Why is the micro USB so fragile compared to mini USB cable ends?

[Rod Speed]

Have a look at the charger teardowns on youtube

You may never buy a non branded mains charger from china again.

[Rod Speed]

Yeah, wondered what that was. Good idea.

Tho I'd prefer model paint since I'd have to buy it anyway.

[Rod Speed]

No, what matters is how much metal there is in the wires in the cable.

Yep.

No, the wire gauge isnt specified in the standard.

You can do if the wire gauge is too low so you get substantial voltage drop in the extension cable.

The best way to check that is to get one of the USB voltage and current meters off ebay for peanuts.

[Jeff Liebermann]

Because the micro-USB is designed to be fragile. The spec for both connectors was originally 1,500 insertion cycles. That's roughly once per day for 5 years, which is more than the average life of the cell phone or gadget which uses the connector. A longer life would just be a waste of money (for the manufacturers). The micro-USB spec was later increased to 5,000 or even 10,000 cycles, which I suspect was more wishful thinking than actual testing.

I've torn apart a few "failed" mini and micro USB connectors, mostly on cell phones. Although most of the permanent damage is from breakage, a fair number of the gold contacts had the plating blown off, apparently from arcing. My guess(tm) is that inserting the connector with the power applied is discharging a large capacitor in the power source, through the connector, to the cell phone. It doesn't take many arcs to destroy the gold plating. The USB 2.0 specification limits the initial inrush current to 0.1A before the chips negotiate to turn on the current to anywhere from 0.5A to 2A maximum current. The spec also limits the size of the load capacitance to 10uf. The idea is to prevent arcing. However, if the power supply vendor ignores the spec, the connector contacts will fry in short order.

Some relevant comments on USB:

[Ralph Mowery]

That is why I asked why the origional poster was plugging in about 3 to 10 times a day.

[Avraham Bernholz]

Ralph Mowery wrote, on Wed, 20 Aug 2014 18:41:59 -0400:

I never formally measured how many times I plug in a day, but, for the smartphone, it's at least 3 to 5 times a day.

For example, I get in the car, and plug in the phone (otherwise the battery will die with the GPS running). I use the GPS and go to the store (I use the GPS with traffic all the time, even if I know where I'm going).

I get out of the car at the store and bring my phone. Back from the store, I plug her back in. Off to my next errand.

Then, I get to work (let's say), and pull it again, and then plug it into the work USB cable. Each time I run to a meeting, I unplug it (the darn thing only lasts a few hours and I've been caught dead too many times).

Then, it's off to lunch, and we plug it back in at the car, and back off, and then back at work we plug in, and off, etc.

Back at home, we run the same routine. So, the total number of plugs in and out is easily about 20 a day (or so), but only about five or ten on any one cable.

If the battery would last all day, that would be a different story, but it won't last more than a few hours.

[Rod Speed]

Which phone is that ? That's obscene.

[Jeff Liebermann]

I'll take the 5 times per day or about 1500 insertion/removal cycles per year. If you believe the 10,000 cycles specification, then you'll get 6.7 years life. Of course, introducing some dirt into the connector should improve the abrasion. Oddly, I read that the reason for the increase in mating cycles is beause of the redesigned stainless shell, not anything to do with the contacts. "With a stainless steel shell, the KMMLX series yields more than 10,000 insertion cycles." Color me suspicious.

[Jeff Liebermann]

It might not be the phone. If the signal from the towers are weak, the phone will loose the connection and go hunting for a better tower. It does this by transmitting it's ID until a tower answers. In strong signal areas, my ancient LG VX8300 phone will last about 4 days. When all the local towers went off the air after some idiot cut the backhaul fiber in 2009, my cell phone battery was dead 6 hours after a full charge.

Drivel: I recently noticed that my Motorola Droid X2 phone battery was barely making it through the day. I replaced the battery, and no change. Looking at the settings, I found that most of the power was being consumed by the backlighting. That's odd, because I only use this phone as a PDA and only to lookup phone numbers and appointments. Hardly any real use that would account for hours of backlighting. Then, I remembered that I had changed the backlighting delay from 1 minute to 2 minutes. The phone was activating in my picket, causing the backlighting to activate in my pocket. With the backlight turn off delay doubled, so was my overall daily current drain. I set it back to 1 minute and the battery life dramatically improved. I later discovered that there was no way to prevent an accidental button press from turning on the backlighting. (Bad design).

[Rod Speed]

That's why I asked, to see if that phone has a reputation for lousy time between charges.

I don't get that effect with mine. I do drive between towns in rural areas with no coverage between them and don't find that I see a much reduced time on battery in that situation and I leave the GPS, wifi and bluetooth on all the time too.

Yeah, I bet the problem is something like that with his.

I also don't get the effect he does that you need to have the phone on the charger to use the GPS in the car either.

