Humminbird Shutting Down From Low Voltage

[pcasciola]

I recently installed an 1198c at the console and a 998c up front, along with a small Lowrance unit up front using the trolling motor transducer, and dual Cabela's Advanced Angler AGMs in parallel using a Perko A/B/All switch. I ran all new wiring with new fuses from the existing fuse panel to provide power to the Humminbirds. My problem is, on the 1198c I see a voltage drop of about 1v for each sonar unit, and about 1.5v for each pump (livewell and bilge pump). This quickly gets me down to the 8.5v lower limit when everything is on, which causes the 1198c to shut down, sometimes within minutes of leaving the dock with freshly charged batteries. With everything off except the 1198c, I see about 13.0 - 13.5V on the display, but as I turn each other device on I see about 1.0 - 1.5V less on the 1198c.

I think what might be going on is that the factory wires from the battery to the fuse panel are too small. They appear to be 14-16 gauge, and I'm wondering if this could cause be causing the voltage drop I am seeing, even though we are only talking about maybe 10 feet from the battery to the panel, 2-3 feet to the 1198 and about 10 feet to the 998 and Lowrance. If so, I'm just wondering what the best approach is.

Should I run new 6-8 gauge from the battery to the fuse panel? Run the Humminbird wires directly to the battery with in-line fuses? Install a second fuse panel just for the electronics? I know just enough about electrical to be dangerous, but DC voltage drop is not something I have no experience with so I was just hoping to see how others might have solved this problem, assuming the wire gauge is causing the voltage drop and not a frayed wire or short somewhere.

[The Rooster]

You could upsize the wires but before I would do that I'd go through with some testing. First, disconnect the depth finders and run a test wire straight to the batteries to power them instead. This bypasses the fuse panel so when you turn everything else on, you get a better sense of what might be causing the problems. If the problem goes away then it's probably the wire size like you suspected. If it's still there then you know changing the wire size alone isn't going to solve it.

Also, you can test whether upsizing the wire will help by simply adding an extra run of wire from the battery to the fuse panel along side of the factory wire. Use one large wire or several strands of smaller wire. Doing this is just as good as removing the original and rerunning a new, larger wire. Use jumper cables if you can, they're a fast source of 8 gauge or more wire that is readily available for a fast test.

It's also possible that one or both batteries could be the problem. I do know that when you connect two or more batteries together, in parallel or series, they will try to equal out to each other. So both batteries must be good, or if one is weaker than the other the weak one will end up killing the other one too. Try testing out everything while only connected to one battery and see what happens. Make sure to have full charge first. What makes me think batteries is that you said they start out full charged. A failing battery can read 13.5 volts in the beginning but drop fast as it has no current flow to give. It's like a false charge. A build up of voltage but no "oomph" behind it, in other words.

Lastly, check all of your connections, especially the main wire to the battery, and at the fuse panel. Weak connections cause all sorts of problems and can create erratic behaviors in electronic devices.

[BKeith]

If it was me, I would start checking voltages with a voltmeter first and see where you are dropping voltages.

First, connect the volt meter across the two cables connected to the battery, (do not touch the post) and see if the voltage drops when everything is turned on. If voltage drops, go across the two post and see if it still drops. If it still drops when across the two post, the battery is bad, if it holds a good voltage, one of the two connections are bad on the battery.

If the voltage holds good when connecting across the two cables, leave the negative test lead connected to the battery and start checking the voltage at different points from the positive post to where the sonar is connected. Check the output of the A/B switch, the power switch, the fuse's/circuit breaker etc. Go on each side of every place the wire makes an connection until you find where you are dropping the voltage. Find the point of the voltage drop and you find your problem.

[Wayne P.]

What you are experiencing is very common with the newest electronics. You cannot just use a voltmeter to check for issues. A voltmeter does not put any load on the circuit to indicate there is any issue. The units shut down due to low voltage because of the load (current draw). That means there is enough resistance in the wiring to not provide the current to operate the unit. The unit voltage readout will give you an indication of what the load voltage is.

Humminbird recommends that the power cord be connected directly to the battery and if the cord needs to be extended, use at least 18 guage wire (I used 12 guage marine grade wire) solder the splices and insulate and use a spade type fuse on the positive conductor. Make sure the battery is in good condition and the connectons are clean and tight.

For a bow installation the resistance of the wire itself has to be included in the trouble shooting since the longer a wire is the more resistance it has. Typical boat wiring harnesses do not have large enough conductors to offset the resistance (voltage drop) due to the wire length.

Any junctions in the wiring also add resistance along with any switches. Remove all of that with the direct wiring.

[Wayne P.]

Additional comments:

What some are doing is adding an additional battery for just the electronics or upsizing the starting battery to the largest Dual Purpose that has the MCA that the engine requires.

You are requiring the starting battey to do deep cycle duty by running the electronics, pumps, lights and any other accessories and you normally don't run the engine long enough to even make up for the amps used to start the engine.

The high end electronics are sofisticated computers that are sensitive to voltage issues just like your home computer is.

That issue is discussed quite often on another site by Humminbird and Lowance owners.

[pcasciola]

Thanks for all the suggestions! I finally got around to playing around a bit, and running 14 gauge directly to the battery with an 5A inline fuse did the trick. My batteries were a little down but it read 12.2V with just the rear Humminbird on, and 12.2V even with all the pumps and other fishfinders turned on.

I am going to leave it this way for my trip this weekend, and I think I will rewire it with 8 gauge and a new fuse panel when I get back.

Thank again everyone.