Any issues with taking a small UPS(Uninteruptable Power Suppy) to BKK for a week vacation?

Background: We brought a portable DVD player with us to the SIN DO in 2004. Can't swear to it but we believe we "cooked" it when we tried to charge the battery in SIN using the 220v 50Hz -->110v 60Hz converter we bought at the luggage store. This year not wanting to take any chances with the new DVD player, or the digital still camera or the digital movie camera or the laptop.... I had an idea.

Why not take the $50.00 UPS I have on my PC to BKK with us. Its' whole purpose in life is to deal with flakey input voltages right? I propose it should handle the output of the converter just fine. When we need to charge up the batteries on our expensive digital toys we unplug the UPS from the "wall" and we should be getting a perfect 110v 60Hz sine wave output. During the day the UPS can be charging up while we are out and about enjoying BKK.

Any holes in this plan? Is NW going to be OK with it in our luggage? Thanx in advance for you thoughts....