Electrical woes

[Petro206]

Hello Ericonsites. So we've had this 34T for a full year now. In that time, somehow we managed to get the Reverse Polarity light to turn on, and can't get it to turn off. And now the latest, the DC panel is completely dead.

The amp meter next to the panel was reading dead batteries, so we took them out and had them tested. Fully charged on both. Put them back in, still dead per the meter read. None of the 12v systems work, bilge, blower, lights, all dead, as is the starter.

The heater runs direct off the battery from what I've seen, and it has power, so I'm leaning towards a fuse or the red battery master switch is dead. Is there a fuse panel somewhere that I'm missing, or is it just the inline fuses per each cable?

The only changes we've made to the electrical system is installing a Smart Plug to replace the standard shore power turd plug, and two of the cabin interior outlets. These are wired correctly per my Receptacle Tester.

This is a 1978 34T with an Atomic 4 engine and just the two batteries.

Thank you.

 

[Frank Langer]

Hello Ericonsites. So we've had this 34T for a full year now. In that time, somehow we managed to get the Reverse Polarity light to turn on, and can't get it to turn off. And now the latest, the DC panel is completely dead.

The amp meter next to the panel was reading dead batteries, so we took them out and had them tested. Fully charged on both. Put them back in, still dead per the meter read. None of the 12v systems work, bilge, blower, lights, all dead, as is the starter.

The heater runs direct off the battery from what I've seen, and it has power, so I'm leaning towards a fuse or the red battery master switch is dead. Is there a fuse panel somewhere that I'm missing, or is it just the inline fuses per each cable?

The only changes we've made to the electrical system is installing a Smart Plug to replace the standard shore power turd plug, and two of the cabin interior outlets. These are wired correctly per my Receptacle Tester.

This is a 1978 34T with an Atomic 4 engine and just the two batteries.

Thank you.

Regarding reverse polarity, have you tried plugging your shore power cord into a different receptacle on the dock? If your light stays on, does the owner of that other boat have his reverse polarity light on too? That will tell you if the fault is on the docks or on your boat, I think. Have you made any other changes/new connections in your A/C electrical system that you might have forgotten? Also does your tester show reverse polarity in the first plug in receptacle after your shore power?
Regarding your DC system, I would start from the batteries, which you have tested to be good, and follow the wiring to look for fuses and all connections you find to look for blown fuse, burnt look to the wire connections, loose or corroded connections. I would also look at connections inside the red battery switch.
I'm not an electrician or expert, but that's what I would do. Others may chime in with additional or better suggestions.
Let us know what you find. Good luck!
Frank

 

[Petro206]

Regarding reverse polarity, have you tried plugging your shore power cord into a different receptacle on the dock? If your light stays on, does the owner of that other boat have his reverse polarity light on too? That will tell you if the fault is on the docks or on your boat, I think. Have you made any other changes/new connections in your A/C electrical system that you might have forgotten? Also does your tester show reverse polarity in the first plug in receptacle after your shore power?
Regarding your DC system, I would start from the batteries, which you have tested to be good, and follow the wiring to look for fuses and all connections you find to look for blown fuse, burnt look to the wire connections, loose or corroded connections. I would also look at connections inside the red battery switch.
I'm not an electrician or expert, but that's what I would do. Others may chime in with additional or better suggestions.
Let us know what you find. Good luck!
Frank

Great ideas Frank, I'll check on those!

 

[Tin Kicker]

If the power delivered to the dock is the problem then others on the dock should have the same issue, so I'd start by asking others. Next, I'd stick atemporary leads from your polarity tester into the dock outlet. After this you are looking at boat issues.

Since installing the Smartplug seems to have been the first thing, then logic suggests it's the problem. Rather than disassemble the plug, unplug it and leave ALL breakers open then switch the two leads to the top of the 30A master breaker. Plug the Smartplug back in (leaving ALL breakers open) and the polarity light will quickly tell whether the problem is upstream. Then put the two leads back as originally found. If there's still question, you may run the boat to a different slip on a different dock.

With respect to the 12V, start by checking to see if there is continuity from the 12V terminal at the batteries to the 12V connections on the back of the rotary battery switch. I'm wondering if your boat has a battery fuse which has either broken or tripped and they look like this so are easy to overlook:

Battery Terminal Fuse

Marine Rated Battery Fuse is a battery terminal fuse that will protect your wire and cable runs from the battery. In stock, fast shipping and low prices!

www.boatwireusa.com

Then check continuity from the battery negative post to the engine block. Circuits need both sides (+&-) to work.

 

[Petro206]

If the power delivered to the dock is the problem then others on the dock should have the same issue, so I'd start by asking others. Next, I'd stick atemporary leads from your polarity tester into the dock outlet. After this you are looking at boat issues.

Since installing the Smartplug seems to have been the first thing, then logic suggests it's the problem. Rather than disassemble the plug, unplug it and leave ALL breakers open then switch the two leads to the top of the 30A master breaker. Plug the Smartplug back in (leaving ALL breakers open) and the polarity light will quickly tell whether the problem is upstream. Then put the two leads back as originally found. If there's still question, you may run the boat to a different slip on a different dock.

With respect to the 12V, start by checking to see if there is continuity from the 12V terminal at the batteries to the 12V connections on the back of the rotary battery switch. I'm wondering if your boat has a battery fuse which has either broken or tripped and they look like this so are easy to overlook:

Battery Terminal Fuse

Marine Rated Battery Fuse is a battery terminal fuse that will protect your wire and cable runs from the battery. In stock, fast shipping and low prices!

www.boatwireusa.com

Then check continuity from the battery negative post to the engine block. Circuits need both sides (+&-) to work.

