Solar-Powered Engines ?

[2012iffy]

Originally Posted by simonpickard

Hello all,

It'll be a few years yet before I can even think about the Cruising life but I'm loving this forum as it's great to soak up all the joint knowledge here.

One thing I've seen recently is a guy who swapped his Diesel engine for an electric one.
Got me thinking.. Are we at a place where tech allows us to power an engine via Solar panels / wind? The advantages of this seem massive if it's doable?

Tried a few searches but not nothing back really. Has anyone done this? Is it possible?

Just think... No more fuel costs.

Regards,
Simon

Newbie here but when I saw this and read all the postings I had to put my .02 in. I am prepared for the flame job as I spent 6 years in the Army and been married 4 times (Thinking about becoming a marriage counselor!)

All of this is derived by my wish to be as marina and fuel dock free as possible. Take it with a grain of salt but what you want is viable now! I do not work for any battery, sailboat, or electric motor manufacturer. Why I am buying a sailboat is to use sails versus a motor and there are many out there today sailing sans motor of any kind! This is researched and hopefully put into service soon. You have probably been looking at solar panels and there are many out there. Mounting them is another story, from spreaders (I now, windage!) to on deck, but are an essential element to charging batteries. Wind generators, same thing but think of this, typically when the sun is not so giving there is usually more wind. There are lots of those also.

Will dismiss my history with diesel engines and just get to the thread's point. It is actually not solar power but battery power. You will lose weight when you remove the smelly, cantankerous, hope it warms up soon ol' diesel motor but will gain it back and possibly a bit more when you replace it with the batteries: 12 V 245 AH AGM 8A8D

The fuel tank, if possible, IMHO, should be replaced with a new one and that new tank used for fresh water. Fresh water can come at a premium.

Here are some electric motor kits designed specifically for sailboats in a broad price range and a variety of designs and promotions as well:

Electric Yacht - Electric sailboat propulsion systems that are cost-effective, yet CLEAN, GREEN and QUIET!

ThunderStruck Motors - Electric Sailboat Kits

And a discussion forum:

Electric Sailing - Electric Seas

Wind generators have become not only more efficient but quieter in function. Little of the 'sounds like a chopper' (helicopter) coming at ya! LCD lighting has not only become a standard but draws very little current and last much longer than iridescent bulbs. How often does one want to change a mast light? Modern electronics are also much more efficient the 'Energy Star' thingy, so the electronics will be less of a draw. Laptops have batteries that are more efficient as well as the machine itself making batteries last longer and requiring less time to charge them. LCD monitors draw far less current than the old CRT units. Computer speakers provide excellent sound, cost little when compared to the typical speaker and since I have all my music on the laptop and an iPod, what do I and who still does need a CD player for? Battery drain I suppose. Movies can be played from your laptop as well and displayed on that 24 or 26 inch monitor (On a 28 to 30 footer will look like a big screen and if it isn't big enough, move closer!) There is also the regeneration from the motor itself when under sail though most systems do little below 4 knots. There is a lot of talk on getting a 'screw' for these systems rather than the inefficient (When used with an electric motor.) props used to push boats around.

If you are desirous of cruising 300 miles(?) at hull speed without pulling your mainsail out of it carefully packed cover and all your electronics are inefficient and all the lights are incandescent and you can't live without your microwave, then you may wish keep that diesel and possibly add a diesel generator that will require a lot more maintenance than all the above mentioned systems combined. If all ya just need a push once in awhile and some assistance in maneuvering into a tight spot and intend to do more sailing than motoring then you may be asking the right question. Oh yes, the diesel engine if in good shape with low hours is worth a respectable chunk of change, at least now.

Also remember when living aboard you have finite resources and must conserve all of them when at sea. If your environment allows it then you can relax, quietly.

Wait till ya see what I wanna do with 26 foot trimaran and a jetboat!

Fair winds!

[STG]

I have an electric motor in my sailboat. Not a great option as far as I’m concerned.

My sailboat is a 35fter. Someone removed the diesel and repowered with an electric 10hp motor a few years back. Sounded like a good idea, and at first pass, I love the thought. It will push the boat up to 5-6mph if no resistance (wind, waves, etc.) and is a great “instant” power auxiliary. It runs off a bank of 6ea 6V golf cart style batteries in series (36 volt system). It is fairly quiet outside, but still loud inside the boat. And, it gets pretty hot as any large electric motor would after being run for a long time. They don’t have cooling systems.

Here is the downfall…. At full speed, the batteries are dead in 45 minutes or less. At ½ speed I understand you can get maybe an hour or two, but of course…it takes twice as long to get there anyway. Then, it takes about 8-10 hours to recharge on shore power. I cannot imagine how long it would take to charge with solar power. Maybe because of the slow trickle charging of batteries, it would be the same, but even still that is all day charging for an hour’s use (if you have enough sun). And the thought of putting in a 40-60 HP motor is way too much as I can’t even keep this 10HP powered with 6 batteries.

