GPS Freezes/Powers Off on Start

[Grizzly65]

My Hummingbird Fishfinder/GPS combo is freezing and/or turning off about every other time I start the engine. It is currently hooked to the accessory switch on the electronics panel. Do I need to run a wire directly to the Battery switch or is there another place to tie into on the panel that will not be affected by the engine start?

[fitz73222]

Hey Grizzly,

First, check your battery voltage and general condition. Charge your battery, wait a day and check the standing voltage. It should be 12.3-12.6 volts after 24 hours. How is your engine cranking? Is it slow and laboring? If the battery voltage checks OK it still doesn't rule out a load issue or a weak cell but it points you in a direction. Your engine starter could be drawing excessive amps or you have corroded connections or bad cables. Check the voltage at the Humminbird power connection and see how much it drops while starting the engine. You'll need two people for this. One to turn the key and one to watch the VOM meter at the power connections while the engine turns over. Make sure all the connections to the Humminbird are clean. I don't think your depth finder will work below 9.5 volts which could cause the freeze up or shut off. I don't think you have a depth finder issue, but a low voltage issue revealing itself from another root cause.

[gran398]

Agree.

Electronics require a full 12V+ to power up.

You'll see it across the board....especially new model VHF's.

Check the working voltage to your panel first. If the batts test good and your electrical system is in good order (clean terminals, good wire, maintained as Fitz suggests)....a solution may be to run lower gauge wire to the panel from the feed.

[Circle Hooked]

How old is the unit ?

[Bergertime]

Grizzly

I had a somewhat of a related issue but it was with my VHF radio.  When I keyed the mic running on batteries w/o anything else on including the engine I was getting a low battery alarm and my VHF radio would shut down and re-start. Doing my research revealed that the particular type of radio that I have is more sensitive to low voltage than others. When I tested the voltage drop when the mic was keyed at my bus in my e-box it was dropping from mid 12s to low 11s which was likely triggering the alarm and causing the problem.  I ended up running a dedicated wire from the power bus under my helm to the switch that feeds the ebox.  This seemed to have fixed the problem along with replacing the bus in the ebox which was starting to get corroded.  I still think I need to replace my batteries though.. My newest is over 2 years old.

Interestingly - I purchased the radio I have now new less than a year ago and it never had this problem (sudden power off when mic keyed) until about a week ago.  Nothing has changed in my ebox or the wiring.  Still curious why this condition would start now and the only conclusion I have is my aged batteries.  However, the re-wiring above fixed the issue with all the other variables remaining constant.  Planning on replacing the batteries soon anyway as a part of my maintenance schedule.

B

[Capt. Bob]

Leaning on what has been already been posted, your 200 is probably drawing somewhere in the neighborhood of 170 amps while cranking. Any of the "things to check" listed could cause a big drop in voltage supplied to your accessory side feed.

Good luck.

[Bergertime]

Bob-

Interested in your thoughts..  If my batteries are starting my boat sufficiently would a standard VHF in 25 watt transmit mode be enough to create a meaningful drop in system voltage?  Seems two deep cycle bats in good condition would be fairly blind to VHF usage. I guess I would assume the power needed to run the VHF would be small in the scheme of things compared to pumps, chartplotter, radar etc..  What ya think?

The manual says power requirement 25 watts output are: 6A@13.8V DC

-Bruce

[dburr]

Low voltage Bruce can also be caused by inadequate wire size. Two deep cells in parrallel would not take a lot of notice of a 6 amp radio, unless the bats are sick.  How do they test on a hydrometer?  Just because you see 12.8 doesn't mean they can hold that if the electrolyte is breaking down or the cells are getting clagged up and that is hard to see with just a meter..  My whaler battery is like that.. Charges up great, holds 12.5-12.8 but put a hard load on it and fuggetaboutit.  20 second crank and she's done... Tests low with the hydro too, so you'd think I'd replace it?!?!..     Next season..

 What size wire do you feed the ebus with?  There are a bunch of resources out there available on Google for wire size calculators/charts and voltage drop calculators..  That would be a place to start, and then get handy with the meter.  It will surprise you how much you will lose voltage wise due to increased resistance of corroded or to small wire.  If it calls for 16 and that's what you have, that doesn't allow for any circuit additions and it it easy to get in trouble adding stuff.  Just turn up the toons and watch what happens.


This link will help with size:
http://www.engineeringtoolbox.com/amps-wire-gauge-d_730.html

Try this link to get line loss:
http://www.supercircuits.com/resources/tools/voltage-drop-calculator

Good luck

[Capt Matt]

Check out your inline fuse and fuse holder, had this happen to me a few times on different units, the ones that come with the unit don't last long as they are spring loaded
Easy fix if that's it
Capt Matt

[Capt. Bob]

Bob-

Interested in your thoughts..  If my batteries are starting my boat sufficiently would a standard VHF in 25 watt transmit mode be enough to create a meaningful drop in system voltage?  Seems two deep cycle bats in good condition would be fairly blind to VHF usage. I guess I would assume the power needed to run the VHF would be small in the scheme of things compared to pumps, chartplotter, radar etc..  What ya think?

The manual says power requirement 25 watts output are: 6A@13.8V DC

-Bruce

 Bruce,
Meaningful? Well it's measurable.

Take my boat.
12 volt AGM battery showing a 12.67 volt state of charge will drop to about a 12.48 v indicated when you transmit at HI power (25 watts). That's a 190 millivolt drop.
Doesn't sound meaningful in that context but....

