Batteries and Being on Shore Power

[btrayfors]

One of the distressing things about the deplorable condition of shorepower connections in some marinas is that they can rapidly destroy YOUR power cord connectors.

Even a new power cord connector can be destroyed in short order by plugging into a shore receptacle which is in poor condition, especially in summer when you're pulling a lot of current for an air conditioner, or in winter when you're running electric heaters.

If you see a connector -- male or female -- with evidence of burns on the outside around the pins, you would be well advised to not use it.

Bill

[rwidman]

Originally Posted by btrayfors

The wiring diagrams should be used for reference ONLY, not gospel. The actual wiring in the boat may or MAY NOT be as depicted in the wiring diagram.......

That's the truth.

As for the OP's original question, there's no hard fast rule on what position to leave the switch in. You stated something about the "1" position. That implies that there may also be a "2" position. "1" would be for one battery or bank, "2" would be for another battery or bank. Either of these positions would normally supply power to the engine starter and other accessories so if you're not turning it "off", it doesn't matter if you leave it in "1" or "2". If you have a "1" and a "2", chances are you also have a "both" switch position.

Your battery charger should be connected directly to both batteries (through fuses) and your bilge pump should be connected directly to one of the batteries, again through a fuse.

If this is the case, leaving the switch in the off position makes the most sense unless there's something on the boat that needs to have power while you are away.

The suggestion to get someone who knows about this stuff to examine your boat and explain it to you is a good one.

[rwidman]

Originally Posted by Zil

I can't understand being away from the vessel for extended time

Seriously? Many boat owners live a hundred miles or more from their boats and just visit them on weekends in good weather. Other owners have obligations, family issues or medical problems that could keep them away from their boats.

Job or military related travel would be another reason.

[rwidman]

My boat stays plugged in at my marina 24/7 unless it's out cruising. No problems. Yes, there's a chance someone will unplug my cord to make room for theirs, but they will only do that one time.

The receptacle on the pedestal is in good condition and if it were not, I would ask management to have it replaced.

All the boats in my marina that have shore power leave it connected 24/7. No problem. Again, if there is a problem, it gets fixed.

[Dockhead]

I have left my boat connected to shore power for weeks at a time with myself gone, with almost no problems.

However, there are a lot of things which can go wrong. This past winter, I left heaters running (the boat was on the hard), and accidentally left the Victron charger/inverter controller on "invert", in which position shore power will be supplemented by or replaced with inverter power in case of need. Well, some breaker or GFCI flipped off while I was gone, and I came back to find flattened batteries, which is very bad, something which is injurious to them at best and fatal to them at worst. That's $2000 worth of Trojans. Fortunately for me, they seem to have survived again (it's the second such incident). Tough batts, Trojans.

Besides that, weeks on shore power creates an additional risk of galvanic corrosion if you don't have an isolation transformer, plus, as has been mentioned, there is a risk of fire.

Kettlewell is right -- it is really much, much, much better to have solar or wind to keep the batts topped off, and leave the shore power disconnected, if you're going to be away from the boat for more than a couple of days.

And yes, batteries should absolutely be isolated when you're off the boat. In that position, your bilge pump should still work and your charger should still have a connection. If not, you need to rewire as necessary so that it will be so.

[rwidman]

Originally Posted by Dockhead

...........Besides that, weeks on shore power creates an additional risk of galvanic corrosion if you don't have an isolation transformer, plus, as has been mentioned, there is a risk of fire.

Kettlewell is right -- it is really much, much, much better to have solar or wind to keep the batts topped off, and leave the shore power disconnected, if you're going to be away from the boat for more than a couple of days.............

I leave my reverse cycle AC turned on either in AC, heat, or dehumidify mode. Also, my refrigerator. This is why the boat stays plugged in to the dock pedestal.

Yes, there is some risk, but there's a risk to just leaving the boat in the water in the first place and a risk to having it hauled and blocked. It's a matter of risk management. Know what could happen and the chances of it happening, then decide.

