Any advantage or disadvantage from 30 to 50 Amp

My boat is in for a massive refit, essentially everything old is gone, including engine and stern drive, all wiring, old inverter and charger, old instruments, old electronics, everything is gone. My boat is basically a gutless bare bones affair right now.

The boat is a 50 year old 29 feet express cruiser style, it had a 30 amp system and I was going to have that re-installed but then it occurred to me that 50 amps would be good for faster charging. Is going from a 30 amp to 50 amp a good thing, a not so good thing, what say you?

The one kept item is a two year old Norcool fridge, not that big, DC only and a new Norcool small standing freezer, roughly 2.5 cubic feet, DC only, extra insulation added into a new box built for it.

I have purchased but not installed 6 Fire Fly batteries for my new house battery bank, two deep cell agm's for my new bow thruster, and of course the engine battery.

Inverter/charger haven't been purchased yet. There is no air conditioning - Pacific North West and Coastal BC. The head is a new composting toilet. Stove/oven is propane. A Wallas diesel heater is going to be installed with water heater system, small.

The new Merc 6.2 litre gas engine - 350 hp - has a 70 amp alternator (can't install a larger one or the new warranty is void). Efoy 210 will be installed.

I am thinking a faster charge rate time when visiting marinas away from my home base, not too important at my home marina since the boat will be tied up for days and weeks at a time.

50 amps really isn't necessary on a boat that size. Unless you plan to have electric heat or air conditioning, 30 would be fine. That said, if the price difference doesn't bother you, probably no down side to more capacity and a better shore power connector.

Ted

Are you planning on a watermaker? IIRC they can have a pretty heavy current draw.

I don't see the need for more than 30 amps as long as you don't have air conditioning. Your AC loads will be a microwave, if you have one, the water heater, if electric and the shore power charger. A 100 amp modern charger will draw about 15 amps peak. You probably can't use the microwave and the water heater at the same time but all you have to do is stagger their use.

And most marinas have 50A 240V outlets, rarely 50A 120V outlets. You can get an adapter to make that work though.

If you want to upgrade you will have to look at your AC panel and upgrade its 30A main breaker to 50A. Then upgrade the wiring back to the shore power inlet to 8 gauge and if you don't have one, put a 50A breaker near the shore power inlet (ABYC requirement). Get a new 50A shore power cord and the adapter mentioned above.

Lots of work, at least $1000 in parts all for little benefit.

David

ran
My vote is for 30A as well w/o A/C, elec Stove or heat.
Batty charging shouldn't be very high Amp AC... 100 A DC only about 10A AC draw. If you install 50A all your components will be higher $ including adapters to use 30A when that's all that's available.

As your boat is about 30ft you should be able to fit into about 100% of the marinas, and assuming that you're going to be traveling far and wide, you'll find a lot of small marinas won't have 50 amp service, only 30.

Thanks for the replies. Decades ago my wife and I lived in a fifth wheel while saving for a home in the Greater Vancouver BC area. The park we lived at had 15 amps. I got really good at understanding electrical power usage after tripping the breaker multiple times. Even with 15 amps we could do a lot. We could use a hair blower as long as it was on medium or low. We couldn't use the hair blower if we were using the TV, that kind of living. The first time we used 30 amps it was like graduation day for us.... lol.

I have decided I don't need a microwave, even in our home it only gets used a few minutes every day but all that we do with it can easily be done without one. But I have bought a convection oven to use when I'm in marinas, it uses 1380 watts with no surge power. So I will be well within 30 amps even using the convection oven.

You might consider a 1 burner butane stove. We've had one from a previous boat and have used it a lot cruising.
Small, stows easily, butane is HOT and heats quickly, canisters last longer than would have ever guessed. These are the kinds used on restsurant serving areas for omelettes, crepes, etc

I will be installing a Force 10 2 burner stove/oven. And there is a bbq on board - a Weber 1200. Most bbq owners don't own a bbq in the true sense of the word. A true bbq is a long drawn out affair like preparing pulled pork in the South, or native Americans smoking salmon, a whole day affair. A contemporary bbq is really an oven and a grill. We once had power go out in our home during a Xmas holiday and the turkey in the oven, which was finished on a bbq.

I am trying to spread power usage out so I have a Dickinson propane heater that came with the boat, but also installing the diesel heater, and an electrical kick plate heater at 750 watts in the V birth area. If I run out of propane I have a heater, if I run out of diesel (gas engine) in the small fuel tank for it, I still have propane heat, and if I poop out on propane and diesel, I have an electric heater for shore power use, a convection oven for shore use and a single burner induction heating plate.

