eneloop Ni-MH "low Self discharge" batteries utilize Panasonic advanced rechargeable battery technology, allowing them to be recharged up to 2100 times. eneloop batteries deliver consistent power performance, maintain 70% of their charge for up to 10 years (when not in use), come pre-charged by solar power (at the factory) and are ready to use out of the package. They also have extreme temperature performance down to -4 Degree F.