how do you know it is 2200mAh?

i see. may be the actual capacity will be lower than that. 

may be you can try buy the 18650 cell on your own and replace it.
See whether there is improvement or not.

may be you can try on it and share here. 

those 4000mAh are over rated. the maximum capacity right now is 3400mAh manufactured by panasonic.
so those with unknown brand and claim their battery capacity more than 3000mAh, mostly are fake.

recommended brand for battery: panasonic, sanyo, or samsung.

calculation can't indicate the actual capacity.
(3.7/5) x (13000) x (75%) = 7215mAh

7215mAh/ 3100 = 2.3 times

75% efficiency i think is because of large current drawn which reduce the efficiency.

RMB280 is quite expensive compared to Pineng.

yes very confirm. it is the same type as shown in above picture from joytest.
but it written 2800mAh for each cell.

it is impossible to label lower capacity because it can't produce the higher output as measured.

it is not possible to label the larger capacity because it is not look those over rated 30000mAh, where actual capacity is far less than half of it.

i thought it is the one as shown in the link


those type 10k, 20k or 30k there are different quality too.
i found the realplay 30k has capacity greater than pn910

just for some info, is there any powerbank that inputs mini usb ports rather than micro usb ports?
i've ordered a powerbank but i'm not sure it's mini usb or micro usb.
i want to buy a spare cable for it as my previous cables already spoilt.
now i'm thinking to buy a mini usb or micro usb cable..
any idea?

this is the 1 i bought: http://www.milkadeal.com/deals/blossomswan...hlightpowerbank

Thanks for the reply.

Assuming that the powerbank is made of multiple cylindrical batteries output at 3.7V, the powerbank consolidates the output of each battery into one main output, the USB interface, which discharge at 5V. Hence the formula used above, correct ?

I have a YooBao YB-645 which claims to have the capacity of 8800mAh. The Input was stated as 5V/1500mA and the output was stated as 5V/1000mA.

So based on what I understand so far,

a) 8800mAh * 3.7V = 32,560 then 32,560 / 5V = 6,512 mAh is the ACTUAL capacity (assuming 100%).
Further Questions :

1) Is 100% output capacity a reasonable expectation for NEW powerbanks or is it by nature not possible ?  (Kinda like buying a 1TB HDD is not possible to get *exactly* 1TB space inside)

2) Input basically just tells you at what rate it is charging the power bank, rite? It doesn't in any way change the total capacity of the powerbank since the capacity is already fixed, right ?

All, I have a question.

Anyone tried this:

1. Charging the powerbank via A/C
2. Connecting the STILL CHARGING powerbank to CHARGE your phone.

I have found that none of my Yoobaos can do this. It's either charge the powerbank or charge the phone.

Appreciate feedback on brand and model.

Thanks for answering correctly

Ok so I must look for something that does both...thinking of making a solar charging setup.