Most of the time, I love when my Nike+ system tells me something new — like I’ve set a new PR for the mile or have run a new long distance. But today, Nike+ told me that its sensor battery was low and I’d have to replace it soon.
What? I thought that the mystical energy emanating from my feet would recharge the sensor with every step I took. Or more realistically, that there might be some kind of kinetic energy recharging system built into the sensor. No such luck. There appears to be a normal expendable battery in the sensor that needs to be replaced after a certain amount of use. How much use? According to Apple’s FAQ, about 1000 “active hours”. Based on what some other runners have written about the Nike+ battery, this appears to include times when the sensor is in motion, even if you aren’t actively sending data to the Nike+ receiver (attached to your Nano). In other words, the motion of carrying your bag to the gym and back or walking around the grocery store in your running shoes counts as active use time.
For me, the bottom line is that I really like the Nike+ system. I’ve used mine for over a year now. The replacement sensor is $19 from Apple’s web site. Honestly, it’s worth paying that cost once per year in exchange for getting reasonably accurate information about how your training is progressing. So with that said, I’m going to place my order for a new sensor, but do what I can to ensure that this one lasts as long as possible.