Stacked Inverters

[nwdiver]

You should look at rigging a mini solar hot water heating system circulating to an insulated tank, one vacuum tube may be all you need in sunny areas, heating water off the batteries is ok for a gal but really a waste of juice. Another option is an electric shower, real popular in Europe or a black painted 10 gal wide shallow tank on deck and a blending system to add cold water in the shower.

Cooking with induction, microwave and convection are easy to set up.

[dennisail]

Hey Bob. Great to see your attitude is much different to most of the people I have seen with this idea. Going by some of your other achievements, you are more than just a dreamer too.

I also made a Hotrod, well sort of. An oldish Nissan that I then fitted a 2JZ supra turbo engine into and got it to run in the 10 sec range for a fraction of the price of what other 10 second cars cost. It used the same amount of fuel as it did before I modified the car and I drove it everywhere, when other slower cars were turning up at the drags on trailers. I was told my methods would not work and my engine would explode because I did not use the same gear everyone else uses and never had it dyno tuned. It then got on the front cover of my favorite car mag.

I would still like to see your own version of a more detailed energy budget of your whole system based on observed figures rather than some of the optimistic figures you have used. My admittedly rough calcs have your boat being able to motor for around 2.5nm per day on average with zero consumption other than propulsion (no cooking etc). I think this could be dangerous. With such a low energy surplus you will be sure to run out in the worst of times IMO and the performance of your boat to windward will be marginal at best.

Also, you would be surprised at the small amount of power your sails produce to move your boat. Considering how inefficient props are, your boat will need some VERY strong wind from behind to overcome the power figures you are listing will be generated from your props. For example my friends heavy 35 foot boat motors at up to 4k with the 2hp tender motor in flat conditions. Imagine the drag of that same 2hp working backwards. It will be like dragging a sea anchor. You wont be going upwind while towing this, which means you will have to claw your way back upwind after one of your proposed charge up trips if you want to get back to your destination. The catalac is not great upwind boat, and that is before you have added all that gear making the situation even worse. I do not think charge up trips will be feasible in most cruising situations. It might work when passage making, but when the wind is strong enough for it to work, you will not need it since, well the wind is up

[Dockhead]

Originally Posted by deckofficer

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.

OK, well, it's a fascinating project, whether it succceeds or fails. My request to you: take good notes, make tons of photos, make systematic measurements and keep a really thorough log of your actual experience -- as in, how many hours of motoring you got this day or that, whether you ran out of power or whether you were in surplus, etc., and write it up. It will make a fantastic article -- I'm sure you'll have all the sailing rags fighting over it.

Good luck and best wishes.

[deckofficer]

I am looking at a lot of unknowns. The cat dinghy was a real eye opener though. I would have never thought a commerically purchased 48 volt clamp on outboard rated at just 5 hp could push hard enough to reach planing speed. Then the 2nd revelation is after planing out, how much "throttle" I could roll off and still maintain a plane, watching the amp meter dropping. I was amazed that ANY wetted surface vessel could cover 1 mile using just the energy of (3) 100 watt lights for an hour, and at planing speed. A dinghy weighing around 500 lbs with batteries and me aboard, I would have been pleased at the 300 whr consumption at a slow displacement speed, put almost 20 mph, I was thinking I was getting some bad readings. To put this in perspective, my best land based consumption at 50 mph was 300 whr per mile on a wheeled vehicle on level ground. Those new tunnel/cat dinghys are the tender for me. I just wonder why more cruisers don't use them?

The Sun21 did the Atlantic on just 50 Kwh stored energy and 10 kw solar and no sails.

[deckofficer]

Originally Posted by Dockhead

OK, well, it's a fascinating project, whether it succceeds or fails. My request to you: take good notes, make tons of photos, make systematic measurements and keep a really thorough log of your actual experience -- as in, how many hours of motoring you got this day or that, whether you ran out of power or whether you were in surplus, etc., and write it up. It will make a fantastic article -- I'm sure you'll have all the sailing rags fighting over it.

Good luck and best wishes.

Dockhead,

I sure will, as I'm very anal about documentation and qualifying results. Must have come from all my years prior to CMA of being a lab tech in R&D labs. Today, blue water cruising due to technology, has opened up to many more people. In the past the two major unknowns was "where am I ?" and "where is the weather?" is now just a matter of weather fax and GPS. No one could graduate from CMA without a proven ability for celestial navigation, not to mention the rigors of all the other disciplines of the California Maritime Academy. I choose minimum wetted surface vessels as my dissertation, because I believed that to be the future of commercial shipping. To date, I've only been correct for fast ferries on that assumption.

[44'cruisingcat]

Originally Posted by deckofficer

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..

You are unlikely to get the amp/hours from a marine system that you can get from a similar sized land based system, simply because the boat doesn't stay still. If you have wind coming from the same general direction as the sun, you'll likely have shadows from the rig on some panels. Also tilting the panels doesn't work as effectively when the boat keeps changing it's angle relative to the sun.

[noelex 77]

Originally Posted by 44'cruisingcat

You are unlikely to get the amp/hours from a marine system that you can get from a similar sized land based system, simply because the boat doesn't stay still. If you have wind coming from the same general direction as the sun, you'll likely have shadows from the rig on some panels. Also tilting the panels doesn't work as effectively when the boat keeps changing it's angle relative to the sun.

I agree and I hope we can get the message across before Deckofficer makes major modifications.
I am Greece with very high insolation values summer has just finished. This was the result from yesterday well below average, but nothing exceptional. If your planning on going to New Zealand there will be a lot of summer days worse than this.

My array is about 12% the size you are proposing. You would have achieved yesterday about 350AHrs or just under 4KWHrs (this is assuming you can position a large array as well as my smaller panels)

[deckofficer]

I'm sorry I haven't kept this thread updated, but I was inquiring about stacked inverters and forgot I got side tracked. Plans have changed slightly, whereas when I take delivery of whatever, my plan now is to get going more quickly. Basically a shake down, refit only what would be needed, and save electric propulsion for the day one of the diesels need rebuild or replacement. This will get me started cruising sooner, not having to pull servicable engines, and keeping one side diesel.

[dennisail]

Sounds like a good plan

[Dockhead]

Originally Posted by dennisail

Sounds like a good plan

+1

I am sorry, however, that we won't be reading about a full electric propulsion conversion. Would have been fun -- even if it would have been unlikely to work.