Why you might consider still keeping your generator

[aqfishing]

“ No longer keeping up with my 120(ish) AH nightly use. Use is also increased from running heaters, which heat my refrigerator and freezer.”

Please may I never end up in a place where I need to heat my fridge and freezer, especially my freezer!!!

[JBsurfin]

Originally Posted by Chotu

Lately, the solar insolation has gone way, WAY down.

Anyone doing higher latitude cruising might want to consider keeping their generator.

The sun doesn't get directly above my boat anymore. Not by a long shot. So, even if it's out, which it is for a short time each day that it's not cloudy, you are getting severely reduced solar power with catamaran style fixed roof mount solar.

Very thankful to have my generators

No, that's not the moon. That's the sun on a "mostly sunny" day. Lol

No longer keeping up with my 120(ish) AH nightly use. Use is also increased from running heaters, which heat my refrigerator and freezer.

Using the generator to top off

I'll stick with my Honda EU2000I Inverter Portable Gas Powered Generator 2000 Watt - SUPER QUIET, cant hear @ 15ft away. holds 1 gal of gas in a fully sealed lid and vent. Runs 8 hrs on 1 tank. I don't carry spare fuel, just fill it when needed. Been using for for over 6 yrs now.

[TPG]

We built a new boat and specifically did not install a genset. Rather, I have a Honda 2200 as a backup and it works nicely for us. I get the same benefit as being on shore power with it and it helps us when we don't take in enough solar. It's a minor pain to use but after our last boat I really didn't want another diesel genset to take care of.

[The Yacht Rigger]

Originally Posted by Shaneesprit

Hmm removed my generator but I have 2 x185A Alternators driven by a Diesel engine aka a Generator! Just saying.

Haha, yup, but equivalent to a MUCH bigger generator without the need for bulky chargers etc, and I got rid of an entire motor, fuel, and raw water cooling system.

[sailingharry]

Originally Posted by Chotu

Lately, the solar insolation has gone way, WAY down.

Anyone doing higher latitude cruising might want to consider keeping their generator.

The sun doesn't get directly above my boat anymore. Not by a long shot. So, even if it's out, which it is for a short time each day that it's not cloudy, you are getting severely reduced solar power with catamaran style fixed roof mount solar.

Very thankful to have my generators

Chotu, I read and remembered this post, even though it should be obvious (but not everything that should be obvious is actually noticed). Then, over on a solar forum (the Electrodacus forum), there was a similar discussion and reference to PVwatts, a US Gov't site that calculates output for panels based on latitude, orientation, location weather, etc. Curious, prompted by this post, I made a small table, showing output for completely flat panels (as most of us have), for the 4 major months (the two equinox and the two solstice months). I assumed a 1kW array. The output is kWh/month, but can be used as a simple index for comparison. I then used locations at Key West, Annapolis, Mt Desert Island, and (for Mike O'Reilly!), St. Johns, NF. The differences are as expected, but still profound.
Two interesting notes.
The equinoxes are not identical. I attribute this to seasonal weather changes.
The deep south, well below the Tropic of Cancer, has LOWER production at the summer solstice than at the spring equinox. I attribute this to the sun being north of Key West.
While not shown in this table, but as pointed out on the solar forum, northern latitudes in winter are better served with vertical panels than horizontal panels (really!), although that's a pretty awful plan on a moving boat.
Note, if you use the rule of thumb that says a solar panel produces 3 times its rated output per day, a 1kW array should make 90kW/month. This table would imply closer to 4-5 times -- but real life has shadows, bird poop, IR wires losses, etc.

[Chotu]

Looks pretty accurate from my experiences traveling these areas.

Nice data.

There are a lot of factors involved. Really, the hours of daylight seems to be one of the main factors. The angle of incidence doesn’t seem to be as brutal as the hours of daylight getting short. You can see from your data, in the north, during the summer, it’s more than Key West in the winter. Like you were saying. I believe that has to do with 14-16 hours of daylight combined with overhead sun.
Down in Florida, it gets light at 6 AM and it gets dark at 6 PM. That’s pretty much it. There isn’t much variation. However, way up north here, it stays light until 10 PM for some of the summer. (Dark at 3pm in winter) That’s a big difference on solar production. That’s also what’s killing me now. Getting dark at 4:15 PM or so. Getting light at about 7 AM. That’s not much daylight. And it also takes until about 10:30 AM for the sun to get up to the right angle to start producing real power at all. And because of that I definitely believe the upright panels would be the way to go. The sun is not overhead here at noon. It’s up over the horizon at noon.

Thanks for sharing the numbers. Definitely shows what I was talking about in this thread. Having a generator to fill in the gaps is really really nice. Keeping a generator around for wintering over away from power sources was kind of the point of my thread even though some missed that I guess.

I have settled on a schedule with mine. I run it three hours every three days. That’s about what it needs. A very small amount of use, but with the efficient lithium batteries, that’s all that’s needed. I can run it less if I get lucky with very sunny days. I have about 100 gallons of gasoline on board and at this generator run rate, it seems like that should last all winter long. Generator takes about 1/4 gph at the battery charging load

[Chotu]

This huge catamaran size solar installation with twin Outback Flex 60 MPPT controllers made 7AH yesterday!!!! Lol

A grand total of 7AH over the entire day from dawn to dusk!

