4*AA battery backup with 3gs - rechargeables ok @ 1.2 volts each?

Hi,

I'm looking into getting a battery backup which uses aa size batteries. I have seen other types of backup batteries but I want to stick with aa rechargeables for commonization with my torch and camera strobes.

This is the type of thing I've been looking at USB Battery Box -Convert 4 AA Batteries to USB Port Power and Portable Emergency AA Battery Charge Extender for the Apple iPhone 3GS - uses Gomadic TipExchange Technology and AA External Battery Extender Backup Charger 4 iPod Nano - eBay, Docks Cradles, iPod MP3 Accessories, Electronics. (end time 06-Oct-10 18:48:18 AEDST)

In the first link a reviewer seems to think using rechargeable batteries may be problematic as rechargables typically hold a charge of around 1.2 volts rather than the 1.5 volts a disposable cell would hold. The notes in the other two links seem to indicate rechargeables are quiet acceptable. Has anyone had any experience with these or similar backup batteries?

Thanks
Splint

I don't know about using rechargeable AA's, but your battery pack looks very similar to the one I bought for my iPod Touch a couple of years ago from Amazon ---

Amazon.com: Maxell P-2 2-G Rechargeable Back-Up Battery Pack: Electronics

Theoretically, it is only supposed to power the unit, but actually it charged the iPod's battery and I was able to get more time out of it (maybe an hour for watching videos). I really don't have any complaints considering the price.