Low Voltage on all electronics??

Marks500

Cadet
Joined
Aug 3, 2008
Messages
7
I have a 2001 Nitro bass boat. The issue I am having is all of my electronics seem to have low voltage going to them ( Nav Lights, Dash Lights, Live Wells, bilge etc). The battery in the boat is good(only 6 months old) and is charging great. The battery starts the motor up no problem so I know it has plenty of juice. The Voltage meter on the dash says its charging at 14 volts when running motor so charging isnt a issue. When I turn my Nav lights on they are very dim, Front and back lights. Dash lights are dim as well. When I turn on the livewell it seems weak, and if I turn on the second livewell at the same time they both just stop. I had to run my fish finders straight to the battery to get them to stay on, when I had them tied into the main power they would flicker on and off. Basically all my electronics dont seem to be getting the proper voltage they need. Or maybe it could be a bad ground? Has anyone ever had this problem? I have no clue where to start, there are a ton of wires under the dash and I dont want to create more problems than I already have lol.... Figured someone could point me in the right direction on what to check. Any help would be great! Thanks
 

GA_Boater

Honorary Moderator Emeritus
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May 24, 2011
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49,038
Flickering FF kinda tells the story - Clean all the connections, both + and -, on the battery including the posts and the feed lines to the dash until they are shiny and bright. Then measure the voltage on the line feeding the dash if the cleaning didn't improve the dimming.
 

Marks500

Cadet
Joined
Aug 3, 2008
Messages
7
Flickering FF kinda tells the story - Clean all the connections, both + and -, on the battery including the posts and the feed lines to the dash until they are shiny and bright. Then measure the voltage on the line feeding the dash if the cleaning didn't improve the dimming.

Thanks, I will give that a try. When you say clean the feed lines are you talking about at the battery or where it does up under the dash? Sorry not to familar with boat wiring but I know basic electrical stuff.
 

GA_Boater

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Yes, both places. The battery and the wire from the battery to some form of fuse block or circuit breaker panel that powers the accessories. I don't know where it is on your boat, the block or panel are often under the dash.
 

roscoe

Supreme Mariner
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Oct 30, 2002
Messages
21,802
Clean and tighten all connections, starting at the battery, until you find the bad one(s).
Clean the negative connections too.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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51,256
by clean, shiny clean, as in clean enough your kids would put the connection in their mouth clean

then when you are done, seal the connections with marine electrical varnish.
 

mike_i

Lieutenant Junior Grade
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Jun 28, 2017
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1,004
I'd also measure the battery voltage and the voltage on the positive buss bar with a digital voltmeter and not rely on a dashboard gauge.
 

Marks500

Cadet
Joined
Aug 3, 2008
Messages
7
Well i cleaned the battery terminals and all the connections really well with a wire brush... I would have eaten off of them. With that there was no change. I followed the wires to fuse panel and cleaned those which were not bad at all. I still got no change. Nav lights are still dim, pumps still sound weak. its kinda overwhelming getting under the dash with all those wires. What would be the next step? I do have a multimeter, something tells me its in one of the main wires before the fuse box?

One other thing I forgot the mention I just thought about . When running down lake when the water is rough and I hit rough water it does make a beeping sound when I hit a wave. Pretty much the same noise it makes when you turn the key and it beeps before starting. Could be a loose connection somewhere?
 
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edit-Insert

Seaman Apprentice
Joined
May 22, 2017
Messages
34
Sounds like a ground fault. Get your meter out and leave all power off. If you don't have a meter with an audible tone on the resistance setting go get one. Its an indespensible tool. Next place the either lead on the positive terminal. The other lead should then be touched to any of the grounding points. If you hear an audible tone then you have continuity which confirms you have a ground fault. If no tone is present. Then turn on the power And do the same testing. If you now get a tone I would start looking at relay failures.

If getting the beep when you hit a wave I would look at the entire wire path. See where it is loose. It maybe has bounced so much that it chafed the wires and rough conditions cause the wires to short.

The only other option I see is to start the motor up. Turn on the electronics and disconnect the negative lead from each device one at a time until power returns to normal. If you take your fish finder off last and the problem is fixed, then start putting them back on in the order you removed them.

The point of this is to determine whether the fault is caused by a device or by the positive negative trunk. If the fault comes back on the first device you reconnect then you know it's a trunk issue.

To find the trunk failure. Disconnect the negative lead of the battery and the negative lead of the first place that wire terminates. Run a jumper wire of the same gauge (i like to use an extension cord with the ends cut off). Now you connect from the negative lead in the battery to the first connection made by the negative trunk, presumably the bus bar. What we are accomplishing is replacing the trunk negative with a known good piece of wire.

If that still doesn't find it then you need to do the same with the positive wire. It is a lengthy process but is the sequence I use when installing low voltage security systems that can span across entire college campuses. They are the same 12 volts. Except my boat is a lot bigger. I also make sure to have extra conductors over long or difficult runs.

One other thought. Maybe quicker for you. Start everything up and leave engine in idle. Measure voltage from the bus bars. Turn on one device. Then measure voltage. I don't know much about the charging system of boats, but I think you would want to rule that out first. And as another reply stated don't rely on gauges. If you have an electrical diagram of your boat, post it and I'll help you determine test points.
 

edit-Insert

Seaman Apprentice
Joined
May 22, 2017
Messages
34
Remember it's only 12 volts and it is direct current. The logic of DC is much easier to understand in my opinion. If you aren't familiar then do the DC theory wiki.
 
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