Easy to use
One of the many uses of the battery pack that I wrote about previously is to charge smaller batteries. I found a 12-volt battery charger in a garage sale that charges AAA, AA, C, D and 9-volt rechargeable batteries. It uses a cigarette light style plug which plugs directly into the battery pack.
With 14 amp hours of power, you could charge large numbers of the smaller batteries. I like the Eneloop batteries made by Sanyo. They can be recharged between 1000 to 1500 times and will hold a charge for several years. See a previous blog on Eneloop batteries http://bit.ly/RXALec.
A quick search of the internet showed several battery chargers that would work with this battery pack.