USB Batteries

An anonymous reader writes "Tired of paying for new batteries all the time? Tired of searching for the charger for your rechargeable batteries? Worry not, because these new AA batteries will recharge direct from your USB port! This is such a cool idea, that I cant believe that no one has done it before." At $24 each I would hate to lose or break them on a regular basis.

Comments

Not so fast...

[crazyjeremy]

Not so fast fellow /.ers. This new product may not be all it's cracked up to be for their price... Unless you have lots of extra ports on your computer and your electronics do not need strong batteries.

USBCELL batteries have a capacity of 1300mAH which is in line with most NiCd and NiMH batteries though some do go all the way up to 2500mAH. It takes five hours to charge a completely flat battery and an LED on the side will light up to indicate charging, flash for 10 minutes after charging is complete as an alert and switch off after that.

Uhm... First of all, using USB for this is generally a bad idea. But if you do want to charge batteries via USB: 1300 mAH is NOT in line with most NiCd and NiMH batteries selling these days. The standard for 4 off brand NIMH batteries from Walmart right now is $6 for 2000 mAH to 2500 mAH (depending on if they've restocked recently as the Generic Brand has upped their standard capacity for AA's).
Let's break this down.

4 batteries - $6 at Walmart for off brand or $10 - $15 for 4 name brand rechargables.
Cheap AA/AAA USB Charger $8 from tiger direct.
OR
Better AA/AAA USB Charger $20 from tiger direct.

The cheapest route gives you 4 batteries, each with twice the mAH for $14 plus shipping. The most expensive route gives you the same thing for $30 plus shipping. Either way, buying a battery with only 1300 mAH nowadays is like buying a midsized car with a 50 hp engine.

Bottom line? For novelty reasons, these batteries look interesting and you do not need to carry an additional charger. But at around $16 US apiece they are expensive and WAY underpowered. Additionally, you need one USB slot for each. If you buy a regular USB charger and use standard rechargeable batteries, you can charge several (up to 4) with one USB slot and spend half the money.

Conclusion? It's a neat novelty backup backup. But it is way to expensive.

It's about the chemistry

[backwardMechanic]

It's all about the chemistry, not some kind of voltage deflation. Zinc cells give 1.5V (alklines, etc). NiCd and NiMH gives 1.2V. Lead acid gives 2 and a bit V. You can't make a NiCd battery at 3V. A battery is a stack of cells, so it can only provide an integer multiple of the cell voltage (2.4 or 3.6V is as close as you'll get with NiCd).