Variable Voltage LED Driver

[Paul]

I have a LED driver that takes voltages between 2.8 and 8.4 V. Does the input voltage affect the performance in any way? And what happens if I use a voltage below 2.8? I'd guess it won't light, but I haven't been able to try.
I'm going to use two 4x AA battery packs, each on 6 V (two parallels with two batteries) and I'm considering what would be the best idea, to put the two packs in parallel or in series.

 

[firewire_bf]

For a good LED driver, the input voltage would not affect the performance (i.e. constant lumen regardless of voltage variation).

The lower voltage, 2.8V, is probably a cut off voltage to "protect" a Li-ion cell from over discharge.
The higher voltage, 8.4V, is probably the upper limit that the electronics can handle. An input to high above 8.4V would probably fry the driver.
I think you should put those batteries in parallel. If you put them in series you would get 12V, and that could be to much for the driver.
I find it hard to believe the "real" spec of the driver voltage is 2.8-8.4V. Some manufacturer would most likely state that voltage range because it's a working voltage of the popular Li-ion cells. I could be wrong.

 

[1 what]

firewire bf has it right.

 

[Paul]

I think you should put those batteries in parallel. If you put them in series you would get 12V, and that could be to much for the driver.

Oh, I didn't mean all batteries in series. The idea was to connect the two packs in series. In other words two parallels with four batteries which gives 6V. If it shouldn't matter I think I'll have them in parallel. Better be safe than sorry...