I'm looking for a battery charger capable of charging AAs and CR123s (maybe even 18650s) from standard USB/Solar adapters.

Any suggestions?

I use one of these for that application. Under ideal circumstances
I use my Maha 9000 (which can run on 12V, not USB, and be powered via solar that way, but that's not what you asked.)

I prefer something that's a little more adjustable, but this one is single-channel and charges basically everything
you throw at it, so it's good for a portable survival type charger. Micro USB input and my panels with USB output
run it fine.

http://m.gearbest.com/chargers/pp_424662.html

Yep...I bought two of the 202s and two of the 100s some months back and they're pretty flexible, charging up just about everything we find ourselves using.

The one caveat is the 500mA minimum charging rate and 16340 (RCR123) li-ion cells, which are dimensionally equivalent to the CR123A, but operate at 3.7v and 3.2v nominally and respectively.

500mA is just a tad high for those smaller cells, but it and the 1A rates are fine for just about everything else.

The Xtar VC4 is a decent 4 bay USB 5v charger with two rates of 500mA and 1A, but unless it has a robust USB adapter (a solid 2.4A,) you'll get a lower rate in my experience, but that works well for the smaller 16340s and 10440s.

Chris

Thanks for the replies!

I'm going to check these out.

Remember, the plethora of 5v USB chargers are vastly overrated and so you want to get the biggest one you can afford, like the Anker 21w PowerPort if you're running a 4 bay charger like the Xtar VC4.  While many are rated for 2.1A smart phone charging, they tend to come up short in that department.  

With the 2 bay chargers like the Liitokala 202, you're a bit less concerned and 1A charging is doable for 2 bays.  Of course, you're down to only 2 bays, so that's a concern, but many of these USB solar panels give you two ports to charge.

I think that I paid $7.75 for my two 202s and $3.75 for my two 100s from GearBest, so they're cheap enough to buy a few and stash them away in cars, or other places.

They're quite flexible and will charge up NiMH, li-ion 3.2v, 3.7v and 3.8v (3.6v, 4.20v and 4.35v hot off the charger) cells.  They can also act as a power bank for charging up stuff with freshly charged cells, even though they're a bit noisy due to digital hash.

Chris