solar or generator?

[dhays]

I mounted a full size panel on my PH roof. I found an AL “L” bracket designed for solar panels, but used three of them to creat an adjustable mount. I then mounted these four mounts to the PH roof using 4200.

This panel has been there for a few years now and has faced all kinds of high wind and jarring seas. It has worked great.

 

[GoneDiving]

On my previous boat I sikaflexed 1" square teak lengths to the FB, screwed right angle aluminum strip to the panel sides, and screwed the other side to the teak strips. Achieving 1" clearance for the panels and no penetration of the FB deck. All stayed in place.

Another good thing is that these are easy to remove when needed or changing panels. I just hooked on my davit crane and slowly winched in until the seal broke. Sounds rough but no damage to underneath and 5 minutes with a utility knife had everything clean.

 

[Simi 60]

^^^^^^Or you could simple undo the bolt holding panel to bracket and bolt a new panel back in.

 

[GoneDiving]

^^^^^^Or you could simple undo the bolt holding panel to bracket and bolt a new panel back in.

Assuming this was a reply to my message:

Not if I am totally changing the number, size, direction and layout of the panels and supports. ?

 

[mcarthur]

I mounted a full size panel on my PH roof. I found an AL “L” bracket designed for solar panels, but used three of them to creat an adjustable mount. I then mounted these four mounts to the PH roof using 4200.

This panel has been there for a few years now and has faced all kinds of high wind and jarring seas. It has worked great.

So it's only held down by the 4200 - couldn't see any nuts or heads in the pictures? That's impressive given the forces involved in being thrown about. I going to see how VHB tape worked, but I'll think about the 4200 as well. Thanks

 

[Simi 60]

I used 150 X 50 hollow plastic garden sleepers for our cut into 100mm sections,
Glued down with sika pro sausage
Have seen 80+ knots with no issues.

 

[mcarthur]

I used 150 X 50 hollow plastic garden sleepers for our cut into 100mm sections,
Glued down with sika pro sausage
Have seen 80+ knots with no issues.

Wow, your engines really push you along ...

Good to know Sika works too, I may be overthinking it .
I was going to mount the semi-flexibles on some open channel polycarbonate, say 10mm, to allow air flow through the 10mm openings which point fore-aft. 3M/Sika the panel to the poly, and same for poly-cabinroof.
I have heard of someone running cooling water through the poly (or similar opening under the panel) for cooling but that seems inordinately complex even if it gives a 15% boost (about 9% for front water cooling and 15% for back cooling according to research).

 

[Simi 60]

Wow, your engines really push you along ...

Good to know Sika works too, I may be overthinking it .
).

And that's the cheap sika not the "marine" stuff
Same same but no boats on the tube.

 

[BruceK]

Wow, your engines really push you along ...

Good to know Sika works too, I may be overthinking it .
I was going to mount the semi-flexibles on some open channel polycarbonate, say 10mm, to allow air flow through the 10mm openings which point fore-aft. 3M/Sika the panel to the poly, and same for poly-cabinroof.
I have heard of someone running cooling water through the poly (or similar opening under the panel) for cooling but that seems inordinately complex even if it gives a 15% boost (about 9% for front water cooling and 15% for back cooling according to research).

My understanding: a 10mm gap(if that`s what`s proposed) between deck and panel doesn`t allow enough airflow cooling in all conditions, recollection is 25mm is recommended, where, can`t recall.
I sometimes use Parfix polyurethane sealant/adhesive(Bunnings sell it),way cheaper than Sika, does the job,but their white yellows with age, Sika doesn`t.
PS: With Simi, it`s "engine".

 

[rslifkin]

As a note on gluing panel mounts down with the 3M adhesive, 4000UV has a stronger bond to aluminum than either 4200 or 5200. So far, my aluminum mounts glued to the deck with 4000UV are doing just fine.

 

[DavidM]

It looks like this thread has gone way off its original topic, so here are my views on the original question: Which is best, solar or generator?

My answer is both since they are complimentary. A generator is great for fast charging for an hour or two, particularly if you have a large enough charger that can take advantage of the generator's output. Then after putting in 100 Ahs or so into your batteries, let the solar panels finish charging them up during the day.

I have a 3.5 Kw NextGen generator that powers my water heater in the evening and coffee pot during the morning as well as my 100 amp inverter/charger. Running the generator for a half to one hour at night and the same in the morning brings the batteries up to about 90% SOC. My 100 watt solar panel finishes the charging during the day (if we have sun). If I had a bigger battery bank (I have 220 Ah) I would run the generator longer and increase the solar to 200 watts.

Works for me.

David

 

[OldDan1943]

Personally, I think there is room for all 3 on a boat, both a generator, alternator (with battery charger) and solar panels. And that is why I have all 3.

