A bit finicky about charging cables?

[Vance14]

I always assume nowadays that any micro-USB device can use any of the various charger/cable combinations I have laying around (which is a great convenience), but I know this is not strictly accurate. With my Nexus 7, sometimes the combination works, sometimes not very well (charge going in and out) or not at all. What are the likely variations that make a difference? Is it the capacity of the block? The quality of the cable?

I like just having charging "stations" around the house to plug any device into, so I need to have ones that work with everything, if possible. Any help is appreciated!

 

[natehoy]

I always assume nowadays that any micro-USB device can use any of the various charger/cable combinations I have laying around (which is a great convenience), but I know this is not strictly accurate. With my Nexus 7, sometimes the combination works, sometimes not very well (charge going in and out) or not at all. What are the likely variations that make a difference? Is it the capacity of the block? The quality of the cable?

I like just having charging "stations" around the house to plug any device into, so I need to have ones that work with everything, if possible. Any help is appreciated!

The Nexus 7 uses a 2 amp charger, and a short cable to minimize impedance (electrical resistance) so as much of the 2 amps can be delivered as possible.

While it is technically possible to charge a Nexus 7 off a lower-capacity charger, it will obviously take longer. I frequently charge my Nexus off a 1 amp charger that came with my Thunderbolt, but that's the cable next to the nightstand and any charging done there is usually overnight, so I don't care about charging time (and I've read that slower charges do less damage to the battery).

Some chargers simply cannot deliver enough power to offer the Nexus a meaningful amount. I have an old BlackBerry charger that I believe is rated at .75 amps (750mA), and it works, but I have an el-cheapo 450mA car charger that the Nexus probably wouldn't even recognize as a power source. It'll charge my Thunderbolt, but VERY slowly, and if I leave the screen on all the time the charger is basically capable of maintaining a charge but not really adding to it.

If you want to be able to charge everything everywhere, get the highest-capacity charger you can find (2 amp minimum for the Nexus 7) with the shortest cable you can deal with.

 

[Vance14]

Awesome, thanks! I was wondering why some were taking so long to charge. Others have a problem where it just won't keep the charge going, it cuts in and out. This may be just a "seating" issue with the connector not fitting very well.

 

[dmmarck]

Awesome, thanks! I was wondering why some were taking so long to charge. Others have a problem where it just won't keep the charge going, it cuts in and out. This may be just a "seating" issue with the connector not fitting very well.

The connector for the N7 is actually longer than most others, that could also be the issue.

 

[natehoy]

The connector for the N7 is actually longer than most others, that could also be the issue.

That's certainly possible. With a 2A load, you're looking at wanting a decent connection to minimize impedance. A longer USB plug would help accomplish that.

Another possibility is simply overloading a lower-amp charger and kicking in overheat/overload circuitry, which is probably a sign that the charger is being frequently overloaded and might fail, possibly performing some amazingly spectacular fireworks on its way out.

In any case, buying a few quality 2A chargers with good-quality microUSB ports and short cables should allow charging of darned near anything that's got a microUSB port for charging.

Until someone comes out with a device that requires 3A, of course...

We all want big batteries, and we all want them to charge quickly. Eventually we'll have to go to some new charging plug because the connection in microUSB will be unable to pump that many amps through at 5V without melting.

Technology marches on...

 

[mkiker2089]

Warning: I know I'm going to butcher the specifics

My understanding is that some of the issues are in how the data lines are grounded. The original USB spec didn't take into account higher amperage. The higher amps are possible buy grounding out the data lines (something like that, experts can correct me) and using that as extra capacity. Some cables (most of mine but I could be lucky) seem fine with it. Some aren't for reasons that are vague and clueless to me (resistance across points or something like that). I'm told it gets even more complicated with Apple products because while the Nexus will charge slowly they will just refuse to charge at all.

Nate, regarding 3 amp chargers. I'm not sure we'll see them. Moores law seems to be applying to power consumption in an inverse way. The Intel Atom for example. As computers get faster they also become more efficient as well since we've darn near maxed out the circuitry from the classic Pentium perspective. What i mean is before we just upped the clock speed and tossed more power at it. Now we have chips that do more with less power and the clock speed is no longer the deciding factor. We'll see where the two points meet. I for one am waiting for a nuclear powered Nexus 7.

edit--

Just speculation but I think the connector is longer for aesthetic reasons. The bezel on the Nexus is larger than most. That's why headphones stick out so far and may not ground properly. The same is true for some USB cables. If they had cut out the bezel on the bottom around the connections they could have stuck with more traditional cables but that wouldn't have been as purty.

 

[techdad2]

I use the same charger for my Nexus 7 as I do for my Kindle Fire without a problem.

 

[flacousa]

The cable from my Garmin 2460 GPS works on my Nexus 7

Sent from my Nexus 7

 

[extraclass]

Most of the tablets use a special charger that will put out about 2 amps of current to charge the 4 Amp Hour (4000mah) battery quickly. A normal wall charger is only good for about 1/2 amp or 500 ma. The USB plug on your computer may put out less current than this! If the small charger tried to charge your tablet with 2 amps it would burn up quickly.

The charger uses a scheme of 2 resistors in the charger to tell the tablet it can charge at the higher rate. The Galaxy tab and iPad use a different scheme as best as I can figure and one charger will not work properly with the other. The Galaxy Tab displays a different Icon to tell you the battery is being charged at the faster rate. The Nexus does not give you this information!

 

[extraclass]

Most of the tablets use a special charger that will put out about 2 amps of current to charge the 4 Amp Hour (4000mah) battery quickly. A normal wall charger is only good for about 1/2 amp or 500 ma. The USB plug on your computer may put out less current than this! If the small charger tried to charge your tablet with 2 amps it would burn up quickly.

The charger uses a scheme of 2 resistors in the charger to tell the tablet it can charge at the higher rate. The Galaxy tab and iPad use a different scheme as best as I can figure and one charger will not work properly with the other. The Galaxy Tab displays a different Icon to tell you the battery is being charged at the faster rate. The Nexus does not give you this information!