[8minute]

Has anyone used these portable powerpads (http://www.electrovaya.com/product/p...d_product.html), or similar products. You're supposed to be able to go for 4-6 times longer than on battery alone.

I'm interested if they are useful and last as long as claimed.

Thanks

[anamexis]

Well, those batteries have 80, 120, and 160 watt hours respectively, and the stock Powerbook batteries have 51 watt hours (brand new). So, that should give you an idea of how much more they will be giving you.
I have not had any personal experience with them.