When I shipped out 20 of the D1600's, they weigh 50lbs each, and I used boxes that were a little bigger than the batts themselves, and stuffed them with Newspaper balled up... Put it on the bottom, so it was about 2 inches thick after being smashed down, and then stuffed the sides and top, taped up like mofo and all was great...
Think packing peanuts would work in the place of newspaper? I got a ton of them from other packages.