Eneloop cells is not a sprinter, it is a long distance runner.  The next generation of nickel-metal hydride batteries. Designed to deliver power longer than a standard rechargeable battery. To extend life, eneloop batteries deliver a constant voltage from full charge to depletion. This helps to increase the time between charges. Unlike dry-cell batteries, which can deliver a high burst of initial voltage before depleting, eneloop is designed to deliver a lower initial voltage for a much longer duration of time. 

Specs:

• Recharges up to 2100 times
• Retains 70% of its capacity after 10 years of storage
• Pre-charged with solar energy