I've been making packs out of those kick butt Energizer NiMH for a while now. I can make a 4 cell AA 1800 mah with plug for about $11.00. I made a 5 cell C 2100 mah NiMH for my big coroplast gasser (needed nose weight) with plug for about $16.00. I use an iron, and tin the cell, then use battery braid to tie them all together. I build them in a padded vise, and use small strips of foam on the soldered ends before I heat shrink them. I haven't had one fail yet.