BATTERIES cont.....
Progress in this area has been so fast that several new and sometimes conflicting considerations need to be outlined. These are mainly how to store, (charged or discharged),  what dangers from over charging/discharging, and perhaps ambient temperatures. 
As well as the progress in secondary (rechargeable types) there has been some progress in the primary types too. I am now strictly of the opinion that Lithium cells (AA or AAA) are best for cameras and remote controllers. We aren't just talking economy here. Reliability & dependability are a far greater issue for these items. This brings up longevity issues and for my money I'd opt for that in the form of Lithium cells. These can be purchased at reduced prices on-line. Try E-bay.