Confusing Charger Amperages & Charge Times

[keleja]

So questions everyone... output specs on phone chargers. I have always assumed higher amperage on output means faster charging. I'm not talking just quick charge stuff either, but also normal chargers. I'm wondering if anyone could explain the following numbers I'm getting when charging a brand new Galaxy S7 (not the Edge or Note) on a series of 3 different chargers.

 

What is up with these estimated times? It seems like none of it is consistent, but I don't have any specific expertise in electrical. Anyone offer an explanation? Thanks!

 

(All were tested in the same outlet (US) with the same micro USB cable.)

 

CHARGER 1 (Samsung Standard Travel Charger)

Input: 100-240V -> 50-60Hz .15A

Output: 5.0V : 1.0A

Est. Charge Time: 2hr 5m

 

CHARGER 2 (Samsung Standard Travel Charger)

Input: 100-240V -> 50-60Hz .15A

Output: 5.0V : 0.7A

Est. Charge Time: 1hr 42m

 

CHARGER 3  (Motorola Travel Charger)

Input: 100-240V -> 50-60Hz .2A

Output: 5.0V : 1150mA (1.15A)

Est. Charge Time: 1hr 47m

 

 

[Electronics Wizardy]

The last one might be mislabed, or your just reaching the phone's max chraging speed.

[W-L]

5 minutes ago, keleja said:

-SNIP-

 

Where is this data from it looks very unlikely that at a lower available amperage it can do a faster job, the higher the amperage units would give shorter charge times as it will be providing the phone a faster charge rate that it can regulate itself at and isn't directly limited by the lower amperage chargers. 

[keleja]

8 minutes ago, Electronics Wizardy said:

The last one might be mislabed, or your just reaching the phone's max chraging speed.

Not sure where you are thinking its mislabeled.

[keleja]

6 minutes ago, W-L said:

Where is this data from it looks very unlikely that at a lower available amperage it can do a faster job, the higher the amperage units would give shorter charge times as it will be providing the phone a faster charge rate that it can regulate itself at and isn't directly limited by the lower amperage chargers. 

The Information on the specs are directly from the chargers and the times are based on the phone estimated time until fully charged. I know its not a "scientific" way of getting the times, but I thought the disparity was large enough to warrant the question.

[meenmeen1103]

The phone draws current from the charger, current isn't forced from the charger to the phone. If the phone can draw a max of 1amp, even a 2amp charger will only give it 1amp. If the same phone tries to draw 1amp from a .5amp charger, it'll get .5amp. It's possible for the 1amp charger to not be able to hold a steady 5v at 1amp, yielding a slower charge. Was the same cable used on all?

[Electronics Wizardy]

Just now, keleja said:

Not sure where you are thinking its mislabeled.

The charger says 1.15A, but idk if it will actually output that. You can test it with a aftifical load if you want.

 

In order to test it right, you need a scope and artifical load 

https://www.bkprecision.com/products/dc-electronic-loads/8601-250-w-programmable-dc-electronic-load.html

[W-L]

2 minutes ago, keleja said:

The Information on the specs are directly from the chargers and the times are based on the phone estimated time until fully charged. I know its not a "scientific" way of getting the times, but I thought the disparity was large enough to warrant the question.

Hmm yeah I think their calculations may be a bit awry but the higher amperage would be able to charge at a faster rate than the others if the charger was the limiting factor. I usually recommend chargers from Anker they make some pretty good units. 

[keleja]

5 minutes ago, Electronics Wizardy said:

The charger says 1.15A, but idk if it will actually output that. You can test it with a aftifical load if you want.

 

In order to test it right, you need a scope and artifical load 

https://www.bkprecision.com/products/dc-electronic-loads/8601-250-w-programmable-dc-electronic-load.html

Well, the charger was labeled with an output of 1150mA which would equal 1.15A... unless I'm a dummy. Which I'm not ruling out.

[keleja]

6 minutes ago, meenmeen1103 said:

The phone draws current from the charger, current isn't forced from the charger to the phone. If the phone can draw a max of 1amp, even a 2amp charger will only give it 1amp. If the same phone tries to draw 1amp from a .5amp charger, it'll get .5amp. It's possible for the 1amp charger to not be able to hold a steady 5v at 1amp, yielding a slower charge. Was the same cable used on all?

This is what I'm thinking and also the kind of info I was hoping for. The chargers are all of various ages so it makes sense how you are putting it. Also, yes, the same cable was used on all the chargers

[Electronics Wizardy]

5 minutes ago, keleja said:

Well, the charger was labeled with an output of 1150mA which would equal 1.15A... unless I'm a dummy. Which I'm not ruling out.

Just because a label says something, doesn't mean its the real output.

 

Test it your self to be sure.