Need decent in car phone charger (mini USB android)

usignuolo

OH has a Samsung S3 mobile phone which has a micro USB charging point on phone itself. Charges fine on mains power using charger supplied. (So does my more modest LG phone which also has a micro USB charging point).

So recently nipped into Halfords and bought the in car charger version for micro USB. Tried out yesterday on the S3. Hopeless, very very slow charge. It lights up, says it is working but only charges at a trickle.

Suggestions why? Alternatives which do work?

(Sorry about headline to this post should of course say micro USB not mini.)

System

what kind of mAh is it outputting, could just be that the phone requires some more juice... OEM can be something like 800mAh, but cheapos can be as little as 200mAh, which would give you a slower charge

Iceweasel

Does it charge OK when it's connected to a computer/laptop using a cable with a normal usb at the computer end and obviously the mini-usb at the phone?

Most phones do.

If so get one of these:

http://www.ebay.co.uk/itm/221153720212?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Much cheaper, neater and usually quicker than the traditional bulky charger that needs lots of adapters to suit several phones.

wba31

I have an iPhone, but i paid extra for the belkin cigarette lighter for mine, it works really well and and has lasted me 2 years now. With things like this i believe its worth spending a little extra for items...

usignuolo

Well doing a bit of scouting about on the web, it does seem there are some issues (aren't there always) with charging the S3. First of all you should not use charger with too many amps or it may "cook" it. Secondly there are some suggestions that in the past mobile phones operated at 0.5amps but now they operate at 1.0 amps and the S3 pin settings have been tweaked to reflect this.

So if you use a generic in car charger it will charge at 0.5 which is why it takes a long time. Plus found this on the Vodafone forum

"AFAIK usb is supposed to be limited to 0.5 A - I think the actual usb cable supplied with the SAmsung (or HTC desire) charger may have something different about the pinout which enables the phone to know its ok to draw more than 0.5A.
Not tried it but I strongly suspect that if you try a standard micro usb cable with the galaxy s3 it will only charge at 0.5 amp and hence will take twice as long."

Strider590

To charge at more than 500mA, the two data pins must be short circuited together, this how most phones "know" they're connected to a mains charger.

Some in car adaptors (I have one), will have those pins shorted internally so as to act like a mains charger.

The cable itself has nothing to do with it.

Look for the one's like this

But be careful with devices like tablets, they might need more current (some upto 3A), if you plug one into a USB power output that has the pins shorted, but is not capable of 3A, it'll do some damage.

My advice is to check the spec of your main charger and buy an adaptor that matches or exceeds the chargers maximum power output.