solar or generator?

Been boat shopping for a while and couple of trawlers we looked at had no aux. power other than a couple house batteries charged by the alternator.

I would be more inclined to install a quality solar system rather than a generator. I would guess my biggest power draw would be refrigeration, planning on gas range.

Usage for now would primarily be New England, Hudson River and canals.

I am looking for the pro and cons either way.

Does anyone run a hard top over the flybridge that that raises/lowers?

Thanks.

I have both a generator and 2X130 watt solar panels (no more physical room to install more) plus a 40amp Xantex stand alone charger. I think the engine alternator puts out 60amp(?) It is the standard alternator that comes with the Cummings 380QSB. All this works with 4X4D batteries (3 house and 1 start) The generator start battery Group24 is totally divorced from everything.
My major day time and night time load, 12vt fridge and LED lights as necessary. That is excluding a couple of 400amp inverters to run the TVs (those loads suggest the inverters could be smaller.)
The main inverter is a Xantex 1800watt inverter. This allows to a 10% overload for starting stuff. The loads on the main nverter are switch control galley outlets (gotta have coffee) OR the 2000amp microwave which sucks the batteries down quickly so I use it sparingly. Normally, I keep the inverter shut off.
My reasoning is sort of obscure.
The alternator or battery charger plus generator, I am told brings the batteries up to 85%, The solar panels just sort of hang around bringing the batteries up to much nearer if not 'full'.
So far everything plays nice.

Sooooooo, after all that and in conclusion, I suggest both a generator, main engine alternator, battery charger AND solar panels.

If I had to make a choice between solar panels and a generator, I would vote for a generator

CharlieO. said:

Been boat shopping for a while and couple of trawlers we looked at had no aux. power other than a couple house batteries charged by the alternator.

I would be more inclined to install a quality solar system rather than a generator. I would guess my biggest power draw would be refrigeration, planning on gas range.

Usage for now would primarily be New England, Hudson River and canals.

I am looking for the pro and cons either way.

Does anyone run a hard top over the flybridge that that raises/lowers?

Thanks.

Click to expand...

I believe the simplest (perhaps over simplified) answer for whether you need a generator is if you want to run air conditioning away from the dock. If you can live without AC underway or at anchor, a good solar and house battery system can support your refrigeration needs especially if you have a good alternator and well configured voltage regulator/charge controller.

I've got 820 watts of solar and a 415ah house bank. Even with the ice maker running from the inverter (which is close to 30% of my daily power use away from shore power), as long as the weather is decent, we've got plenty of power for as long as we want. On good, sunny, mid-summer days, we have more power from the solar than we know what to do with. We leave the inverter on 24/7. Powers the ice maker and all of the outlets, but not the stove, microwave, etc. However, when I add a hard top at some point, I'll probably add more solar to get us to about 1200 watts to get production closer to our usage on cloudy and rainy days.

We also have a generator on board. For us, if we're away from shore power, we either use it to make up some power if we get a really dark, rainy day where the solar doesn't put out a lot, and then for 40 - 60 minutes every evening to warm up the water heater for showers and to make dinner (galley is all electric on our boat). Generally in a season, we put 1/4 - 1/3 as many hours on the generator as we do on the engines, and the only time it gets run for much more than an hour in a day is if we have really bad weather, or a miserably hot, humid, rainy afternoon and need to run the A/C for a bit.

So for us, the generator doesn't get a ton of use, but it's useful to have. If we could fit more solar and bigger batteries, we could probably ditch the generator. I'm thinking it would take doubling the solar or a little more and 3 - 4x the battery capacity. Then we could cook on solar / battery as well as manage hot water from it, plus having enough buffer for cloudy days, etc.

I think on a trawler, solar is a great way to augment power, but not a suitable primary power source. The reason is that you usually cant fit enough solar for it to be a primary power source. Some people manage it, but I think it's more the exception than the rule.


Other considerations, or perhaps the biggest consideration, is how you use the boat. How many days between stops at a marina where you can plug in to recharge? Do you anchor out in the same place for days on end, or are you underway in between anchoring spots. And if you are underway, is it for long enough to get your batteries recharged fully?


