2 NiMh in series

[BrianG]

You may need to lower the shift point. Or maybe it is already locked in second somehow?? Hard to say since I can't see it in person. 8XL on 38/15 should be fine, especially since you have the two speed intact.

I don't have an 8ight, maybe the Hyper 8 is what you're thinking?

No problem! That's what we're here for....