I am going to look into the idea of trying to run it directly off of a portable genset or something for longer trips, but need to figure out how much the motor draws, and how big of a unit I would need to power it, etc. That will be later down the road.

As was mentioned in an earlier post in this thread…it is great for entering and leaving the marina and docking, and even a quick boost to get out of a commercial boats way when the wind is down, but that is all it is really good for. I find myself afraid to use it outside the marina for fear it will die when I return and am trying to dock.

For traveling any long distances where there may be little or no wind, I have a 15hp outboard attached to the back (like the smaller boats). It also pushes me at about 6mph and is a secondary auxillary for longer trips, can run all day non-stop, but is a pain in the arse to use as it is in the back and I have a center cockpit. It is worthless for docking. So I have to have two motors depending on what I want to do. Also, the electric motor lowers the resale value considerably (per my surveyor) even though the previous owner said he spent quite a few thousand installing the system.

My vote….although a nifty idea, I’d stick with the diesel if I had a choice for cruising (especially for longer distances). I don’t know about other motors, but you’re not likely going to keep one like mine charged with (reasonable) solar panels, and if there is enough wind to power a wind generator, well then…. you use your sails.

That’s my opinion anyway based on my system.

[pillum]

Originally Posted by STG

I have an electric motor in my sailboat. Not a great option as far as I’m concerned.

My sailboat is a 35fter. Someone removed the diesel and repowered with an electric 10hp motor a few years back.

Here is the downfall…. At full speed, the batteries are dead in 45 minutes or less.
As was mentioned in an earlier post in this thread…it is great for entering and leaving the marina and docking, and even a quick boost to get out of a commercial boats way when the wind is down, but that is all it is really good for. I find myself afraid to use it outside the marina for fear it will die when I return and am trying to dock.

My vote….although a nifty idea, I’d stick with the diesel if I had a choice for cruising (especially for longer distances). I don’t know about other motors, but you’re not likely going to keep one like mine charged with (reasonable) solar panels, and if there is enough wind to power a wind generator, well then…. you use your sails.

That’s my opinion anyway based on my system.

Thanks for the "real world" feedback. I agree with you, right now it's pie in the sky for practical purposes. Interesting that it's still noisy with the electric motor, and logical that it will get pretty hot, electrical motors in enclosed spaces need external air ventilation to work well.

[skipmac]

Originally Posted by STG

I have an electric motor in my sailboat. Not a great option as far as I’m concerned.

My sailboat is a 35fter. Someone removed the diesel and repowered with an electric 10hp motor a few years back. Sounded like a good idea, and at first pass, I love the thought. It will push the boat up to 5-6mph if no resistance (wind, waves, etc.) and is a great “instant” power auxiliary. It runs off a bank of 6ea 6V golf cart style batteries in series (36 volt system). It is fairly quiet outside, but still loud inside the boat. And, it gets pretty hot as any large electric motor would after being run for a long time. They don’t have cooling systems.

Here is the downfall…. At full speed, the batteries are dead in 45 minutes or less. At ½ speed I understand you can get maybe an hour or two, but of course…it takes twice as long to get there anyway. Then, it takes about 8-10 hours to recharge on shore power. I cannot imagine how long it would take to charge with solar power. Maybe because of the slow trickle charging of batteries, it would be the same, but even still that is all day charging for an hour’s use (if you have enough sun). And the thought of putting in a 40-60 HP motor is way too much as I can’t even keep this 10HP powered with 6 batteries.

I am going to look into the idea of trying to run it directly off of a portable genset or something for longer trips, but need to figure out how much the motor draws, and how big of a unit I would need to power it, etc. That will be later down the road.

As was mentioned in an earlier post in this thread…it is great for entering and leaving the marina and docking, and even a quick boost to get out of a commercial boats way when the wind is down, but that is all it is really good for. I find myself afraid to use it outside the marina for fear it will die when I return and am trying to dock.

For traveling any long distances where there may be little or no wind, I have a 15hp outboard attached to the back (like the smaller boats). It also pushes me at about 6mph and is a secondary auxillary for longer trips, can run all day non-stop, but is a pain in the arse to use as it is in the back and I have a center cockpit. It is worthless for docking. So I have to have two motors depending on what I want to do. Also, the electric motor lowers the resale value considerably (per my surveyor) even though the previous owner said he spent quite a few thousand installing the system.

My vote….although a nifty idea, I’d stick with the diesel if I had a choice for cruising (especially for longer distances). I don’t know about other motors, but you’re not likely going to keep one like mine charged with (reasonable) solar panels, and if there is enough wind to power a wind generator, well then…. you use your sails.

