Thanks Agro, I’ve been waiting for this thread! Just ordered the green one with XPL Hi NW yesterday, so I’ve got something to play with until the D4 is back in stock.
In terms of power this is true. The reason you have the same recommended batteries is because the D1 and D4 are both FET driven. This means that you get maximum output with batteries that have least voltage sag, so batteries that are (most) high drain. So with both the D1 and D4 you have maximum output with cells like the VTC6 and 30Q, and you have less output with something like a NCR18650GA (but more runtime on lower output due to higher capacity).
Absolutely. Check out HKJ’s comparator here: Battery test-review 18650 comparator
Punch in Sony VTC6 and Sanyo NCR18650GA. Then mark 5 or 7 amps. You then see that the VTC6 has a higher voltage (less sag) than with the GA. The led is sensitive to minor differences in voltage, so with the VTC6 you get a higher output.
So this means that even if you have less than 10A current, there is still a difference in output depending on cell.