+1 on SMC batteries. I have 5 of them and they have all performed flawlessly. Always balance to within .001 @ 4.2v

No problems with splitting cases, or solder joints coming loose like some of the super "bargain" brands which usually last less then 4-5 months of racing.

SMC packs have never failed in any way. They are top quality and have super customer service should you ever need it.