Electrical Propulsion vs Diesel Propulsion

[GordMay]

Greetings and welcome aboard the CF, DITB.

[4134me]

Thanks for the clarification mcarling.

One more idea I had was to run ac motors and an ac generator sized to be most efficient at around 60-70% of the motors max output.

House needs would be covered by a battery bank charged by solar, wind, regen etc and also a smaller dc gen if required. A large inverter would be used which could power large appliances and also the motors if required.

Long periods of motoring in all but the worst conditions could then be done running the motors directly off the ac gen. Short slow periods leaving dock etc could be done from the batts running through the inverter, efficiency would be less important in this instance as batts would likely be sized to only give 10-20 mins before the ac gen would need to be started. If Higher speed was ever needed or for headwinds etc then both generators could be run giving the motors full power.

I would really like to have 2 gens if possible to allow for mechanical issues, would this be a sensible way of setting it up? I imagine the cat would spend some time as a motorboat while I save up for a rig so would be good to have a reliable, efficient system. would it be possible to power ac motors from an ac generator and from batteries via and inverter simultaneously?

[mcarling]

I would choose DC motor(s) and DC generator(s). The less rectifying and inverting, the better, in my opinion.

[finleyg]

What a great thread! I've been experimenting with EP since this spring. I have a Corsair F28R, with a Torqeedo 2.0 for propulsion when it's not windy. Motor happily pushes the boat near 6 knots at full power, and I have two battery banks. I have 180AH at 24v, then that bank has a converter that steps down to 12v for my house battery of 180AH. They are li-po batteries that weigh @180lbs total. I use 260 watts of solar to recharge the 24v bank. Works great so far. Never dipped under 95% capacity even when motoring at 3-4 knots for @ an hour or running stereo, fridge and running lights all night. Obviously, nowhere near the loads that some of you are using, but the system supports the 2000 watt draw of the outboard, led lights, 2 cabin fans, fridge, stereo, chartplotter, radio and autopilot very comfortably. I'm taking my wife to the florida keys in March, we'll get a real test, then. So far, only cruising lakes in Missouri, so no real test, no current to fight, etc. I'm bringing a honda generator just in case.

[Hyprdrv]

mcarling is correct, DC to DC is better and more cost effective when it comes to buying equipment. Your AC needs are much smaller on a boat than the DC equipment you carry. I have a 15KW genset that is rectified to 144V DC to run the motors and charge the Batteries with a 144V to 12V charger to the house bank. All means of charging (at this point) is from the Propulsion bank. Much simpler to manage. Once I get the Solar cells on board those will power the House bank only. I tried to come up with a plan to charge the Propulsion bank but at 144V there isn't much equipment out there to do that without having the Queen Mary bank of solar panels. It kind of made more sense since the load on the House bank was the largest load under sail and removing that load off the Propulsion bank will be a great help in extending the "under power" time. 6 knots is a comfortable speed to "motor" at (power consumption to time) and I haven't pushed it to the max yet, no need to.
Fin, sounds like a junior of my system. The other guys Love the Honda as a way to extend their distance.

Steve in Solomons MD

[mcarling]

Hyprdrv, since you have decided to power your house bank rather than your propulsion bank with your future solar panels, depending on the daily load on your house bank and the capacity of solar panels you are able/willing to install, I would consider leaving your 144V-12V DC-DC converter as a manually engaged back-up. In other words, I would try to power the house load entirely from solar if possible, with a backup in place in case of an equipment failure or an exceptionally long period of darkness. Of course, that would require a large house battery bank. Do you know your average/peak daily house load?

[Hyprdrv]

Exactly MC, I plan on a relay (with alarm) to energize the 144Vto 12V charger when the house bank gets low. Roughly 400W of usage with 700W of solar. Would like to do a dual eliment HWH to take the excess charge off the Panels. As far as the "emergency" no sunshine mode, I'll hit the genset button.
Steve in Solomons MD

[mcarling]

Originally Posted by Hyprdrv

Roughly 400W of usage with 700W of solar.

