The latest evolution of Nora circuitry is capable, using li-ion batteries, of running at high output well into the discharge curve of the cells. Good output is possible even when batteries are getting quite flat. When batteries are getting flat, output is reduced, this being managed by the Nora 3 software.
It is important to appreciate that AA batteries have a much lower power density than li-ion cells and sag significantly under load. They are not capable of delivering the amount of current required to run highest lamp settings at full output. Good output is however possible, and other than a reduction in light level when using higher settings, the lamp will operate as normal.
Nora 3 light output levels achievable will depend on the specific type and condition of the AA batteries used.
The maximum discharge of good quality NiMh rechargeable cells is probably no more than 1.7 Amps when fully charged. Consequently maximum output will be naturally limited to around 800 lumen max. When using AA batteries, the higher light settings would arguably best be used sparingly.
As a rule of thumb, using good quality AA cells such as 2000mAh Eneloops, you could expect 5-6 hours operation on default setting 1, 2-3 hours operation on default setting 3, or 15 hours if using low flood (if you include this level in your sequence of settings). We would anticipate similar durations for good primary cells, such as Duracell AAs, but this has not been evaluated in any detail. As a rule NiMh batteries are the better bet, as primary cells sag more under load than NiMh. Durations for lower settings are easier to estimate as AA cells are more than capable of running these light levels at their regulated power. This is of course trickier for higher settings that AA batteries cannot sustain throughout the discharge cycle of the cells. Combined with the wide choice of AA batteries available, it is difficult to give much more guidance on the use and performance of AA cells other than to say that you will just have to suck it and see!
When using AA battery holder, take care not to damage lamp connection wires inside of battery box.