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

[Jeff Liebermann]

That's probably un-necessary if you have a quality charger and properly designed cell phone. 0.1A inrush current is not going to do any damage to the gold plating. However, if you have a no-name charger, or worse are charging from a "stiff" 5v source, it's worth checking what the charger does. I have a USB extension cable where I cut the heavy 5V positive wire. I put various ammeters in series to measure current drain. Today, you can get such devices on eBay for very little: However, these will not show the required 0.1A inrush current limit or any current spike caused by an oversized capacitive load. For those, I insert a 0.1 ohm resistor (actually a length of nichrome wire). Using a dual trace oscilloscope, I put the Ch A probe on one side of the resistor, and the Ch B probe on the other, and the scope in differential (A-B) mode. That's necessary because grounding the +5V power line with the scope probe ground is not a good idea. I can post a photo of what it should look like if anyone needs a sanity check.

Note that USB 3.0 is different. Current is now up to 900 ma and overload protection is required:

Simulation of USB 2 inrush current:

The design of the micro-USB connector system intentionally moved all the failure prone parts to the plug. There's not much you can do to improve or protect the receptacle on the phone end, but plenty you can do on the cable and charger end.

There is an amazing amount of junk USB power supplies out there: The real Apple charger: and the not so real clone:

I bought a few cheap USB car chargers on eBay, and stupidly passed them out to friends as presents. After I looked inside, I had to run around and confiscate them before they blew up someones phone. Notice that there is a short across the data wires (used to fool the phone into believing that the maximum current available). The front has two USB jacks, labeled 2A and 0.5A. With the short, they're both identical. I tried to build an LTspice model of the device, but failed because couldn't identify the chip used.

I later bought some of these which are fairly cheap, and won't kill your phone:

[Jeff Liebermann]

Just try the foil wrapped box test and see for yourself. I think you'll be unpleasantly surprised. If you don't want to run the battery to total discharge, just run it for a few hours an look at the percent charge remaining on whatever battery monitor application you have available, and extrapolate the results.

Incidentally, don't try using an (unplugged) microwave oven for this test. They leak too much at cellular frequencies.

[Jeff Liebermann]

Or, just buy a cable with a connector that fits both ways: Too bad it's only available for the large USB connector.

Or, just wait for the new Type C USB connector, which is reversible:

Find a microscope and look at the gold plating on the connector. If it's nice and shiny gold, you win. If it looks dark and dingy, like some of the base metal is showing through the plating, it's much too thinly plated.

Strictly speaking, the USB connector system is a bad joke. Ask any connector or switch manufacturer about switching DC with a gold plated connector and they'll cringe. Gold plating is suppose to be for "dry" loads (i.e. no DC). If one must run DC through a gold connector, the power is suppose to be disconnected and all caps are suppose to be discharged. For "live" loads, one is suppose to use silver. However, the USB connector has both a dry data load, and a live DC power load. Therefore, we see all the inrush current protection on the DC pins.

Before you declare your cables to be junk, you might want to run some bench tests with your five(?) assorted power supplies under various load conditions. Also check what they do for inrush current. My guess is that at least one of them will be problematic and possibly the culprit.

The thin USB cables may actually be an improvement. The higher resistance wire might reduce the inrush current a little. For short circuit protection, they'll probably make a tolerable fuse. I'm too lazy to do the calcs and measure the wire gauge.

[Rod Speed]

Where are you getting those from ?

[Jeff Liebermann]

Amazon and eBay. Available in white and Darth Vader black:

Grumble... I paid $15 and now the price is $10. Oh well.

[The Real Bev]

I'm getting bummed out on Duracell chargers and rechargeables. Several years ago (maybe 2008) I bought a set of the precharged Duracells -- supposed to maintain a charge while sitting on a shelf for nearly a year

-- and the spares (charged at the same time as the ones in my camera) are dead when the ones I've been using in my camera die. The Duracell charger (the BIG one!) stopped working within 2 years. I now carry more Kirkland AAs with me Just In Case.

Are the Eneloops any better?

