Switching phone charger not going on progress

[abdulbadii]

Why is the switching phone charger not going on progressing with open being read 5.11V 181 mA by DMM although claimed 500 mA output?
Is it really just a faulty low current or there's more common fault/defect, how to solve and fix it ?

 

[ChrisP58]

Why is the switching phone charger not going on progressing with open being read 5.11V 181 mA by DMM although claimed 500 mA output?
Is it really just a faulty low current or there's more common fault/defect, how to solve and fix it ?

What are you using for a load when you are measuring the output current?

 

[rjenkinsgb]

USB charge systems need all the USB signals connected through, and are also often very sensitive to cable resistance; cheap thin "data" cables may not work well for charging.

I don't see how you can measure USB charge current safely and reliably with a multimeter? There are cheap test units made specifically for that, which pass all the signals with minimal effect.

Something like this should work reasonably well:

Keweisi KWS-V20 In-line USB Tester Voltage Current Power Energy Capacity Meter | eBay

Indispensable in the toolbox. Although it's USB, it can handle up to 9V. Just cobble together a USB breakout cable. Output: USB. Input: USB. Size: 7.3cm 2.3cm 1.35cm (LXWXH). Current: 0-3A ( 0.4% accuracy).

www.ebay.co.uk

And remember that the current rating of any power unit or battery is the maximum it can provide & whatever is connected will only take the current it needs, no matter how big the source.

Voltage must be correct, but if a device has a maximum charge current of eg. 800mA then 20A rated source won't give faster charge or more current than a 1A one.

 

[abdulbadii]

The phone/device is at 3% when observed get stuck there
USB cable was tested works well as other one-cell-Lion chargers that was worked/fixed is using it and stably got in progress up to the end
Yep, I have & work or fix many these chargers all simply the same: it has output only 2 pins: + - DC which I always got it soldered to proper + - USB-A pins, but just this one exhibit this weird fault

 

[Nigel Goodwin]

Could very easily be high ESR electrolytics inside it.

 

[rjenkinsgb]

Check that the two data pins on the USB socket are linked together, and/or connected to a voltage divider between power and ground.

If one is open circuit, the phone may not register that it is connected to a power source rather than a data connection.

 

[abdulbadii]

Original suspect is true, s.t error in rated current I design

as measured 12 Ohm load (near max 5V/0.5A Ohm) DC current is even less to 50 mA

anyone expert on SMPS so confidently know where the fault of weak P or I, it's:

Samsung travel adapter TAD 137 Rev. 1.5

 

[Nigel Goodwin]

Original suspect is true, s.t error rated I design

as measure 12 Ohm load (near max 5V/0.5A Ohm) DC current is even less to 50 mA

anyone expert on SMPS so confidently know where the fault of weak P or I, it's:

Samsung travel adapter TAD 137 Rev. 1.5

Already done in post #5.