Stacked Inverters

[deckofficer]

Originally Posted by Tellie

Got any drawings of what this boat is going to look like both on deck and below Deck officer?<grin> Also what are your cruising intentions? I think this last question should be explained before any input would be meaningful.

What is meant by the <grin> popeye? I am a deckofficer, my union is Masters, Mates, and Pilots, graduated 3rd in my class at CMA, my discertation was on minimum wetted surface hulls, and my license is Unlimited Tonnage. While others gave meaningful comments, I have a hunch you are sniping. As to cruising intentions, I would say the same as most, My schedule and my destinations instead of the shipping company. Generally 90% hanging out soaking in new cultures and 10% passage making.

And yes, I do want to make an enviormental statement, that you can live without petrol. After working container ships, I worked on dynamic positioned drill rigs for the oil industry. I have zero love of that industry.

[noelex 77]

I think you will need to make several changes to make this project work. The easy ones would be:

Water heating :
To generate electricity and use an electric heating element is very inefficient. A small circulation pump and a surprisingly small amount of black pipe on deck would do the job in sunny climates.

Cooking:
I cannot see an electric galley, run on solar, working. If you can make the modifications in a way that would allow conversion back to propane, with minimal changes, you have a way to save a lot of power if the sceptics are right.
The electrical appliances themselves, an oven and microwave, are inexpensive and could be thrown away with little impact on the overall cost. You can try an electrical galley, but go back to propane if you make provision for this contingency at the planning stage

[deckofficer]

Originally Posted by Dockhead

Umm, I usually hate to join choruses of skeptics, but I can't hold back here.

16 panels of 185 watt nominal produce theoretical maximum power of 2,960 watts. There is a big difference between theoretical maximum power and "average production". In fact, you will be lucky to get an average of 1,000 watts into your battery banks even in a sunny climate.

Then there is the question, raised by someone, of where are you going to put them? 16 185w panels will occupy about 21m2 of space. That's an area of something more than 10 feet by 22 feet. I doubt if you have that much deck space on a cat that size. How will you mount them?

I always love to see skeptics proven wrong, so I will cheer if you can make that work. But to be honest it doesn't sound very realistic to me.

Works out to 220 square, so you hit it right on the head. Shadows will be an issue. I was hoping for (4) panels cantilevered from each port and starboard deck edge railing (beefed up, and on a cat you shouldn't have any concerns about deck edge immersion), (4) over cockpit, and the last (4) mounted to the electric dinghy.

I encourage the skeptics because when they are knowledgable as you appear to be, makes me research my concepts to a finer degree. If I didn't mention it in this thread, the mock-up will be a lower cost project of converting the dinghy to electric power first.

This is the room available on a 1985 Catalac 12M

[deckofficer]

Hot water will be 2 1/2 gallon, 110 volt, a point of usage, no long showers. Water maker is a 1500 watt consumer of power, but will make 20 gallons for an hour of operation. Oven cooking will be micro/convection, and stove top will be induction, so the fancy assed glass pots and pans aren't going to work.

[noelex 77]

Originally Posted by deckofficer

I have a hunch you are sniping. As to cruising intentions, I would say the same as most, My schedule and my destinations instead of the shipping company. Generally 90% hanging out soaking in new cultures and 10% passage making.

Tellie provides some great advice on this forum. If you have any problems with your watermaker his posts are always accurate and detailed.

Tellies question about cursing intensions was I think more about climate. You have based your output calculations on the ideal summer conditions in sub tropical areas.
Are you planning to sail the boat long distances to try and maintain these conditions?. Or perhaps planning to only use the boat for a few months of the year?

[deckofficer]

Full time, hanging in the familiar waters of the Sea of Cortez (where I won't have a problem hitting those solar projections). On to New Zealand where I have a few good friends and in all my travels, have never pulled into port there. From there during the weather window to the Med where I have spent a lot of time, after that, who knows. Since the birth place of the Catalac is the UK, might be a good place to sell, or maybe an Atlantic crossing and the Caribbean.