[Dockhead]

Originally Posted by rwidman

I leave my reverse cycle AC turned on either in AC, heat, or dehumidify mode. Also, my refrigerator. This is why the boat stays plugged in to the dock pedestal.

Yes, there is some risk, but there's a risk to just leaving the boat in the water in the first place and a risk to having it hauled and blocked. It's a matter of risk management. Know what could happen and the chances of it happening, then decide.

Yes, and I also leave my boat plugged in during three months in the winter so that I can run heaters. That's different if you have a good reason to need AC, like you do.

But if you don't really need AC power, or during periods when you don't need it for anything other than battery charging, then Kettlewell's point is true, I think.

[rwidman]

Originally Posted by Dockhead

Yes, and I also leave my boat plugged in during three months in the winter so that I can run heaters. That's different if you have a good reason to need AC, like you do.

But if you don't really need AC power, or during periods when you don't need it for anything other than battery charging, then Kettlewell's point is true, I think.

I leave my refrigerator running because we go to the boat for lunch or spend the weekends on it at our marina.

Assuming that the boat's electrical system was designed and installed according to ABYC and USGC standards and in a workman like manner, and assuming that it has been maintained and inspected from time to time, I don't think it's much different than leaving the power on in your home when you are away.

As part of my maintenance and inspection, I replaced thee shore power cable and the boat's shore power inlet because of slight blackening and corrosion of the terminals. Checking the dock pedestal and boat connections with an IR non contact thermometer when a significant electrical load (like the AC) has been running for a couple hours is a good test of these components.

[Zil]

Originally Posted by rwidman

Seriously? Many boat owners live a hundred miles or more from their boats and just visit them on weekends in good weather. Other owners have obligations, family issues or medical problems that could keep them away from their boats.

Job or military related travel would be another reason.

No not serious. Just another lame boat joke, like the hole in the water one.

I try not to assume the dock owner's stuff is up to par. My home wiring is. It is my wiring. My vessel wiring is up to par. it is my wiring.

[Dockhead]

Originally Posted by rwidman

I leave my refrigerator running because we go to the boat for lunch or spend the weekends on it at our marina.

Assuming that the boat's electrical system was designed and installed according to ABYC and USGC standards and in a workman like manner, and assuming that it has been maintained and inspected from time to time, I don't think it's much different than leaving the power on in your home when you are away.

As part of my maintenance and inspection, I replaced thee shore power cable and the boat's shore power inlet because of slight blackening and corrosion of the terminals. Checking the dock pedestal and boat connections with an IR non contact thermometer when a significant electrical load (like the AC) has been running for a couple hours is a good test of these components.

I would be less worried about a fire, assuming your gear is all in good shape, and it sounds like you stay on top of it, than I would about killing the batts in case the shore power flips off or gets disconnected or someone knocks your plug or someone does something to flip off a GFCI, etc., etc.. It happens quite often, and has happened to me. A DC load like refrigeration is the worst thing for a case like this. A heater or air conditioning or other AC load wouldn't matter (unless you forget to switch off your inverter like I did last winter ).

I would not personally leave refrigeration going if I were off the boat more than a day or two. I always throw everything out and wash out the fridge and freezer, and leave it all open to air out, when I'm off the boat. YMMV.

[rwidman]

My inverter only powers the receptacles, nothing else. And I keep it off unless I'm away from the dock.

I understand about the refrigerator, but we're at the boat most weekends when we're not away from the dock. I believe, but I'm not sure that the refrigerator shuts itself off if the DC voltage gets too low. The biggest danger would be eating food that had been thawed, then re-cooled or refrozen if the power went off and then came back on after the refrigerator had shut down.

The marina is in an area with reliable power and my slip is where others are unlikely to mess with my power. Granted, it could happen but it hasn't in five years.

