Generator or No generator, that is the question

[Dockhead]

Originally Posted by s/v Jedi

. . .About panels being speed brakes while sailing upwind: we installed 1,875W and our first offshore passage was a Gulf Stream crossing from Florida to the Bahamas a couple months ago. We had 15-20kts wind, at a close reach, buckling the current a bit to make Memory Rock to cross onto the bank. . . .

The issue is not close reaching -- it is going upwind. Do you record VMG to windward on dead upwind legs? I would be curious to know what values you achieve.

[parachute]

Lithium-ion batteries commonly used in consumer electronics are notorious for bursting into flame when damaged or improperly packaged. ... "If the battery is damaged and the plastic layer fails, the electrodes can come into contact and cause the battery's liquid electrolyte to catch fire

List of UK Lithium battery fires: https://resource.co/article/lithium-...llion-annually


On the generator front I asked a number engine repair shops in the Caribbean what they had to repair least. First, engines was Yanmar with nobody close, generators Northern Lights with Westerbeke a very close second.

[s/v Jedi]

Originally Posted by parachute

Lithium-ion batteries commonly used in consumer electronics are notorious for bursting into flame when damaged or improperly packaged. ... "If the battery is damaged and the plastic layer fails, the electrodes can come into contact and cause the battery's liquid electrolyte to catch fire

List of UK Lithium battery fires: https://resource.co/article/lithium-...llion-annually


On the generator front I asked a number engine repair shops in the Caribbean what they had to repair least. First, engines was Yanmar with nobody close, generators Northern Lights with Westerbeke a very close second.

Really? Still today, after all those years of explaining how batteries aboard should not be Lithium Cobalt because of thermal runaway but rather Lithium Iron Phosphate LiFePO4 to prevent fire aboard.... and you missed that? Some still put Tesla batteries in, ignoring the coolant channels and connections but it is rare.

For generators I know our Northern Lights has the highest reputation but I was under the impression that Kohler was higher up than Westerbeke ?

[s/v Jedi]

Originally Posted by Dockhead

The issue is not close reaching -- it is going upwind. Do you record VMG to windward on dead upwind legs? I would be curious to know what values you achieve.

I have been lucky this year not needing any upwind sailing yet. Don’t plan any either

That said, as you heel, most of the underside of the array would be in the wind shade from the hull? Also, most boats with our setup on a stern arch have their dinghy right under the panels so it won’t make much of a difference either way.

[Dockhead]

Originally Posted by s/v Jedi

I have been lucky this year not needing any upwind sailing yet. Don’t plan any either

That said, as you heel, most of the underside of the array would be in the wind shade from the hull? Also, most boats with our setup on a stern arch have their dinghy right under the panels so it won’t make much of a difference either way.

It depends on the height of the array. I don't know about your boat, but on my old boat the solar panels were high enough to avoid the wind shadow of the hull. In fact the solar panels on my boat were right in the acceleration zone where the wind curves around the rail, multiplying the drag. I think that's pretty typical; however I don't know about your particular setup.

Dinghy hung in the breeze is even worse than solar panels. Getting rid of that was one of the first things I did when I starting working to improve upwind ability of my boat. I still have davits, but I strike my dinghy up on deck, deflate and fold it and stow it on the foredeck, before starting upwind legs.

In the tropics you might not have much need to sail upwind, so maybe none of this matters to you. For us at our latitude and the kind of passages we do it's really important. I have had to sail upwind for 1000 miles at a time. I avoid tacking much on long passage -- preferring to work wind shifts -- but that doesn't mean that I can always avoid sailing hard on the wind for long distances, maximizing VMG to windward.

[Cpt Mark]

Originally Posted by JustMurph

Totally doable. I have a Bauer Junior II that I run purely on solar generated power. There are a few ways to do it. The issue you need to get around, is that the startup power draw of the 2.2 kW single phase motor is just over 10kW for around a second. My 5kW Victron Multiplus which is rated to do 10kW for 30 cycles, can't quite start it.