[Dockhead]

Originally Posted by deckofficer

Works out to 220 square, so you hit it right on the head. Shadows will be an issue. I was hoping for (4) panels cantilevered from each port and starboard deck edge railing (beefed up, and on a cat you shouldn't have any concerns about deck edge immersion), (4) over cockpit, and the last (4) mounted to the electric dinghy.

I encourage the skeptics because when they are knowledgable as you appear to be, makes me research my concepts to a finer degree. If I didn't mention it in this thread, the mock-up will be a lower cost project of converting the dinghy to electric power first.

This is the room available on a 1985 Catalac 12M

Well, I don't quite understand how you will have panels cantilevered over your rail. How will you dock? Will you tilt them up?

I would be surprised if you can accomodate them practically, and without ruining sailing qualities with windage. But if you do, it will be a great achivement and be sure to post a full report here.

And you should run the numbers carefully based on real yields and not nominal power -- they are very different, usually by a factor of two or three as far as I understand, even in ideal conditions.

Don't forget the power lost going into and out of the batteries; efficiency factor of inverters and so forth.

I am pretty sure that you will find that you will have to sit in the sun for several days before motoring for a few hours. Remember that the power needed to move your boat under power in rougher weather is much greater than in flat water. Don't forget about getting off lee shores -- those Catalacs are not the greatest pointing boats in the world, especially in some weather.

Of course it is possible to run a sailboat without any auxiliary power at all. So if part of your plan to meet your energy budget is to just accept that you cannot motor as far or as long as you might like -- then that will help.

However, I think you will find that it is hard. Some auxiliary generating capacity would transform the situation -- say a 6kW diesel genset. Without it you may find yourself in situations where you just can't cover your energy needs.

+1 to solar water heating. Heating water with electricity so hard won, photon by photon, is crazy. I would also not cook with that hard-won electrical power -- alcohol or propane will be much more efficient.

[deckofficer]

If shortages of electrical energy become a real issue, then it is just a matter of a day sail when the winds are up, dragging two props ahead with astern pitch. You remember the Max prop, if you return to neutral from ahead propulsion and hoist the sails they will feather, giving much lower drag, but if you go from astern propulsion to neutral and set sail, they stay pitched 180* out. By my rough calculations, just robbing 2 kts, from 6 to 4, will generate a little over 1 kw per motor. The 1845 lb LiPo battery bank (not the 2 tons of AGMs) of 76.8 Kwh could be recharged from a 50% DOD in under 24 hours of sailing. The early stage for proof of concept will be the same 30 kw peak, 12 kw cont motor mounted on a 50 hp lower drive from an outboard on the cat/tunnel dinghy. My numbers say at 17 kts that speed will allow one mile of distance for 300 wh. The LiPo batteries for the dinghy will be 317 lb and 14.4 Kwh. That works out to over 20 miles to 50% DOD (calm waters). I'm looking forward to freeing up some time this Spring to get the dinghy converted.

Again, I'm all for the skeptics helping me see the light, because I have been wrong in the past and I'm not immune to being wrong in the future. I started my own hot rod forum because lets face it, the average forum participant on this forum is generally the cream of the crop for any forum, and that is the membership I pulled from other hot rod forums. The folks that believed I could design a power train for my hot rod that is high 10 second in the 1/4 mile, and break 30 MPG on steady 65 mph cruise on a level highway. My little Track-T does both, and the knuckle-dragging neanderthals that swear that the only Ts that can be fast are going to get 5 MPG are still on a forum that I was a member of, and most the believers have joined me on my new forum. 7 months old and over 6600 posts in such a specialized niche. I just like a challenge and enjoy fabrication. Before going to CMA, I spent many years in R&D labs.

Yes the rail side panels will tilt for both max exposure (nothing more fun than either washing panels are tilting towards the sun and watch the jump in the amp meter, for us that are easily amused) and docking.

