Review: Eneloop Rechargeable Battery Power Pack Kit

Photo of an Eneloop AA battery.

Batteries! They are the bane of parents who succumb to the allure of electronic toys. Unless you like throwing cash away as often as you throw away batteries, consider these two solutions.

First, buy some fast-charge nickel-metal hydride (NiMH) batteries. They’re not your best option, but in an emergency you have power in a pinch. Read about the Duracell 30-minute Battery Recharger.

Second, buy newer (within the past two years) “low discharge” NiMH batteries such as Sanyo’s Eneloop. They hold their charge longer so you are swapping batteries in your kids’ toys less often.

All batteries suffer from “self-discharge,” meaning that sitting unused they will naturally lose their charge over time. Estimates vary, with Wikipedia claiming as much as 30 percent loss per month. Sanyo is more generous to its competitors, stating a 25 percent drain after six months with a rapid increase to being completely drained after a year.

The big breakthrough is that Eneloop retains 85 percent of its charge after one year. That makes them perfect for toys, remotes, flashlights and so on. They even come precharged, usable right out of the store packaging.

They are also versatile. The Eneloop comes in two sizes – AA and AAA. For C and D batteries you insert a AA into a C or D-sized shell adapter. The nifty thing about AA batteries is that they’re the same voltage of C and D batteries; they just might (?) last less time than a true C or D.

Photo of a side view of an Eneloop AA battery partially inserted into a D battery adapter, and a view of the bottom of a second D adapter with a AA battery fully inserted.

I bought an Eneloop Power Pack Kit at Costco, essentially a starter kit for these type of batteries. It comes with 8 AA and 4 AAA batteries, plus 2 C and D adapters and a compact charger that handles 4 batteries at a time (either AA or AAA). It all comes in a carrying case, making storage quite tidy.

Typical NiMH batteries are good for up to 500 recharges. Sanyo claims theirs are good for up to 1,000.

Eneloop is rated for 2000 mAh (milliamp hours). Think of the mAh rating as the size of the gas tank on your car. The higher the mAh value, the longer the battery will provide consistent output at a given level. Today’s best NiMH batteries are up to 2500 or 2700 mAh for high intensity applications, but the Eneloop is sufficient for digital cameras, and perfect for workhorse applications such as learning tables, toy trains and baby monitors.

The major drawback to these batteries, for me, is the charging time, which is officially 4 to 7 hours, and 5 hours in my experience. A 2- to 4-hour fast charger is also available that offers worldwide voltage (if you have a socket adapter for your particular country). Sanyo’s recharging unit shuts off afterward so that you don’t overcharge the batteries.

Because NiMH doesn’t suffer from “memory effect” (the need to drain your battery before recharging it) you can really plan ahead.

For example, I plan to charge all of my batteries once a year and keep a few more batteries than I need at any given time. My Eneloop carrying case is filled with my extras: 8 AA and 4 AAA batteries. When the need arises, my pre-charged extras will be good as new and not leave me in a hurry to recharge the drained ones.

Photo of an Eneloop carrying case opened to show the batteries and charger sitting snuggly in custom-fit compartments.


3 Responses to “Review: Eneloop Rechargeable Battery Power Pack Kit”

  1. Elliott Kim - 21st Century Dad says:

    Thanks for posting the review. I didn’t know Sanyo made a whole kit like that. The C and D battery adapters are much nicer looking than the ones I found. I did a little writeup on the LaCrosse BC900 battery charger and I recommended Eneloops too.

    There are two kinds of people who are hardest on AA batteries – photographers and babies. There’s one of each in my house!

    January 29th, 2008 at 9:39 am

  2. Mark says:

    I’ve seen deals for those on various bargain websites but didn’t really know what they did. I try to slowly stock up on rechargeable batteries, but if the price is right at Costco I may check out that starter kit.

    January 30th, 2008 at 9:33 am

  3. brettdl says:

    I’ve been using this 15-minute charger to great success:

    February 14th, 2008 at 12:00 pm