Anyone got a better way to join 2, 6 cell Nimh batteries together, ill be using them in a B4, i've got some velcro aswell, will this be enough?

Or has anyone got any better ways of securing them both together?
Please share

Don't think that will hold them. Use velcro, wide stuff, between the batts and on the bottom to help hold them in place. I'd also get battery straps and use those as well.

the best way if you need to join those is to get heat shrink (the clear stuff holding each pack together) and heat shrink both packs together as one unit.