I think the best answer to your question about range would be to extrapolate from the LX specs and compare range of other bikes with similar specs. I would simply say that if you want to go more than 40-50 miles on a single ride, you should absolutely get the second battery. A battery for the XP costs $299 from Lectric, which I think is really inexpensive. With a 500W motor, a 48V 10.4aH battery, I would think 50 miles would be an absolute limit based on ranges of similarly spec'ed ebikes. That would be with no throttle, 2-3 PAS, no extra weight and level terrain. Range is such a variable thing that, if you have any range anxiety at all, invest in the second battery. Even if someone did do a range test to give you a more definitive answer, THEIR range limit may not be YOUR range limit.