well these guys make some valid points however there are some good reasons to make your own packs and IT IS NOT THAT HARD IF YOU ARE WILLING TO LEARN. saving $$ is rather minimal but can ad up. Not every place has a convienient hobby shop or electronics store nearby and open when you need it.some times you will need a custom pack or modify a pack to your needs. almost certainly you will find the need to attach connectors.are you going to wait untill they open up & be totally dependent on someone else? besides, just how do "they" do it?- by applying a learned skill. you will find plenty of uses for the investment in a good solder iron ( you do not need a gun-infact a gun can cause problems sometimes. the proper wattage for the task is what is important .cleanliness & quality components . spot welding is not always that good a way to attach cells -just a quick way for mfgrs. it is not neccesary to over heat cells to solder. Keith Shaw proved that. you may have heard of him?? pre tinning the cells will go a long way to ease process.use a light pana vise to hold the cells while soldering. use copper braid wicking - works superbly to attach cells.screwdriver pressing down the braid holds it in place & draws away excess heat that may accumulate.