://www.ebay.co.uk/itm/iSDT-SC-60...oAAOSwA3dYNFMk