StepDown converter AAA 1.5V for wireless keyboard + mouse

Just wondering if I can use two 18650 or 26650 batteries in parallel to step down to 1.5V (or it might be 3V because there are two AAA batteries in wireless keyboard)

Step Down Converter

The batteries are Defiant from Home Depot, Alkaline LR03 800-1200mAh.

I am replacing the two batteries every 3 months in the wireless keyboard, and every 4-5 weeks in the wireless mouse. The wireless keyboard & mouse will be used for the HTPC (Home Theater PC). And the desktop will go back to the regular wired setup.

buy a better quality mouse and keyboard i get close to a year out of my battery's (2 x AAA) and they are used about 12 to 14 hours a day

So Logitech K330 wireless keyboard and mouse are crap then, if you are getting a year out of your primary batteries.

i dont know if there crap they just seem to be hungry from what you say