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Author Topic:   GPS turns on by itself?
Dan posted 07-12-2001 08:10 PM ET (US)   Profile for Dan   Send Email to Dan  
6 weeks ago I installed my Standard 150 GPS -- it works great. Thing is, most times when I turn my battery selector switch to 1 or 2 the GPS turns on by itself. I wired it to the fuse panel in the console. Any thoughts?
Peter posted 07-12-2001 08:36 PM ET (US)     Profile for Peter  Send Email to Peter     
Was it turned off before the battery selector switch was set to "off"? Does that make any difference?
Dan posted 07-12-2001 08:41 PM ET (US)     Profile for Dan  Send Email to Dan     
Yes, GPS was turned off before selector was turned off.
dfmcintyre posted 07-12-2001 08:53 PM ET (US)     Profile for dfmcintyre  Send Email to dfmcintyre     
Heck, I wish my Garmin 135 _would_ do that.
Peter posted 07-12-2001 09:07 PM ET (US)     Profile for Peter  Send Email to Peter     
I know this is off topic but I cruised over to your harbor last week and anchored very briefly at Sand City Island.

I doubt its designed to do that so I would get a volt meter and check the voltage when you switch from the "off" position just to make sure everythings OK.

Peter posted 07-12-2001 09:10 PM ET (US)     Profile for Peter  Send Email to Peter     
Also, does it do this when you disconnect/reconnect the power lead from the back of the unit when you are switched to "1" or "2"?
Dan posted 07-12-2001 09:17 PM ET (US)     Profile for Dan  Send Email to Dan     
I've been leaving the GPS on the boat connected, and not removing/attaching power connection.

Peter -- Sand City -- usually good for fluke -- I'm usually by Lloyd Point / Cold Spring Harbor areas. Lately it's been windy, and the warmer water has fishing a bit off. Hoping to go out tomorrow. I often see a 1972 21 Outrage in great condition nearby.

blackdog posted 07-13-2001 09:30 AM ET (US)     Profile for blackdog  Send Email to blackdog     
Call Tech support at Standard. I have called Garmin for my GPS and Standard for my Radio- both were very helpful.

Blackdog

Whaletosh posted 07-13-2001 09:46 AM ET (US)     Profile for Whaletosh    
Dan,

Is this the CP-150, the one that is WAAS and a chart plotter? Other than this little bug-a-boo how do you like it? Normally I am a Garmin fan, and thinking about the GPSMAP 176, but the CP-150 looks pretty nice for $100 less. I like the Garmin becuse of the PC support for map uploads and for waypoint management. But with an chart cartdrige mapping would not be needed. And waypoint management wouldn't be as needed.


Now as far as your problem goe you could go to Radio Shack and buy two items, both pretty cheap. Get a silicone rectifier diode, a 1N4000/1N4001/1N4002 or any of the 1N400 series. Also get a 1000 to 4700 microfarad electrolytic capacitor, make sure it has a 35 volt or higher rating. An axial lead styly is best, this will have leads on both ends, not just one which is radial lead.

Here is our goal:

1) Put the diode in series with the positive supply; the one for the GPS. Anode goes to the incoming power, the cathode to the GPS. The cathode is the end of the diode that has the greyish/white band. If you get it backwards, no harm will come to the diode or the GPS unit; the GPS unit simply won't turn on. Diodes only allow curent flow in one direction, so if is backwards current sinply won't flow, thus the GPS unit won't turn on. BUT NO HARM WILL BEFALL THE GPS UNIT.

2) Wire the capacitor with the + lead to the cathode side of the rectifier. The negative lead goes to ground.

What this will accomplish is two fold. If your GPS is switching on because there is sudden drop in the voltage with corresponding quick rise then the capcitor will retain a charge long enough to hold the voltage steady on the GPS power lead until the voltage comes back up. The charge on the capicitor canbleed back into the boats electricl system because it is blocked by the diode.

On the other hand if it is a voltage spike that is causing the GPS to turn on the capaicitor will help filter it out.

This may help, and since it would cost you less than $5 to $10 you could gamble on it. You don't even need to permanantly install is until you are sure it works.

I could e-mail you a schematic if you like.

Sean

Whaletosh posted 07-13-2001 09:51 AM ET (US)     Profile for Whaletosh    
"capicitor canbleed back into the boats electricl system because it is blocked by the diode."

should have read:

capacitor can't bleed back into the boats electrical system....

where2 posted 07-13-2001 10:45 AM ET (US)     Profile for where2  Send Email to where2     
As for the CP150, one thing that might be of interest to others is that the antenna is only an external antenna. Unlike alot of Garmins that can be picked up in either an internal or external format, The Standard CP150 is external only. Standard says the cable is "tuned" for length, so chopping it shorter (it's quite long!) doesn't seem to be an option. Another quirk is that if you try to mount the antenna within 3" of the right hand side (as facing the unit) it has too much RFI bleeding out of the case and will take forever (8-10 minutes!)to get initialized, and loses lock alot. If you put the antenna near the left side of the unit, there is no problem and you will get initial locks within the MFG specified 45 seconds. Warm running re-init within 20 seconds.
All in all, nice unit. Unfortunately, if you liked the transportability of the Garmin from the boat to the car for street maps, you won't get that option with the CP150 and C-Map cartridges. C-Map has no plans to offer any terrestrial road maps. The flip side of this is that the C-Map cards blow the doors off the Garmin Mapsource shorelines that I have seen so far, although that was an early version, so I might find better on Garmin's site today.
triblet posted 07-13-2001 11:04 AM ET (US)     Profile for triblet  Send Email to triblet     
Garmin has new nautical charts coming. They
are out for their new cartridge chartplotters
(2006/2010), and will be out on CD in August.
They are called BlueCharts. More info at
[url]http://www2.garmin.com/cartography/bluechart/[\url].
Click on screen shots to see some examples.
Reliable sources say they will probably work
with the Vista and 162, and the newer
downloadable chartplotters.

