Electrical Gremlin...?

[fogducker III]

I recently installed a 12V power outlet (fancy cigarette lighter) on the dash to power my GPS/Mapplotter, I plug it into the receptical to use and can easily remove the unit to use in my other boat. I took power off the fuse block from constant hot and ground from the main common ground.

The unit works fine with ignition off or on, problem is, with the unit on with engine running, if I turn the engine off, unit stays on, which is fine, but when I restart the engine the unit shuts down and I have to hit the power button to restart it...? Any ideas??

[Carl C]

Mine did the sme thing so I ran a heavy gauge wire direct to the battery with an in-line fuse and it still does it. It's really frustrating to have to reboot the gps all the time. Just wanted to let you know that it is not something you did. Hopefully someone has a solution.

[HOWARD O]

I recently installed a 12V power outlet (fancy cigarette lighter) on the dash to power my GPS/Mapplotter, I plug it into the receptical to use and can easily remove the unit to use in my other boat. I took power off the fuse block from constant hot and ground from the main common ground.

The unit works fine with ignition off or on, problem is, with the unit on with engine running, if I turn the engine off, unit stays on, which is fine, but when I restart the engine the unit shuts down and I have to hit the power button to restart it...? Any ideas??

I had this very same problem on my fishing boat. It was a fancy Furuno chartplotter/fishfinder and the drop in voltage would cause it to turn off on restart. Real pain in the neck when fishing because the whole thing would have to reinitialize. My unit was hard wired. I don't think you're having an electrical gremlin, the unit is probably designed to shut down when it detects a drop in voltage, such as starting the engine. Someone told me once what I needed to fix it, that keeps that circuit at full voltage but I believe it involved the dual batteries.....probably not much help to you.

Now the Lowrance unit I have in the truck is plugged into the "power port" just like yours, but it won't shut off on a restart. I sure see the screen dim when I start the engine though!

[fogducker III]

Thanks Carl, ya it is frustrating and probably not good for the unit...:frown:

All I can guess is the ignition is drawing enough at start-up to draw enough to trick the unit into shutting down...? Perhaps the only way around it is a second battery not on the ignition circuit?

[RickR]

Probably getting enough voltage drop during start up for the GPS to shut down from the low voltage.
Better, bigger battery or if a circuit directly to the battery solves the problem, larger starter and ground wires might help.

FYI: Don't ignore the ground. Saltwater corrosion/ground issues are common.

If your GPS has the "Voltage" page check the drop. Your manual shoud give you minumum voltage.

[fogducker III]

Yup, double checked the ground, all good, I just re-did my dash, all new wiring and connections. Battery is a brand new Optima marine battery and all power/ground leads are new, heavy gauge and connections checked..:garfield:

I beleive my unit has a volt "page" I am heading out today for a run so I will definatly have a look at the draw, thanks for the input.

[gcarter]

When I had a dash made for the Minx, I had them include an "accessory" circuit breaker and dash switch which included two lighter type power ports. The source of the power was the main battery switch, not from under the dash. I also included a ground buss which originated from the block at the main ground lug.
Needless to say, I never had any problems.

[yeller]

I have absolutely no idea if it would solve the problem, but if you can get your hands on one, try it with a capacitor installed. You know...the ones used in the auto stereo biz to prevent voltage drops to the amps.

[txtaz]

I have absolutely no idea if it would solve the problem, but if you can get your hands on one, try it with a capacitor installed. You know...the ones used in the auto stereo biz to prevent voltage drops to the amps.

Yep a 1 farad cap should to do the trick. First test with a volt meter while starting the engine (make note). Install cap and retest. Should stay above 10Volts for a few seconds.

Da Taz

[RickR]

yeller, txtaz
Radio Shack item?
Positive side? In line or parallel?

[txtaz]

Uhmm, I need to make a correction...

If you place the cap in parallel with the GPS (+ - ), it would be supplying power to the starter when it cranks (not good for the little wires going to your power block). Talk with the car audio guys to see if they use them in series with devices. And 1 farad may be a bit much. This is a little out of Radio Shacks league.

The car guys use them in parallel to amp power line in to provide extra current on big bass notes.

Da Taz

[zelatore]

If you have a dual battery set-up, there's another option we use on bigger boats.

Use one battery as a dedicated starting battery and the other as a dedicated house battery. Seems a bit overkill on a small boat with no real house loads, but it would do the trick. Also works well if you like to hang out with the stereo cranked up for hours on end.

You can then specify the battery type for each application. A deep-cycle battery for the house load and a starting battery for the engine.

[HOWARD O]

When I had a dash made for the Minx, I had them include an "accessory" circuit breaker and dash switch which included two lighter type power ports. The source of the power was the main battery switch, not from under the dash. I also included a ground buss which originated from the block at the main ground lug.
Needless to say, I never had any problems.

