I recall this decision being a very big issue for me. I'm happy with the location it ended up, which is my left hip/butt area....far removed from waist line of clothing. It sits down lower, outta the way. However, not once did I ever consider the wallet issue. That's a good point!
Whichever side you wear your wallet, maybe go with the opposite side for the battery. Also keep in mind - are you right-handed or left? I'm right handed, so it works out good for me to have my battery on left side. When charging, I have my right hand free to operate the charger controller while my left hand keeps the charger over the battery until I get in a comfortable position in a chair/recliner. I usually watch a movie or something to pass the time.

While trying to decide, I even put some tape over the area I was considering having the battery placed. Then, I went about my business around the house to see if there would be any problems with having it there. It didn't interfere with the chairs I would sit in, or clothes that I wore, so that helped to give me an idea.

Plus, your doctor pretty well knows where the most practical place would be. You'll be good to go in no time!

Rae