What about buying voltage converter for charging it when you're outside the US? http://www.amazon.com/gp/aw/d/B000W9DJ1Q/ref=mp_s_a_1_1?qid=1398962657&sr=8-1&pi=SY200_QL40 I have that one. It's a little heavy, but works very nicely.
It depends where you are moving to. Some cities have 120v, and they would work there. Some cities are 220v. They might work there.. but you need to look on the light to see if it says 110-220v on it. They might still work... but they might be destroyed. I guess you could test 1 of them.
If you're putting them in a stand alone lamp, you could plug in an transformer.
If you have a lot more stuff, get a much bigger one. That is a small one, ok for small items, don't plug something big in there. Lights, small stereo, etc.
If you are bringing a hair dryer, you need a big one. 3000w, but they weight like 30lbs.
Or something simpler
I had bought 3 voltage transformers in airport while traveling. One burst the fuse of my relatives house, 2nd one had some smoke and stopped working and the 3rd one still working (I left it there). 240v is not always 240v, it fluctuates +/- 10% of 230v and hence many of these step down transformers might fail. You might want to look up in Amazon for the one that got best (and many) ratings. Found the below one in Amazon, has around 3,170 global ratings of 4.3/5.
https://www.amazon.com/dp/B000W9DJ1Q/ref=cm_sw_r_cp_apa_fabc_80bYFbPW41JQZ