The round trip of center console mounted batteries can (depending on the length of the hull) run 30 feet. Take the standard 2 AWG battery cable size, use the 170 amp cranking draw and you can realize a 13+% voltage drop. That equates to a supplied battery voltage of 10.4 v when cranking. Using an 8AWG supply wire to your accessory buss (total run of 10 feet) and the supplied voltage at your radio (or depth sounder/GPS) can drop to 10.3v or so. Remember, this is based on excellent connections and wire condition plus as mentioned before a really healthy battery.

If, as stated, 9.5 volts is a threshold, poor/corroded connections and/or wiring, not to mention an aging power source greatly increases the chances of crossing that threshold.

So is .20 volts meaningful?
In a robust system, no but when instrument failure occurs like Grizzly's, it should be looked at as an indicator to the overall health of the system.

[gran398]

Bob-

Interested in your thoughts..  If my batteries are starting my boat sufficiently would a standard VHF in 25 watt transmit mode be enough to create a meaningful drop in system voltage?  Seems two deep cycle bats in good condition would be fairly blind to VHF usage. I guess I would assume the power needed to run the VHF would be small in the scheme of things compared to pumps, chartplotter, radar etc..  What ya think?

The manual says power requirement 25 watts output are: 6A@13.8V DC

-Bruce

 Bruce,
Meaningful? Well it's measurable.

Take my boat.
12 volt AGM battery showing a 12.67 volt state of charge will drop to about a 12.48 v indicated when you transmit at HI power (25 watts). That's a 190 millivolt drop.
Doesn't sound meaningful in that context but....

The round trip of center console mounted batteries can (depending on the length of the hull) run 30 feet. Take the standard 2 AWG battery cable size, use the 170 amp cranking draw and you can realize a 13+% voltage drop. That equates to a supplied battery voltage of 10.4 v when cranking. Using an 8AWG supply wire to your accessory buss (total run of 10 feet) and the supplied voltage at your radio (or depth sounder/GPS) can drop to 10.3v or so. Remember, this is based on excellent connections and wire condition plus as mentioned before a really healthy battery.

If, as stated, 9.5 volts is a threshold, poor/corroded connections and/or wiring, not to mention an aging power source greatly increases the chances of crossing that threshold.

So is .20 volts meaningful?
In a robust system, no but when instrument failure occurs like Grizzly's, it should be looked at as an indicator to the overall health of the system.

Good stuff.

For the  VHF....you'll know you're without adequate working voltage when you key the mike on 25 watt (high power) transmit.

 If it fails to transmit, and returns to default mode "monitor"....you have voltage drop issues. Time to rewire the feed.

[Mcdiver]

Another possibility to check.  I had a similar problem. Checked the entire system and all was well.  For whatever reason, I replaced the switch on the helm and problem went away.

[Bergertime]

Thanks all for the suggestions and info!  As far a my VHF I think that I have resolved the issue by a simple re-wire and new buss up in the ebox but what struck me as odd is that this problem just started out of the blue and existed when nothing else is running or on with both batts active.  I guess that kinda scream's a power supply issue which my solution seemed to fix.

My boat is 15 years old and much of the wiring is original or looks that way plus the PO did not subscribe to creating quality electrical connections on anything he touched.  I still find junk crimp-on connections that are not sealed and in various stages of decomposition. There was even crimp on "non sealed" connections in the bilge supplying the bilge pump/float switch and trailer brake lights..  uggh!  I have already replaced and re-wired (with sealed connectors) both ground busses and both + busses at the helm and ebox.   I fix others as I go but I still think that I need to replace both group 24s as the newest is from 7/2011.  

That begs another ?...  What is the conventional wisdom about group 24s or larger.  Seems that a boat my size would have larger batts?  I don’t have a windless or trolling motor, however, I do run my live-well and some electronics for extended periods of time when offshore or at the sandbar.   Is there a meaningful need to move to a larger deep-cycle or is it overkill?  Guess too much battery capacity could never be overkill but the cost difference is there.  A group 29 is twice the cost of a group 24 which in my case, needing 2, would be over $100.

B

[Capt. Bob]

I have run Group 27's since 96 and they seemed to have worked well. I'm still running a 27 Gel that was purchased in 2002 from WM. It doesn't crank as well as it use to and at the end of a long day, it gets (like its owner) a little tired. I had two Gels on board but recently replaced one with a Group 31 AGM. The 31 fits in the battery box but weighs "several" pounds more. The Gels have priced themselves beyond even my strange rational for such things so I went with the AGM.
 
The 31 cranks the motor well and is still frisky at the end of the day. The newness and the larger capacity of course is the reason. Also, the vibe is that Gels are suspect to failure when not properly charged. I would venture a guess that the charging system on a 91 Yamaha 200 is not the best device for said charging but apparently no one explained that to my old gel. Proper charging while not running (in the yard) is the key to extended life.

I also found that the larger gauge cables (2/0) I ran has helped in getting the voltage back to the batteries and supplying them with juice during the day. Less voltage drop from the battery to the starter and from the charging circuit back to the battery.

I still use deep cycle batteries (both) and use only one battery per trip, rotating to the other on the next trip. Old school but it still seems to work as long as the system is in good shape.

You must ask yourself where you want to spend your coin. A big screen GPS/sounder, stereo, speakers, cooler, fishing gear etc. any of which will be just what the doctor ordered when you need to crank that motor. Knowing how you use your boat is the best indicator to your battery needs. Group 27s should work well based on your description of use. Boaters like the axiom, "you can never have too much horsepower" but alas, that's not always true. I would think that you should replace "horsepower" with "battery capacity" and you would have a much more concrete saying.
 
Good luck.

[Bergertime]

Thanks.. I may bump up to 27s.. It would be an extra $40 for two.  Thanks again Bob.


B