The answer and I am sure you will not like it - but it is the best advice - is
WHY risk a garmin gps - by connecting to a made in china generic - 12v power socket/twin usb at a cost of 99C
http://www.ebay.com/itm/301656939475?_trksid=p2057872.m2749.l2649&var=600511114029&ssPageName=STRK:MEBIDX:IT

when the advertised product does not even state the output voltage
If it is not correctly and reliably regulated and I cannot see it being so at such low cost you are placing your GPS at risk
For instance if the charging voltage is meant to be 5V at a certain current demand from the garmin and that cheapo socket does not supply that voltage at that demand but supplies in excess of the voltage - you stand the chance of at best cooking the battery and at worst damaging beyond repair the garmin circuitry

It is quite common for some garmin and other devices to behave as though they are on data transfer when connected to charging - equipment that is not exactly matched to the requirements of the device.

 

re my last
the difference between what you have and Garmin
https://buy.garmin.com/en-US/US/sho.../en-US/US/shop-by-accessories/adapters/high-speed-multi-charger/prod142325.html
Add 2 high-speed USB ports to your vehicle's 12 V outlet without losing the ability to power your compatible device. Use each USB port to charge a phone, tablet or any other device that needs power on the go.

• INPUT : 10-30v 5.4A max
• Output USB : 4.75-5.25v 2.1A
• Output Socket : 10v 2.4A max ->30v 0.8A max

note the stated voltage and current

However you would have to check if that suits your GARMIN

 

You actually should be using a 12-volt port replicator. Here, just one example, is one with three ports plus a USB.

Of course, all you apparently need is one with just two 12-volt ports. Until recently I frequently used one of those for my Garmin and an XM radio and sometimes a cell phone.

 

Whatever is used the critical aspect is that - unbranded generic 99C 0.99$
cannot IMHO be trusted
the garmin device I listed provides two usb ports
Output USB : 4.75-5.25v 2.1A
has a certified output and the cheapo could be providing a very questionable voltage

 

Yes I certainly will look at the specifications on my charger and Garmin unit. So you think it's the splitter and not the cable? I had a 12 V splitter that went to two separate 12v cigarette lighter outputs, similar to the devices you both referred to, but the car vibration kept on vibrating the big clunky device out of the socket. I thought that something smaller like what I got would be less likely to vibrate out of the socket, and this definitely is so. It hasn't vibrated out yet, however the setup isn't working, so maybe there's a Plan C or D that I can go to?

 

but the car vibration kept on vibrating the big clunky device out of the socket.

You need to find smoother highways!

The 3-port one I have (w/o USB) looks similar to the one to which I linked. It has a way to attach it (adhesive or 2 small screws) to a surface or can just be laid on the floor or seat. I first had a clunky two-way splitter like you describe and also found it not very useful. But the three-port one with cable was very useful.

 

• Output USB : 4.75-5.25v 2.1A

note the stated voltage and current
However you would have to check if that suits your GARMIN

Well on the GPS unit I couldn't find any power markings. On the Garmin charger, it has...
"Input: 10-30VDC1A(Max)
Output: 4.75-5.25 VDC 1.0A"

So it looks like I should look for a charger/adapter that has an output of about 5V to the USB cable. And I guess at least 1 Amp output as well for each output.

The 3-port one I have (w/o USB) looks similar to the one to which I linked. It has a way to attach it (adhesive or 2 small screws) to a surface or can just be laid on the floor or seat. I first had a clunky two-way splitter like you describe and also found it not very useful. But the three-port one with cable was very useful.

The one you referred to also has a 5V USB output. On adhesive or screws to stop it from working its way out of connection, I don't really want to do this. Maybe if i get a small screwdriver and tweak out the two side metal connectors ("springs") it may make the connection tighter. But I'm also looking for a streamlined look as well, not with additional clunky cigarette lighter outlets, just sticking with 2 (or more) USB outputs. I thought the USB voltage output would have been universal on these.

 

Well it looks like I can get the best of both worlds, specs that fit and a non-clunky, more connection-loss proof, more streamlined system. I'm going to order this...
USB 2 PORT CAR CHARGER ADAPTOR - http://www.ebay.com/itm/281736611486

It has an output of 5.0VDC and 2.1A, with one USB port going up to 1.0A and the other port going up to the Max of 2.1A. Since the Garmin charger only goes up to 1.0A, then either port should work for it, and for only 99 cents. What do you think? BTW, the original unmarked item I obtained from eBay (http://www.ebay.com/itm/301656939475) was really 99 cents Canadian, or only 74 cents USA.

 

This is probably a limitation of the Garmin unit. Have you looked at support for the unit to see if it works via a USB port versus a car / cigarette charger port?

 

You might have a point there Tony. I may be stuck with the clunky cigarette lighter splitter in order to get this to work out, but then there's the problem with the clunky unit vibrating out of the socket.

I obtained this identified 5 Volt, 2.1 Amp USB splitter on Ebay... http://www.ebay.com/itm/131614692776

I'm having the same problem with both the 1 Amp USB outlet and the 2.1 Amp outlet. So it's either a Garmin limitation issue requiring the specific Garmin charger (I hate proprietary systems) or maybe it's a cable issue.

 

It's as I first suspected, IT IS THE CABLE. I did some research, and Garmin Nuvi's have special proprietary USB cables, something special with the 5th pin. It's explained more at these links...

• Garmin Nuvi 2595 keeps restarting into usb mode? - https://forums.garmin.com/showthread.php?72222-Garmin-Nuvi-2595-keeps-restarting-into-usb-mode
• Garmin Nuvi USB Power Cable Demystified - http://advrider.com/index.php?threads/garmin-nuvi-usb-power-cable-demystified.666156
• Garmin Nuvi GPS Power Connector pinout - http://pinoutsguide.com/GPS/garmin_nuvi_power_pinout.shtml

I will be getting a special USB cable off of Ebay specific to the Garmin Nuvis and will report back on if it's successful. Macboatmaster, I won't be able to get this for less than a buck this time. It'll be about $1.70.

 

I agree with the cable purchase but also
Way back on post 3 I sent you the link for the proper Garmin 12 volt socket to usb charger
Have you ever checked the link to see if it lists your model
As I said on post 2 why risk a garmin with a cheapo 12 v to usb

 

It seems that this has already been recognised

It's as I first suspected, IT IS THE CABLE. I did some research, and Garmin Nuvi's have special proprietary USB cables, something special with the 5th pin. It's explained more at these links