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Charging current

3rd September 2014, 05:07 PM |#1  
decmk's Avatar
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I just tested, and discovered something weird.
When using original HTC charger, and original HTC microUSB cable, the charging current is 1A, but when I use USB extension cable or spare microUSB cable charging current is 0.5A (490mA) using same original HTC charger.
What's wrong with the USB extension cable or spare microUSB cable?

Original charger and original cable


Original charger, original cable through USB extension cable


Original charger spare microUSB cable
(spare microUSB cable is 1.6m long)



HTC ONE M8
Last edited by decmk; 3rd September 2014 at 05:33 PM.
 
 
3rd September 2014, 06:56 PM |#2  
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I've moved this to Q and A - more suitable.

To answer your question - and I don't think your ammeter is particularly accurate - a USB port provides up to 0.5A. The Phone should only draw about 450mA (controlled by the phone) to leave a margin.

The mains adaptor will charge at a higher rate (again controlled by the phone) and in your case appears to be about 1A.

Note that the rate of charge from the mains depends on a number of factors - the temperature of the battery, the actual charge of the battery (the rate slows progessively from about 90% upwards and so on.
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3rd September 2014, 07:29 PM |#3  
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Quote:
Originally Posted by LenAsh

I've moved this to Q and A - more suitable.

To answer your question - and I don't think your ammeter is particularly accurate - a USB port provides up to 0.5A. The Phone should only draw about 450mA (controlled by the phone) to leave a margin.

The mains adaptor will charge at a higher rate (again controlled by the phone) and in your case appears to be about 1A.

Note that the rate of charge from the mains depends on a number of factors - the temperature of the battery, the actual charge of the battery (the rate slows progessively from about 90% upwards and so on.

Thanks for the answer, but I'm always using original HTC charger witch is 1.5A on the output side, only difference is extension USB cable.
When I connect to USB port on the PC always is 0.5A no matter what cable or extension cable I'm use.
Using extension cable has big difference, i don't know what the clue?

HTC ONE M8
3rd September 2014, 07:33 PM |#4  
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The USB port will ONLY supply 450mA - 500mA (0.5A) - no more. It's limited by the USB 2 spec...

The HTC charger can supply UP TO 1.5A. However, the phone will only draw what it needs - in your case about 1A.

You can put a 5A charger on and it will only draw 1A...

EDIT: Just re-read your OP - the issue you have is likely to be related to the way the HTC USB charging cable is wired.

On some phones, when you connect to a USB port, the phone KNOWS it's a USB port due to the wiring. When you connect to a charger, the charger shorts a couple of pins together (or in Apple's case, a resistor) and the phone then KNOWS it's connected to a wall charger. That's how the phone tells you on screen what kind of charging you're doing...

Sounds like HTC use a proprietary cable...
Last edited by LenAsh; 3rd September 2014 at 08:11 PM.
3rd September 2014, 08:19 PM |#5  
decmk's Avatar
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Probably the phone is detecting voltage.
When I use short cable 25 cm or original microUSB cable voltage is 5.05V, with extended cable is little below 5V (4.95V) and then phone is changing with only 0.5A (490mA).

HTC ONE M8
3rd September 2014, 08:22 PM |#6  
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Or proprietary cable.

HTC ONE M8
3rd September 2014, 08:26 PM |#7  
LenAsh's Avatar
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Quote:
Originally Posted by decmk

Or proprietary cable.

HTC ONE M8

That's the most likely. Bad HTC....!

The voltage is not the issue - it can be anything from 4.75V to 5.25V without problem.
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