Chargin question

[PFStella]

Hey everyone,

So I have a question about charging: When I plug the phone into the wall using the OEM wall to usb and usb 3.0 cable that came with the phone, i thought from what I understood that it shoudl be delivering about 2 amps. Is this correct? My question is: I installed CurrentWidget, and it says I am only getting 1 amp (1MA to be precise, but this is what is meant by 1 amp, 2 amps, etc, right?).

So why is this? And am i getting a slower charge than I should have expected?

Thanks very much for all your insight and explanations!

 

[Harry2]

The battery app shows only the amperage which streams into the battery. If you use the phone while charging then the phone takes amperage directly off the charger and the battery will just get what remains.

Edit: Another thing, did you read the CurrentWidget's graph amperage (mA) by time?
If so you'd see that only if the %-capacity is near to 0% then the amperage will get its max ... and only for a short time. Then the amperage decreases at the same grade as the %-capacity increases.

 

[rally123321]

I can't really answer the specifics. My phone charges from pretty much dead to almost fully charged in about 2 hours with the charger it came with. I have a 1 amp charger from another phone I have and it takes hours longer.

 

[PFStella]

Thanks very much for the info, Harry2. That is interesting. My currentwidget app seems to be having some trouble with the log--the file won't open when i try to look at it--but that is ok; i am persuaded by your explanation.

The part I find interesting though and a little confusing is what you say about the amperage reducing as the phone gets more and more charged. Why is this? I mean, why not simply charge the phone at max amperage all the time so it finishes charging as quickly as possible? Is there some tradeoff--some reason it is desirable to have the amperage reduced as the phone gets closer to fully charged? What's the point of this?

Thanks!

 

[Harry2]

It's because of the complex charging behavior of Li-Ion batteries.

The battery's Li-Ion cells can take their specified max amperage until they reach their max allowed cell voltage. Now the charging controller has to prevent increasing of the cell's voltage because this would destroy the cells. The effect of this move is that the charging amperage is steadily decreasing until the cells are fully charged.

Hope my clumsy description is understandable

Edit:

It's a screenshot of the charging log graph of my HTC Sensation, using 'Battery Monitor Widget'.
Your Note's might be slightly different, maybe longer time on max amperage ... but this decreasing amperage while on the remaining charging time should be similar.