Sanyo Eneloop Rechargeable Battery
Charger and 4 AA batteries – $17
4 AA batteries – $10
+ Good battery life
+ Inexpensive recharges
+ Lightweight charger
- Less capacity than NiZn cells
- Slow recharging
With its white packaging and simple blue lettering you might think that Sanyo’s Eneloop batteries are generic, or store brand products. They are anything but, and we came to appreciate their minimalist design. These cells use second-generation nickel-metal Hydride technology to inexpensively provide long battery life.
The cells come pre-charged and are available in a four pack of AA batteries with a charger for $17, about half the price of the PowerGenix NiZn batteries. A package of four AA cells costs $10.
Fully charged, their output of 1.41 volts is much less than the 1.79 volts that the NiZn batteries deliver. The Eneloop cells have a rated capacity of 2,000 mili-amp hours, which is 25 percent less than the NiZn cells. There are adapters for “C” and “D” batteries, but they are not free, as is the case with the PowerGenix cells.
According to Sanyo, the cells can survive 1,000 charge cycles, putting Eneloop on a par with the PowerGenix NiZn batteries, but ahead of the Rayovac and Energizer products. They come with a 1-year warranty.
The Eneloop batteries lasted for 13 hours and 35 minutes running the CD player, about an hour longer than with the Duracell disposable batteries, but half an hour short of the PowerGenix cells. The flashlight stayed on for 4 hours and 5 minutes, an hour short of the disposable cells, but the winner for rechargeable batteries.
At 3.6-ounces, the Eneloop charger is the lightest of the four, and has a fold down two-prong plug. This makes it the easiest charger to travel with, but unlike the PowerGenix charger, the Eneloop charger requires that two or four cells be charged at once, which can be an inconvenience at times.
The charger can accommodate AA or AAA cells and you can’t put them in backwards. Its LEDs blink green while it’s juicing up its cells and changes to a steady light when done--a step ahead of the Rayovac charger which left me guessing when the batteries were ready. Sanyo helpfully let’s you know if you’ve got a defective cell: if no LED lights up, the cell is bad.
A pair of AAs took 4 hours and 45 minutes to get refreshed, halfway between the more efficient Power Genix NiZn cells and the slower Rayovac ones, which required nearly 8 hours. They emerged from the charger warm at 87 degrees F. At 2 watts, the Eneloop charger matches the power use of the NiZn charger and should cost about 3 cents a year in power if used weekly.
Like the NiZn cells, the Eneloop batteries should last for 1,000 charge cycles, according to the company. They may not last the longest or be the fastest to refresh, but Sanyo’s Eneloop rechargeable batteries are inexpensive and should last a long time. Overall, Sanyo’s Eneloop batteries were the best of the bunch.