boosters

I have a Ring Pro which seems to have become juiceless. Long shot, but does anyone know if a new battery can be fitted, I know some packs allow for this, but can find nothing relating to Ring kit. Also, anybody got any idea what the minimum specs of a booster needs to be to start a 6 litre...

Anyone else noticed their average MPG go down the pan since it got cold!! Mine has dropped by a lot, almost 10mpg according to the computer :eek: