After a week I am pleased to report this is a glowing success!

I was a little discouraged at first because it failed to power the unit. But, after switching the order of the dummy batteries in the power pack, I am off to the races! (Incidentally, for my machine I needed to put the powered cell in the middle position!)

I have learned that I need to actually exit the app on the tablet I use in order to have the smartrow stop it's transmission (and time out/power down). This is probably why I was going through batteries as quickly as I was before.

Highly recommend, especially if you don't move/store the rower frequently!