[The Real Bev]

Do you feed in the store as a destination? If not, how does it have any beter idea of traffic than you do by looking out the window? Or are you using one of the Sigalert/511 apps?

Theory has it that you maximize battery life by letting it run down to less than 30% and then giving it a full charge rather than keeping it topped up. What do you think?

[The Real Bev]

FWIW, I've never had any problems with cables -- or anything else -- from DealExtreme.

There have been problems with some items right out of the box -- PS2 to USB keyboard connectors, and a never-could-have-worked mp3-player-to-cassettte adapter. I emailed them and sent photos of the items in question, and they credited me immediately.

The disadvantage, of course, is the 2-3 week shipping time. Big deal :-) They now sell some stuff out of their warehouse in California with much faster delivery, but if they're doing it legally they'll charge sales tax on that stuff, and I believe in avoiding sales tax whenever possible.

[Jeff Liebermann]

Yes. I use them in my various cameras. Hardly any self-discharge after many months.

[Chris Uppal]

So you got the cables from Fry's, who got them from Roxgo, who got them from Zendex, who may be the US marketing arm of a Chinese factory (or group), or may be another middleman sourcing cables (etc) from whichever Chinese factory is cheapest in any given week...

It seems that either you got rare a rouge batch, or that that entire supply chain doesn't include /anyone/ who cares as much about quality control as I'd prefer :(

-- chris

[BenignBodger]

Not in my experience. I've literally never had a micro nor a mini fail. The only USB failure I've had was a cheap A-B cable that came with some piece of equipment and that was a conductor failure in one end caused by the too-thin wires. Perhaps the key is to simply be gentle when working with any sort of connector. If you are going to be rough with your cables, at least buy some good ones -- the 'basics' cables from Amazon seem to be well-made and aren't expensive.

[Andy Burns]

I thought someone wanted orange, not red ...

[Chris Uppal]

Don't blame me, blame the spellchecker ;-)

Ta

-- chris

[Avraham Bernholz]

Chris Uppal wrote, on Fri, 22 Aug 2014 14:26:08 +0100:

I suspect it's the latter as Frys was selling them cheap.

I do remember one failing right off the bat, and they replaced it without even looking at it, which is odd, for Frys (who is usually a pain to return stuff to).

So, I now conclude they are used to getting *these* cables back. Too bad Frys has such a short warranty period (something like two weeks or so).

[The Real Bev]

The Burbank and Industry stores have been OK about returning stuff, which is good because we've returned a LOT of stuff. They clearly sell a lot of questionable stuff, but the prices are frequently so good that we're willing to risk it. Over the years we're clearly ahead of the game, even taking the cost of gas for the return trip into account.

There are penalties for procrastination :-(

[Dave Liquorice]

Yep, nothing to talk to they don't try. Getting the damn thing to wake back up when you know you are back in coverage can be PITA.

Going in or out of coverage be that coverage weak or strong really drains the battery as the thing is constantly logging in, losing tignal, getting it back, logging in again, etc etc. If this is happening in a weak signal area the drain is higher as the phone will crank up it's output.

[Rod Speed]

Poutnik wrote

That doesn't happen. If it did, it wouldn't see coverage return when you get to the next town that does have a tower.

It always does that, because coverage will return eventually when you are driving around in a car.

Like I say, I don't get that effect with mine.

[Poutnik]

I usually set a phone for airplane mode in such areas, to save battery. Good thing is that GPS receiver works in that mode as well, as it is not transmitter.

[Kees Nuyt]

Same here.

It's my general rule: Plug in the most fragile first, the least fragile last.

This is what I tell my girlfriend ...

Start charging:

1. Plug micro USB into phone/tablet
2. Plug USB A into charger
3. Plug charger into mains

or

1. Plug micro USB into phone
2. Plug USB A into laptop

And after charging:

1. Unplug charger from mains
2. Unplug USB A from charger
3. Unplug micro USB from phone/tablet

or

1. Unplug USB A from laptop
2. Unplug micro USB from phone/tablet

Never had a USB cable fail on me.

[Aaron2]

Way too much hassle. Just leave the cable and charger plugged in all the time. The micro end still receives the same number of inserts.

Me neither.