 

[DavidM]

Personally, I think there is room for all 3 on a boat, both a generator, alternator (with battery charger) and solar panels. And that is why I have all 3.

I agree but it takes a high output alternator with an external regulator to charge much. My last boat just had the OEM alternator so it wouldn't charge very well. My previous boat, a sailboat with no generator had a Balmar alternator and regulator and would charge at decent rates at least until the batteries got up to 85+%. The solar panel would finish it off.

David

 

[Hippocampus]

Depends on the boat. Last boat for full time living had the genset one hour per month. Had to think about getting enough load and exercise it.
This boat has the genset on just about anytime it’s underway in order to power up the SeaKeeper. Totally different way of living.
As said multiple times during this thread do a energy audit. Do it when on shore power, underway and at anchor. Then you know what you need. Look at your local environment. We got more power from the D400s while in the trades during winter then the Kyoceras. Look at your usage of the boat then decide. Although with wind and solar we really didn’t need a genset but when we did we did and it made a huge difference in quality of life.

 

[ksanders]

Personally, I think there is room for all 3 on a boat, both a generator, alternator (with battery charger) and solar panels. And that is why I have all 3.

That is the way to go, all three.

The fact remains that most folks choosing Either solar Or a generator do so because they cannot afford both.

If I were making that choice I would choose the generator.

Why??? The generator is more versatile. It will work in cloudy weather. It will power your whole boat 100% of the time and also recharge your batteries.

The only real reason to choose solar is if you look at the cost of energy produced by your generator vs the cost of energy produced by a solar installation and the solar comes out cheaper.

I have not done that math, figuring in the lifecycle costs of both systems. All I know is that with todays technology and my available space for solar panels, solar cannot fill all my needs even on a perfect day. If I add in the need to wash clothes, produce hot water, and desalinate water, the generator is even more so the only way to supply those needs at anchor.

On the flip side, on a cruising day, if I am underway all day I can cover pretty much all my loads plus recharge my batteries using my propulsion engines 150 amp alternator.

 

[rslifkin]

That is the way to go, all three.

The fact remains that most folks choosing Either solar Or a generator do so because they cannot afford both.

If I were making that choice I would choose the generator.

Why??? The generator is more versatile. It will work in cloudy weather. It will power your whole boat 100% of the time and also recharge your batteries.

The only real reason to choose solar is if you look at the cost of energy produced by your generator vs the cost of energy produced by a solar installation and the solar comes out cheaper.

I have not done that math, figuring in the lifecycle costs of both systems. All I know is that with todays technology and my available space for solar panels, solar cannot fill all my needs even on a perfect day. If I add in the need to wash clothes, produce hot water, and desalinate water the need for the generator becomes obvious.

Or if a generator just doesn't fit well into the boat in question (which may be the case if the boat was built without one, particularly for smaller boats). In those cases, it may be a matter of trying to avoid the generator unless it's really necessary.



That said, I wouldn't be without my generator. We don't need it a lot (we've put a whopping 20 hours on it this season, including a few exercise runs), but when we need it, we need it.

 

[OldDan1943]

Or if a generator just doesn't fit well into the boat in question (which may be the case if the boat was built without one, particularly for smaller boats). In those cases, it may be a matter of trying to avoid the generator unless it's really necessary.

That said, I wouldn't be without my generator. We don't need it a lot (we've put a whopping 20 hours on it this season, including a few exercise runs), but when we need it, we need it.

There are small 2 or 1 cylinder generators that should fit.

 

[mvweebles]

The choice isn't solar vs generator, choice is air conditioning or not (well, Seakeeper adds a wrinkle). A few posts up, Hippocampus mentioned his previous experience - he rarely needed a generator, but when he did, it really made a difference. I'd bet good money the back story includes sweltering, calm, humid days. Add a swarm of no-see-ums......

A generator can run a battery charger. Solar is a battery charger - 800w of panels will pump up to 60a of current, over 400ah on a sunny summer day with a nice regulated tail current to top off a bank. You don't have to do a thing - might even be able to unplug from your home-slip.

To the OP - If i had to chose between solar or generator? Well, I simply wouldn't buy a boat that couldn't accommodate at least 800w of panels.

Peter

 

[sbman]

The choice isn't solar vs generator, choice is air conditioning or not (well, Seakeeper adds a wrinkle). A few posts up, Hippocampus mentioned his previous experience - he rarely needed a generator, but when he did, it really made a difference. I'd bet good money the back story includes sweltering, calm, humid days. Add a swarm of no-see-ums......