I tried using the same softstarter that Big Beakie uses on his similar setup, but had no luck. So, I swapped out my single phase motor for a 2.2kW 3 phase motor and bought a small Siemens single phase to three phase VFD (variable frequency drive). This lets me ramp the motor up to full speed over 5s, bringing the peak power down within the inverters rating. It works really damn well. The downside is that you add another layer of inefficiency to the system, but functionally it hasn't proven to be an issue so far.

I have a similar Bauer as well. My thought on the start up current was to open all the stage valves 1st then start it up and close each stage one at a time as it runs and can handle it. Bauer told me a 3hp motor would not be able to run the compressor. I didn't quite believe that one and am so glad you've proved it can be done.

[s/v Jedi]

Originally Posted by Dockhead

It depends on the height of the array. I don't know about your boat, but on my old boat the solar panels were high enough to avoid the wind shadow of the hull. In fact the solar panels on my boat were right in the acceleration zone where the wind curves around the rail, multiplying the drag. I think that's pretty typical; however I don't know about your particular setup.

Dinghy hung in the breeze is even worse than solar panels. Getting rid of that was one of the first things I did when I starting working to improve upwind ability of my boat. I still have davits, but I strike my dinghy up on deck, deflate and fold it and stow it on the foredeck, before starting upwind legs.

In the tropics you might not have much need to sail upwind, so maybe none of this matters to you. For us at our latitude and the kind of passages we do it's really important. I have had to sail upwind for 1000 miles at a time. I avoid tacking much on long passage -- preferring to work wind shifts -- but that doesn't mean that I can always avoid sailing hard on the wind for long distances, maximizing VMG to windward.

We have wildly different opinions on cruising... what you are doing is racing. I bet you take your dinghy belowdecks on passage, right?

Don’t worry, you’ll have enough solar... a couple years in the tropics will fix you haha

[JustMurph]

Originally Posted by Cpt Mark

I have a similar Bauer as well. My thought on the start up current was to open all the stage valves 1st then start it up and close each stage one at a time as it runs and can handle it. Bauer told me a 3hp motor would not be able to run the compressor. I didn't quite believe that one and am so glad you've proved it can be done.

I tried opening all of the bleeds, but that didn't help unfortunately.
The VFD is 3kW to give it some over head, but with that nice slow 5s ramp up there's no surge to any more than full load power.

One thing I meant to mention is that there's another option, which is what we'll be doing for my mate's dive compressor, hopefully some time later this year. That is going a brushless DC motor and ESC. This will be by far the most efficient and probably cheapest option. That said, the motor probably won't be a direct bolt on like 3 phase motor was and we've found that finding a 2.2kW 24V is difficult, while 48V is pretty easy.

The next stage for the setup is automating the condensate drains and auto shutoff at full pressure. The Siemens V20 VFD that I'm using has basic PLC functionality with all of the inputs and outputs I need, so hopefully it can do it. It'll just depend on how configurable it is. Otherwise I'll buy a small PLC (Siemens LOGO). But that's a project for when I have some time on my hands and have the many other more critical boat jobs done.

[Cheechako]

Originally Posted by MarkHopk

Hi Fellow Sailors,

We are putting together a energy system for our 40 ft Catamaran.
Please can we get your suggestions on the below:-

We will be powering, lights, laptop, navigation, fans and other day-to-day household needs.
We will on occasion utilise a washing machine, aircon and small low amp dishwasher.

Could we do this without a generator and by just having the right lithuim battery, inverter and solar panels? And if so How much AH lithium batteries and how much solar Watts would we need?

Thanks.

With those I would definitely have a generator.
I removed a generator from my 42 cat and never missed it, never had AC in the Caribe. Never felt I needed it either. But to each his own.

