I have the FL-18 Ultra and the battery is fully encased with charging ports on the front of the unit. No matter what pack you go with, you can carry the battery right on the pack. The Blue Genz pack is the cheapest, but it doesn't have the charging ports.. still it's not a big deal to charge them that way... the biggest thing is that with the more economical packs, you have to buy the battery guage and all that separate