That’s my opinion anyway based on my system.

Thanks for the comments on your electric systems. If you are thinking about a generator maybe I can help a little in determining what size.

To start, 1 HP is about 0.735 KW, so if your electric motor was running constantly at full power it would take a 7.35 KW generator to power it. That's a big generator. However, in the real world I doubt you are drawing anywhere near max power when cruising. If your motor has an ammeter showing current draw then the approximation is Watts = Volts X Amps. So for example if your ammeter shows your motor is drawing 100 amps at 36 V then you are using about 3.6 KW so would need a generator that size to run.

If you don't have an ammeter then you can estimate the current draw by how the size of your battery bank and how fast it is depleted.

Bottom line, my research is that a generator big enough to give constant power to an electric drive in a boat is more expensive than a new diesel engine for the boat.

[STG]

Originally Posted by skipmac

Bottom line, my research is that a generator big enough to give constant power to an electric drive in a boat is more expensive than a new diesel engine for the boat.

Thanks for the tip. I am leaning towards your conclusion too. The cost is not worth it. I like some of the perks about the instant power, and the fact that it is fairly free (other than cost to recharge which is probably small). However, I don’t need or want a big genset on the back deck, nor would I want it running while I am cruising. And if I have to buy fuel, then it defeats the purpose of the electric in the first place. If I decide to keep this boat, I will likely repower with diesel.

[CoastalCowboy]

Check out the system at Oz marine. OZ MARINE AB Have not spoken to or had contact with anyone that has used the system, but on paper (or web) it looks pretty good. Will be a few years before I am ready to set off for my retirement before the mast, but by the time I'm ready I'll bet this tech is ready. The OZ system is very interesting. Electric engine, and the when sailing the prop freed up and by dragging it actually generates a charge for the batteries. This, combined with a reasonable number of solar panels and maybe a wind gen might just wean you off the diesel. It does give you something to think about.

[deckofficer]

Here are the folks that have already done it. 5~6 kts, 24 hours a day, across the Atlantic. (2) 8 kw motors, 1040 a/hr 48 volt battery bank, and 10kw worth of panels.

http://www.transatlantic21.org/boat/

[barnakiel]

Originally Posted by CoastalCowboy

(...) Electric engine, and the when sailing the prop freed up and by dragging it actually generates a charge for the batteries. This, combined with a reasonable number of solar panels and maybe a wind gen might just wean you off the diesel. It does give you something to think about.

No whay, mate.

Look up Vetus regular catalog where they say on the test they made. I compared their data with tables that stipulate how many hp per LWL/disp you need to drive the boat at such and such speed - the hp requirement is roughly equal and there is no way to generate this amt of energy from solar or wind. Let alone the issue of how and where to store this energy.

I love the el-motor idea and I think I may give it a try, but from my calculations it is clear (perhaps wrongly;-)) that I will need a not so small petrol or diesel genset onboard to use the el-motor over anything more serious than a half-an-hour gig leaving, and returning to, our marina berth.

But it is a great idea, just the technology (batteries, I think) is not yet there.

b.

[downunder]

Originally Posted by deckofficer

Here are the folks that have already done it. 5~6 kts, 24 hours a day, across the Atlantic. (2) 8 kw motors, 1040 a/hr 48 volt battery bank, and 10kw worth of panels.

transatlantic21: Boat

Hardley a regular crusing vessel ?

[barnakiel]

Originally Posted by downunder

Hardley a regular crusing vessel ?

Yup. Seen her docked in Cadiz. Then again, if that's what one likes, a viable alternative. It will have to be:

a) light,
b) a cat with very high elongation ratio (or whatever the term is),
c) even with huge solars, half of the day being night - huge batteries.

And, if so, where do we keep all the rhum?

b.

[deckofficer]

Originally Posted by downunder

Hardley a regular crusing vessel ?

True, but it did cross the Atlantic. Go to 1/3 the battery weight with LiPo and a more comfortable cruising vessel could be utilized.

[deckofficer]

PlanetSolar :: First Around The World With Solar Energy ::*The boat*

[deckofficer]

Currently (no pun intended) circumnavigating.

[deckofficer]

This boat is running 700 large scale LiPo batteries equal to about 150,000 lap top batteries, and somewhere north of 1 Mw/h of storage. 93.5 Kw/hr of solar panels.

[familycruisers]

Lithium polymer is light, has high discharge rates, and as long as they are treated properly ( such as not discharging below 30% capacity) are great.
The down side is you must have RELIABLE smart chargers with cell monitoring capabilities so to not over charge any one cell about 4.2v, otherwise damage to the pack can occur.
Secondly is if there is a problem Lipo batteries make a very large, very hot fire, very quickly.