Save Moixa MXAA02 USBCell AA Rechargeable USB Cell Batteries 4 Pack Kit

This product (Moixa MXAA02 USBCell) is based on a great idea - the kind of idea that makes you smack your forehead and exclaim "Why didn't *I* think of that!" Basically you take a '3/4 AA' NiMH cell, and attach an USB-powered charger on top of it. Now you've got a rechargeable AA battery that can be charged from any USB port. So you'll never be caught without a battery charger - as long as there is a computer nearby.

Great idea aside, there are practical limitations for this USBCELL:
- It is very expensive (about 4 times the cost of a typical AA NiMH cell).
- Its capacity is only 1300mAh (compared to 2000-2700mAh for a typical AA NiMH cell).
- Its charging time is relatively long (5 hours to charge to 90%)

The product description claims that you can also recharge the USBCELL in an "approved NiMH charger" at 250mA for 7 Hours. But make sure that the charger is a 'smart' one. A timer-based 'dumb' charger will badly overcharge the USBCELL, because it treats all cells as having a typical capacity of 2500mAh.

It is true that you don't need to buy a separate charger for the USBCELL. But the economy of scale is stacked against it in any demanding appliances such as digital camera. For the price of just two USBCELL, you can buy a good charger+battery package (such as the Sanyo USB Charger or Sanyo Travel Charger). This way, you get much greater battery capacity and shorter charging time. For anything that requires more than two AA cells, the USBCELL solution becomes even less cost-effective.

It is also true that using USBCELL instead of disposable alkaline cells can reduce your 'carbon footprint' on this planet. But the same can be said for any rechargeable batteries. Compared to a typical AA NiMH cell, the USBCELL requires more energy to produce, and has a shorter lifespan (lower capacity means it has to be recharged more often). Therefore it generates more waste in the end.

Of course, for certain niche applications (such as wireless mouse) the USBCELL is still a good option. At least it looks cool, and makes a great conversation piece.Get more detail about Moixa MXAA02 USBCell AA Rechargeable USB Cell Batteries 4 Pack Kit.