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Old 17-07-2021, 12:50   #271
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Re: Replace Diesel with electric engine

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Originally Posted by Adelie View Post
Locomotives use diesel electric because there is not effective mechanical transmissions when a train becomes very long and heavy. Mechanical transmissions just don’t hold up when trying to start a train from a full stop. D-E is used on ferries because they can be throttled and reversed quickly. Cruise ships use it because they have very large ships that may need to pull in at destinations that do not have tug services so bow thrusters and Azi-pods are needed to dock.

The losses involved in converting mechanical power to electricity and back easily outweighs any efficiency gains from operating the prime mover at its optimum RPM.

Where a combustion engine is an auxiliary energy source then using a series hybrid system makes sense for a small vessel. For cruisers this would be like using a Honda 2200EU occasionally. If used continuously it would be able to propel a boat of about 34’ at 4kt. Where an engine is a major energy source or the prime mover it makes more sense money and efficiency wise to use a parallel system where the engine is connected to the prop. This would be appropriate for crossing the doldrums or running the ICW on a schedule.
Very interesting. Thanks for the information and clarification!

On a related note, Kabota has a diesel engine that also functions as a water generator! I haven't done any reading on it yet, but Leo of the Sampson Boat Company (Tally Ho on YouTube) was talking about it. It looks like it combines some of the best features of both worlds.

Edit: On an unrelated topic, why do my posts always get two or sometimes many more spaces between paragraphs? I always have to go back and edit out the excessive lines between paragraphs. Is there a setting I need to change?
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Old 17-07-2021, 13:31   #272
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Re: Replace Diesel with electric engine

Seems to me that a motor driven watermaker works well if you are motoring a significant amount at least once a week.

If you are trying to get by mostly on solar etc then a PUR with the pressure recovery pump is the way to go.
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Old 17-07-2021, 23:30   #273
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Re: Replace Diesel with electric engine

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My opinion is that neither boat has gone all in on solar. Yes they both have significant solar but both could almost double what they have by building a cockpit Bimini with solar panels.
As I said: upgrade with 4 AAA monocells and harvest by recuperation.
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Old 18-07-2021, 10:39   #274
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Re: Replace Diesel with electric engine

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Originally Posted by Adelie View Post
Seems to me that a motor driven watermaker works well if you are motoring a significant amount at least once a week.

If you are trying to get by mostly on solar etc then a PUR with the pressure recovery pump is the way to go.

25 years ago, with a 6 GPH Village Marine unit drawing 20A, we found that reducing the membrane pressure from about 850 PSI to 500 would drop the amps to 10, and the output to about 3 GPH of good water, allowing our 150W solar to meet our day's water need with about 3 hours of tropical sun.
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Old 18-07-2021, 11:40   #275
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Re: Replace Diesel with electric engine

Good to know. Thx.
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Old 25-07-2021, 21:19   #276
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Re: Replace Diesel with electric engine

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Hi, I am new here, please let me know if I post in the wrong spot or make any other rooky mistakes

We live on an Amel Super Maramu in La Rochelle, France and work through our refit at the moment. We planned to go cruising soon but the diesel died so we are now looking at an electric conversion. We did toss many ideas around and landed on a system that I hope is easy to work on, easy to find parts for and good enough to get some first experience. Then, over the coming year, we plan to build out the system so it is fit to sail us home from France to New Zealand.

The system is built around a 48V Lithium battery bank that will service the boat needs and the engine. I have some initial drawings around the idea and would love to get feedback from those who have built systems like this.



The drive system will most likely be a oceanvolt AXC which runs on 48V.

The plan for the battery bank looks like this at the moment:



cheers
Lenz
Sorry, I haven't read all the posts between the first and this one, so if it has already been covered please just disregard this post.

Looking at your proposed battery bank I see a number of issues.


!) Five separate 48v batteries will require 5 sophisticated BMS systems and an incredibly complex cell balancing system. This can be easily fixed by putting the 5 x 200Ah cells in parallel to build the 1000Ah @ 3.2v, then join each of these in series to build a 48v 1000Ah battery. We built a similar battery, all be it at 24v and 1200Ah, that has so far run faultlessly, as far as the battery pack is concerned, for going on 3 yrs now. The problems we have had so far are due to electricians who don't seem to understand the basics regarding load sharing and overload protection requirements. The inverter failures have stopped since I fixed their misguided efforts.

