hard wire the charger?

That's something that I've wondered about. I almost never turn my Nuvi off and it is always charging. Does anyone know if I am causing any damage to the unit or battery?

I would love this infor as well. I would love to be able to hardwire the unit!

I did a search before posting this, and didn't find any that discussed it. It obviously seems like people are interested so if there are any car electronics installers on here, we could certainly use your expertise.
Thanks all for a great website, I'm really please I found the Factory

Here is a website that has a DIY w/pictures. I have not done this, but I am interested in your results.

To find more info also try searching for "Hardwiring" or "Directwiring"

Good Luck!

http://www.drumart.com/nuvi/

His DIY appears to work, but I'm not sure that the circuit board of the cigarette lighter piece is required if the correct fuse is used. When I see hardwire kits for radar detectors, they are just bare wire with the appropriate connection. I think I'm going to check with a local car stereo installer and see what they would recommend.

The circuit board is still needed in most (probably ALL) cases. This is because most electronics don't actually run off of the 12v supplied by the battery. The circuit board typically steps this voltage down to 3v or 5v or whatever the unit actually requires. If you know the actual power requirements of the device, you could (probably, but I never tested) use a step-down transformer from radio shack in line with the device instead of the circuit board. But the original circuit board is ideal if you have it. Without the circuit board (or transformer?), you are in for a day of blowing fuses.

Obviously you still need to use the fuse that came from the cigarette lighter adapter as well, or else you are in for a day of frying GPS units.

Hope this helps.

to modifying the charger, you could use an inline accessory socket, like the one shown here. Although I have used the technique of connecting to the charger's PCB in the past, the Garmin units seem more difficult to open than most. (The one shown in the DIY project is presumably 3rd party - as characterised by the absence of the 90 degree USB plug).

Regarding the output voltage, the Nüvi's is certainly the USB standard 5V, but the Streetpilot seems to have the voltage drop components built-in (The Streetpilot's battery diagnostic page shows the input voltage, (from the charger) as 13.4V (or thereabouts)).

Using that accessory socket is the way to go, so you get to keep an inline fuse and the proper voltage with your cigarette lighter charger.

However, I warn all who leave their GPS plugged in - there is an awful lot of message traffic floating around the net right now about GPS units pulling car batteries down. Some of these devices will keep their receiver's in a "warm" standby mode, meaning it's pulling more power when hooked to a power source than it would if off charge and on batteries. Many of these units use a "smart charge" function that measures a small current draw over the power pins on the usb connectors (if that's your charging source) and if there's no current draw the unit shuts the receiver down completely to prolong battery life.

You can find hundreds of stories out there now about "my car died and couldn't be restarted" because they left their GPS plugged in while gone for several days. One happened with me at Charlotte airport, guy was in the parking lot with a dead battery so I tried to jump start him. Newer model Ford pickup, dead dead dead battery. Couldn't get it up with a jump, needed a deep charge to get it started. Had to leave the poor guy there scratchin his head. He said the only thing he had was a hard wired Nuvi... hmmmmm...

Leaving anything connected to the battery will eventually discharge the battery. I think common sense applies here.

As far as hard wiring the GPS, I see no real advantage and one huge disadvantage .... a pile of ashes where your GPS used to be.

I don't recommend hardwiring unless you know what you're doing. You can't use a "Step-down transformer" with DC, only with AC. Therefore, if a transformer is used, DC has to first be changed to AC, stepped up or down with the transformer, and changed back to DC. These voltage converters are sometimes called 'switching power supplies'. These are more common in step-up applications.

The easiest way to lower the voltage is with a resistor in series with the device. This only works if the current draw of the device is constant.

A more common method of lowering the voltage is with 'voltage regulators'. There are several websites with information on building your own. You can also buy regulators for most all purposes.

Before changing the wiring, check if the center of the connector to the GPS is positive and what the voltage is under load. DON'T ASSUME ANYTHING! BE CAREFUL!

RT

I would be careful about not using the Garmin plug with the circuit board and in-line fuse. There are power surges (i.e., when the starter motor kicks in/out). Also the Garmin vehicle adapter uses a specific 1 amp ceramic fuse (Type F with a
high-breaking capacity: F1AH250V).

See http://www.gpspassion.com/
forumsen/topic.asp?TOPIC_ID=94837&SearchTerms=

Another approach is to obtain a cigarette lighter socket and insert the vehicle adapter plug into it. Mount this under the dash and run two wires to your fuse panel or other power source. This way you aren't changing the Garmin circuitry.

Leaving your Nuvi in the vehicle is a bad idea. Thieves look for them and even evidence of one (i.e., a dashboard mount, circular smudge on windshield left from suction mount, disk on dash). I use the bean-bag and take the Nuvi with me at every stop and remove all visible evidence.

The circuit board that came with the nuvi is definitely required. Lithium ion batteries in the nuvi or any other product are very sensitive to how they are charged. They must have circuitry to sense when they are charged or the battery could explode or start a fire. After market chargers may not have a circuit that is compatible with your battery. The batteries also have protection circuits that are different from one product to another and must be compatible with the charger. We have all heard of notebook computers that start on fire due to the batteries which is the same problem. These batteries are not as forgiving as NiCd or NiMH batteries that have relatively simple chargers.

Before buying my Garmin C340 I read through many of the reviews for it on Amazon.com

One of the comments stated that keeping the unit plugged into the car charger all the time caused damage to their unit. This might not bethe case for all Garmins. I would check with tech support, at least if they tell you it's ok and something happens, you might get them to fix it for you.

As I recall, these 'battery explosions' were caused by defective batteries, not by defective chargers or incorrect charging by the users.

RT

These are all great comments from these knowledgeable folks. I've had 20+ years and am an Elec. Designer. I also was part owner of a car stereo sales and installation shop in my very early days.

If I could, I'd just like to summarize the information that's been so knowledgeably presented here:

1. For the Nuvi that charges off of the USB port - the little circuit board in the plug is an absolute prerequisite. It takes the 12 Volts DC and converts and regulates it to the USB spec of 5 Volts DC. I'm positive the Li-Ion battery charge regulators are built into the Nuvi itself as they also monitor battery temperature.

2. Always follow the recommended fuse requirements. Just hooking your unit to the car's ignition switched power doesn't guarantee that the circuit you hook to has a low enough fuse rating to prevent a fire if the unit shorts out. Most Accessory circuits in vehicles are 10-20 amps. The fuses in the Garmin plugs are typically 1 Amp fast acting fuses.

3. I would never leave an accessory unit powered up with the ignition off and me gone. Direct wiring should always be connected to the Accessory part of a cars wiring so that the ignition switch kills the power when off. This for the reasons mentioned above, the potential battery drain, and the theft potential also mentioned elsewhere here.

4. The C series definitely lends itself more to direct wiring as it has both USB and normal 12 VDC inputs (via the cradle) with the one caveat of using the fuse mentioned in #2 above.

Personally, I'm just going to leave mine powered up through the normal accessory plug as supplied.

Great info in this thread folks!

Rick

Now I know why the vehicle owner's manual says to use the Acc plug and not the cigar lighter. Thanks.

While most cars may behave as described, some do not: 2007 Lincoln Town Car ignition switch does not cut power to the Acc plug.

YMMV