Nexus 7 tablet?

[Jason]

Hey Jason,

Thanks for asking. I haven't tried using other USB cable. Can I use my Nexus 4's cable? Although it's LG's, I supposed any USB with microUSB port is fine right?

Yeah, like everyone else has stated, any standard MicroUSB cable will work.

If it is the cable, and you decide to replace it, keep it under 6 ft in length (anything longer will be an impedance), and make sure the MicroUSB connector end is about 6.0mm in length, which is standard, but there are cables who's male end run shorter and those interfere with the N7's case.

 

[Shyuan]

Yeah, like everyone else has stated, any standard MicroUSB cable will work.

If it is the cable, and you decide to replace it, keep it under 6 ft in length (anything longer will be an impedance), and make sure the MicroUSB connector end is about 6.0mm in length, which is standard, but there are cables who's male end run shorter and those interfere with the N7's case.

Thank you for your advise.

Apparently, I tried using my new LG's USB cable (belongs to my Nexus 4's) with my Nexus 7's Asus original charger. The outcome is still the same i.e. N7 is charging very slowly via wall socket (10-12 hours). I downloaded Battery Monitor Widget app to see how much does my N7 takes (estimated) while charging. Surprisingly, it only takes about 500-700mA while charging, whereas my Nexus 4 can take as high as 900mA by using the same Asus charger + LG USB cable and via the same wall socket.

Another thing I do noticed is, sometimes it shows my N7 is "USB plugged" but sometimes "AC plugged" under the Settings > Battery even if I always use the same wall socket, charger and USB cable.

Any idea?

 

[Jason]

Thank you for your advise.

Apparently, I tried using my new LG's USB cable (belongs to my Nexus 4's) with my Nexus 7's Asus original charger. The outcome is still the same i.e. N7 is charging very slowly via wall socket (10-12 hours). I downloaded Battery Monitor Widget app to see how much does my N7 takes (estimated) while charging. Surprisingly, it only takes about 500-700mA while charging, whereas my Nexus 4 can take as high as 900mA by using the same Asus charger + LG USB cable and via the same wall socket.

Another thing I do noticed is, sometimes it shows my N7 is "USB plugged" but sometimes "AC plugged" under the Settings > Battery even if I always use the same wall socket, charger and USB cable.

Any idea?

You should be seeing something above 1000mA (closer to 2000mA) with the charger that comes with the N7 when charging from AC, so that seems to point to a hardware issue. Either the charger or the charge circuit in the device itself. You could rule out the charger by testing a load of 2.4-4ohm 10W. However, since it's fluctuating between "USB plugged" and "AC plugged", after trying a new cable, it could very well be the device. It's only pulling 500mA because it believes you're charging from USB.

The device uses the two data pins (D+ & D-) to distinguish charging from USB and AC. If you're the creative type, you could modify the charger by shorting the two data pins. If you've never done this before, I don't recommend it, as it risks damaging your charger and the N7 itself. Another, and far easier approach is to modify the cable, by shorting the data wires on the MicroUSB end, leaving them open or not connected at the charger end. You can also short the data pins on the N7 itself, but it's rather pointless -- it won't affect the charging rate.

The only other things to suggest is trying a different wall outlet (yes, that sometimes works), or trying another N7's adapter (they may have sent you a mislabeled charger). It's difficult to use third party adapters, since the N7 is very picky when it comes to charging.