usb charging in car and using gps at same time

It may be easier to use a usb adapter in the 12v outlet. I use one with my nuvi. As you say the charging is slower. You can get them on Amazon for a couple of dollars.

It will work until one day this constant plugging - unplugging game will kill your USB connector on device. Just go to any electronic store and ask for USB power only cable. It will cost probably a few bucks and will solve your problem. Device will be only powered up and will not switch to "computer mode".

If you decide buy this cable be sure to check it, as sometimes happens that some of them will not work correctly and GPS will switch into "computer mode". But you should be able to find working cable without problems in local store.

Easier yet spend about $5 on eBay and get a replacement car charger then you don't have to worry about the slower charging.

I am confused as to your model number, you say
"I have a garmin 710 or 720". I would imagine you would know the correct model number. As far as I know there is NO Nuvi 720.

Assuming you have the 710, that unit uses a powered cradle mount, you must use a cigarette lighter charger and plug it into the CRADLE MOUNT, NOT INTO THE NUVI. This will put it into operating mode, not the computer connected mode you are seeing.

The ony assumption I can make is you bought this used and the seller didn't include the power mount.

Please advise if you have the power mounted cradle the Nuvi came with.

Why can't you assume that he knows what he has in the way of charging options? He stated that the mount broke and the USB is the only option he has left to power and charge the GPS.

To the OP, there are several options open to you to fix or replace the broken items. You can order a replacement mount on e-Bay. You can order a replacement cable for your mount through Amazon.com. You MIGHT be able to find a Garmin USB cable that doesn't put the unit into computer mode...I don't know it something like that is available though. Used Nuvi 7xx series GPS's are listed on e-Bay from time to time, you might be able to pick up a replacement through them. In any case you will have to spend some money to fix what you have. If you don't need the options available on the 7xx series then you might be better off getting a new unit for around $100.

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I am interested in a better understanding of "power" versus "computer mode".

Here is my recent experience. While on vacation, my 765T ceased to get power from my auto. I could not tell whether it was the traffic cable that had gone bad or the mount had failed. Turned out to be the mount.

I think what happened is that the constant movement of my beanbag mount from my dashboard to under the seat was straining the connection of the traffic cable (with its squeeze release from the mount) at the mount until finally that mount connection failed. I have since (after replacing the mount) learned to loop the traffic cable around the mount once to (hopefully) minimize strain on that connection.

Prior to the trip, I had gone to Walmart and purchased a dual USB cigarette lighter adapter. Since I had my laptop with me, I had a USB cord that would let me attach my 765 to the laptop.

When I used the adapter and the USB cord, the 765 woke up, went into the mode indicating it was attaching to a PC, "thought" for a few seconds after the green bar finished its left to right movement across the Nuvi screen; and then went into normal operation arriving at the Where To? screen.

It would seem that the nuvi recognized that it was not attached to a computer and concluded correctly that I wanted to navigate.

So, what would be the advantage of having a "power only" USB cable?

I've seen many posts where the OP was confused as to what was what. I may not agree with muell9k's choice of wording, but I agree with his attempt to verify the facts.

Regards

The OP - erock007 - just joined us yesterday on 9/13. His post was late in the evening. As I read his post, he was not asking a questions so much as telling us what worked for him. That is why I posted what happens to me with my 765T plugged into a USB in my auto.

My guess is that erock007 will check in this evening after work.

@erock007, welcome to the site.

Since you are new, you may want to do a couple of the Beginner Exercises.

To make it easy, when you click on the first link below, hold down the "Cntl" key as you left-click. That will open a new "Tab" in your browser in the "Tab" bar. Click on that 'Tab" to do the first exercise - leaving the "Tab" you are now reading open and available to click on and return here.

The first link makes sure settings on your computer are such that you can do more advanced POI loading.
http://www.poi-factory.com/node/30393

This next link helps you get a backup by attaching your GPS to your computer. (NEVER do anything to your GPS until you have a backup)
http://www.poi-factory.com/node/30394

That 765 is one of the best Nuvi's Garmin ever made..

I wish my 750 worked like that, it just goes into computer mode and stays there. The "power only" USB cable would not put the GPS in computer mode so you couldn't use it to program or transfer data between your computer and GPS. But it would power the GPS in navigate mode and slowly charge the battery.

I operate my Garmin Nuvi 350 powered through the mount this way normally. The nice thing about that is when I use a cigarette lighter plud dual USB adapter I still have one USB port left for another device without having to get a second adapter.

