GPS flakes out when I restart engine

[JASinIL2006]

Hi, I have a Humminbird 385ci GPS+Fishfinder on my boat. I use this not only as depth finder but also for the GPS speedo feature, which is really nice when I'm pulling skiers or tubers. I really like this unit, but every time I turn off the engine (i.e., to allow a skier to climb in or out of the boat), the GPS feature stops working -- it freezes and won't display a speed unless I power-cycle it.

The GPS is powered through an always-on circuit, so it doesn't power off when I shut off the boat. (The GPS/fishfinder only turns off if I manually shut it down.)

I figure something about starting the boat is causing a power spike or dip that interferes with the GPS; has anyone else experience this? Is there any sort of filter or similar device that might insulate the unit from whatever is causing the GPS to flake out? I do have a secondary battery in the boat; the only thing hooked up to it is my backup bilge pump, and the battery has to be manually charged before I go out (it's not connected to the alternator at all). If absolutely necessary, I could get an add-a-battery kit and use the secondary battery to power the GPS, but I'm hoping there is a simpler (and cheaper) solution.

Any ideas?

Thanks,
Jim

 

[jhebert]

Re: GPS flakes out when I restart engine

Believe me, there is no effect on the Global Positioning System when you start your outboard engine. It's up in space and it does not "flake out." What you describe sounds like the battery voltage in your engine cranking battery is sagging. If you are trying to run your boat electronics from the engine cranking battery, you will have to endure those devices rebooting themselves when the voltage you provide them sags too low. If you don't want all the electronics on your boat to reboot every time you crank over the engine, run the electronics from a separate battery.

 

[bruceb58]

Re: GPS flakes out when I restart engine

Believe me, there is no effect on the Global Positioning System when you start your outboard engine. It's up in space and it does not "flake out."

When are you going to get over saying this all the time? You the GPS police?

Gps - Definition and More from the Free Merriam-Webster Dictionary

: a navigational system using satellite signals to fix the location of a radio receiver on or above the earth's surface;
also : the radio receiver so used

 

[bruceb58]

Re: GPS flakes out when I restart engine

To the OP...My GPS reboots when I start my engine if its any consolation. I have a Lowrance.

 

[JASinIL2006]

Re: GPS flakes out when I restart engine

Sigh... Obviously I didn't think my boat was affecting the GPS satellite system... I was using the colloquial 'GPS' to refer to my GPS receiver. :facepalm:

What's puzzling is that only the GPS function (of MY unit, not the satellite system in orbit over the Earth) is affected; the unit's display doesn't flicker, the depthfinder works....

Maybe I will just isolate it from the starting battery.

Jim

 

[Bondo]

Re: GPS flakes out when I restart engine

Hi, I have a Humminbird 385ci GPS+Fishfinder on my boat. I use this not only as depth finder but also for the GPS speedo feature, which is really nice when I'm pulling skiers or tubers. I really like this unit, but every time I turn off the engine (i.e., to allow a skier to climb in or out of the boat), the GPS feature stops working -- it freezes and won't display a speed unless I power-cycle it.

The GPS is powered through an always-on circuit, so it doesn't power off when I shut off the boat. (The GPS/fishfinder only turns off if I manually shut it down.)

I figure something about starting the boat is causing a power spike or dip that interferes with the GPS; has anyone else experience this? Is there any sort of filter or similar device that might insulate the unit from whatever is causing the GPS to flake out? I do have a secondary battery in the boat; the only thing hooked up to it is my backup bilge pump, and the battery has to be manually charged before I go out (it's not connected to the alternator at all). If absolutely necessary, I could get an add-a-battery kit and use the secondary battery to power the GPS, but I'm hoping there is a simpler (and cheaper) solution.

Any ideas?

Thanks,
Jim

Ayuh,.... My guess is it's voltage drop,...

Usin' the other battery should fix the issue,...

Get a switch to charge both batteries,....

 

[Thalasso]

Re: GPS flakes out when I restart engine

To the OP...My GPS reboots when I start my engine if its any consolation. I have a Lowrance.

Then it's wired wrong because i have a Lowrance LMS520C and it doesn't do that

 

[bruceb58]

Re: GPS flakes out when I restart engine

Then it's wired wrong because i have a Lowrance LMS520C and it doesn't do that

Depends on how much voltage drop you get. Every boat will be different and it will be different depending on where you grab power.

I happen to have the LMS520C as well.