[Jeff Liebermann]

Well, there are tests for battery life. This one is nice because you can adjust the results by your usage pattern. Too bad it doesn't include accidentally turning on the back lighting in one's pocket:

Well, try this simple test. Put your phone inside an aluminum foil bag or box. The foil should provide a fairly good RF shield simulating a zero signal situation. If you're not sure if the shielding is working, try calling your cell phone from another phone to see if it rings. If it does ring, you're either too close to a cell site, or the shielding is somehow inadequate. I've only done this once using a Motorola Droid X and the battery was nearly dead in about 8 hrs. This is higher than "normal" because in the foil box, the backlighting never came on, no calls were made, and no videos were played.

I vaguely recall that some older phones, like my ancient AudioVox XV-6700 had a feature that only enabled the GPS when it was plugged into a car kit. The GPS sucked so much power that it would rapidly deplete the battery if left on. So, that was a battery saving feature.

[Rod Speed]

I effectively do that test when I drive between major towns.

Yeah, some did operate like that. Plenty didn't tho, most obviously with the TomTom stand alone GPSs which I never bothered to plug into the car, just made sure I charged it up before moving it to the car at the start of a trip.

[Poutnik]

Dne 20.8.2014 v 23:57 Jeff Liebermann napsal(a):

I instinctively plug micro USB end into a phone, before I plug the USB end into USB socket of PC or a charge.

[Poutnik]

Dne 21.8.2014 v 05:27 Rod Speed napsal(a):

Perhaps there is difference between no coverage ( phone may give up, not listening any tower ) and weak coverage ( phone tries to communicate by high power to weak signals of distant/terrain shielded towers ).

I remember my old Siemens feature phone M50 lasted usually 4 days. But in the mountains with bad coverage, it was drained in few hours of whole day ski trip.

[cl]

I think it was actually the EU (European Community) that sort of persuaded them, it's only a voluntary code though.

Apart from anything else it's not easy to work out the right way up, I'm sure lots of minor damage to plug and socket comes from attempts to push the plug in the wrong way up. Mini-usb is much better from that point of view because of its obvious shape,

[Avraham Bernholz]

Poutnik wrote, on Thu, 21 Aug 2014 07:18:51 +0200:

One thing I've just learned, from Jeff Liebermann, is to do the same!

[Avraham Bernholz]

cl wrote, on Thu, 21 Aug 2014 09:19:06 +0100:

I put a dab of the wife's pink nail polish on the USB top of the connectors, and, in the case of the less obvious device ports, on the device itself, where the pink dots are to be visually matched *before* one plugs in the connector.

So, at least in "my" situation, that's not why the USB nibs are failing. I think it's a bad batch of cables from Frys.

I found an unopened original cable still in its packaging from Frys (I had bought about a dozen cables at the same time):

Those cables stink!

Roxgo,

Manufactured and exported by Zendex, Inc, South El Monte, CA 91733, Made in China, UPC 851556004031

[Chris Uppal]

I'd imagine that wherever you buy this kind of kit, and whoever is named as the "supplier", it's actually produced by some unknown factory (probably in China as things stand today, not that it makes any difference). And, more, that it won't always be the /same/ factory -- it'll be whichever offered to make the stuff cheapest.

So you really have no hope of identifying an /actual/ supplier, let alone of finding a good one.

But what you /can/ do is buy from a brand with a name that a reputation (good or bad) will stick to. Such brands have the incentive to monitor the quality of the stuff they are getting from the /real/ suppliers, and will switch suppliers if the quality drops.

Of course, even a brand might let a bad batch slip through: one with the wrong steel for the connector, or the crimping machine out of adjustment (so that it makes the crimps too sharp, and hence fragile). But that won't happen often /precisely because/ they are taking steps to avoid it.

Well, you answered that in your first post ;-) It turns out that micro-USB plugs have to be assembled to a certain standard or they stop working. (This is still on the assumption that something else isn't causing the breakage)

Can't make any recommendations. I generally buy cables in shops (not online), and avoid "cheap" shops at that, but I don't consciously buy by brand. As I say, I have had exactly zero problems with USB[*] so far (full, micro, or mini), but to what extent that's down to luck, differences in the way I use USB, buying higher quality cables, or whatever, I can't say.

-- chris

[*] Unlike bloody Ethernet connections...

[Avraham Bernholz]

Chris Uppal wrote, on Thu, 21 Aug 2014 12:52:31 +0100:

I found an unopened package of the dozen or so cables I had bought from Frys.

Roxgo,

Manufactured and exported by Zendex, Inc, South El Monte, CA 91733, Made in China, UPC 851556004031

My recommendation? Don't buy those cables! :)

[chris]

Yup. European Commission to be exact.

It's a not voluntary code though; it's an agreement between the manufacturers and the Commission. Probably because if there hadn't been an agreement, the Commission would have imposed a regulation.

Although true, I doubt any current smartphone is thick enough to accommodate a mini-usb socket.