less than 2 amps running, startups on small ballasts (depending) isnt THAT much more than running, instead the output chokes till it gets going.
i would say no on 8X nimh, the balasts faulter below thier voltage, and from what they say its isnt good for them or the bulb item (i forget which).
figure your lows at ~1.0 and your highs at ~1.3 for each ni-mh item, UNDER the load, and go from there.
so if it needs at least 9V then you probably should use at least 9, that all of course depends on other resistances and stuff and how it all acts, which should be tested prior to picking something you cant change.
some voltage ranges on some ballasts has some instalations of it regulating voltage prior to the ballast, but you should be able to get within the range Easily. i think its harder to get within range with li-ion, because adding in ONE item changes the voltage SOO much, with ni-mh you have much better flexibility in selecting a range that the balast would be happy with.
remember ALSO, that it would be nice if the thing DOES cut off before any single cell is depleated in series, so it is a bit of a tossup Too, choke the balast, or kill the batteries when run to low. and i am NOT saying that anything is massivly critical, just the factors involved.
