Fish finder puzzle

[Lively1]

My Garmin 551C is acting strange. I have two power cords, one for a battery pack for the canoe, and another hardwired to the boat cranking battery. It operates normally when connected to the battery pack, but won't turn on when plugged into the boat. This started a few weeks ago when I was out on the boat going along and it suddenly quit, and hasn't run since, in the boat.. But continues to operate fine from the other power source. I did wire in a float switch for the bilge pump and upgraded the radio a few days before this happened.. they both appear to be operating normally.

 

The strange thing is, my voltmeter shows 14 volts across the pins on both plugs (boat and canoe), so I think the wiring to the unit is good; no blown fuses, shorted wires, etc.  And I know the unit works OK.

 

What should I check next?

[lakebound88]

Check that 14 volts under load. For example use a test light or a bulb of a sort. If it's getting voltage but not amperage, it will not work properly. Don't rule the fuse out. Be sure to double check

Sent from my SCH-I545 using Lake Ontario United mobile app

[Rich s]

I don't know how others wire up their sonar units but I made what I believe a mistake of wiring my unit to the main (starting ) battery..  What happened was that any variation in amperage such as starting the boat, the unit shuts off and I have to restart the unit.. 

I haven't switched it to the accessory battery yet but  I don't think the downriggers , lights or radio would cause enough amp draw to affect the unit  as would the starting battery does.  

 

Question:

Did the unit operate properly on the boat before ? If so did it just start once you put the auto bilge switch in ?  

If so then you need to dissect the issues one thing at a time , it could just be a grounding problem...

Good Luck:

Rich

[muskiedreams]

You most likely have a poor connection somewhere between the battery and the Garmin.

 

You can try just wiggling every connection (both 12 volt and ground) from the battery to the Garmin one at a time and then see if it turns on. If it does, wiggle the same connection again to see if it causes it to shut down. The voltage may read fine until you try to turn the unit on. Once you turn it on and there is a current draw, a poor connection can cause a substantial voltage drop which will cause the unit to shut down again. If that happens, replace, repair or clean corrosion at that connection. keep in mind that copper wire that does not have a shiny copper look is corroded and will need to be cleaned with sandpaper or scotch brite pad before making a connection to it. All connections must be tight and clean of corrosion. You can use sand paper or a scotch brite pad to clean corrosion. If a connection is loose, you might be able to tighten it up by squeezing connector with pliers to give a tighter fit. Sometimes connectors that are crimped to wires can be just a  little loose (almost not noticeable). Keep in mind that there can be more than one poor connection so if you find a problem, go through the same procedure and check every connection again.

 

Another thing you can do is just inspect and clean and/or replace/repair every connection between the Garmin and the battery. If it is at all questionable, replace, clean and/or repair it. Sometimes a connection can look ok but if it is a little loose or there is a slight amount of corrosion, that could be a problem. In a boat there can be multiple connections causing the same problem and this is not uncommon because of the environment. It is not a matter of if you will have these kinds of problems. It is a matter of when. You can be proactive and check for these kinds of problems periodically. It can be a real problem if your boat's running lights fail to operate and you don't find out until you need them.

 

A voltmeter might help you to isolate or verify a poor connection but it will not necessarily show a drop in voltage unless current is being drawn by the Garmin at the time of measurement.

 

Every electrical connection is a potential point of failure. There are methods that are used to help seal and protect connections from the harsh environment which can help greatly.

[muskiedreams]

I don't know how others wire up their sonar units but I made what I believe a mistake of wiring my unit to the main (starting ) battery..  What happened was that any variation in amperage such as starting the boat, the unit shuts off and I have to restart the unit.. 

Rich, if that happens,

1) the battery is weak or of insufficient rating for the starter

2) the starter is drawing too much current for some reason

3) the wiring to the fish finder is inadequate

Or a combination of the above.

[Rich s]

Since we are on the subject, I posted that my fishfinder/sonar/gps unit shuts off when I start the motor due to what I think is to much amp draw from wiring to starting battery.. I have an I/O 4.3..

 

Where do most get power source from to the unit ? Starting or deep cycle accessory battery ? This will also help me resolve my issue (connections)  / complaint

Thank You

Rich

 

EDIT:

 I posted while you responded,

1.New starting battery and checked with meter on out put from alt & regulator  also load amps to starter.

2. New lowrance  elite-7 , new cable/wire connections, it has done this right outta the gate.. (old lowrance unit didn't shut off, but im sure it was far less sensitive to an amp spike) ..

3. Do most cabin/dual battery boats wire to accessory battery or main starting battery for their unit ?

Thanks:

Rich

Edited June 8, 2015 by Rich s

[Xxx]

Check that 14 volts under load. For example use a test light or a bulb of a sort. If it's getting voltage but not amperage, it will not work properly. Don't rule the fuse out. Be sure to double check

Sent from my SCH-I545 using Lake Ontario United mobile app

This is probably your issue, do the same with the ground, it could be that your ground is loose or dirty, a bad ground will create a heavier amp draw and that's what's causing a weak link to come into play with a power loss, even though your reading 14 volts with a digital meter. If you have a tail light assembly hook that up to your power source and see if the light comes on and use the ground source of the finder, should be nice and bright, if not use processes of elimination until problem solved? Edited June 8, 2015 by pap

[Lively1]

Thanks guys.  Your comments make me realize I might as well bite the bullet and rewire all the accessories to the other (deep-cycle) battery. I was planning on doing it sooner or later.. it might solve the fishfinder issue at the same time.

 

All the accessories are fed from a fuse box with one power lead coming in. Question: Can I just move the red power lead from the cranking battery to the trolling motor battery (only), or do I also need to move the ground wire (black side) from wherever it is connected now, to somewhere else (like the black/neg terminal of the trolling motor battery)?

 

Thanks

[Rich s]

You need a ground wire in the same circuit . You can do as you describe and run a black ground from starting battery across to accessory battery , just make sure it is at least 10 gauge wire , even 8 gauge would be better