that;'s why I said from that 5V going into the phone circuit will be reduced back to 4.2-3.7V charging.. the capacity wont be just 2072mah..

think in terms of WH, 2800mah x 3.7 = 10.36WH  at 5V it'll still be 10.36WH

when it goes back into the phone battery of 3.7V it'll still be 10.36WH (less conversion inefficiencies)

there is a reason why powerbank say 10000mAH charge 3000mAH battery 3times..  cos you can ignore that USB 5V thing..  it steps up to 5V then IC controller in the phone steps it down to whatever the battery needs. (cos it assumes storage is same type of battery like the phone battery 3.7V type.)

the more accurate way is state the WH rating..  cos if cross comparing different chemical batteries then using WH is more proper.

so maybe 11200 battery to your battery is only 0.7 efficiency when charging battery to battery lor..
what has that got to do with step up or step down voltage via USB interface losing 30% of the power?
those up n down function using ICs are in the range of 95% efficiencies

definitely there is gonna be losses.. but where are those losses coming from, dont just say oh it's because 3.7 change up to 5V USB interface where 30% losses went there.. so just calculate as 3.7/5 ?

yes notice 4 says total losses "including" heating and voltage conversion.. it doesnt say 30% loss formula is derived from 3.7/5 figure did it?

1st post
empirical means derived real readings from tests.. so go ahead and use a resistor n discharge your powerbank and get the real readings lor. say empirical but still use theoretical formula? which as you know differs from brand to brand.. heck even same brand different batches will have different cell quality..

i think u got it wrong with ur calculation,...

4.93VX0.94A=4.6342Watt , not watt hours,... = power

4.6342Watt x 7.33 hours = 34 watt hours...= actual energy used

rated energy suppose to be:
5V x 11200mAh = 56 watt hours (how come u use 3.7V when the actual output is 5V ??)

so the efficiency shud be only 34/56= 60.71 % instead of 82%

Hi,I wanna ask,can I reuse the battery from dead laptop?
how do I test each of it if it is still in good condition?

i have this and i think no.

Congrats TS, Your post was linked to Asia CNET article.

Keep the good work to save the power bank community.

My pineng unit also can't do this. It has higher priority to charge the phone than A/C charge your powerbank.

http://www.kickstarter.com/projects/625327...smartphones-and

this one has something called 'charge through technology'.

Any seller in Lowyat Plaza or Amcorp Mall sell cheap powerbank? Preferably around RM 40-100

My custom powerbank 

Made from LUC charger + 2x 18650 batt

i'm a vaper (e-cig)

so this setup is necessary to my hobby

EFEST LUC

i bought the charger from a seller at Old Klang Road area. 18650's can be purchased from various e-cig seller

http://legadgets.com/batteries
http://www.vapebrothers.com/accessories-parts.html

Lowest price for 18650 i ever see is RM15 apiece

https://www.facebook.com/photo.php?fbid=101..._count=1&ref=nf

yes my wife do have a Note 3.. will test it for you. maybe report back in 2-3 days.

currently it shows 800. does it takes time to get accurate reading?

I have a 30,000 MaH that isn't in use and would like to know it's true capacity. Was wondering if you could do a test for me?