I ended up getting the 42% Products Zeus ibec from Valley View RC. They tell you the voltage input and output range on the website and have the instruction manual. Has built-in regulator. With three US made products on the market we have a few to choose from. I'd like to know which one uses the least power when dropping the voltage to 5 volts from 6 or 8.6 volt input. The nice thing about the Zeus is the variable output in case you have a EVO 26 engine with the high voltage ignition you can use your 4.8v receiver battery and it'll work.
http://www.valleyviewrc.com/Zeus%20f...20Products.htm
http://www.syssaaircraft.com/cart/pc...&idcategory=11
http://www.troybuiltmodels.com/items/WRCIBEF.html
I've made my own switching regulator battery eliminators for cameras and transmitters out of TI parts and caps that worked very well and could handle eight amps with better than 80% efficiency. The TI reg was over $25.00 alone. Fully assembled they would cost too much to be profitable.