USB application gone wrong

the amperage output of the USB plug to the 12v cable, I bet you're not getting enough amperage to sustain the GPS.

Garmin requires a different configuration for their USB cables than found in stock cables. If you have a cigarette adapter that accepts a USB then you have to use a Garmin USB cable between the units.

It's not the cable, but the adapter. Garmin adapters have a resistor that determines the mode of operation. Without the correct adapter, the unit will never charge.

See here or here for details.

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I probably could have been nicer and said, "I'm sorry Box Car, but I have to disagree with you and here is why" before I mentioned what I did.

Typical bull in the china shop am I.

@Strephon_Alkhalikoi and Box Car

Nice to see civilized folk on forums.

we pad the 2x4s we use to beat each other soundly about the head and shoulders. Sometimes not.

Thanks for your responses.

Ok, The cable is suppose to work at charging and power at the same time. I just got an email from the place I bought it and they insist that it should do both. They urged me to check my usb adapter.

These cables are specifically designed to operate the nuvi's, so I guess the issue is with the adapter. Again, the unit powers up with the cable but can't sustain power over time.

The links you sent did not enlighten me as I'm not an electrical expert. Do you think I could buy a USB adapter that has more amps? Would this fix my issue? I'm guessing the one I have is less than 1 amp.

Ideas?

You probably want to make the equipment you bought work, which is fair enough. However if it doesn't and you have to look for a replacement I have a couple of places I'd recommend, based on my personal experience of cables and chargers for Nuvi's, iPhones, other phones, Palm, general computer cables, USB hubs etc.

For cables, hubs, general small electronic accessories

http://www.monoprice.com

Good solid equipment, excellent reputation and I've never seen anyone beat their prices.

For specialist chargers and a complete flexible charging system for multiple devices

http://www.gomadic.com

I have a fairly full set of options from them - wall, car, AA and Li-Ion chargers and have only ever had one problem with the kit I bought. Gomadic sent a "no questions asked" replacement to me in the UK (I was on vacation) the same day I called them under their lifetime warranty. Excellent quality and customer service. They have tips specifically for the Nuvi's, both for charging and for portable operaton.

Between the two of them there isn't much that isn't covered for small devices.

Does the cable power and charge the GPS when plugged into a computer's USB port? If not then your problem isn't the adapter but the cable.

USB ports are current limited to 500 mA or 0.5 amps. Anything designed to be powered or charged from a USB port will require less current that that.

Hook up your GPS to your standard data cable, it should go into computer mode. It will also charge the battery while in computer mode. Using your data cable, connect the GPS to your adapter to see if your battery is charged. If it is then the problem is with your new cable.

I've been dealing with monoprice.com for years, never a problem and outstanding prices. If they have what you want you won't be disappointed.
Shipping is from California and usually ships USPS Priority. Shipping may be a little higher than expected, however, the items great price will still save you money from competitors. The quality is excellent.

For the record the typical Garmin charger is 4.75 - 5.25 volts, 1 amp.

Getting a "beefier" adapter I don't believe will solve the underlying problem here, which is that the Garmin charger uses a USB lead where the pinout is modified from the standard pinout through the use of a resistor.

A standard USB cable and a Garmin power adapter have five pins. Pins 1, 2, and 3 (+5V power, data line 1, data line 2) are identical in both the USB cable and a Garmin adapter. The difference is in pins 4 and 5. In a standard USB connection, pin 4 has nothing attached to it and thus "floats free". Pin 5 is a ground. In a Garmin adapter, pin 4 has a resistor attached to it that also connects with pin 5.

The resistor makes all the difference in the world. Without the resistor, the GPS goes into data mode and charges the battery, which is not very useful on a bike or in a car. Use the resistor to short out pins 4 and 5 and the device goes into navigation mode as well as charging the battery, which works a lot better.

If not wishing to use the Garmin adapter, the only other option I can think of is learning to use a soldering iron to connect a 17.3K Ohm resistor between pins 4 and 5 of a USB cable or the USB adapter itself.

Thanks for hi-jacking my question with ads. That's pretty rude.

The cable I have is not a data cable! With that said, I shouldn't have to solder a resistor or any other part. Again, the cable is suppose to charge and power the unit when it is in use.

I have seen USB adapters that are 1 amp; I even saw one at Walgreens a few days ago.

It's obvious that no one here has used a USB adapter to power their Nuvi. Looks like I'll play with a 1 amp USB adapter and see how that works. I'll also play with the cable if the USB adapter does not fix the issue.

I have used USB adapters and have even made some, but am not sure what is causing your problem.

The "power" USB cable you bought no doubt has an imbedded resistor in it's mini USB type B plug,

I would suspect the USB extension cable – it may be causing too high of a voltage drop because of length or faulty connectors. How long is it? You may want to check the charging results without the extension cable in the loop.

I don't have a 765 but all of my nuvis will charge and operate at the same time even when using a 500ma source, but I guess it is worthwhile to try a higher current source (if the USB extension cable is not the problem.)

With my 295W I can measure the ID pin resistor value of the cable plugged into it, as well as monitor the charging current rate, and voltage levels. If you know someone with a 295W they could check out the charging circuit for you.