Bacchus said:

You might consider a 1 burner butane stove. We've had one from a previous boat and have used it a lot cruising.
Small, stows easily, butane is HOT and heats quickly, canisters last longer than would have ever guessed. These are the kinds used on restsurant serving areas for omelettes, crepes, etc

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Wonderful for having Korean B-B-Q's at your table! However once you use/puncture the butane canister it will never seal tightly closed again, so store it with your LPG tanks when not in use.

rsn48 said:

I am trying to spread power usage out so I have a Dickinson propane heater that came with the boat, but also installing the diesel heater, and an electrical kick plate heater at 750 watts in the V birth area. If I run out of propane I have a heater, if I run out of diesel (gas engine) in the small fuel tank for it, I still have propane heat, and if I poop out on propane and diesel, I have an electric heater for shore power use, a convection oven for shore use and a single burner induction heating plate.

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Now that's what I call redundancy! The only thing you're missing is nice little wood burning stove in the salon, with a glass face, to cozy up to on a cold winter's day.

Now that's what I call redundancy! The only thing you're missing is nice little wood burning stove in the salon, with a glass face, to cozy up to on a cold winter's day.

Funny you should mention the little fireplace, yes I did a great deal of consideration to a wood fire place until my refitter said a diesel heater would be more functional, use very little diesel and if I installed it then adding a water heater was more financially logical.

So in the space I had allotted for the fireplace, a space behind the helm seat in the salon, actually under the seat, the seat was standing on stainless steel legs, I've added an insulated box built to take a dedicated freezer. And in that same area, I'm having a fold up board to but the convection oven and induction plate on when at anchor. So in essence I will have two galleys sort of, one in the V birth area (the main one where the refrigerator is) and one in the salon when at moorage. Redundancy in galleys.... lol.

PS: I do much more off season cruising than most, in fact I probably do more in off season than in season. I'm an introvert and going into a busy moorage and anchorage like Squirrel's Cove in Desolation in summer is more an irritant, going in during spring and fall and early winter - a joy, almost no one there.

One advantage of 30A that has not been mentioned is the cost and weight of the cords. 50A cords are really spendy and really heavy/awkward to handle compared to 30A. I don't think I'd go to 50A unless I needed it.

rsn48 said:

it had a 30 amp system and I was going to have that re-installed but then it occurred to me that 50 amps would be good for faster charging. Is going from a 30 amp to 50 amp a good thing, a not so good thing, what say you?

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Are you talking about the shore power connection, or the battery charger?

Whether the shore power is 30amp or 50 amp (120 VAC), the battery charger is going to push relatively the same amps (12 VDC) to the batteries. That is unless you were going from a 30 amp charger to a 50 amp charger.

If you're talking about shore power connections, does the power stanchion provide 50amp service? Many provide 2 x 30amp.

In my marina location, I have 30 amp hook up. I was thinking more at away marinas. For me the 30 amp hook up isn't that big a deal as by the time I leave from where I was to getting "home," I'm looking at minimally 3 hours usually and my alternator is 70 amps so I will have most of my Fireflies recharged by the time I tie up.

But I have decided everyone is right, I am wrong and 30 amps it is. And besides I just spent money on a decent 30 amp power cord, not one of those orange pieces of junk that people use "to save money," which receives lots of amps through 16 gauge wire that wasn't designed for all those amps.

makobuilders said:

Now that's what I call redundancy! The only thing you're missing is nice little wood burning stove in the salon, with a glass face, to cozy up to on a cold winter's day.

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Like this???

We berth our vessel in BC. 30 amp at the dock very common. We are an all electric boat. if you choose to go 50, you can get a cord adaptor to connect to a 30 amp pedestal. That is what we do and with a little care we can run AC too. Without a 50 amp hookup or running the genset we cannot run washer and dryer though.

The AT uses 2X30 amp service. One leg is for the reverse cycle A/C.
The second is the house. There are 2 resistance heaters. If you turn them on, you cannot do anything else electrical for they reside on the house breaker. I have 1500 watt inverter .... that means I can use the microwave or support one, possibly 2 120 vt outlets.
I have gotten used to the 30amp house service.
To cook a big meal you must plan the electrical use carefully.
You will learn the phrase, "load shedding". It would be nice to have an Amp use meter in the galley so you can see how close you are to the edge of the "world".
I have one 120 vt light ..... When that goes dark, I start shedding the AC load and resetting breakers.

I agree with DougCole.... the 30 amp cables weighs less, cost less and are easier to handle than the 50 amp cables.

What I am considering is an additional 'service' point, forward. Now I only have a service point aft. Just another pipe dream, I think.

If you currently have a 30 Amp boat and go the 50 amp, you are going to need a good marine electrician to determine what needs to be change ..... shore power breakers, maybe the main internal cabling. These things are way above my pay grade.

My Cutwater 28 is an all electric boat. Electric stove top, it has Air Con, two microwaves. With 30 amps it works, but I have to be a bit careful on what gets turned on. You're doing a refit where you could think, "in for a penny, in for a pound" and upgrade. As mentioned you can carry adapters to plug into virtually anything.

