With all those charging devices available, we kept both of our iPhones alive for several days. My wife forgot to turn her iPhone off one night before we went to shivery sleep; since it spent all night trying to cling to spotty cell networks, the battery was on its last legs by morning. When you cant charge overnight, be sure to turn your iPhone off, or at least activate Airplane Mode.
We intentionally didn't plug our iPhones into the battery cases or other charging devices at night, because we only wanted them to charge when we could manually stop charging as soon as the batteries were nearly full. Otherwise, wed needlessly drain extra stored-up juice from the chargers themselves.
I read on my iPad during the blackout -- clearing out the bulk of my Instapaper queue and reading a few iBooks -- with its brightness all the way down and Airplane Mode on. With relatively lengthy reading jags for a couple hours at a time, I squeezed five days of reading out of the iPad (a third-generation model) before its battery gave up.
One step at a time
Even now, more than a week after Sandy plowed its path of devastation, the cell reception around our home vacillates between awful and unusable, with patches of great and terrible service as we move about town.
Now, though, our power is back, so managing our batteries isn't a challenge any longer. Our new problem is finding reliable Internet access: Our home service is still out, and AT&T is offering EDGE speeds at best in our neighborhood. If I couldnt rely on the kindness of family friends, who are letting me use their Wi-Fi until our connection starts working again, Id need to consider a Verizon MiFi or a Verizon iPad with tethering; its the only cell carrier offering fast, reliable data in my area right now.
But, believe me, any connection at all is better than what we had a week ago.