Are you saying that since your source of power was from the battery switch, that you're not going to get a voltage drop? This I do NOT understand? You never had any problems with what?

[zelatore]

I think George is basically saying he had a dedicated line run straight to the battery to power those 12v outlets. In theory, pulling power from the under-dash 12v buss is fine, however in reality that's one more connection to corrode, increasing resistance & cause a loss of voltage plus that much more current to pull through the existing wires to the buss which means that much more possible voltage drop.

[HOWARD O]

I think George is basically saying he had a dedicated line run straight to the battery to power those 12v outlets. In theory, pulling power from the under-dash 12v buss is fine, however in reality that's one more connection to corrode, increasing resistance & cause a loss of voltage plus that much more current to pull through the existing wires to the buss which means that much more possible voltage drop.

Oh, I thought George was saying that since he was wired to the switch, there wouldn't be a voltage drop. I didn't understand how his setup would insure a problem with a GPS shutting off due to a voltage drop.....I guess it wouldn't at all. Thanks Zelatore.

I think I would search a fishing website, like thehulltruth.com and see how those folks wire this receptacle up.......I've run across it a few times while reading there. Wanted to do something about it on my fishing boat, but boat gone before I got around to it! :lookaroun:

[gcarter]

My positive wire to the dedicated breaker was a #8 I think, and the ground buss was wired w/a #6, I think. Of course the ground wire and buss was for everything under the dash.
While cranking, you do see a voltage drop from the starting battery, the set up I described will limit it to the actual battery voltage, not the 2-3 volt additional drop you might find under the dash.
As I said, I never had a problem w/ my GPS.

[fogducker III]

So I thought I understood the various posts, I wired the Johnson outlet to the McPherson inlet and hit the "on" button, Jacqui screamed and her hair stood on end, her bikini top fell off and when I laughed she stepped back, fell on the battery and her ass shorted out the terminals and sent a spike to the rest of the electrical system and cooked the dash............. good thing was she was not out of red wine and we were close to shore.........:wink:

Paddled in and found another battery and dash, scrapped the 12V plug and working on star gazing now.............:popcorn:

[gcarter]

So I thought I understood the various posts, I wired the Johnson outlet to the McPherson inlet and hit the "on" button, Jacqui screamed and her hair stood on end, her bikini top fell off and when I laughed she stepped back, fell on the battery and her ass shorted out the terminals and sent a spike to the rest of the electrical system and cooked the dash............. good thing was she was not out of red wine and we were close to shore.........:wink:

Paddled in and found another battery and dash, scrapped the 12V plug and working on star gazing now.............:popcorn:
You're pretty funny!:)

[fogducker III]

Best I got.............

[BigGrizzly]

What happens is that line drops when the solidness is energized. Run the wire directly to the battery post and bypass the fuse block. The problem is some GPS, drop off when there is a low voltage sensed. another way is a battery backup. I have three on my boat and sometimes the main one drops but not always. I had a bad starter at the time.

[HOWARD O]

My positive wire to the dedicated breaker was a #8 I think, and the ground buss was wired w/a #6, I think. Of course the ground wire and buss was for everything under the dash.
While cranking, you do see a voltage drop from the starting battery, the set up I described will limit it to the actual battery voltage, not the 2-3 volt additional drop you might find under the dash.
As I said, I never had a problem w/ my GPS.

That would minimize the drop, I guess it just depends how sensitive a particular unit is. I know my Furuno was fairly sensitive. I have a Garmin now but have yet to install it. I figure I might as well wait until my boat actually RUNS! :cool:

[fogducker III]

That would minimize the drop, I guess it just depends how sensitive a particular unit is. I know my Furuno was fairly sensitive. I have a Garmin now but have yet to install it. I figure I might as well wait until my boat actually RUNS! :cool:


I have the Garmin 178C GPS/Map-plotter unit, I watched the voltage reading on the unit with the unit on, engine off, then started the engine, volts dropped and unit shut off, looked like it happened at about 8 or 9 volts..?? It was hard to tell because it went off so quick.......:eek::nilly:

I am going to try what Griz suggested and just hard wire the dash receptical straight to the battery and see if that fixes it. I don't really want to put a second battery in the boat just to power the GPS....:frown:

[HOWARD O]

Oh, that's not good news for me either, I have a 182c.

[DickB]

A capacitor in parallel with the outlet should work. A diode from battery to capacitor/outlet will prevent the capacitor from being discharged by the engine cranking. Depending upon the size of the capacitor, the diode would need to be stout, as there can be a sizeable inrush of current when initially charging. A knowledgeable stereo installation shop could advise. If you can measure or determine current draw of your GPS power adapter, we can determine the size of capacitor needed.

[BigGrizzly]

If you have batteries in the 172 it should not drop off. I have Lowrance and battery back up units don't drop. However 8 volts will cause that unit to shut down for battery draw reasons as a safety.