Personally, I would install the solar system first and see how it goes. Also pay close attention to what consumes power on your boat. There are often a bunch of background loads that continuously eat away at your available power.

twistedtree said:

I think on a trawler, solar is a great way to augment power, but not a suitable primary power source. The reason is that you usually cant fit enough solar for it to be a primary power source. Some people manage it, but I think it's more the exception than the rule.

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This is a big one. Some boat designs can fit a lot of solar relative to their size, power draw, etc. Others run out of space long before you have enough. Cats (sail or power) are often at a big advantage for having enough surface area to cover with panels.

Gdavid said:

I believe the simplest (perhaps over simplified) answer for whether you need a generator is if you want to run air conditioning away from the dock. If you can live without AC underway or at anchor, a good solar and house battery system can support your refrigeration needs especially if you have a good alternator and well configured voltage regulator/charge controller.

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This is a really good starting point for a decision.


And someone later brought up hot water which is another important consideration.

twistedtree said:

This is a really good starting point for a decision.


And someone later brought up hot water which is another important consideration.

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As well as desalinization.

Few boats will be able to carry enough solar to allow for their boat's loads plus running the watermaker.

twistedtree said:

And someone later brought up hot water which is another important consideration.

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hot water can be heated via the main engine.
my water maker is 12vts. No idea what the draw will be.

OldDan1943 said:

hot water can be heated via the main engine

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If plumbed for that, yes. But having to warm up the main and let it run for a bit to heat water is a pain if you weren't planning on moving the boat that day.

rslifkin said:

If plumbed for that, yes. But having to warm up the main and let it run for a bit to heat water is a pain if you weren't planning on moving the boat that day.

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Very similar to relying on the alternator as a charging source, it really depends on how you use the boat. Some people tend to move every day, others hang out in one spot for a week or more. Hopefully the OP is getting some food for thought as he is still boat shopping. Many of us also know that the way you use your boat can be very different from what you expected going into it. I doubt most dock queen owners planned to never leave the dock yet that seems to be the case for about half the boats in any given marina.

Charlie,

I have both solar panels and a gen-set. The solar panels supply all the power I need (no microwave, water maker or air conditioning, can heat water on engine.

But… I was once tied to a dock for three days waiting for a storm to pass. Rain, Rain, and clouds when not raining. Batteries ran low and had to run generator.

Alternative to a gen-set might be an Efoy fuel cell, if you have a methanol source.

Also consider that you can plug into a marina for many many nights before you equal the cost of a generator.

John

Our main usage to start would be weekends off and on the dock with maybe a couple week long trips after a while. Would really like low maintenance and I have no problem monitoring power usage and investing in efficient appliances.

I know one of the boats I looked at ran a small inverter generator to run his window A/C. Usually I do not like that set up but in that one it was not as terrible looking as most I've seen.

Some boats I have a hard time seeing where I could put solar panels with a flybridge.

CharlieO. said:

Some boats I have a hard time seeing where I could put solar panels with a flybridge.

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There are flexible solar panels that can be secured to the top of biminis on flybridges pretty easily. Some installations look better than others but the new panels and plug and play configuration options are very good. They have come a long way in terms of affordability and efficiency.

CharlieO. said:

Been boat shopping for a while and couple of trawlers we looked at had no aux. power other than a couple house batteries charged by the alternator.

I would be more inclined to install a quality solar system rather than a generator. I would guess my biggest power draw would be refrigeration, planning on gas range.

Usage for now would primarily be New England, Hudson River and canals.

I am looking for the pro and cons either way.

Does anyone run a hard top over the flybridge that that raises/lowers?

Thanks.

Click to expand...

400W+ of solar and 300AH (usable) of battery storage will keep a 40-ish footer in decent power for everything except A/C. You are at-risk of prolonged periods of rain, but engine alternator can be pressed into service. The cool part of solar is it works quietly every day there is sun - some boats don't even plug into shore power.