A generator can run a battery charger. Solar is a battery charger - 800w of panels will pump up to 60a of current, over 400ah on a sunny summer day with a nice regulated tail current to top off a bank. You don't have to do a thing - might even be able to unplug from your home-slip.

To the OP - If i had to chose between solar or generator? Well, I simply wouldn't buy a boat that couldn't accommodate at least 800w of panels.

Peter

800W is just two residential sized panels, not too hard to do or a small collection of flexible 'marine' panels.

However, even with 800W of solar, it isn't enough for hot water or heating the cabin. It's enough for cooking, but even that assumes you see quite a bit of sun daily or near daily. In southern CA that's not much of an issue.

If you intend to be off the shore power cord and sitting in one place for long you probably need a generator unless you've reconfigured the boat to live on a few hundred watts per day, or can fit a lot more solar.

I think that in many cases a generator is going to be required. Even with a generator solar can improve the longevity and health of your lead acid batteries with a frequent 100% top up. Moving frequently can help with that too if your alternator is sufficient to charge up our house bank.

 

[ksanders]

The choice isn't solar vs generator, choice is air conditioning or not (well, Seakeeper adds a wrinkle). A few posts up, Hippocampus mentioned his previous experience - he rarely needed a generator, but when he did, it really made a difference. I'd bet good money the back story includes sweltering, calm, humid days. Add a swarm of no-see-ums......

A generator can run a battery charger. Solar is a battery charger - 800w of panels will pump up to 60a of current, over 400ah on a sunny summer day with a nice regulated tail current to top off a bank. You don't have to do a thing - might even be able to unplug from your home-slip.

To the OP - If i had to chose between solar or generator? Well, I simply wouldn't buy a boat that couldn't accommodate at least 800w of panels.

Peter

I think saying 800W of solar as a requirement depends on the size of the boat, and the lifestyle of those onboard.

On my boat before heating/cooling, desalinating, cooking, washing clothes, or making hot water we draw between 35 and 45 amps at 12 volts all the time. I have seen it dip down to 30 amps but that is pretty rare.

If i had to give up my generator it would require much more than 800W in solar panels, plus it would require a larger energy storage capability.

I guess the point is that there is no one size fits all solution. On a larger more complex boat it becomes much more difficult to give up the generator.

 

[mvweebles]

As has been said, an energy audit is in order. There is a practical limit for a small-ish sized solar system. What is that limit? For boats under 50-feet or so, somewhere in the 4kwh-5kwh per day range (an array of 800-1000 watts or 4-5 square meters), which is in the range of 300-400 ah (12V). For Kevin's Bayliner, that's not even half his energy budget. Either he goes on a diet, or he runs a generator. It's a lifestyle decision.

Peter

 

[healhustler]

My Northern Lights genset engine locked up a few months ago and I’ve been struggling with finding a replacement, getting parts to repair, and/or the decision to chuck the genset in favor of solar. Last evening in our umteenth discussion about it, we decided to go with 2000 watts of Solar. It was EIGHT years ago that I cleared and re-skinned our pilothouse roof for that purpose but have delayed and delayed over and over, figuring that the next year the prices would be substantially lower.

I was right all eight of those years. It seems we needed the genset to totally crap out to finally push us over the edge. Here in FL, 2000 watts combined with an appropriate battery bank will take care of all our needs aboard. Prices, even for LiFePo4 units have come down enough to make it practical for our usage as a recreational vessel and an alternative home. We’re doing it.

The only thing I don’t like about the idea is putting the weight up high. Semi-flex panels are light and easy, but lifespan not so good. The rigid panels are 50lb each. Not a disaster, but I’ve been conscious of every pound of weight I’ve added and subtracted from our boat. Having that weight so far above the waterline just rubs me. There’s space for four 420 watt panels on the 8.5 x 12.5 roof and one on top of the dinghy davits. I may add some ballast.

 

[Simi 60]

My Northern Lights genset engine locked up a few months ago and I’ve been struggling with finding a replacement, getting parts to repair, and/or the decision to chuck the genset in favor of solar. Last evening in our umteenth discussion about it, we decided to go with 2000 watts of Solar. .

As a full time cruiser I will ask.
Remind me what happens on rainy days with no sun?

. There’s space for four 420 watt panels on the 8.5 x 12.5 roof and one on top of the dinghy davits. I may add some ballast

Why them?
Why not cheap and plentiful residential panels
We got 2500w of 2nd hand tier 1 Jinko 270w with 9.5 years of the 10 year warranty remaining for about $650 in total delivered to the boat when out for antifouling.

 

[sbman]

As a full time cruiser I will ask.
Remind me what happens on rainy days with no sun?




Why them?
Why not cheap and plentiful residential panels
We got 2500w of 2nd hand tier 1 Jinko 270w with 9.5 years of the 10 year warranty remaining for about $650 in total delivered to the boat when out for antifouling.

