How about adding some discussion of the new, big kid on the block-the Inergy line. High capacity, with the ability to expand, by adding more batteries, as you need more power. It look pretty tempting. Reviews have been generally positive.
I figured you were aware, but just wanted to make sure. I suggest just saying 120V is a form of arithmetic average. That should be easy enough to understand, no?
A 120V outlet actually bounces between approximately +170V and -170V. Or 240V peak to peak.
120V is an RMS rating. That is very inaccurate info. to be giving people. Otherwise, a great article, and very helpful for beginners.
Alternating current (AC) is what comes from your wall outlet. Unlike DC power, AC rapidly alternates back and forth between positive and negative voltage, so a 120 V outlet (the standard in US homes) actually bounces between +120 and -120 volts with a frequency of 60Hz.