I know this is covered but I guess I am looking for a short sharp answer...

I am interested in a solar charger for the pack. I don't use this gear regularly as I, for the most part don't need power or have it covered with a couple of spare AA batteries.
There are however times where I would want to now charge some AAs/CR123 batteries and maybe recharge an iPhone (that I hate with an almost psychotic passion - but it was issued and forced upon me...!!!).
What is the popular direction on these chargers ????
Andy