My experience with this kind of thing shows the battery volts raise fairly quick to about 1.25V. Takes a while to get them to 1.35. Takes a long time to get them to 1.4 or 1.45V.
With 2000mah AA batteries, its going to take 10 hours of full (high noon) sun. That rate, C/10, is good for the batteries too.
For faster charging, it could use 2 PVs for C/5 without much problems. I would either watch them or use a 4.2V 5W zener diode for a charge controller.
Give it a couple days. I bet its working like it should.
G-