Yeah i read Gary's report on the ones he used for his Boner (sorry) it may be that i buy ones with a larger C rating than woulod normally be required so even if it is bull it might still be enough. There's one i found with a 65 - 130c rating so i'll give it a go and see from there. This bot probably will be quite power hungry as i'll be running the blade and 4 gearmotors on the drive. If all else fails like you said the Optipower ones are the real deal and i should consider them an investment discount or not.