Today it is a rainy and overcast day. With 1100 watts of solar, I still collected 1000 watts over the course of the day at about 200 watts per hour, with batteries full by 1 PM. A lot less than a fully sunny day could have been, but if your battery bank is sized to go for a few days with less power input, you can get through.

I actually collected more power earlier today than usual on sunny days because the overcast sky reduced the shading I typically get in the mornings replacing it with diffused, even light. If it had rained hard all day I would not have collected much until tomorrow.

 

[Simi 60]

A lot less than a fully sunny day could have been, but if your battery bank is sized to go for a few days with less power input, you can get through.
.

And if it's grey and overcast for several days?
Or in winter where the sun angle and less daylight hours has production down.

I guess what I am saying is we would be fked without a Genset, even if it is rarely used.
And I would think you would be as well.

 

[sbman]

And if it's grey and overcast for several days?
Or in winter where the sun angle and less daylight hours has production down.

I guess what I am saying is we would be fked without a Genset, even if it is rarely used.
And I would think you would be as well.

That is what you are saying, but it's geographically and system/usage specific. It is nearly winter here and the days are shorter and sun angle poor, the panels are facing north, but it is also only 32 degrees latitude in San Diego. It won't get a lot worse here.

Take the same system to Seattle or even farther north, or increase the consumption and it's going to perform quite a lot differently. Each user has to take all that into account when choosing how much power they get from all available sources and if it meets their needs or not. For some, a 30 amp shore power cord is marginal, others can live on 800W of solar with a Honda 2000 as a backup.

 

[OldDan1943]

HealHustler, I am just a tad bit confused. Your NL locked up? Have you had a tech come out to investigate? Did he give you an estimate?
I would not consider a boat with a broken generator.
Many many NL techs around here, aka Ft Lauderdale, Miami etc.
Let's face it, repairing you NL is not going to get any cheaper.

 

[healhustler]

HealHustler, I am just a tad bit confused. Your NL locked up? Have you had a tech come out to investigate? Did he give you an estimate?
I would not consider a boat with a broken generator.
Many many NL techs around here, aka Ft Lauderdale, Miami etc.
Let's face it, repairing you NL is not going to get any cheaper.

Haven’t had a tech look at it, but I’ve spent the last two months soaking and coaxing it, finally had the head off and I see she’s going to need disassembly and at least honing of the cylinders. Apparently, one of our storms pushed water up the exhaust. We haven’t used it since the raw water intake clogged two years ago. Covid and yard delays pushed our usual haulout & maintenance way back…consequences of neglect.

 

[Hippocampus]

I’ve often wondered why you nearly never see wind generators on power boats. As mentioned before we consistently got more power from our 2 D400s when down in the islands for the winter. In Grenada you’re at 12N but the day is ~12h the year long. Given the trades when anchored out you see no less than 10k and more often closer to 20 so you’re well above the knee in the power production curve. Unlike earlier versions the newer wind generators are nearly soundless. Given ours were above a hard Bimini we had to look to see if they were turning.
Up north in the summer the days are longer and the steady trades are gone. Then the solar but only then the solar came into its own. Still, the biggest difference between sail and power is no engine while underway so no alternator. Here having both solar and wind was important.
Most boats, even those of active cruisers, spend 90% of their time still. Think especially for small boats with Pb battery banks an important question is how much time are you not plugged in. This is especially important for those with AGMs. There’s no way you’ll get a decent service life out of AGMs unless you bring them all the way up to 100% fairly frequently. So if you sit on a mooring or you spend time mostly at anchor when cruising there’s going to be times you’ll approach or even exceed that terrible <50% SOC and kill your batteries quickly. Even with stuff off and only parasitic draws. Much less likely with wind and solar. Very rare you have poor solar days without it being windy. Never happen with a brief genset run to bring the bank to at least float or near float before you leave (if on a mooring) or every few days if at anchor for awhile.
If I was space or boat buck limited to the point a small phasor (stay away from fisher panda or a gas Honda imho) made a NL or equal quality genset couldn’t happen I’d put one or two wind generators on my boat. They run 24/7/365. No maintenance, nearly silent power and commonly give you power when solar is poor and vis a versa. Great combo for small boats solar and wind. Don’t understand why not seen on powerboats.

 

[Simi 60]

Decent (quiet) wind gens cost big $$ and aren't actually very good
Low output for $$ compared to solar

Eg: if I am reading this right, $4000 to provide the same power we get from $150 worth of panels

https://chsmith.com.au/Products/DuoGen-D400-Wind-Generator.html

https://bla.com.au/product/silentwind-wind-generator-400-turbine-series/