Sure got side tracked from stacked inverters. I haven't found an owner's manual that addresses if each inverter shares the input DC load so I can stack (2) 5 kw, 48 VDC inverters and tap two legs of the 96 volt battery bank.

[noelex 77]

Have a look at the Outback range of inverters. I am not sure they will do what you want but the owners manuals are avialable online.

OutBack Power / Products / Sinewave Inverter

You will need a good solar regulator and they also make the best. I am normally against loosing redudancy on a boat, but the combined inverter and regular package can talk to each other and it allows effecency and monitoring possibilities that are not otherwise available.

[deckofficer]

Originally Posted by noelex 77

Have a look at the Outback range of inverters. I am not sure they will do what you want but the owners manuals are avialable online.

OutBack Power / Products / Sinewave Inverter

You will need a good solar regulator and they also make the best. I am normally against loosing redudancy on a boat, but the combined inverter and regular package can talk to each other and it allows effecency and monitoring possibilities that are not otherwise available.

I prefer redundancy and will incorporate at every opportunity. The (3) motors, two for the big cat and one for the cat dinghy will be all the same. The DC power matrix board will be a schematic with multiple dual high current connectors that require bridging between banks, controllers (both drive and charge), and inverters, so that any configeration can be used to make up for a single failed component of the system.

[deckofficer]

Originally Posted by Dockhead

Umm, I usually hate to join choruses of skeptics, but I can't hold back here.

16 panels of 185 watt nominal produce theoretical maximum power of 2,960 watts. There is a big difference between theoretical maximum power and "average production". In fact, you will be lucky to get an average of 1,000 watts into your battery banks even in a sunny climate.

Then there is the question, raised by someone, of where are you going to put them? 16 185w panels will occupy about 21m2 of space. That's an area of something more than 10 feet by 22 feet. I doubt if you have that much deck space on a cat that size. How will you mount them?

I always love to see skeptics proven wrong, so I will cheer if you can make that work. But to be honest it doesn't sound very realistic to me.

Your experience with solar panels appears to be quite different than mine. I almost think you are either running "RV" style panels, or your in hot climates and didn't choose a higher than "average" voltage panel. Electrons flow from a panel to a battery bank because of the voltage differiential between them. Voltage drops on hot panels. RV panels that some will use with no charge controller take forever to top off a battery bank. These panels can have as few as (24) 0.55 volt cells in series. Folks that are using a nominal output voltage of 16~17 volts per 12 volt battery bank are going to see a lot of taper at 80% SOC in hot climates. I would go no lower than 18.7 nominal. Much better to give up a couple of amps and of course use a charge controller to ensure much faster completion of charge. With LiPo, I would have to run at the higher end because voltage drop during different states of discharge is much less than lead acid.

[noelex 77]

Originally Posted by deckofficer

These panels can have as few as (24) 0.55 volt cells in series. Folks that are using a nominal output voltage of 16~17 volts per 12 volt battery bank are going to see a lot of taper at 80% SOC in hot climates.

The 24 cell "self regulating" panels are almost never used on boat installations. I have only ever seen 1 panel like this on any boat.
Many of the members of this forum will give you their real world output figures for solar systems on boats.
You could easily upscale these figures for your larger array and determine a realistic output for your solar system.

[DotDun]

Many of the Victron models support 48v and stacking/paralleling. I don't know how they handle the load sharing, might be worth checking with them.

[deckofficer]

Off topic I know, but vessel names have always intrigued me. DotDon conjures visions of a Dot Com gone public, and the principal cashing out and gone sailing. Thanks for the tip on Victron.

[DotDun]

Originally Posted by deckofficer

Off topic I know, but vessel names have always intrigued me. DotDon conjures visions of a Dot Com gone public, and the principal cashing out and gone sailing. Thanks for the tip on Victron.

You're real close! But not a principal! And suppose to be retired, but still working... (damn markets!)