But if you want A/C, there is no practical alternative to a combustion engine to generate power.

As far as lowering a hard-top, I doubt that's practical. Canvas Bimini would be the choice if there are air-draft concerns. If it's to do The Loop, may be practical to have the hard-top removed then re-installed once past the offending bridge.

Peter

Should you go solar, this site is a great place for information on LiFePO4 batteries, banks and charging. https://diysolarforum.com/forums/marine.10/

Charlie,

I added 2x110 watt flex panels on top of bimini last summer. New deep cycle batteries this spring rated 464 amp-hrs at 20 hr rate. Main loads are a front loader Norcold in the galley and a large Igloo cooler topside converted to fridge/freezer, both spinning small Danfoss compressors.

This summer used the portable Honda 2200 genny only once to lift the house bank due to cloudy weather, so I'm happy with this setup. Another panel would be nice but no easy way to mount it with unobstructed view of the sun.

If you pick your weekend trips for good weather 2 or 3 flex panels will run the boat (no A/C.) Beyond that you need a non-solar way to recharge. If I move the boat every other day or so in good weather the alternator and panels get the job done. But trips longer than a week mean you'll need a way to recharge in inclement weather.

Having unlimited ice now is almost as much fun as a new boat!

I can now provision for much longer trips, that has been nice for covid-free cruising.

I can't roll the bimini back on sunny cool days because of the panels mounted on top.

Changed all the lighting to LED, lighting loads are now trivial, better light spectrum too.

Spent summers in New England and winters in windwards. My experience is the same as Fatty’s. In the summers due to the longer days and lighter winds the solar out performs wind generators but there are frequent rainy days so a 3 day block of time may go by with little production. The opposite is true in the tropics.
If you’re running AGMs or flooded lead acid even without running any air you will be below 50% SOC on occasion if you’re not plugged in or moving. You need to get to 100% periodically to prevent sulfanation. Solar is fine to get to 100% if you’re already on float or real near it but you’ll rarely get to 100% with even a very modest draw such as frig/freezer requirements. Depending upon your engine and your alternators unless you can have them under a decent load( i.e. moving) you may hurt the engine ( modern common rail maybe an exception). Also consider how fast your battery bank can accept charge. Sure numbers improve rapidly when on bulk but much slower near the end if you have Pb. Assume you’re in New England so would wonder if your times moving are long enough to get completely to 100%SOC. We’re blessed with a new to us lovely historic coastal town every 10-15 m. Often with an opportunity to anchor close by. So not infrequently during the spring and fall a short genset run was required every few days even without HVAC. The rainy low output days are commonly the bumpy days as well.
Do an energy budget. Assume no input for ~3 days at times and longer periods of decreased production. Suspect you’ll see you will either need to be plugged in or have a genset if you want a decent service life from your batteries. Other choice is Oversized Li or carbon. Given costs may make sense to go with solar as a trickle charger when there’s no loads and a genset backup when cruising. Stay away from any high revolution genset if you can. If you’re going to hold on to the boat even a small Northern Lights makes sense. When we did the numbers it was ~5 years of ownership that the upgrade to a low rpm unit made sense. We did shop the NL so got it well below list. If you want any friends in the anchorage don’t use the ubiquitous Honda gas generators.
Hope that helps.

If you’re forced to go with a low cylinder count unit hear good things about Phasor. There’s much bitching about fisher panda. Don’t know the truth.maybe they shake themselves apart or maybe there’s more complaints because there’s a lot of them out there. Do firmly believe low rpm units last longer, are easier to maintain and aren’t noisy so get my vote.

ksanders said:

As well as desalinization.

Few boats will be able to carry enough solar to allow for their boat's loads plus running the watermaker.

Click to expand...

We did fine for six weeks this summer making water from our 700W flex panels. But we have a Specra Venture which is about the most efficient watermaker out there. 10a draw at 8.5gph.

We heat our water with solar as well, but this would not work in a less sunny climate (I have a thread about this somewhere).