Going to a 1 amp adapter should work since that is what the Garmin adapter calls for. As Evert notes, your cable must have the resistor embedded in it, which would have been good to know earlier. I will defer to his judgment and echo his suggestion: check your extension cable. But do note that nüvi 7xx series receivers are notorious for not playing nice with generic USB adapters, so even with the right cable and the right amperage there is still a possibility that it won't work. Don't ask me why that is however. I don't have a 7xx unit.

I am sorry you feel I hijacked your question with ads. My sole intention was to suggest a site I know to be relaible should you need a cable to resolve your problem.It was relevant to the question posed.
I would hardly consider that RUDE.

Good luck with your problem, I hope you get it fixed.

When I followed your link and looked at the specs of the USB Power Cables for Garmin™ GPS, it did not indicate that it would work with the 765 (and yes I know that you had been your 200 charger and it worked). I wonder why 3BRPowerSports did not list any of the 7xx series?

Despite the fact that you complained about ads hijacking your question, maybe what you need is something from one of the links others provided to Monoprice - a multiport car charger. Perhaps http://www.monoprice.com/products/product.asp?c_id=108&cp_id...

Not elegant - but you could go back to using your 200 charger and get the USB capability also.

That cigarette multi-socket is huge. I have a Moto Guzzi Griso with very little room under the seat. That will not work for my purposes. This weekend I will experiment with the cable/extension/adapter. I will find the problem; I was just hoping that someone here would have run into a similar issue. By the way, I incorrectly stated that I have a 765. It's actually a 760.

Regards.

I have a couple of spare USB cables from cameras and they have worked perfectly fine. I beileve the configuration is standard.

There are actually a couple, maybe three, different configurations used for USB cables. A standard "data" type cable only uses four, not five, leads. There are two data leads and two power leads. Some devices, like the Garmin GPS, require special signaling modifications to the cable to indicate which of their modes of operation that cable supports. Cell phones, iThings and a few others require a resistor of about 1,500 ohms across the data leads in order to switch into charging mode. The trick is to find out which modification your device requires and I don't know of any data base that lists them.

Here are the pinouts for the Garmin power connector and USB cable and tells how the cable dictates which mode the GPS is put into.

http://pinouts.ru/GPS/garmin_nuvi_power_pinout.shtml

The claim that there are special Garmin cables is interesting, but does anyone have a link to actual information provided by Garmin, or are people just repeating misinformation that they heard before? I tend to not believe this, at least for current Garmin devices. Here's why:

I got a Garmin 250 about 3 years ago. It's the new style, with round + and - on-screen buttons and more internal memory. When I went to register it I had some questions so I called Garmin. The support person was telling me how to register it on-line and I asked him, "If you expect people to register it electronically by connecting the GPS to the Internet, why don't you include a USB cable with it?" He was a little embarrassed and said "yea, we keep telling management that they need to do that" but went on to tell me that I could use any USB to micro-USB cable (which I had already figured out). Fortunately, I have a few since every other device that uses micro-USB comes with a USB cable.

I've charged my Garmin GPS (and loaded maps) just fine with several very standard USB to micro-USB cables, just as Garmin advised. So I'm not inclined to blindly accept that Garmin has a cable that is wired differently that they don't bother to provide to most customers unless someone has a genuine Garmin link about it or wants to provide detailed technical info about how it is supposedly wired.

The Garmin USB cables that came with my Etrex Venture HC and my Nuvi 285W has a Garmin logo on them, a full size Type A male connector (AKA plug) on one end and a mini Type B plug on the other end. The mini plug has no connection between the ID pin (pin 4) and ground (pin 5).

That cable configuration is the same as several camera USB cables I have.

The Garmin cables that are permanently attached to a cigar plug or a wall wart on one end and have a mini or micro plug on the other end, do have a resistor between the ID pin and ground. The value of the resistor varies a bit amongst these "power" type cables that came with the three models of Nuvis I have.( My 295W is capable of measuring and reporting the value of the ID resistor of the mini plug that is plugged into it.)

According to USB 2.0 specifications, cables that have a full size Type A plug on one end of a cable should have nothing connecting the ID pin of the mini or micro plug on the other end to ground. That is, the ID pin should be "floating".

However some third party manufacturers are making cables that have a full size Type A plug on one end and a mini or micro plug on the other end that has a resistor between the ID pin and ground. These cables are to be used with their "power sources" that have a full sized USB female connector (AKA socket) on one end and various power sources on the other end. (It is against USB standard specifications to have a fullsized Type B socket attached to such a power source.) Garmin Nuvis will detect the resistor and will charge at a higer rate than it would if there was no resistor. (With no resistor, the Garmin would think it was hooked to a computer and would limit the charge rate to 500 mA maximum.)

The "USB Power cable" sold at the OP's link is one of these non standard cables, having a full size Type A plug on one end and a mini Type B plug with a resistor from the ID pin to ground. Note on that site they state "Note: this is power cable, not a data cable. It cannot be used for data transfer." I don't have one of those cables but I would bet that there are no wires inside to connect the data pins at both ends.

Most all Garmin GPSr units should charge ok with any of the above configurations albeit will charge at a lower rate when the unit sees no connection from ID to ground.

Additionally, some units such as the 700 series have problems with being able to be in the operating mode while charging via cables with no connection between the mini plug ID pin and ground.