If you are running a generator for when you hang on the hook (as I do) you may have to plan for max 30 amps anyway so the planning may become second nature anyway.

Go to the 30 and get more battery's and a bigger inverter to absorb any spikes you might have extra advantage is you at anchor you have power
Plus I agree 50 amp cores are heavy and a bitch when cold
Ee use 50 amp and sometimes use 2x30amp cords
One 30 will keep us alive
We have a huge bank of battery's and very large inverter but we are 90 feet

I've no problem man handling a 50' 50 amp cord. When I do, then it becomes two 25 footers. But as I mentioned earlier, you can rig the boat for 50 amp but use one 30 amp cord for the common BC 30 amp pedestals.

makobuilders said:

As your boat is about 30ft you should be able to fit into about 100% of the marinas, and assuming that you're going to be traveling far and wide, you'll find a lot of small marinas won't have 50 amp service, only 30.

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This is especially true in BC. Where we boat, most 50 amp boats plug into a pair of 30s, if available, or just run on 30 when away from their home dock.

You haven't mentioned a genset. Without one, you won't be using big electrical loads at anchor, so unless you never anchor, don't need to be wired for any big loads, and won't need more than the 30 amps you had.

When you put in a propane stove, diesel or propane heat, no A/C, the need for 50 amps goes away.

In this part of the world, you often find boat slips sized to fit your smallish vessel have only 30-Amp shore power available, making the big 50-Amp cable on your boat a PITA to deal with physically and electrically.

My 30-foot boat has two AC units (10K and 13.5K Btu), electric water heater, one burner electric stoptop, and microwave. The larger AC unit (rooftop) has its own 30-Amp shore power inlet - so we carry two cords in case we want to use it at a marina. Thanks to a couple of Micro-Air softer starters, we can run all this on our 3.5 KW Nextgen generator.

Smaller boats usually don't get along side the 50amp outlets on the BC coast. They are few and far between, and generally reserved for the big boats.

Lots of places are still 15 and 30 amp.

Current boat has 2 - 30 A systems and no issues here either. Load shedding is only needed when running the space heater. My family loves popcorn so they are hard on the microwave breaker but that is a different story.

Northern Spy said:

Smaller boats usually don't get along side the 50amp outlets on the BC coast. They are few and far between, and generally reserved for the big boats.

Lots of places are still 15 and 30 amp.

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Right you are in many locales. The newer docks in Comox have many 50 amp hookups. Toba Wilderness Lodge, Campbell River, Port McNeil as well. Once into AK, lots of 50 amp too.

Ted said:

Like this???

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Absolutely beautiful! ?

I’m not making a case for 30 or 50. The right answer is what do you need for the type of winter boating you do. You can always use adapters if the right plug is not available.

In the summer I only need 30 amps. I just plug an adapter into my 50a socket and use a 30a cord. In the winter I need 100a so I use a 125/250 50a cord with no adapter. If I must I can get by with a 2x30a splitter.

Everyone’s needs are different so for each a different answer.

Sea Q said:

Go to the 30 and get more battery's and a bigger inverter to absorb any spikes you might have extra advantage is you at anchor you have power
Plus I agree 50 amp cores are heavy and a bitch when cold
Ee use 50 amp and sometimes use 2x30amp cords
One 30 will keep us alive
We have a huge bank of battery's and very large inverter but we are 90 feet

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I recently purchased a 50 amp cord from Smart Plug. It is heavy but is not at all difficult to coil up, even when cold. The insulating jacket is soft and pliable. The old yellow cord was a beast, so much so that I threw it away rather than salvaging it as a spare.

rsn48 said:

The boat is a 50 year old 29 feet express cruiser style, it had a 30 amp system and I was going to have that re-installed but then it occurred to me that 50 amps would be good for faster charging. Is going from a 30 amp to 50 amp a good thing, a not so good thing, what say you?

I am thinking a faster charge rate time when visiting marinas away from my home base, not too important at my home marina since the boat will be tied up for days and weeks at a time.

Click to expand...

Might be a useful difference if you have a large enough AC (current) load to need more than 30 amps (a single shorepower connect), or especially more than 60 amps (twin 30s).

But your charge rate is a discussion between batteries and charger, not much to do with how many amps you have coming into the boat (assuming sufficient to power the charger in the first place). For example, a 40-amp charger will use about 5A AC (a guess) to produce up to 40A DC... without regard to your shorepower source... if you have enough juice to light the charger at all.

Then the batteries will accept charge at whatever rate they will accept charge, up to the limit the charger can supply (40A in the example). Varies by battery.

As others have said, 50A cordsets are heavy, expensive... and in your size boat, with no AC (aircon) and relatively few huge AC (current) loads... 30A should be sufficient... and even twin 30s if necessary would likely be easier to schlepp around than a single 50.

-Chris