It really does depend on use case as others have said, and also what's already installed on the boat. If you don't have A/C, and have no generator currently installed I'd make a run at going without the generator, as you can always add later and it's very pricey to add from scratch.

In general, I think many boaters don't realize how good and cheap solar has gotten, and how efficient 12VDC electronics are. The monster power draws/obstalcles are:

- A/C (almost impossible with solar, no good alternative to a generator/shore power)
- Hot water (I use excess solar, good for sunny climates or large PV arrays, some compromise relative to limitless hot water from a generator, possible with propane but needs care for a safe install)
- Cooking (Probably possible with LiPo batteries, but propane works really well for this)

Powering efficient refrigeration, LED lights and modern electronics with solar is, IMHO, now trivial for most applications.

CharlieO,
1. been looking at boats for awhile.
2. 'starting out as a weekend boat'.
3. cruise the Bay.

Okay, that answers 3 questions.


Boating experience?
Long term plans with the boat?
What range of lengths are you considering?
Length of voyage?? Day trip, overnight..... a week vacation, longer?
How many of your 'newly discovered friend' do you anticipate being onboard

Have you considered chartering a boat of the approx length you are seeking? Dont run the gen or AC or hot water. See if you and your 'other' will enjoy the 'no gen', no AC effect. Remember, before the availability of solar panels folks would charge batteries off the main engine or shore power or generator. (Oops, scratch the generator)
Without a generator you will be close to camping. Yes it can be done but, do you want it?
As was pointed out, solar panels can supplement but without a bunch of solar panels, you may be going down the wrong road.
Just because you have a generator does not mean you need to run it 24hrs/day. (unless you are running the AC all day.)
You can run the gen in the morning for electric cooking and heating the water. Determine the percentage charged during that time.
You are anticipating a gas stove. That will eliminate the electrical cooking load. Take cold showers? Been there done that and dont want to do it again.
Plumb the engine to the water heater coil. That will do doing double duty with the main engine run, charging the batteries and heating the water.

There are many ways one can live without a generator and AC..... be creative in your thinking and planning but try not to be disappointed when things just aint right.

Ah someone mentioned a fuel cell. That has not been a popular discussion. Fuel cell to charge the batteries. Yes, it can be done but cant run the AC electric stove or water heater with that fuel cell setup.
I will let other chime in with their recommendations for number and size of batteries.

OldDan1943 said:

CharlieO,
1. been looking at boats for awhile.
2. 'starting out as a weekend boat'.
3. cruise the Bay.

Okay, that answers 3 questions.


Boating experience?
Long term plans with the boat?
What range of lengths are you considering?
Length of voyage?? Day trip, overnight..... a week vacation, longer?
How many of your 'newly discovered friend' do you anticipate being onboard .

Click to expand...

Been on a couple a whale watch cruises.

Plans for this is boat is learning including hiring a training captain.

Start out as dock condo working our way up in experience to couple week cruises combo marina and anchoring

All new friends must look acceptable in a bikini and know how to fish

Looking at 32-36 footers with two state rooms

CharlieO. said:

Been on a couple a whale watch cruises.

Plans for this is boat is learning including hiring a training captain.

Start out as dock condo working our way up in experience to couple week cruises combo marina and anchoring

All new friends must look acceptable in a bikini and know how to fish

Looking at 32-36 footers with two state rooms

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2 stateroom??? Might want to seek mid 30ft to mid 40ft length.
This is going to be your retirement boat?
Look at available storage space. never enough
Also a training captain....
Insurance availability may be difficult to get if you have not owned a boat of any size.
I suggest you begin by chartering a boat with a training captain. That will quell the insurance company. He will watch and show

Old Dan, I do like to jest a bit. My last boat was a 20ish cuddly cabin. I have worked ona variety of commercial vessels in Alaska when I was a bit younger. This more than likely will not be our retirement boat, we do have our 8 year old son too We’d like this to be our learning boat so we can really narrow down what we want and need before we buy our full timer.. We really like a gulfstar 36 we looked at. Single Lehman with a bow thruster.

