Sorry to post in an old thread but I'm ready to buy the 2x and batteries would need to deliver 4.5amps on high not just over 2 as current does not add up in series...right?
You're right current does not add up in series. But being that the led is being driven at 4.5A at ~3.8v yet you're giving it 8v from two cells is series it takes less current from the cells because of higher voltage. Basically it turns the batteries on and off very quickly to give an average of 4.5A to the led if that makes sense