Panasonic Eneloop Pro rechargeable batteries have been around since 2011, building on the standard Eneloop cells that were originally launched by Sanyo back in 2005. Like the original they’re based on reinvented NiMH (Nickel Metal Hydride) technology, designed to have neither a memory effect nor to discharge significantly over time when unused.
That’s a major plus point compared with conventional NiMH rechargeable batteries. Previously, you could find that fully charged batteries could lose most or all of their charge over just a few weeks so, by the time you actually come to use them, they’re pretty much flat. It also enables them to be sold ‘pre-charged’, so they’re ready to use as soon as you open the box, instead of needing to be charged up first.
