Plugged In Or Not? Alternatives

[Evergreen]

Hello:

Just about the time I think I have most of my boat maintenance issues under control another question raises its hand.

My question: When returning to the dock do you plug in to AC power or not and why? If not, do you do anything to maintain the charge in your batteries?

As a new "Big" boat owner I just assumed everyone plugged in. Walking down the docks it appears that most people do. Then I started thinking about batteries being over charged, stray current issues and associated corrosion, etc.. My surveyor even suggested installing a galvanic isolator which have become very expensive recently due to the new alarm requirement. After communicating my concerns with my marina manager he pointed out that most people do not need to remain plugged in all the time and I will avoid a whole host of problems and expense if I try to avoid it except when I return to the dock with my batteries depleted.

I welcome your thoughts on this matter.

Thank you, Philip & Sharon "Evergreen"

PS: I promise to make an effort to stop asking so many questions soon.

[Oswego John]

Hi Philip and Sharon,

Let me mention a few viewpoints for us to consider. Probably one of the top meat and potato reasons for the CDSOA board being so great as it is is because it teaches and helps others understand the boating problems at hand. The answers given follow the questions that are asked. Without questions, such as yours, this board would be nothing as compared to what it is today. To all, keep the questions coming.

Philip & Sharon:
My question: When returning to the dock do you plug in to AC power or not and why? If not, do you do anything to maintain the charge in your batteries?

O J:
Some owners do and some owners don't have AC systems on their boats. The two most common ways that I believe that batteries are kept charged are by running the engine and having the alternator replenish the charge, and by the use of a battery charger that is plugged into AC shore power.

P&S:
As a new "Big" boat owner I just assumed everyone plugged in. Walking down the docks it appears that most people do. Then I started thinking about batteries being over charged, stray current issues and associated corrosion, etc.. My surveyor even suggested installing a galvanic isolator which have become very expensive recently due to the new alarm requirement. After communicating my concerns with my marina manager he pointed out that most people do not need to remain plugged in all the time and I will avoid a whole host of problems and expense if I try to avoid it except when I return to the dock with my batteries depleted.

O J:
I agree with your marina manager. The use of shore power is common when recharging batteries. However, many boat owners live aboard for varying periods. They use shore power for lighting, air conditioners, fans, entertainment, refrigerators and a host of other uses. The power demand would deplete the batteries in short order.

You mention that the newer models of galvanic isolators are expensive. Marine insurance for your boat could be considered expensive, too. When tied up in a slip, a galvanic isolator is electrical insurance for your boat. What is the worth of your boat? Would you deny protection from electrical corrosion for your shaft, wheel, rudder post and through hulls to save a few bucks. Your 36 foot CD is quite an investment that, in my mind, is worth the insurance and the peace of mind that goes with it.

To gain some insight into galvanic isolators, go to

http://www.dairyland.com/index.php?page ... ts_gi.html

At the column on the right, scroll down to "TYPICAL APPLICATIONS" Click on Marine Galvanic Isolation.

P&S:
I welcome your thoughts on this matter.

Thank you, Philip & Sharon "Evergreen"

PS: I promise to make an effort to stop asking so many questions soon.
_________________
Philip & Sharon

O J
Keep the questions coming. Many others benefit from your questions, also.

Fair breezes,
O J

[Neil Gordon]

Lack of AC power doesn't seem to bother the hundreds of boats that bob around on moorings.

I don't have AC and have never had a battery problem. Motoring out of the slip and back in has proved sufficient. On the one hand, I'm not a heavy user... no TV, no popcorn popper, no hair dryer, etc. But I have lived on board and used the radio, powered my laptop, used the lights, charged my phone, etc., all without a problem.

As an aside, I alternate between two batteries... using #1 in the odd months and #2 in the even months.

Before investing in expensive gizmos, I'd monitor the batteries and see if you actually had a problem.

[Jim Davis]

With sailboats in our sizes the real question should have been "Do I leave the refrigeration running all the time?" If the answer is "Yes", then you will have to stay plugged in or it will shut down after about two days when the batteries go flat. Galvanic isolators are cheap insurance against your neighbors poor electrical installation. On Isa Lei I used the Newmar - no bells just simple and hopefully it works. ( http://www.defender.com/product.jsp?pat ... 6&id=52807 ).

