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Old 05-12-2019, 19:29   #1
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Hybrid Electric Sail Boat Generator Question

Hi Guys,

New to the forum but have been reading it on n off for years.
I've just bought a Roberts 45 with a Hyper 9 120HP Electric Motor.
It has a battery bank but it's currently not being charged by solar or wind, it will be eventually, but for now I just need to get it moving.
I am looking to buy a generator to charge the batteries... It'd be great to run the motor straight off the generator but therein lies my dilema.
Is it too hard? Should I just buy a small petrol generator to charge the batteries - petrol being dangerous onboard, but there will be some anyway for the tender- and save my money for boat renovation, or is it possible to run off a geni.
I spoke to Tim at EVWorks Western Oz (who was really helpful) who supplied the motor and he suggested I just buy a cheap generator and cheap battery chargers for now and he'll supply a quality charger once I have it moved and can tell him what batteries I have on board. He also said peak power of the motor is 80000watts. But the guy I bought the boat from says it's detuned via the operating software and only draws a max of 70amps and normal running is at only 30amps (120vdc) and suggests I could buy a diesel generator and use a bridge rectifier to change the 240v to 120vdc.... But that sounds dangerous on board a boat.
Buying a generator upfront without knowing how I intend to use it could be a waste of time, so I am seeking advice on what way I should go.

Another issue, I've read that 2 stroke engines can handle bad fuel that's sold in remote locations- I intend to cruise- so if I buy a 4 stroke petrol geni, I may run into reliability problems?


Does anyone have any use full opinion on what I should do?
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Old 05-12-2019, 21:50   #2
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Re: Hybrid Electric Sail Boat Generator Question

I just spoke to a marine electrician and he recommended just getting a small generator to charge the batteries for now.
I read on another post the Honda EU22i is a good machine, so I think I will get that for now... and then get a sparky out to check the feasibility of running it straight from a geni later.
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Old 06-12-2019, 03:52   #3
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Re: Hybrid Electric Sail Boat Generator Question

Greetings and welcome aboard the CF, Ozzie.


Quote:
... Buying a generator upfront without knowing how I intend to use it...
Indeed.
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Old 06-12-2019, 03:55   #4
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Re: Hybrid Electric Sail Boat Generator Question

Hiya Thank You
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Old 06-12-2019, 04:57   #5
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Re: Hybrid Electric Sail Boat Generator Question

Somethings don't add up:
- 80,000w motor but draws 8,400w max (70ampx120v).
- Why would you rectify to 240v AC...when you are charging DC batteries? Get ahold of a 120v charger.
- How big is the battery bank? To feed that motor at 80kw for an hour, you need an 80kwh battery bank (roughly the size of a $15k tesla battery bank).


I would suggest getting an independent expert to review anything proposed...example: solar array would need to be massive to get anything useful. A 4kw solar array would take about a week to charge up an 80kwh battery bank...this assumes you don't run any other house loads.
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Old 06-12-2019, 06:31   #6
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Re: Hybrid Electric Sail Boat Generator Question

Quote:
Originally Posted by valhalla360 View Post
Somethings don't add up:
- 80,000w motor but draws 8,400w max (70ampx120v).
- Why would you rectify to 240v AC...when you are charging DC batteries? Get ahold of a 120v charger.
- How big is the battery bank? To feed that motor at 80kw for an hour, you need an 80kwh battery bank (roughly the size of a $15k tesla battery bank).


I would suggest getting an independent expert to review anything proposed...example: solar array would need to be massive to get anything useful. A 4kw solar array would take about a week to charge up an 80kwh battery bank...this assumes you don't run any other house loads.

Hiya thanks for your comment.
The supplier of the motor said it's rated to 80000.
The previous owner said he detuned it via programing to reduce it to 70amp max, any stronger and it'll damage the boat apparently. It cruises at 4knots at 30 to 40amp... If I ever get stuck in a strong current I may be in trouble....

The purpose of rectifying 240v to 120vdc would be to run the motor straight off the geni. I was thinking maybe I should buy a big yanmar diesel generator.

I wouldn't want to run it straight off the geni often, but it would be useful for crossing the panama canal or if the rig fails. I think I will have to avoid the canal and take the long way round...

The previous owner doesn't know how big the battery bank is, he's not being very helpful in that regard. I haven't seen it yet, I'm just trying to prepare to move it once I get there on Monday.

I spoke to a marine electrician today and he said to just buy a small geni and several chargers and charge the batteries individually until I can get an electrician in to look at it, which is what the motor supplier also said.
To be honest I was panicking when I first made this post, unsure of what to do, as I have to move the boat asap after taking delivery, but after speaking to the motor supplier and the marine electrician I am confident everything will work out ; )

Again thanks for your comment.
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Old 06-12-2019, 07:25   #7
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Re: Hybrid Electric Sail Boat Generator Question

Quote:
Originally Posted by Sailing Ozzie View Post
... I haven't seen it yet, I'm just trying to prepare to move it once I get there on Monday.
... I have to move the boat asap after taking delivery...
From where to where, or how far?
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Old 06-12-2019, 08:25   #8
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Re: Hybrid Electric Sail Boat Generator Question

[QUOTE=Sailing Ozzie;3030176]
Another issue, I've read that 2 stroke engines can handle bad fuel that's sold in remote locations- I intend to cruise- so if I buy a 4 stroke petrol geni, I may run into reliability problems?