2) You require 16 cells for a 48v battery if you wish to avoid destroying the cells due to low cell voltage or over voltage when recharging.
3v x 16 cells is 48v where 3v x 15 cells is 45v and getting close to system shut down.
3.6v x 16 cells is 57.6v where 3.6v x 15 cells is 54v and that is not an end of charging voltage or float voltage setting most charging systems have available.

3) Thing seriously about using GBS cells, they do not have a great track record as far as cycle life V capacity retention, and they leak electrolyte vapour something fierce from my own experience with them in the rear of my hybrid electric vehicle. From experience over the last 10 yrs or more, you will get a lot more bang for bucks with Winston LYP cells.

There are good active balancers on the market for 16 cell batteries, combine that with a BMS that can isolate the battery from charging for a timed period if a cell goes over 3.6v and doesn't reconnect the charging until the cell voltages are all below 3.6v, then resets to watch for a repeat over voltage occuring. The BMS should also set off a warning if a cell drops to 3v, actually isolating the battery if that voltage drops below 2.5v really depends on just how much of a life and death situation is occurring, better to possibly killing a battery cell group tather than dying to save a battery pack ....

T1 Terry
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Old 25-07-2021, 22:43   #277
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Re: Replace Diesel with electric engine

Haven't read all the posts either. An important question for the OP: Are you planning to go through the Panama Canal on your journey from France to NZ? If so, you will not have enough power to make it on your own. You would have to pay a Canal tug to tow you through. The cost would probably exceed the cost of a new diesel engine.
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Old 26-07-2021, 00:10   #278
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Re: Replace Diesel with electric engine

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Originally Posted by stormalong View Post
Haven't read all the posts either. An important question for the OP: Are you planning to go through the Panama Canal on your journey from France to NZ? If so, you will not have enough power to make it on your own. You would have to pay a Canal tug to tow you through. The cost would probably exceed the cost of a new diesel engine.
I've done the math on this before for a different boat and it's doable with outboard and maybe generator assistance.

Amel Maramu
LWL 41.3' (let's use 42', some of the overhangs will immerse underway)
Displacement - 35,250lb. Let's call it 42,550 (an even 19 long tons)
Using Gerr's formula 12kW (16hp) will propel the boat at 5kt.

Panama canal is about 37mi (32nm) lock to lock and 47mi (41nm) anchorage to anchorage unless they can stay overnight part way.
Canal Authority requires that vessels be able to maintain 5kt thru the water.

Let's assume that the day is overcast and there is essentially no insolation falling on any solar panels and the whole transit need to be in one day.
So the vessel needs to be able to transit 41nm, in about 12hr using outboard, generator and battery.

Let's assume they get a 9.9hp (7.4kW) outboard and mount it to push the mothership. Because the motor is intended to push a dinghy at planing speeds, not the mother ship at displacement speeds, let's derate that and say it is only providing 6kW effective. That leaves 6kw that needs to be made up thru the mothership's electric drive.

An electric Maramu probably has a 20kW or larger motor so there is no worries about exceeding that capacity, only in supplying it enough electricity.

A Honda 2200 puts out 1800W continuously.
With the outboard that's 7.8kW total meaning 4.2kW needs to come out of the batteries.

Let's not worry about he 5mi at each end, transit to and from the locks and into and out of them will only be at 5kt part of the time, and since time in the locks is on the order of 2hr or more at each end, the generator can bring the battery back to full on the way into the canal, and can put back enough at the exit locks to make the last 5mi at the required speed.

So the battery needs to be able to provide 4.2kW for the time it take to transit the 32nm between locks at the highest level. 32nm / 5kt = 6.4hr.
4.2kW * 6.4hr = 26.9 kWh. Let's call that an even 30kWh to give us a little wiggle room.

30kWh is 625Ahr @48v. If you are discharging the bank to 80% DoD that means the bank needs to be 780Ahr. For a boat of this size that might or might not be a bit large. I'm more used to 35' boats where the recommendation is for 300Ahr @ 48v.

Let's say you have a 15hp dinghy outboard, and no generator.
Derate the outboard to 12hp or 9kW. That leaves 3kW for the batteries to provide. That's 24.6kWh delivered over 8.2hr. So the bank needs to provide 512Ahr @48v. For 80% DoD that's a 640Ahr bank.