Is that 400W of peak usage? I guess you don't mean 400Wh per day, unless your consumption is very frugal. Do you know your typical/average/peak house consumption in either amp-hours or watt-hours per day?

Originally Posted by Hyprdrv

I plan on a relay (with alarm) to energize the 144Vto 12V charger when the house bank gets low. As far as the "emergency" no sunshine mode, I'll hit the genset button.

I think that's a good plan if you have a nominal peak 700W feeding your house bank.

Originally Posted by Hyprdrv

Would like to do a dual element HWH to take the excess charge off the Panels.

I guess you know that you can get a 144V charger that will accept variable DC input from 80V to several hundred volts. If you can get 700W of solar, I would expect you could string enough panels in series to stay above 80V anytime your array is generating significant power. I might look one more time at the possibility of powering the propulsion battery pack from the solar array.

[mbianka]

Originally Posted by Hyprdrv

mcarling is correct, DC to DC is better and more cost effective when it comes to buying equipment. Your AC needs are much smaller on a boat than the DC equipment you carry. I have a 15KW genset that is rectified to 144V DC to run the motors and charge the Batteries with a 144V to 12V charger to the house bank. All means of charging (at this point) is from the Propulsion bank. Much simpler to manage. Once I get the Solar cells on board those will power the House bank only. I tried to come up with a plan to charge the Propulsion bank but at 144V there isn't much equipment out there to do that without having the Queen Mary bank of solar panels. It kind of made more sense since the load on the House bank was the largest load under sail and removing that load off the Propulsion bank will be a great help in extending the "under power" time. 6 knots is a comfortable speed to "motor" at (power consumption to time) and I haven't pushed it to the max yet, no need to.
Fin, sounds like a junior of my system. The other guys Love the Honda as a way to extend their distance.

Steve in Solomons MD

Steve:

Sounds similar to how I operate except I have 48 volt solar panels for the propulsion bank and 48 wind generator too for the propulsion bank. For the 12 volt house bank I am able to get by with two 75 watt Siemens solar panels even while operating a ENGEL in freezer mode most days. I do use a 48/12 DC converter when I want to use my laptop at anchor since the propulsion bank is just sitting there being topped up by the solar and wind generator I figure I might as well tap into it's energy since I'm at anchor. Though after a day or two of heavy cloud cover I may have to bring out the Honda 2000 to top up the 12 volt house bank on occasion but, it's not run that long or often.

[Octopus]

Originally Posted by jostalli

I love hearing positive reviews from the Lagoon 410 hybrid guys. What is confusing is why did almost all of the hybrid Lagoon 420's convert to diesel? I have been searching for the last remaining hybrid 420's but cannot find any left. Apparently there was still the option of purchasing the latest hybrid system in the 420 (maybe even the 421) but I have not heard of anyone going that route.

The new Yanmar hybrid saildrives seem to be a great option to offer new boats but Lagoon isn't offering them (maybe because they were burned before by hybrid).

Originally Posted by jostalli

Wait, did you not read my last post? Almost all of the hybrid Lagoon 420's have been converted to conventional diesel by the owners. I am asking for someone to find me a hybrid Lagoon 420 owner who is happy with the hybrid.

We have been very happy with our Lagoon 420 Hybrid for over five years and approximately 15000 nm (including 2 transatlantics). We have no plans to convert to conventional propulsion unless it proves necessary to sell the boat (when that time comes).

If you are interested, see my posts on the subject.

I'm not convinced that the Lagoon design is the best hybrid diesel-electric solution, but it has performed faultlessly for us and delivers the performance promised.