[Statistical]

Originally Posted by chrisr

while i don't disagree totally with the thought, what a lot of non-cat folk don't realise is even with the big roof space it is not always possible just cover it with solar panels

eg you need access to the boom (for reefing, maintenance etc)... there are hatches to open...toys to stow...control lines

of course we all have the targa bar, but there are windage and trim issues

sure we can fit more solar than a mono, but it's not not as easy as you'd think

cheers,

Agreed although challenges aside the potential solar "acerage" is probably my biggest envy of a cat. As challenging as it is on a multi it is expontenially more challenging on a mono especially one in the 40 to 50 range beyond the "easy" 800W or so on a solar arch /davits.

[SailingFan]

And on my tiny H27... sheesh.. NO room if I want a dingy on the cabintop (not much room on the foredeck either, I am considering installing the 2 old 110w panels I have on the guardrails I am replacing the lifelines with, or maybe making them into the overhead of a hard dodger/bimini arrangement, but that might get ugly....er.....)..

[zboss]

We have a 5000 watt generator that we run several times a week for up to two hours each time. We use it to charge batts, heat hot water for showering, and run the washing machine.

Typically, we are only using about 6000 watts over those two hours to complete those tasks... maybe 3 times a week for a total of 1500Ah @ 12 Volts. Our generator cost about $10K to install and of course requires regular maintenance and periodic replacement of the powerhead every 3000-5000 hours. Also, it burns diesel.

We don't have the solar capacity to handle both our daily loads (about 150-200Ah in 24 hours) and filling up 1500 Ah of battery juice but for about $8500 we can get that same Ah weekly utilization using lithium batteries that could be supplementary charged by the engine alts. They would weigh a little less than the generator and since we aren't going to use batts to charge batts, probably would be more like 1000Ah of battery capacity.

The lithiums wouldn't need oil changes, diesel fuel, maintenance... and they could accomplish the same thing as the generator. if we were able to equip the boat with more solar and maybe two wind generators, we may never even need to run the alts to charge the batteries in a typical tropical winter cruise.

[Perfect Ride]

IMHO Even a small generator is a desired tool for energy. Perhaps not essential, but there will be times solar and wind will not generate enough and you will need to run propulsion engines as a generator even if drastically modifying your energy lifestyle. Living with the noise, heat and other aspects of running propulsion as a generator makes a generator a nice piece of equipment even if only used on occasion.



This from 5+ years living full time on a 44' cat sailing about six continents and many oceans and seas.

[dbraymer]

You are asking the wrong question. A good question, a highly technical question, a question where you should be familiar with the answers and the methods employed to arrive at the answers.

A better question: How much simpler would it be to equip the primary engine(s) with alternators and additional fuel, and just run them daily to charge up the existing battery bank(s)
1. You gonna need the/those engines eventually, why not test them daily?
2. Solar does not work if the sun does not show up brightly.
3. Wind generators do not work if the wind quits.

If you equip the primary engine(s) with alternators, you can charge independent of sun and wind conditions. In an emergency, you could have more fuel to go farther, naturally against the wind. You will be able to run critical devices like GPS and Chart plotter, regardless of who used a hair dryer.

Finally you were smart to ask this forum to do your electrical budgeting. Now carefully read all those people who answered the original question and start thinking through what a real electrical budget looks like, How often and for what period of time do you actually need to use the "extra nice" gadgets?

An additional add on is that if you run an engine daily that has water cooling, you can have a daily hot water shower period at zero additional cost.

[SSgtPitt]

I love reading these posts as they increase my knowledge and help me think of new options.
Our 36’ mono has 400w of solar and 480ah of lead acid batteries. The panels are on a SS tubing frame over the bimini. The Honda 2K and 2.2K generators make our lives more comfortable and are a CYA for shading and no sun days. We use them as needed.
Our cruising experiences are limited, a year on the water so far.
We’re in a work yard now getting ready to splash and there are two other monohulls that have made or are making hard tops for their biminis so they can do solar.
These things are so heavy two full grown men can pick them up but it’ll take 4 men to get them on the boat.
For me, this seems to be a horrible plan having that much weight that high above the water
line. I told one of the guys he’s gonna need more ballast to keep the boat right side up :-)
He was not nearly amused as I was.