Thanks Tin,

So the Smart Plug came in after the fact from the Rev Polarity, but the previous plug had a burn mark in it, so we wanted to get that replaced asap. We have two plug-ins at our locker for our slip. I tried plugging into the other one last night, and the light remained on. We'll talk to the harbormaster and some neighbors today, and use the multimeter to test the polarity.

Not sure if this changes anything, but the RP light stays on whether I shut off the main power switch or not. In other words, it only turns off when I unplug the shore power cord.

As for the 12V, I took the battery switch off last night, tested it, cleaned it....it checks out. So I feel like it's a fuse thing, but we've tested the fuses and can't find any issues so far. I've attached a few snap shots of this rats nest.

 

[Frank Langer]

Thanks Tin,

So the Smart Plug came in after the fact from the Rev Polarity, but the previous plug had a burn mark in it, so we wanted to get that replaced asap. We have two plug-ins at our locker for our slip. I tried plugging into the other one last night, and the light remained on. We'll talk to the harbormaster and some neighbors today, and use the multimeter to test the polarity.

Not sure if this changes anything, but the RP light stays on whether I shut off the main power switch or not. In other words, it only turns off when I unplug the shore power cord.

As for the 12V, I took the battery switch off last night, tested it, cleaned it....it checks out. So I feel like it's a fuse thing, but we've tested the fuses and can't find any issues so far. I've attached a few snap shots of this rats nest.

What you are calling a "rats nest" looks much better than wiring on most boats! However, it looks to me like quite alot of corrosion on the battery terminals, maybe not enough to cause your DC problem, but worth cleaning up in case it's contributing to that problem.
Frank

 

[Christian Williams]

Was the Smart Plug installed on an old shore cable? I guess it is possible to put the white and neutral wires in the wrong holes. If you didn't install the plug yourself, I'd feel obliged to check the plug wiring.

Bob can do that with his brain (Post #4) but I have to actually look....

 

[Petro206]

What you are calling a "rats nest" looks much better than wiring on most boats! However, it looks to me like quite alot of corrosion on the battery terminals, maybe not enough to cause your DC problem, but worth cleaning up in case it's contributing to that problem.
Frank

Sorry! That's an older photo. We've since cleaned it all up. Forgot to mention that.

 

[Petro206]

Was the Smart Plug installed on an old shore cable? I guess it is possible to put the white and neutral wires in the wrong holes. If you didn't install the plug yourself, I'd feel obliged to check the plug wiring.

Bob can do that with his brain (Post #4) but I have to actually look....

Hey Christian, so it's interesting you mentioned that. We're 100% positive we installed the plug correctly, but seeing as how the Reverse Polarity light doesn't turn off ever, it makes me think that either the cable is bad, or the supply of the slip.

I will add this note on the DC, when my buddy wiggled some cables, we heard something engage....but then nothing ever again, so a loose cable or corroded terminal on the DC end possibly.

 

[Jerry VB]

It probably isn't your problem, but the floating fuse connector has exposed "hot" wires. You should replace the disconnects with fully insulated ones (e.g. HomeDepot).

 

[Dave G.]

Hey Christian, so it's interesting you mentioned that. We're 100% positive we installed the plug correctly

Did you test the cable end to end after you installed the plug to be sure the polarity was correct ? May be possible that someone in the past reversed the conductors but as they were the same on each end it still functioned correctly.

 

[Petro206]

It probably isn't your problem, but the floating fuse connector has exposed "hot" wires. You should replace the disconnects with fully insulated ones (e.g. HomeDepot).

View attachment 47715

Good call! I have some of those. Thanks Jerry.

 

[gareth harris]

A meter similar to the one below can answer a lot of questions (I have linked a cheap model which appears to have the basic functions, plenty of other options are available, mine is more advanced and expensive).

When faced with a DC problem I check for voltage between red and black at every stage starting at the battery until I find no voltage.

Some components that have a high current draw are not that simple since there may be 12V available but excessive resistance somewhere in the connections causes the voltage to drop off as soon as the current draw is turned on. Corroded wire is often the culprit and the original wiring on my boat was cheap automotive wire that had no place on a boat. Such a problem is harder to find.

Reverse polarity can also be tested for with such a meter by checking the AC voltage between live and earth, and between neutral and earth, and seeing which registers 125V. Do not touch anything live as you do so.

https://www.amazon.com/Klein-Tools-MM325-Multimeter-Manual-Ranging/dp/B0B57L9FNL/ref=sr_1_11_sspa?crid=31JVWN51HRE62&keywords=craftsman+meter&qid=1690447549&sprefix=craftsman+met%2Caps%2C270&sr=8-11-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9tdGY&psc=1

Gareth
Freyja E35 #241 1972

 

[markvone]

Was the Smart Plug installed on an old shore cable? I guess it is possible to put the white and neutral wires in the wrong holes.

Petro,

You never mentioned if you replaced the old shore power cable with a new orange Smart Plug cable when you added the Smart Plug.
If you didn't, I'd check that old Shore Power cable. I'd also highly recommend replacing any old Shore Power cord with an unknown history.

https://ericsonyachts.org/ie/threads/bzzzzzzzztt.11930/

Mark

 

[Petro206]

Sorry for the wasted discussion all. Turns out my co-owner forgot to replace a cable to it's post that was causing all the problems. However, we did get to know our electrical system quite a bit better, so it wasn't a complete waste! LOL.

Interestingly enough, in regards to the Reverse Polarity, I was reading a survey done on the boat in 2004, 2 owners ago, and it showed up on their report as well, so we know its not from shore power. Possibly a faulty sensor?

 

[AlanO]

There's no sensor in my panel. It's a simple circuit. Perhaps a PO accidentally reversed the neutral and hot wires on the polarity light so it is always on when correct polarity and off with reverse polarity.