For those interested spoke to the Redarc guys today and they are releasing the new Manager30 Lithium model which will be able to do lithium batteries but also be able to do the standard gel etc so kinda backwards compatible, of course the batteries all need to be the same type but sort of future proof's your investment........ use it for the standard GEL etc ones you already have and then upgrade to lithium when they become a bit cheaper and you don't have to replace the Manager30. Due out in the next few months but they advised closer to December, so I will be waiting for that one, maybe a nice xmas present 
BTW, no association with Redarc, just another great Australian product
BTW, no association with Redarc, just another great Australian product