> 15,000 mAh * 5V / 1000 = 75 watt-hours It would be less, given the (dis)charging efficiency. Quick look at search results suggests about 80% (so ~60Wh), whic

> 15,000 mAh * 5V / 1000 = 75 watt-hours It would be less, given the (dis)charging efficiency. Quick look at search results suggests about 80% (so ~60Wh), which is still nice for that price though.