May 2007 Update: According to Sanyo, Eneloops are only charged to about 75 capacity at the factory.
Like any rechargeable battery, Eneloops should not be left connected to a low current wall-wart type slow charger indefinitely.
Without more testing, I cant confirm this, but my results show they are already far better than traditional NiMH rechargeables.Notice that the predicted six-month capacity matches very closely the capacity I measured on the six month old just-purchased cells.This may explain the differences you have seen.Sanyo doesnt specify what the optimal storage conditions are for fully charged cells.I have a home-made computer-controlled battery charger/discharger/tester that Ive used on my R/C batteries for years, so I used that to perform the tests.I am not sure to which degree they are charged before being sold in Canada.For other battery powered devices, such as visual certexam suite v 3.3 crack wall clocks, flashlights, and TV remotes, disposable alkalines made more sense because rechargeables would crack partition table doctor 3 run down more quickly from self-discharge than due to the power needed by the device.My radio equipment uses AA sized cells and my planes are powered by high-discharge Sub-C sized cells.This works out to a capacity retention.6 (a loss.4) over the course of 47 days, which translates to the following results for differing time periods: subaru legacy manual repair Time Period Charge Retention Charge Loss Day.0.0 Week.3.7 Month.8.2 Six.Thus, my extrapolation from the seven week discharge is overly pessimistic.At this point, Eneloop technology is still relatively new.
Heres a graph of that first discharge: Discharge curve of a 4-pack of AA Eneloop cells.2A, fresh out of the package.An estimation of long-term discharge rate by extrapolating short term storage results is not correct and leads to rather poor results.Eneloops are probably best charged with a 1 to 5 hour quick charger (like this do-it-yourself USB powered one ) that automatically turns off on charge completion, and then removed and stored until needed.Even after one year, the Eneloops would still have half their rated capacity, whereas a regular NiMH battery would be virtually dead.May 2007 Update: Sanyo will be introducing their own USB powered Eneloop charger on May.I performed the same initial-discharge test on these and found them to have a capacity of 1316 mAh, which works out to about.Additional testing is required to determine this.Like regular NiMH AA batteries, Eneloops are also a great choice for high-current devices like digital cameras that like to eat batteries.They are also available in a kit with 8 AA and 4 AAA with a charger through Amazon.The analyzer measures the resistance either immediately, or when the battery first drops below.2V per cell.(Six month and one year values are predictions.) Although these cells start out with about 20 more capacity than the Eneloops, they lose their capacity more quickly.In other words, it lost.1 of its charge over the course of 7 weeks.Most batteries require three to five cycles before they reach their rated capacity.
Also, the storage conditions (transport, warehouse, shop, etc.) are unknown (see point 3 below).
I chose a discharge rate.2 Amps (1200mA with the following results: Measurement, four Cells, one Cell, measured Capacity @.2 A 1367 mAh.