15 of 20 people found the following review helpful
2.0 out of 5 stars
2100 MaH IN REALITY. Looks pretty tho., 16 Dec. 2013
This product is in fact only 2100 maH when you account for the following, Anker said this; "due to voltage conversion and circuit resistance. This unit has an efficiency of 70% while most of other brands in market have an efficiency which is lower than 65%.The built-in battery cell has a voltage of 3.0-4.2V. The PCB will boost it from 3.0-4.2V to 5.3V to give a USB output to charge you devices. This procedure consumes power, plus the power will also drain on the Resistance of the cable and phone's circuit, those makes the anker external battery have an efficiency of about 70%. Therefore, the actual output of this external battery is 70% (3000x70%=2100mah). It is supposed to charge your phone 0.8 circles." This product doesn't fully charge the Galaxy S4 just in case you were thinking it does. It only charges up to 76 percent as I found out with both the astro mini's I bought. I should add that it did charge an iPhone 5S fully. Slightly annoying because I assumed that it being 3000 MaH it would charge the 2600 MaH battery in my phone. I feel like I've been conned, if I had expert knowledge on electronics I would have known that the advertised 3000 MaH just doesn't apply. Silly me for not knowing about the hidden 'charges'. Now you know.