[FlyingCloud1937]

This is how I set up all Yachts, boats will depend.

First the the big bat switch that is normal, is what I call an Emergency/Service Disconnect. So the only time that switch is moved is in an an emergency, or for service work.

Next I setup a House Panel DC Disconnect, it is the the only DC switch the owner has to kill when he/she leave the yacht.

All 24/7 loads are live unless the Emergency/Service Disconnect is opened, all other loads that could drain the battery bank are isolated, by the House Panel DC switch. When the owner leaves the yacht, they only have to remember to turn one switch!!.

That's not to say that the 24-7 loads won't drain a battery bank, it depends on ho much water a yacht ships I suppose. If the yacht is shipping that much water then the owners should know it.

The question becomes? Do I want my refer on my 24-7 load. It depends on the owner.

Same goes for the AC Panel. I setup 24-7 loads, and Ships AC loads. Now the owner has 2 switches to remember. It's as easy as AC/DC

Lloyd

[macbeth]

I can only tell you of my experiences.

1) I once left my shorepowered battery charger on while I was away for a week. The battery, one year old, developed a bad cell (in the middle of the summer), and started gassing. When I returned to the boat, the charger was at 20 amps, and the battery was very hot, so hot it had melted down the plastic clips underneath it. These plastic clips contain the strap that holds the battery down. I resolved after that never to leave my charger on when I was away from the boat.

2) One winter, in Cornwall, Ontario, I left one battery attached to a 0.5 amp solar panel. I visited the boat once a month for 5 months. Every time I did so, I had to add more water to the cells. I think it was due to the very dry atmosphere. Never did that again.

3) A marina owner where once I had a slip, would pull shorepower plugs OUT if he thought the owner was absent. He had over 400 boats in his marina. His insurance company demanded this action. I guess they had a reason.

4) In the summer, if I am away for a week or so, I leave the my wind generator going. It doesn't deliver enough charge to ever worry about it !

5) In the winter, I take home the house batteries, and put them on a Battery Minder. I leave the starter battery (combination deep cycle/starter) inside the boat, fully charged. Never had a problem. This in the freezing cold of Ontario !

6) Even when I used to take all the batteries home, and before I had a Battery Minder, over a number of years, I had two starter batteries go bad on me. I did an Internet search and discovered many sailors had switched to deep cycle batteries for starting, due to problems of keeping starter batteries (thin plates) going over a winter.

My 2 cents !

[donradcliffe]

In addition to all of the above, leaving the boat plugged in may have cost considerations--some marinas don't have individual meters and will charge by the day/month.

Leaving the boat plugged in also subjects it to the risk of electrolysis from stray currents, particularly in the US where the AC and DC grounds are supposed to be interconnected.

If the boat was new to me, I would pull the cables off the batteries and reconnect only the bilge pump. Many boats have enough 'owner wiring' to flatten the batteries in a week even with the switches turned off. I just replaced the batteries on a Catalina 30 that had 8 wires hooked to the positive terminals!

[foggysail]

Originally Posted by Kettlewell

It depends on your definition of "very." To me, one fire is too many. I have been disappointed how often shore power connections at the dock are in bad shape, to the point it is difficult to get a good connection in the first place. And, even if you don't get to the point of a fire you can get arcing, or such a bad connection that you lose power. But, one of the biggest problems is that when you are not around someone will inevitably unplug your cord, and/or replug it badly so that it is loose. In my experience there is nearly a 100% chance of this if you leave the boat for a few weeks in a busy marina. It has happened to me when mine was the only boat on the dock in the middle of the winter--some workman came by and unplugged the cord for some reason and left it, so no heat on the boat. In other words, my advice is don't rely on shorepower to keep your batteries up in a busy marina unless you are there fairly frequently monitoring things.

Power cords! If there is no or little current flowing, there will be no heated connectors.

The only times I left my boats with the batteries switched off was if they permanently moored rather than parked in slips. But to each his own.