67i battery capacity?

Yes, same 3100mAh battery.

Did you mean 3100*mA*hr * 3.0*V?  That would be 9.3*W*hr.  Amp*hours is not a unit of energy.

Thanks, atlas_cached.  I didn't intend to offend.  I marked your last reply as the answer to my question. If that's the label of the 67i battery, then it holds about 25 percent more energy than the 66i battery, according to Garmin support.  A couple of years ago, Garmin support told me the 66i battery held 9.3 Watt-hours.  (FYI, you're not alone in thinking amp-hours are units of energy.  They are not.  Check on it if you don't believe me.  An amp-hour times the potential is a unit of energy.  So you have to know the potential and the Amp-hours to know the energy capacity.  What the label means is that 3.8 Volts multiplied by 3.1 Amp-hours = 11.78 Watt-hours.)  In my opinion, the information is worth knowing in case you want to carry an external battery to recharge your 67i.

All I know is the mAh rating is what most want to see as it informs them how much run time they can expect from the battery. In this example,  3100mAh means it will provide power for 1 hour at 3.1A draw, or 3.1 hours at 1A draw. Or 31 hours at 100mA draw. 

With portable electronic devices,  Wh dont really mean anything to me. 

Household appliances are rated in watts, however,  they all run on AC power.