How long does each O-Power bubble take to recharge?

I've been using my O-Powers on my hapless roommate in the hopes of levelling them up. Sadly, this doesn't seem to have happened yet, and I've run out of bubbles to use.

I can see the little clock thingy turning in the corner, but I have no idea how long it takes to recharge, so I'm definitely using them less often than I could be.

So, to maximise my efficiency in levelling them up, how long does each bubble take to recharge?

Solution 1:

15 revolutions of the little clock decal will recover roughly 1/4 of a single O-Power bubble. As each revolution takes about 3 seconds, this means that it takes about 3 minutes to recover an O-Power bubble.

Note that O-Power energy will recover even if you don't pay attention to it, so you don't have spend time constantly looking at that clock decal.

The energy also recharges faster based on the number of steps you have taken that day with the 3DS.

• 0-1999 is x1
• 2000-2999 is x2
• 3000-3999 is x3
• 4000+ is x4

Solution 2:

It depends on how many steps you have taken with your 3DS. The game dose not need to be on for this.

  Steps      time to recharge each bubble
   0-1999             4 minutes
2000-2999             3 minutes
3000-3999             2 minutes
   4000+              1 minutes

This resets at midnight when the step counter resets. However on one occasion I had been walking late at night and had over 3000 steps (these steps could have been after midnight). The multiplier was still in effect at 07:00 when I went to bed when I got up at 16:00 it had reset to 1. The game was running the whole time with the 3DS closed.

Sources:

Personal experience and a stopwatch testing each level.