To answer the refrigeration question: Do you plan to leave food or beer in it? Also they do take time to pull down. For weekending you will want to hook up the power cord on Friday night when you move on board and load the refer up. Let the marina provide the power over night. Once operating the engine will support you. For your planned trip to Maine, you will spend most of the time on the hook or a mooring. Here if you stay stationary for several days you will need to run the engine, or other source of electricity every couple days.

Short answer On the isolator - why not.
On the refrigeration - your call.

[Dean Abramson]

Philip & Sharon,

Our current CD31 is the first boat we have owned that has an AC circuit. We have chosen not to use it at all. It seems to me that for our boat usage, the negatives outweigh the positives. When I installed my new hot water heater, I did not even bother to connect the AC feed.

The alternator charges the batteries just fine. While cruising, we are never at docks, so if we want hot water we motor some that day. Actually it's more like, "well, we had to motor for a while today; I think I'll take a shower."

You might want to use the boat for a while, then decide how much you care about AC. It will mean icebox, not refrigeration. To us, that is no big deal. We make liberal use of out plotter/radar, radio, pressure water pumps, lights, stereo, etc., and power consumption (from two AGMs) has just not been an issue. Our boat lives on a mooring.

Best of luck with it all.

Dean

[Boyd]

Hi All:

Lead acid batteries internally self discharge at about 1% per day so keeping a 3 stage battery charger going on float is very good if you dont get out sailing as much as you would like. Nothing ruins planns like having to charge the batteries for an hour before leaving.

As for the other loads, unless you are living there nothing else should be on so the battery charger is it. The only exception is if you have a leak that requires a lot of bilge pump activity. In that instance fix the leak asap.

Most good battery chargers are isolated anyway so the chances of galvanic problems from yours would be quite limited. If you are concerned about stray current in the marina, some simple tests with a multimeter will help put your fears aside. One of the most common culprits in marinas is open boats that keep a "non marine" battery charger running. These are often the source of leaks to ground. Also look for extension chords that are laying in puddles.

I keep my boat which is docked at my house on shore power 24-7 when not out sailing and have had no problems at all. A lot of boats around me run the A/C continuously to keep mold problems under control and I dont seem to have galvanic problems as a result.

Another option is to get a solar float charger to keep the batteries topped up.

Boyd
s/v Tern
CD30 MkII
Fort Lauderdale, Fla.

[Matt Cawthorne]

One more thing for consideration. I don't leave my boat plugged in all week because of the extremely remote probability of a battery charger going south and lighting the boat on fire. I leave it plugged in only when I am going to be close by.

As for flooded lead acid batteries internally discharging by 1% per day, I have never found that to be the case. I have left the boat for up to two months on rare occasions and found only about a 3% loss of charge. That is provided that everything is turned off.

Matt

[John Vigor]

Philip & Sharon:

I have never owned a boat wired for shore power. I admit I'm of the Spartan persuasion, but I've never had any battery problems.

I have a CD27 with two deep-discharge batteries. I use both of them together for starting and charging while the engine is running. At all other times I switch to #1 battery, and #2 is reserved for starting (although, as I say, I always use both together for starting.)

During the winter I run the engine for 20 to 30 minutes in gear in my slip once a month or so just to charge the batteries and shake the creepy-crawlies off the prop.

Last year I was overseas for three months (without my boat.) When I came back there was plenty of juice left in the batteries for starting the engine. And, incidentally, my cars started right up, too. So, if you leave your batteries reasonably well charged up, you can expect them to maintain a decent charge for several months--as long as they're not being used.

I don't have anything on board that needs electrical power when I'm not there--no automatic bilge pumps or fridges or anchor lights to drain the batteries--but I guess I'm in the minority there. You could do the same thing, though, even if you have power requirements, by dedicating one battery as a starter battery, and isolating it while you're away. Then, if even your bilge pump runs down the other battery(ies) you'll still be able to get the engine going and charging again.

Cheers,

John V.

[bottomscraper]

Since we keep our boat on a mooring plugging in is not an option. We do have a small 5 watt solar panel to keep the battery topped off. We have two battery banks. Bank 1 has a single 12V group 31, bank 2 has two 12V group 31's in parallel. The panel is hooked to bank 2. When time comes to replace them I think bank 2 will be changed to two 6volt batteries in series, having batteries in parallel isn't ideal. The solar panel has worked well for us for the past few years.