I know many people that turn all their electronics off before they start the engine. Not a big deal to me.

 

[dan t.]

Re: GPS flakes out when I restart engine

Yep my Standard Horison GPS and my Lowrance fish finder both flake out on restart, voltage drop, I dont worry about it.

 

[Thalasso]

Re: GPS flakes out when I restart engine

Maybe mine is supplied by the house battery. I have three. My engines have there own

 

[Splat]

Re: GPS flakes out when I restart engine

You can also try a 1F capacitor and diode in line. The current draw on the GPS should be low enough to allow a 1farad cap to supplement power for the second or two during engine cranking.

 

[bruceb58]

Re: GPS flakes out when I restart engine

You can also try a 1F capacitor and diode in line. The current draw on the GPS should be low enough to allow a 1farad cap to supplement power for the second or two during engine cranking.

Severely doubt it would do a thing. You have the added problem that it would drain your battery unless you switch power to it. No capacitor is perfect and you will have resistive leakage. Audio people seem to think these are great band aids to put on a car stereo. The truth is they do nothing.

 

[jhebert]

Re: GPS flakes out when I restart engine

Maybe I will just isolate [the electronic device] from the starting battery.

That was my recommendation. You never know in what sort of situation you might be in on a boat when you have to suddenly start your engine, and to lose all your electronic devices--GPS receiver, chart plotter, depth sounder--while they rebooted might be very inconvenient. I think it is an important safety consideration to make boat electronics operate correctly during engine starting.

 

[marine 1]

Re: GPS flakes out when I restart engine

Constant rebooting from voltage drops is one of the worst things you can do to your electronics. Newer boats are now coming out with all the navigation tied to the house bank but I rewire at least a dozen boats a year to isolate the electronics. Add the extra breaker and fuse panel to the house bank to avoid this problem.

 

[jhebert]

Re: GPS flakes out when I restart engine

Constant rebooting from voltage drops is one of the worst things you can do to your electronics.

Yes. I agree completely. It is insane to buy a $2,000 electronic device and then torture it with voltage transients, sags, and drop outs. That is why I recommend running the electronics on your boat from a battery that is isolated from the engine starting circuit.

 

[Splat]

Re: GPS flakes out when I restart engine

Severely doubt it would do a thing. You have the added problem that it would drain your battery unless you switch power to it. No capacitor is perfect and you will have resistive leakage. Audio people seem to think these are great band aids to put on a car stereo. The truth is they do nothing.

True, however once saturated the draw should be minimal.

They do nothing, I wouldn't completely agree with that, they sure don't work like most people think they work, they create no power as many people believe.

 

[bruceb58]

Re: GPS flakes out when I restart engine

Of course they don't create power...they store energy. The more I think about it and running a few calcs, the capacitor may work but I would love to see the size diode you would need to handle the inrush current for a 1F capacitor that had leaked down. Not even going to talk about the wire and fuse that needs to be sized accordingly. You will be looking at current way over 30A which is more than the current cabling to the helm I am sure.

As far as the voltage sag damaging electronics, probably not a huge issue. If it was, your vehicle's engine computer wouldn't survive it either.

Best solution is to run the electronics on a second battery if you don't want it to restart.

 

[JASinIL2006]

Re: GPS flakes out when I restart engine

Until I installed the second battery for my backup bilge pump, everything on this boat ran off the starting battery, just like on a car, I suppose. It never seemed to be a problem until I bought this new GPS+fishfinder combo. Before the current model, I used an auto GPS in the boat for its speedometer function (trying to be careful while pulling kiddos on the tube, and the pitot-based speedometer doesn't seem very accurate). The auto GPS didn't have this problem, and I'm wondering if that's because it has it's own internal battery that keeps everything working even in the case of power sags.

In any case, it seems the easiest solution is to isolate the GPS unit from the starting battery, so I guess that's what I'm gonna do...

 

[jhebert]

Re: GPS flakes out when I restart engine

As far as the voltage sag damaging electronics, probably not a huge issue. If it [were], your vehicle's engine computer wouldn't survive it either.

Because one electronic device has been designed and manufactured to tolerate a wide range of operating voltage does not imply that all electronic devices will.

 

[bruceb58]

Re: GPS flakes out when I restart engine

Because one electronic device has been designed and manufactured to tolerate a wide range of operating voltage does not imply that all electronic devices will.

Agreed, but I disagree about your statement that a voltage sag will cause damage. If that were the case, there would be warnings in the specs. There aren't any.