Using Energizer Ultimate lithium AA 3500 MAH ( according to Energizer)
I’ve seen the runtime test os Zeroair, but he was using low capacity 14500’s, not AA’s
2 x 3500= 7000 mah
At 400 lumens this led seems to use 2 amps
So 7 ah ÷. 2= 3.5 hours - inefficiencies ~ 25% j=~ 3 hours at 400 lumens
Is this correct?
It’s better to work in watts and or watthours.
2x 1.5V 3500mah cells is 3v 3500mah because you have them in series. This gives 10.5Wh.
In parallel they would be 1.5v and 7000mah.
LED voltage plays a role too- 2A of a 3v (6W) led is different to 2A of a 12V (24W) LED.
The 519a is a 3(ish)V LED. So 2A is 6W to get your 400lm.
10.5Wh/6W = 1.75 hours which is 1h 45 min(ish).