[Parfait's Provider]

At an annual CDSOA meeting some years ago, I was the only person who admitted to staying plugged in. My excuse was the flattening of the batteries if I was away for a month or two. Well, the surveyor congratulated me for having the guts to admit it. We later found a dezincified prop which, fortunately, wasn't right for the new engine anyway. It is an expensive and still fairly heavy paper weight/spare.

If I had repaired the leak, I probably would have a Perkins 4-108 with 1000 hours on it that I hate. Instead, I love my new expensive Yanmar. If you stay plugged in, get an isolator; they are much cheaper than engines, sole refinishing, salvage operations, etc.

[Neil Gordon]

Lead acid batteries internally self discharge at about 1% per day ...

My batteries are idle, no load and no charging, from about November 1 through April 1. I've never had a problem with either discharge or battery life.

[John Danicic]

Philip and Sharon:

We keep Mariah at a dock with the AC cord plugged in and a True Charge 20, 3 stage charger on float when we are not around. Being in the fresh waters of Lake Superior, I don't believe (and please, someone correct me if I am wrong) that galvanic corrosion is as big a problem as our sea water brethren experience. We have a few dubious boats and "interesting" AC wiring in our marina so I have dutifully checked the sacrificial zincs and notice no change at all. In the winter, I set up a 12 watt solar charger to keep the batteries fed as AC is unavailable in the storage yard.

With four, six volt T106s in one bank and a starter battery in the other, we like to return to the marina, clean up and head home letting the charger slowly replenish the amp hours used and thereby be ready to head out immediately when we return. We never run the fridge or any other electrical device while we are away. So in other words, in fresh water, our experience being plugged in has been good.

As for questions. Always ask and all who read will learn. It's the best thing about this board; we are all always learning something from it.

Sail on.

John Danicic
CD 36 - Mariah - #124
Lake Superior

[Mark Yashinsky]

Does your club or marina charge for plugging in? Given the price of electricity, more and more are charging for the privilege.
As was mentioned above, do you have a high tech battery charger, one that wont cook your battery if left connected for a week?
Is your AC system up to the power that shore power can provide? What I mean is, is your shore cable, boat AC connector, internal wiring, AC panel and appliances up to spec and regularly checked. I believe BoatUS had some recent articles about the connections between the power cable and boat and how many of them were melting and/or burning up. Also, are you leaving items plugged in while away from the boat? This summer, during the overnight layover of a two day regatta, hosted by my Club, a boat that was plugged in to shore power at a slip, had their AC powered, portable boom box fry itself and destroyed one of their sails. Needless to say, they were literally "out of the race". Then there was another fire at a Yacht Club up the Hudson River, last February, that I believe was started by a hauled boat that was left plugged in (to charge the batteries). Then there is always finger pointing if zincs start disappearing quickly.
The big question is, what is your power load going to be and when is that power needed?

[Jim Davis]

Assuming that you make the decision to keep the refrigeration on line and running all summer. To reduce the chance of frying your batteries add a heavy duty timer to the system. Set it up so the charger is only available about 6 hours a day. Because of the load from the refrigeration a charger senses low voltage and will meet the load and then some. If the charger is only available part of the day it will top off the batteries during its on time and the batteries will keep the beer and food cold during the rest of the day.

Irreguardless, if you have a built in AC system, the isolator is cheap protection from your neighbors.

[bilofsky]

Having a power boat, I probably carry more batteries (4 x type 27 house bank) than most folks here. I leave my boat plugged in because (1) I run my fridge, and (2) if a leak springs, I'd like the bilge pumps to operate longer than until the batteries run out.

(If there is a real serious leak, the bilge pumps probably won't keep up with it anyway. But I'd still rather try.)

If you do stay plugged in, be sure you have a modern three stage battery charger. My boat came with a ferro-resonant charger. These may be decent anchors but they are not very good chargers. Batteries lasted about three years with them. So I replaced it with a Truecharge 40 three stage charger.

I turned off the float charge, figuring that the less I hassled the battery, the happier it would be. With float off, the Truecharge still wakes up every three weeks and tops the battery off.

Well, the house batteries have seven years on them and are still OK. I also have a single Type 27 as an engine starting battery, and I don't even have it connected to the charger. I think the Truecharge's three "bank" outputs are just connected together, so if the house battery needed a charge, the starter battery would be needlessly cooking away, and vice versa. The starter battery is also seven years old and still OK.

The fridge runs on AC if it is present, so the 12 volt panel is left off when the boat is not in use. The bilge pumps don't go through the panel, so they can't be turned off accidentally.