You can't do the whole canal on EP but with an outboard and maybe a small generator it's not unreasonable to do.
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Old 26-07-2021, 00:28   #279
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Re: Replace Diesel with electric engine

Using zloitapok's power to speed estimator a Maramu would need 4.65kW to reach 5kt and 9.3kW to reach 6kt.

Let's assume 6kW to reach 5kt motoring into a moderate wind. The electrical schematic above shows a 48kWh bank. Let's assume 80% usable, that's 38.5kWh. That's enough to motor 5.5hr. No enough to transit lock to lock, but almost, and the other schematic shows a generator built into the system.

I don't think these folks would have any problems getting thru the canal. Especially if they put a outboard mount on as back up for the generator failing.

https://files.dnevki.net/power_calculator.php
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Old 26-07-2021, 20:40   #280
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Re: Replace Diesel with electric engine

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Originally Posted by Adelie View Post
Using zloitapok's power to speed estimator a Maramu would need 4.65kW to reach 5kt and 9.3kW to reach 6kt.

Let's assume 6kW to reach 5kt motoring into a moderate wind. The electrical schematic above shows a 48kWh bank. Let's assume 80% usable, that's 38.5kWh. That's enough to motor 5.5hr. No enough to transit lock to lock, but almost, and the other schematic shows a generator built into the system.

I don't think these folks would have any problems getting thru the canal. Especially if they put a outboard mount on as back up for the generator failing.
The Super Maramu is 52 feet. Time to recalculate.
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Old 26-07-2021, 21:19   #281
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Re: Replace Diesel with electric engine

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The Super Maramu is 52 feet. Time to recalculate.
LOA for the Maramu and Super Maramu are 52',
LWL for both is 41.3'. All the various speed estimating charts and formula use the LWL. As boat speed increases some of the overhangs will be immersed and the LWL will increase. Using LWL is conservative, and will over estimate the required power.
Just a question of which formula you want to use since they provide somewhat different answers.
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Old 27-07-2021, 00:16   #282
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Re: Replace Diesel with electric engine

Especially if they put a outboard mount on as back up for the generator failing.

Good luck. Best you take 4 AAA Monocells and the missing link is recuperation.
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Old 01-08-2021, 11:26   #283
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Re: Replace Diesel with electric engine

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Alg sligthly updated, now graph climb increased at high speed. This is fits better real tests data
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Old 03-08-2021, 16:14   #284
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Re: Replace Diesel with electric engine

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I have looked at this system, with it you can drop the generator and some of the batteries, it looks like respectable regen for the speed you can travel........you have the diesel when absolutely necessary.

https://betamarine.co.uk/portfolio-i...id-propulsion/
Antares Catamarans are planning to install this system coupled to 40HP Yanmars starting next year. Hybrid Marine will only sell the electric motor coupled to a new Yanmar or Beta if you want to convert. I have pretty new Yanmars and Hybrid Marine wouldn't even entertain a conversation about converting existing engines.
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Old 05-08-2021, 09:45   #285
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Re: Replace Diesel with electric engine

SouthernWind has announced a BAE HybridGen system for their new 96' boat. In this system, the battery bank, diesel gen and electric motor all are >100KW. So the diesel can power the boat as long as the fuel is available to run the diesel. AFAIK.

My 1984 sloop has a Perkins 4236 which needs rebuild or replacement. The shipyard offering to do the work has recommended that I consider using one of these systems as part of a gut refit of the boat. Interior will be coming out to get at old tanks, plumbing and some welding repairs on the hull (aluminum)

Am still evaluating the refit vs replace analysis vis a vis the boat and this is one of the big ticket expenses.

These systems are being used successfully on ferry, research and other commercial vessels in New England.

For me, this would probably mean a 100KW genset/diesel which would power a 100KW electric motor with >50kwh of storage. Have yet to see a formal proposal but that's the broad brush. I don't have (but require) a gen set and this would provide an alternative. I anticipate adding heating and cooling to the boat so my hotel loads will go up.

I just don't understand fully what the implications are for range estimation for a given fuel supply. Am sure that there's a lot that I don't know and am looking to do a deep dive into any available research, data or similar forum threads.
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