In regards to the original poster his radio is 2.4 and as such I am of the opinion that 4.8 packs are just a brownout just waiting to happen therefore my personal recommendation stands. Further I do not believe its just a brand thing and I beleve it has everything to do with and is generic to 2.4. Now I definitely do not beleve its first is limited to just Spectrum and that Spectrum fixed anything much but instead education got a whole lot better. And that means much more careful charging techniques and practices than we formerly tended to use as well as a definitely safer 6 volt packs of much higher capacitys than we formerly tended to use.

You say you are a Hitec user RCJetflyer and that's wonderful so am I (extensively). If you read very carefully between the lines in various places in the manual you will find yes you can use 4.8 but rather strong reccomendations for 6 volts. Its obvious these veiled comments are mearly for the various brands trying to compete with each other. We would be deluding ourselves if we beleved we are immune to brownout because we use brand X or that brand Y fixed it.

I believe brownout still happens (any brand) in most cases because of new folks combined with very poor charging practices I see this a lot and it greatly helps simply by in most cases with the few exceptions I used in my former post, to use 6 volt packs of capacitys of around three times what we formerly used in the past with 72 systems.

John