I can't address any of the electrical issues but I can comment on the engine. I will say up front you will get many opinions as most everyone loves their outboard and will defend it to the death.

In the past year I have been traveling, off and on, with a group of about 5 (5 + our boat) buddy boats. All have modern 4cycle engines in the 15 to 25 HP range. Except us, we have an older Yamaha Enduro 15 HP 2cycle outboard. Every single 4cycle has had issues and I have pulled more than one back to the safety of their mothership.

We have owned the Yamaha for over 2 years, it came with the mothership when we initially purchased. I have never even flushed the engine with fresh water as most internal parts are SS (that is what makes it an Enduro)! I mix the oil in the gas to spec and have never had to change a spark plug. The engine starts first pull, every time, even when cold. When cold I will pull the choke but only when cold.

Going down all the islands from Florida to Grenada we have noticed an abundance of Enduro outboards and I have asked several folks, on different islands "why?" I was told nothing but positives and to sum the up: "best outboard you can own" and "If it doesn't start on the first pull, something is wrong" and "Much more powerful than comparable 4 stroke."

The last statement, from above, it undoubtable because 2 cycle engines have more torque than 4 strokes, will pull better and get you on plane faster.

One day about a month ago a sailboat ran aground on a reef here in Grenada. A call went out on the radio asking for anyone and everyone with Enduro outboards to respond to help pull the boat off.

Now for the negative: when we had the mothership surveyed prior to purchase the surveyor told us to keep the Enduro covered up. He said it was such a high demand item it would attract the less than desirable who would want it for themselves.

Caveat: All 2 strokes are not equal..

I would buy another in a heartbeat if i needed it but would have to do it here as you can't get the small 2cycles in the states anymore.

Final thought, not picking on 4cycles, there are plenty of good ones but I think they are more susceptible to bad fuels and shoddy routine maintenance.

Enough said..

Just my two cents worth.
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Old 06-12-2019, 09:51   #9
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Re: Hybrid Electric Sail Boat Generator Question

Quote:
Originally Posted by Sailing Ozzie View Post
Hi Guys,
(snippage) the guy I bought the boat from says it's detuned via the operating software and only draws a max of 70amps and normal running is at only 30amps (120vdc) and suggests I could buy a diesel generator and use a bridge rectifier to change the 240v to 120vdc.... But that sounds dangerous on board a boat.
If something goes wrong, 120 volts DC will kill you just as dead as 240 volts AC.

[/FONT]
[FONT=&quot]Another issue, I've read that 2 stroke engines can handle bad fuel that's sold in remote locations- I intend to cruise- so if I buy a 4 stroke petrol geni, I may run into reliability problems?
[/QUOTE]

Neither two stroke or four will run on really bad (sour) gasoline. I read more reports of issues with poor quality diesel than gas. And you're not likely to find a two stroke generator, anyway.

I wish you luck, and hope you REALLY love that boat, because your electric propulsion is going to be expensive and for the time being, far more labor intensive than a plain old diesel engine.
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Old 06-12-2019, 10:19   #10
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Re: Hybrid Electric Sail Boat Generator Question

A few thoughts. Depending on how long the move is have you thought about hiring a genset? If you only need it for a week could save having to buy something that then becomes redundent. If you are getting a gas genset as a temp solution look at open frame, much louder than something like the Honda but will be about 1/3 of the cost. The idea about gas being a less fussy fuel is not one I have heard, storing larg amounts of gas would be a safety issue and a better way of dealing with potential fuel contamination issues would be to fit a fuel scrubber. As a permenant solution for charging the batteries or running the engine in diesel electric mode might be to fit an inboard diesel DC generator that provides enough power to run at cruising speed. You say the boat will do 4kn at 30a so that would be 30x120 or 3.6Kw. No problem for a small DC genset.
The other thing I am wondering is that if the boat has ever been used it must have a means of charging, who would fit an electric motor without a charger!! Or is this a 'part install' that someone has abandoned before finishing?
I suggest you either get more info on the setup or look at getting a gas outboard rather than a geny. It is quite feisible to tow a 30ft boat with the dingy and outboad in and out of habour then sail it for the delivery as long as it is not to far or difficult. I can see potential for real problems if the electric motor is not properly set up.
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Old 06-12-2019, 12:58   #11
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Re: Hybrid Electric Sail Boat Generator Question

If you want a cheap but reliable petrol gen set google Kings 3.5kva. It's open frame pull cord start very basic but will do the job and has a largish tank. AUD399. I live in Nth Qld so power supply in the wet is not terribly reliable. I picked one up for household power backup.
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Old 06-12-2019, 13:03   #12
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Re: Hybrid Electric Sail Boat Generator Question

Something sounds inappropriate or incorrect as to the specifications.

