For preparedness, having one of the best rechargeable batteries will assure you an advantage of battery life longevity and a high number of recharge cycles throughout it’s life.
There is a relatively new type of rechargeable battery available which has a set of features that are highly desirable. They are called Low-Self-Discharge, or LSD batteries. They are the latest type of Ni-MH (Nickel-Metal Hydride) rechargeable batteries and have become widely popular.
Here is a list of the eneloop AA features:
Very low self discharge while it sits idle on the shelf. It maintains 70% residual capacity after 5 years of storage after a full charge!
High performance even at low temperatures.
High capacity (2000 mAh).
Designed for enhanced performance for high drain applications.
Can be recharged for up to 2100 times, providing big savings by replacing hundreds of throw away AA Alkaline batteries.
Can be rapidly charged with any ‘Ni-MH’ style quick charger, smart chargers, plug in charger or universal chargers.
This is the Ni-MH (smart) battery charger that I use at home:
Maha Powerex MH-C808M 8 Cell Multi-Charger for AA/AAA/C/D
Panasonic (the ‘eneloop’ battery) is an industry leader in Ni-MH battery technologies, and produces quality cells in consumer sizes (including the popular AA, AAA).
The most popular size consumer battery is the AA size, of which the eneloop ‘LSD’ Low-Self-Discharge rechargeable battery is the most popular for many portable electronic devices, radios, flashlights, etc..
You may want to consider the following economical solar battery charger for emergencies:
Solar Power Battery Charger
For more power, the following article discusses a solar powered battery charging system:
Off-Grid Charging System (AA, AAA, C, D, 9v, USB)
Related article: AA Rechargeable Battery