He is lucky his unit detected no negotiation in USB and switched to normal mode. USB power only connections need to have a couple of resistors on the data lines (forgot values) that are pulled up (or is it down?) and that lets the device know that they are in charging mode.

Actually, it's only one resistor, and it bridges pins 4 and 5. When powered, the current is shunted from pin 4 to pin 5 through the resistor, preventing the unit from going into PC mode. It's likely that a unit that uses a powered cradle does not have its USB port modified to have pin 5 be the negative power and thus will function normally. Units that plug the power cord into the device, e.g. 2x0, 2x5, 1xxx will have the modified USB port.

has both a powered cradle and a USB connector. The USB cable needs the modification to work powering the unit as a GPS and not go to storage mode.

Perhaps I should have said, "units that do not use a powered cradle"?

The 885 doesn't invalidate my general point I hope.

@Strephon, thanks for the clarification. From the start, I have learned that your answers were authoritative so I was confused when my experience with the powered cradle was different.

Keep up the good work.

Normally if you plug in the USB Vehicle Power Cable to the nüvi and connect the other end to your computer, your nüvi does not operate as a GPS unit - it goes into some sort of charging mode. However, if you FIRST turn on the nüvi in the battery mode then go into the test mode (press the battery icon for about 8-9 seconds) from the main screen, THEN PLUG in the USB cable, and finally exit the test screen, your nüvi will restart (reboot) and it will operate just like it was plugged into the cradle connection in your vehicle.

> This mode will charge the battery AND operate as a GPS.

It works with my computer USB cable, my cell phone charger and my car charger for my cell phone.

Don't forget to turn off the nüvi before unplugging."

None of that works with my 770. When I plug the USB cable under test mode, it detect the cable. When I exit the test mode, it goes briefly into "loading map" but then gets stuck on the initial jpg image with the copyright notices replacing the "loading maps" at the bottom. It never goes past that. I have to manually shut down the unit to get out of that.

My 750 works like garystevens described.

Found that the unplugging and plugging back in doesn't always work...
1.unplug (shows start--where to?)
2. Hold battery icon until setup test pops up
3. plug in
4.press exit

Should keep on the start menu from there while still plugged in

I wanted to take my Nuvi 2450 tomorrow to make sure all works before a vacation trip.
I didn't want to use the Power mount. (Lazy, as more trouble to take the mount)
I took 3 cables to the car. The short one that came with my Nuvi 2450 only put it in computer mode. Another longer cord and not sure what it went with and it also only put it in computer mode.
I have another card that I don't know what it came with. I tried it and it powers up my Nuvi 2450 in the car for navigation.

Just in case anyone else needs this information, try different cards.

Edit: I plugged the card into my PC with my Nuvi and it went into navigation mode also. I looked at my drives and it did not show it was attached and then I went to eject and the PC did not show it was connected and did not give me the option to eject. I turned it off before I removed it just to be safe. It said "charging the battery" after I turned it off.

... that cord will simply be a power only, as opposed to a data, cord.

Bad news is that you will not change that behavior from 770. Basically all old units are switching to data mode when connected via "data" cable. They will stay this way until "data" cable is connected. In newer units, if after some time gps will not establish connection with computer, it will switch into "working" mode. In even newer units you can actually at this same time work on device and use it as in data mode by default. They not switch into exclusively data mode.

It's just way the old units behave. So either you have proper cable or there is nothing to be done with them.

I found this -

I simply waded up some aluminum foil and stuck it in the connector so that pins 4 and 5 were shorted. Works.

not my fix but worth a try. the 5v is on the opposite side and the shell may also be ground.

I usually just power it up and do the pull plug thing as soon as it starts powering up.

Digging up the dead, as it were.

there is so much demand on 12v outlets, either the fuse blows or they stop functioning altogether.

I had a 2016 BMW 328 loaner for almost 4 mos., so it would have been nice for the 12v outlet in the console to work. I jumped on a forum, and it not working was a common and known issue, not the fuse.

Forums are amazing, though, the consensus was to use the hidden one that is vertically oriented, under the glove box. HUH? I look and sure enough, there is one hidden there, and it worked.

12v outlets are so innocent these days, until you look at how much the part alone costs to replace. And when they stop functioning, you may move to outlet #2 and #3, but have a long unsightly cable running up front.