Help Usb Micro Usb Car Charger 1A

galaxyuser10 · Jun 8, 2012

Hi, there are variations to this topic on the forum which dont cover my issue.

Ever since I installed android ICS (through Kies) my usb car charger will not work, it shows in battery info it i scharging however the charge drops. the charger I am using is a 1amp max charger, I used my friends usb car charger which is 0.5amp max and it works.

Recently I have noticed though when charge is at 50% or over then My car charger works, but if its less than 50% then I have the same problem mentioned above (please note this 50% isuue happens occasionally).

I have tried different usb leads smasung make and they work as tested with my friends charger.

Any help would be appreciated as ICS has caused me a headache i didnt expect.

3waygeek · Jun 11, 2012

When your charger is connected to the SGS2, go into Settings/About Phone/Status, and look at "Battery status". It should say "Charging (AC)" -- i.e. the SGS2 thinks it's attached to an AC charger.

The SGS2 has circuitry that measures the resistance across the two micro USB data pins; that's how it figures out if it's plugged into a USB cable, AC charger, MHL adapter, car dock, etc. If it senses < 200 ohms resistance across the USB data pins, it assumes it's connected to an AC charger, and will draw up to 650 mA (in stock ROM -- other ROMs may have different limits) from the charger.

If it senses high or infinite resistance (i.e. there's no connection between the two data pins), the SGS2 assumes that it's connected to a USB cable, and thus will draw a maximum of 450 mA (the USB spec says any USB 2.0 port should provide at least 500 mA, so 450's a safe value for any compliant port).

It sounds like your 1A charger may not have the low-value resistor across the USB data pins (the two center pins, 2 & 3, on the standard rectangular 4-pin USB). A quick test with a continuity tester (with the charger unplugged from both phone & car) should bear that out. If the resistance between the USB data pins is high, or infinite, you can crack it open & attach a jumper between the data pins. Once you do that, your SGS2 should see the charger as an AC charger, and will thus draw more current from it.

andy_48 · Oct 17, 2012

Wow! Sorry for resurrecting this thread but I only just found it and 3waygeek's excellent reply provided a light bulb moment for an issue I've been grappling with for months - ever since my SG2 went flat on a long car journey despite being hooked up to a USB charger.

I had bought a Griffin PowerJolt Dual Universal Micro Car Charger that's supposed to deliver 1 Amp to my phone (or so I thought) but never would - and now I know why. I've checked the device and it does indeed deliver 1 Amp but the SG2 won't accept it.

So:
1) is there a micro USB cable that I can buy (preferably in the UK) that my SG2 will 'think' is an AC charger? or
2) can a standard cable be 'doctored' and if so how?
3) failing this, can anyone recommend a really top-notch car charger for the SG2, please?

andy_48 · Oct 26, 2012

The HTC CC C200 Micro USB Car Charger appears to fit the bill.

Genuine HTC CC C200 Micro USB Car Charger: Amazon.co.uk: Electronics

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Help Usb Micro Usb Car Charger 1A

galaxyuser10

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3waygeek

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andy_48

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andy_48

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