Wow. Such a dramatic difference from making 140 AH and ending the charging cycle before noon in the summer

9 hours of daylight, sun very low on the horizon at noon and a rainy day makes for no electricity and probably needing to take vitamin D supplements or eat a good amount of fish.

Don’t ditch that generator if you’re north in the winter.

Not only did the solar production go down, but the power consumption went up. Running the heaters 24 hours a day takes a lot of power. It also creates a lot of power demand from the refrigerator and freezer since they are kept warm.

Power consumption was way down when I went snowboarding for the weekend and turned the heat off.

All in all, this is quite a test for a boat’s electrical system.

[noelex 77]

Originally Posted by Chotu

Running the heaters 24 hours a day takes a lot of power.

Heaters that do not use any electrical power are more practical if you want to cruise cold climates without a generator.

[Chotu]

Originally Posted by noelex 77

Heaters that do not use any electrical power are more practical if you want to cruise cold climates without a generator.

Naturally.

This is the first time I have ever used these very popular forced air diesel heaters. I now understand their popularity because they are not radiant heat. They evenly heat the boat like nothing else really can.

I usually winter over with wood heat. Have done a good Dickinson propane system (no electricity) and have done a Dickinson drip diesel which I hated.

Lots and lots of experience

The thread and post is about not getting rid of your generator. I don’t care what heater you are using, 7AH per 24 hour period is not a good daily power generation figure. Ha ha ha

[noelex 77]

Originally Posted by sailingharry

Note, if you use the rule of thumb that says a solar panel produces 3 times its rated output per day, a 1kW array should make 90kW/month. This table would imply closer to 4-5 times -- but real life has shadows, bird poop, IR wires losses, etc.

These rules of thumb are often repeated on sailing forums, but in my view they can be very misleading. In reality, solar insolation varies enormously Unfortunately, there is a tendency to use these rules of thumb to plan an electrical system.

There are cruising grounds such as the Caribbean where the solar insolation is excellent year round. In these areas you can can do better than rules of thumb would suggest, but in many other areas solar insolation is poor at least for some parts of the year. The rules of thumb can be wildly wrong, as this thread shows.

It is much better to design an electrical system taking into account the solar insolation for the areas you wish to visit rather than using these rules of thumb. Cruising areas of reasonably poor solar insolation is feasible without a generator, but you need to install equipment and systems that take this into account.

[noelex 77]

Originally Posted by Chotu

Naturally.

I don’t care what heater you are using, 7AH per 24 hour period is not a good daily power generation figure. Ha ha ha

What is your average solar panel production at this time of year?

[Chotu]

Originally Posted by noelex 77

These rules of thumb are often repeated on sailing forums, but in my view they can be very misleading. In reality, solar insolation varies enormously Unfortunately, there is a tendency to use these rules of thumb to plan an electrical system.

There are cruising grounds such as the Caribbean where the solar insolation is excellent year round. In these areas you can can do better than rules of thumb would suggest, but in many other areas solar insolation is poor at least for some parts of the year. The rules of thumb can be wildly wrong, as this thread shows.

It is much better to design an electrical system taking into account the solar insolation for the areas you wish to visit rather than using these rules of thumb. Cruising areas of reasonably poor solar insolation is feasible without a generator, but you need to install equipment and systems that take this into account.

Not feasible. You’re not designing a solar system to work here.

I have 1500 watts of solar and 120A of MPPT charge controllers.

7AH production over 24 hours yesterday.

Until you try it, you just don’t know. What is forgotten (and can’t be accounted for empirically)is the weather.

[Chotu]

Originally Posted by noelex 77

What is your average solar panel production at this time of year?

I don’t know. I haven’t existed at this time of year yet at this latitude with this boat

Bottom line? Don’t toss the generator if you’re off grid in high latitudes in the winter.

Solar won’t cut it on a boat, no matter how much you have and I’d say 1500 watts with 120A max charge controller output is a pretty generous size system.

Insolation is weak and it rains and snows a lot. Quite thankful I DID design a good electrical system that can be used anywhere on Earth. That includes alternative power production methods such as the generator. (Or alternator for some folks)

Throwing out that capability is a mistake for high latitude destinations

[rslifkin]

If Chotu is getting winter weather anything like we get here, then I agree, solar alone won't keep up in the winter. You'll get reduced, but still decent output on the good days. But there can be a week straight of solid overcast with rain, snow, etc. and resulting poor output. To get enough solar in that weather you'd need more panels than you could ever fit on a boat. I've seen it go grey here for so long (over 2 weeks) that when the sun finally came out it was actually disconcerting seeing sunlight coming in the windows.

That said, winter is often windy here, so a wind gen might make a good supplement to solar.

[Matt Johnson]

Originally Posted by Chotu

Not feasible. You’re not designing a solar system to work here.

I have 1500 watts of solar and 120A of MPPT charge controllers.

7AH production over 24 hours yesterday.

Until you try it, you just don’t know. What is forgotten (and can’t be accounted for empirically)is the weather.

They live it. Wintering over in Scotland at anchor with 1000w of solar, agm batteries and no generator. I saw them do it with my own eyes