Boat problems - please help

To me this is really weird but im hoping this has happened to someone and they can provide an answer. Recently everything worked on the boat except the front navigation light. I thought I would just get to it when ever since I really dont get out that early these days. Then about 3 weeks ago, the same light wasn't working up front but also the bilge pump and live wells wouldn't turn on but only when I was on the water. At home, off the water, all items worked except the front navigation light worked like I mentioned.

A week ago when I would try and turn on the live wells or bilge, it would intermediately shut off my depth finders. Again, only when im on the water.

As of yesterday, I dropped the boat in the water and no electronics would turn on as well as none of the bilge, live wells, lights etc. No electronics.

I get home last night and hook the boat back up to the charger and EVERYTHING except the front navigation light worked like before. I even turned my bilge, live wells and depth finders on at the same time they worked.

Please help. I hope this makes sense.

how old is your battery?

Likely the battery but could be a ground problem somewhere. Checking the battery across the terminals with a volt meter does not always tell the story. Sometimes they will show 12V doing that but will not have 12V under a load.

Wayne

Starting and 3 others are all 2019 batteries and have stayed charged.

I bought these back in Q3-Q4 and just started having this problem. Could that still be the batteries?

Im feeling like a ground problem also.

I would love to fix this on my own vs taking to a shop. Especially in March....

The first thing that I would do is gte the battery load tested. If it is good then start checking connections.

Sounds like a bad battery. The depth finder is voltage sensitive and any voltage drop will shut it off. Is this battery also your starting battery?

Well with all the battery’s being pretty new, and this is a come and go issue. A connection problem is what it sounds like to me. I had a similar issue on a boat in the past and I ended up replacing the fuse block panel. Corrosion on the terminals inside was causing me to loose power to lights, pumps ect. I would start at the battery checking connections and looking for any green corrosion build up. A good grease on all terminals is the way I go. With boats all the light pumps, electrical ect have a positive and a ground to every device. The common point is in your dash. This could be the plug in the main wiring harness. I have seen that too. That bow light not working could help you locate the issue! It’s hard to find a problem that comes and goes. Now if the stern light works then there might just be an issue with the bow light. A test light goes a long ways. The new ones show red and green for neg/ positive. This will help in hunting an open circuit. What other said are true too. Depth finder shut off under low voltage. But for you pumps to work some time and not others? That’s saying connection issue. But a load test it free at any auto parts store. Never know. Good luck! I love troubleshooting! Just not while I’m trying to fish! Lol

About 10 minutes ago, I had everything on except the front nav light, twisted one of the nuts on the battery and it shut all of my electronics down on the boat (to be expected). Voltage on the starting battery was 13.2 and has a 11/19 sticker on it so its not old.

If you have wing nuts on your battery’s replace them with stainless hex nuts with flat and lock washers. I have seen too many wing nuts work loose!

This ^^^^

Wayne

Sounds like a grounding issue.

Voltage on a battery is fairly meaningless if there is no load. A fairly wrecked battery can still "look good" measured at rest.
Before you remove the battery, I want to ask this question: What outboard do you have, and will it start readily with that starting battery? This may be sufficient evidence to negate the hassle of taking the battery out to get a load test. If you're starting a big outboard with no issue, you probably don't have a bad battery. Yes, others are correct that electronics can dropoff when there's a weak battery, but in your case you have many other issues in common. That makes it a connection issue.

You say you "twisted one of the nuts on the battery". With your hand? Are you implying it moved? If it moved, that's bad. Hand-tight wing nuts are NOT tight for this application. They should be tight enough nothing moves, and there should be no corrosion. As suggested, you need stainless-steel nyloc nuts on these terminals. Many outboard manufacturers require them. A loose connection can cause a lot of damage to the outboard electrical system in some cases, so you need this regardless of the current problem.

I'm going to guess you tie your power for electronics into pwr/ground under the dash. This may work, but it's not a great approach for reasons we don't need to discuss right now. But, if electronics get power under the dash - as do all those other things - do you see the common point of failure? There are wires at the battery for +/- that go to the dash, where a sometimes mess ties everything together. I'd be looking for trouble at one end of that wire run or the other. In other words, at the battery, or where those wires go TO under the dash. Start with the stainless locknuts, and make them snug. There are two common nut sizes: 3/8" and 5/16". Some batteries have one of each to help avoid getting polarity reversed if the correct ring terminals are installed on the wires. Take the wing nuts with you if not sure what you have.

Does your anchor light get flaky when the bow light gets flaky? If it doesn't, that tells us something. Both lights get positive power from the same source through the light switch, so if they act differently, then your problem is on the GROUND side of circuits. This is noted from common power, but separate grounds for each light. Ground is typically black wires on a boat if the standard boat wiring code was followed. Look for loose connections or corrosion at points of +/- under the dash. Have the light on and someone watching as you "fondle" connections under the dash to isolate the area of the problem.