CharlieO. said:

Old Dan, I do like to jest a bit. My last boat was a 20ish cuddly cabin. I have worked ona variety of commercial vessels in Alaska when I was a bit younger. This more than likely will not be our retirement boat, we do have our 8 year old son too We’d like this to be our learning boat so we can really narrow down what we want and need before we buy our full timer.. We really like a gulfstar 36 we looked at. Single Lehman with a bow thruster.

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LOL CharlieO, I did 7 war patrols on nuclear powered FBM. I was all the way aft with the 'pressure cooker' that did not impress the insurance company.
I never did steer the sub. SHRUG

I did have an admiral proudly say, he was the one who directed all the subs on the east coast. I looked him straight in the eyes and said, 'I am the one who got the sub there.' Lucky for me, I was no longer in the navy and he was retired. LOL

I have an all-electric boat, 700 watts solar, 1000 ah batteries, 5 kw genset, diesel heat,, no AC. During PNW summer cruising, the gen gets used very little, only for the galley stove. But if I had to do it over, I would add the maximum solar panels the boat could carry but still have a generator. I consider it to be a layer of redundancy that I like having, especially in remote areas when we're far away from any support.

Ken E. said:

I have an all-electric boat, 700 watts solar, 1000 ah batteries, 5 kw genset, diesel heat,, no AC. During PNW summer cruising, the gen gets used very little, only for the galley stove. But if I had to do it over, I would add the maximum solar panels the boat could carry but still have a generator. I consider it to be a layer of redundancy that I like having, especially in remote areas when we're far away from any support.

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Putting aside the electric galley stove, why do you need the generator if just for redundancy? Presumably you have two alternators already. I know it's not great to use the main engines as massively oversized and inefficient generators, but they'll certainly do the trick in a pinch. To me, redundancy means it can get you through the cruise until a repair can be made. And solar is really really reliable.

I wouldn’t be without a generator. And that’s because I want hot water, fast recharge while at anchor, water maker for limitless fresh water, washer and dryer, and air conditioning.

So I thing you need to decide what matters to you, what can practically fit on your boat, then evaluate power needs. Lots of people live happily without, and lots of people don’t want to live without. Your pick.

Ken Williams, another serial Nordhavn owner, wrote about his decision matrix when building his recent GB60. A lighter weight boat, he agonized over having a single generator. He and his wife had long ago decided they were a "generator" boat meaning 24/7. As TT says, it's a lifestyle decision to have a floating apartment with all amenities.

Just depends on your priorities. Frankly, if I wanted 24/7 comfort, I wouldn't leave the dock. My sensibilities run towards old world cruisers. Not a knock or anything just when I close my eyes and picture cruising, it's desolate, close to the water, and spartan. I've traveled on a no-limit expense account. It's not my preference. Personal choice - Solar is ideal for me, but my sense is my style is more austere than many in similar circumstances.

Peter.

mvweebles said:

Ken Williams, another serial Nordhavn owner, wrote about his decision matrix when building his recent GB60. A lighter weight boat, he agonized over having a single generator. He and his wife had long ago decided they were a "generator" boat meaning 24/7. As TT says, it's a lifestyle decision to have a floating apartment with all amenities.

Just depends on your priorities. Frankly, if I wanted 24/7 comfort, I wouldn't leave the dock. My sensibilities run towards old world cruisers. Not a knock or anything just when I close my eyes and picture cruising, it's desolate, close to the water, and spartan. I've traveled on a no-limit expense account. It's not my preference. Personal choice - Solar is ideal for me, but my sense is my style is more austere than many in similar circumstances.

Peter.

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That's a good way to look at it.

Please though, if you are gonna be a generator boat... please... either make the damned thing so quiet I can't hear it or run it very sparingly during the day.

Cat Harbor a few weeks back a big Hatt sporty pulled up to the mooring next to us and their generator was like a lawnmower running on deck. They started it up at 6am and stopped it (per the rules) at 10pm, blowing fumes downwind into our cabin most of that time. It sucked. I hate generators. Same when camping.