The main advantages are:

• Very quiet motoring at cruising speeds (with genset on)
• Outstanding controllability and manoeuvrability under power in marinas etc.
• Very good fuel economy
• Low maintenance effort and cost
• Abundant AC power and huge battery bank for powering all modern conveniences and (low cost/high-efficiency) AC appliances, including 300 l/hr AC watermaker, electric oven, induction hob
• Silent motoring under battery power (something we rarely do)
• Generates serious amount of RE when under sail, provided you are willing to sacrifice up to 1.5 knots of speed (we rarely are)

The disadvantages are:

• Intimidating complexity of control systems
• Cost of battery bank replacement every 5 years
• Barely adequate top-end speed and power (but in my view it is adequate)
• Prop drag when sailing. This is more of an irritation than a disadvantage, as the drag can be eliminated by setting the motors to operate at low speed
• additional weight of 12 x 210Ahr lead-acid battery bank compromises sailing and motoring performance

The system was never well-suited to charter use and so these were converted to conventional propulsion early on. Most owners have converted either because:

• they had more than their fair share of early teething problems
• they couldn't sell their boat as a hybrid owing to bad press and conservative buyers
• they wanted more top-end power/speed

[mcarling]

Octopus, I'll be interested to read your impressions after your current batteries give out if you make the switch to lithium phosphate.

[Hyprdrv]

Hi Chris,
It's great to here from a 420E owner that is Happy with the system. I've posted a number of times what I had heard where the problems with your system and I believe you mentioned all of them here.
The Lagoon 410 was on the cutting edge of technology when they came out. Because of their success Lagoon decided to try and do it on their own and created quite a few problems from the get go. You don't give a 16 year old a Ferrari to learn to drive. If you did they would hate the Ferrari. If you give a bunch of non electric people a complicated Electric Boat your going to run into problems. The Technology was so different from the way an ICE boat was operated that many couldn't grasp the concept. Once you "got it" the system is a dream. Add to the fact that Lagoon and owners put them into charter and you have a disaster on your hands. Charters are abused enough as it is let alone one an Electric drive system that does take monitoring in a different way.
The 410 system is different than the 420, the hull is different also. but the concept is pretty much the same as far as electrics go. Lagoon tried to "Idiot Proof" the 420 system and it caused issues from the start. I'm happy to here that you got the bugs out and are operating at the Enjoyment level.
The Lithiums are the way to go once your current bats are ready to be replaced. The original batteries where nothing special or for that matter good quality. Mine where replaced with AGM's 7 years ago and still going strong. I'll do the LiPo thing once these go and get probably over 10 years out of them.
I can do 8 knots but for a short period of time under bats only.
You are correct on the prop drag, put it just off of neutral and the prop drag is gone with virtually no battery usage.
The Battery weight is a HUGE issue and one I will see disappear once the bats go to LiPo.
In conclusion the system was just way ahead of it's time. Over all I couldn't be happier.

Steve in Solomons, MD

[4134me]

Thanks for the clarification hyprdrv, sounds like dc-dc is the way to go. what kind of efficiency should I expect from a modern puresine inverter of approx. 5kw running off a high voltage battery bank for cooktops etc?

I am looking at forgetting the sails altogether and going for an economical displacement powercat, has anyone confirmed the claims that EV can be just as if not more economical than shaft diesels? To have a well insulated engine room with near silent and vibration free motoring would be of huge appeal on a boat which was motoring at all times.

[mcarling]

Originally Posted by 4134me

Thanks for the clarification hyprdrv, sounds like dc-dc is the way to go. what kind of efficiency should I expect from a modern puresine inverter of approx. 5kw running off a high voltage battery bank for cooktops etc?

If your goal is to maximize the efficiency of your inverter, use 144V DC for a 115V AC inverter or 288V DC for a 230V AC inverter. My own plan is to use 144V DC and run everything possible directly from DC without an inverter.

Originally Posted by 4134me

I am looking at forgetting the sails altogether and going for an economical displacement powercat, has anyone confirmed the claims that EV can be just as if not more economical than shaft diesels?

Permanent magnet machines (generators and motors) reduce the losses to about the same as the losses from a gearbox (which of course you won't need).

[4134me]

Brilliant sounds like the way to go. Just one more question if that's ok.. I am happy to have only a few minutes of motoring off batteries only, but if I am running large house loads via an inverter from a 288v bank will there be a minimum AH requirement? Or will it be ok having an autostart gen kick in at a certain state of discharge on a small bank?