OP stated the motor is rated for 80kw but its controller is derating the power supplied to about 8 kw. So reducing the boats propulsive force from about 100 hp to say 10 or 11 hp.

One needs to have exacting clarity of the motor controllers specifications as to DC voltage supply options and as to the rated amperage capacities, then one works back towards the power supply source requirements.

Don't even think about what kind of genny or battery bank, or power conversion electronics are necessary until there is complete clarity of how the motor controller is functioning and capable of functioning and also as to the specifications of the motor.
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Old 06-12-2019, 13:24   #13
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Re: Hybrid Electric Sail Boat Generator Question

The one thing you don't discuss in your post...Sailing. Its a sailboat.

Your setup with electric drive is EXCELLENT, provided you sail most of the time. The engine is just for getting in/out of docks/marinas or the last quarter mile into the sheltered bay to anchor.

Electric motors are GREAT. The problem is range. Battery technology is improving every day. But as of today, you will need a lot of batteries...like 10 or 20 or 30 to give a modest range of maybe a few hours of motoring at a reasonable speed.

I almost agree with your electrician et al...charge up the batteries at the dock. Use the engine sparingly to get to open water, then SAIL as close to your destination as possible. Before doing this, you may want to do a test...maybe run the engine at 30 amps for an hour or two to see what sort of range you currently have. But then you'll need 2 or 3 days to recharge the batteries fully.

I'm going to speculate that the boat needs new batteries...hence the seller's apparent lack of knowledge on the topic. Anyone with an electric drive absolutely knows the status and range of their batteries. Assume you will need all new batteries, costing several thousands of dollars.

I love the little honda genset. But it will take hours (or days) for it to charge your batteries, if you have a big bank, especially if they are old.

Please don't misunderstand. I think electric drive is excellent and I look forward to owning one myself one day. Once you get some solar, wind, and maybe hydro charging installed (Watt&Sea) you will have an awesome setup.

Do you follow Sailing Uma? They travel with an electric drive and have extensively documented their experience with it on their sailing channel: https://www.sailinguma.com/the-motor

What do people do when their engine dies? They sail. And maybe get a tow with a dinghy the first/last 100 feet if needed. I personally love sailing with no engine. I used to sail in/out of my busy marina with no engine. I sail on/off of anchorages and docks whenever possible. I've done this in boats up to 60 feet. And there are still people who enjoy sailing with no engine at all. Have you seen How to Sail Oceans: https://www.youtube.com/channel/UCTm...f_7nTLw/videos

I wish you luck, and please let us know how your delivery goes.
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Old 06-12-2019, 13:29   #14
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Re: Hybrid Electric Sail Boat Generator Question

This boat is not adding up. A Roberts 45 should have 60 to 90 hp (~50-60kW). the PO buys a motor with significantly higher output, then says "it will damage the boat if run higher than 11hp." That would freak me out! Is this sea worthy?? I highly doubt 3.6kW (4.6hp) will push that boat at 5knots, certainly not into any wind!! Did you take it for sea trials before purchase or have some way out of the contract?



The OP doesn't know the battery specs, make statements evident of structural issues and makes claims about performance that are dubious at best. I would be very concerned leaving the dock without another propulsion option, like a tow. And I'd find out why you can't push more than 11hp with the motor before using it.
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Old 06-12-2019, 13:40   #15
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Re: Hybrid Electric Sail Boat Generator Question

Quote:
Originally Posted by zstine View Post
This boat is not adding up. A Roberts 45 should have 60 to 90 hp (~50-60kW). the PO buys a motor with significantly higher output, then says "it will damage the boat if run higher than 11hp." That would freak me out! Is this sea worthy?? I highly doubt 3.6kW (4.6hp) will push that boat at 5knots, certainly not into any wind!! Did you take it for sea trials before purchase or have some way out of the contract?

The OP doesn't know the battery specs, make statements evident of structural issues and makes claims about performance that are dubious at best. I would be very concerned leaving the dock without another propulsion option, like a tow. And I'd find out why you can't push more than 11hp with the motor before using it.
Devils advocate:

Perhaps its just a misunderstanding. Its not uncommon to use a high powered electric motor at a lower power. For example, some common electric trolling motors run just fine on 12volts, or you can run at 48volts for much more power. Same motor. Maybe this is what's been done. High power electric motor installed. Will run with whatever current you want to provide.

Following this idea...if you actually ran the engine at full power, it would likely fry the batteries and burst off its mounts. But you would never do that. You would never be able to do that because of the limitations of the batteries and the controller. Your power cables would likely melt before you got close.

So maybe this whole thing is a misunderstanding as the new owner gets to know his new boat.

My advice...a good voltmeter to check each battery individually, and try some simple engine tests at the dock.
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