Whaletosh: waypoint management is necessary
in either case, if only to do backups. The
GPS is a computer, computers need backups.

The 1Nxxxx diode will cause about a 1V
drop in the voltage. This may cause a new
set of problems, like shutting down on start
(though a bigger capacitor might help that).

Chuck

triblet posted 07-13-2001 11:04 AM ET (US)     Profile for triblet  Send Email to triblet     
Ooops:
http://www2.garmin.com/cartography/bluechart/ .

Chuck

Whaletosh posted 07-13-2001 02:48 PM ET (US)     Profile for Whaletosh    
The diode will drop about .7 volts which is the junction voltage of silcon junction. Larger power diodes drop more because a factor called bulk resistance. Bulk resistance will cause voltage drops that increase with current, just like any resitive load. The .7 volt drop is going to be negligable. Even if the .5 amp load that the CP150 draws does cause a 1 volt drop in the supply line it would still be at least 11 volts delivered to the CP150. The voltage range for the CP150 is 10 to 35 VDC. This means that the CP150 would still get enough voltage to work even if the battery voltage were to drop all the way down to 11 volts.

A bigger capacitor isn't going to do anything except strore more energy to power the CP-150 during that brief little power slump, if that is what it is causing this problem. The voltage on the cap will simply be the voltage of the boats electrical system minus the drop across the diode, which is negligable. It will only fall briefly during the switch, but not as rapidly as the switch induced voltage drop. Again this is assuming that voltage drop is the culprit.

If it is a power spike a bigger cap won't help. Electolytics have to much internal resistance to react fast enough for spikes. A large film cap, a 10 microfarad Mylar (polyester) for example, would be better choice than an electrolytic. I didn't want to confuse Dan by throwing that into the mix.

Something is happening at the moment that the battery swich is turned. Either a temporary voltage drop or a spike, maybe both. A storage 'scope would pobably help determine what it is, but that is really overkill. This cap and diode circuit is simple, inexpensive, and could very well be the solution. If not there is only a little bit of time and very little cost.

This circuit could also be used to help with another common electronics problem. Some people have problems with the electronics shutting down when they start the motor. This is becuase the starter draws the terminal voltage of the battery down below the lower voltage range of the electonics, and the unit shuts off. The diode and cap solution works by storing energy in the cap, energy that can't go back through the diode, so it only dissipates through the electronics, thus keeping them operating for the short period of time that it takes to start the motor. On caveat, the higher the current draw of a device the bigger the cap that is needed; the capacitance (microfarad) needs to be larger not the voltage rating.

Sean
Sean

Whaletosh posted 07-13-2001 03:03 PM ET (US)     Profile for Whaletosh    
Chuck,

I only meant that they aren't as important. With a funtioning chartplotter I wouldn't need to have the St. Joe light set up as a waypoint, it would be clearly marked on the chart. If the chartplotter isn't working then waypoints don't matter at that moment.

Fishing, diving, etc. waypoints of course would need to be stored and backed up. This is one of the reasons that I have always like Garmin units, they have lead the pack on computer interfacing for long time. My 1st choice in a new GPS for the Whaletosh is a Garmin GPSMAP 176. This unit will accept Mapsource, Blue Chart carts, and the forthcoming Blue Chart on CD-ROM. One of the thing that bothers me about the CP-150 is that there won't be any cartography of the inland lakes I boat on. The GPSMAP 176 will allow me to use Blue Charts for the Great Lakes and Map Source for inland lakes. Dan may very well not care about htis as he may boat in an area that is well covered by the C-Map chart he already has, or the base map of the CP 150 is all he needs.

At any rate, it is definately nice to see that chart plotters are finally down to where most people can afford them.

Sean

Dan posted 07-13-2001 09:53 PM ET (US)     Profile for Dan  Send Email to Dan     
The replies contain some fantastic advice! Thanks. I went out on my boat this evening. The GPS didn't turn on until I turned it on -- this time. The CP 150 works very well and I'm happy with it. I got it at West Marine for 399 with a local chip for free (a limited time promotion) -- I kicked in 150 to get the large trip -- covers all of Long Island, NY habor to Block Island. Opened West Marine charge for 10% discount and applied 30$ internet coupon -- with tax the whole thing wound up costing about $525! Still can't believe it. It links to my Standard Intrepid VHF and displays coordinates on my radio and will radio position in distress. The unit is longer horizontally, which makes it less obtrusive on my console. You can get a blank trip for $40 to store favorite spots and other data.

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