Low self-discharge (LSD) NiMH batteries have been mentioned at least 3 times before on Cool Tools under the Eneloop brand name. These batteries retain 85% of their charge after a year in storage, making them almost as convenient as alkalines (keep a few charged ones on-hand, ready to go). At about $2 each, they pay for themselves after 4 or 5 uses.
This review is about chargers, which are not all made equal. The Duracell CEF23 is superior to other chargers in several ways:
- “Smart” charger – doesn’t just use a timer, but looks for specific behavior of the battery voltage to determine when charging is done
- Independently charges each battery – can mix AA and AAA’s and start/stop each battery independently.
- Charge speed of about 4 hours is a happy medium between reducing the life if your cells (very rapid charge) vs. having to wait very long
- Ability to charge from an AC outlet -or- 12VDC (e.g. car plug or solar panel)
- Ability to act as a USB device charger – powered by AC, 12VDC, -or- the 4 batteries in the charger
Those last 2 points put this charger above most others. In emergency situations, you can recharge batteries without needing AC, and you can use any 4 AA’s (NiMH or Alkaline) to top off your cellphone or other USB devices. You could pop one of these in an emergency kit and give it a recharge every year or so.
Unfortunately, Duracell stopped making the US version of this charger. But you can get the Australian-plug version (CEF23AU), bundled with a US-plug adapter and 4 AA LSD NiMH batteries, for about $20. That’s cheaper than most other chargers, which don’t have the extra features this one does. Not bad!
If you add a generic 12V car power cable (e.g. from Radio Shack), a few extra LSD AA/AAA’s batteries (consider Tenergy brand), and some “AA spacers” that let you use the AA batteries to replace C/D batteries, you’d be totally outfitted with LSD batteries for about $60.