Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 22-08-2015, 15:58   #76
Registered User
 
Wireless1's Avatar

Join Date: Jan 2012
Location: Southern California, USA
Boat: Beneteau 473
Posts: 145
Re: Electric Inboard

Quote:
Originally Posted by TacomaSailor View Post
"I think you would be wise to look into the differences in torque that the electric motor provides, also the adjustable pulley reductions you can tune. I don't see you calculating the torque advantages of electric propulsion swinging large oversized props. "

Torque is only a force but it is power that moves the boat.

HP = (torque x RPM) / 5252
Torque = HP x 5252 / RPM

If you double the torque with gear or pulley ratios you slow the RPM and the horsepower stays the same.

Increasing torque by decreasing RPM (that is what gear ratios do) does not increase the HP and HP is what moves the boat.

Torque is measured in foot pounds (at least in the US) so if you move 550 pounds one foot you've exerted 550 foot pounds of torque. But, that says nothing about the time taken to move that weight that distance.

Horsepower measures the energy produced/consumed per unit of time and ONE Horsepower is the power needed to move 550 pounds one foot in one second. One HP is equivalent to 746 watts of electrical energy.

So I can move that 550 pounds one foot in one second while using 1 HP or I can take 10 seconds to move it and use 1/10 of a horsepower.

So - you can have very high torque, as shown in a stalled electric motor, but produce no horsepower because there is no shaft rotation and nothing moves - but there is still the torque (force) available.

You can change the gear and pulley ratios all you want but the power needed to move the boat will remain the same.

A boat has weight and drag and to move that weight and overcome that drag will always require the same force at any given boat speed. You can increase the torque (force) but if you do that only with gear ratios you will decrease the RPM and therefore the power (energy per time unit) will remain constant and the boat speed will remain constant.

If you increase the torque and maintain the RPM then the power required will increase at the same ratio as the gear ratio.

Using a bigger prop makes the prop more efficient but as you increase the prop efficiency you also let it put more power into the water thus requiring more power from whatever drives the prop shaft.

You can not gain boat speed except by applying more power thru the prop to the water and that power has to come from somewhere.

You can not make any additional power, just by changing gear ratios and prop sizes without adding watts (amps x volts) delivered from the battery.



Power and Force have always confused me and if you find something wrong in what I have written above - please let me know 'cause I copied most of it from some physics books.
I really do appreciate you taking the time to look all this stuff up. Yes, it is fascinating for sure. But how about trying this just for fun >>
I have an idea! How about instead of assuming nobody is getting the mileage and range the factory shows is happening in the real world, (in essence calling all those people liars), why not work your numbers and calculations backwards to see where your calculations are perhaps letting you down? That is done all the time in good science. See where a coefficient, or a factor, is simply wrong? Or no longer valid? You seem confused a lot so why not reverse engineer say a boat going 3.2 knots and drawing 20 amps? People are getting these numbers with their boats. It's being done and it is conservatively projected for my hull from the factory. Maybe give that a try? Why not? What have you got to lose?

You know not meaning to go OFF THREAD but; what's going on here is similar to other things being argued today. It kind of reminds me of the global warming crisis. The research numbers show it's happening, 95% of the world's scientific community says there is no doubt it's happening, but the nay-sayers say it's impossible, so they run around trying all sorts of "numbers" to prove it can't be happening. I guess this kind of thing happens a lot when science is approached with a preconditioned mindset that something new can't be breaking the rules or the concrete laws we have had forever. There are the same kind of heated arguments taking place regarding the use of LiFePO4 batteries versus lead acid batteries. You wouldn't believe those wars, unless you've tuned into them here. There are even people thinking I am installing a giant bomb in my boat! LMAO!.... Oh well, just some thoughts.
PS-I'm wondering when or if this thread will be moved to the Propulsion Forum?
__________________

__________________
s/v "Bamboleo" - Freedom 32 (Hoyt)
Farrier Trimaran -- Morgan 41 Classic,
Rawson 30
Wireless1 is offline   Reply With Quote
Old 22-08-2015, 16:19   #77
Registered User
 
Wireless1's Avatar

Join Date: Jan 2012
Location: Southern California, USA
Boat: Beneteau 473
Posts: 145
Re: Electric Inboard

Quote:
Originally Posted by TacomaSailor View Post
Let me preface this post with a clear statement of my admiration and respect for those trying to advance the engineering and technology of electric propulsion in power boats. I love technology and love numbers. My questions and comments are an attempt to understand how the leaders in the new frontier of electrical propulsion plan to overcome what most of us thought were well established limitations based on solid physics and electrical engineering.

Please do not think I am trying to stop folks from moving forward - I just really want to know how you plan to overcome these limits.

"I hope the numbers below will give you some food for thought in your calculations. Here you go >> (it's from a graph so I will interpolate as best I can).
Motor: 10Kw PMAC @ 48 Volts
Shaft HP: 9 with 40:24 reduction
Prop: 15" x 12" (I have gone up to a 16.5" variable pitch Kiwi feathering prop)

Amps vs. Speed Graph
10 amps - 2.4 knots
20 amps - 3.2 knots (hoping to squeeze another .8 knots our of my variable prop?)
40 amps - 4.5 knots
65 amps - 5.0 knots
80 amps - 5.5 knots
120 amps - 6.3 knots
180 amps - 7.0 knots "


I am always glad to learn new things and play with new numbers. Some of what you report above is confusing.

The high efficiency motor you cite is 10 Kw and 9 shaft horsepower. But, 10 Kw is actually 13.3 HP at 100% efficiency. Your reported 9-shaft HP is only 67% efficient. What do I misunderstand here?

10 amps at 48V is 0.63 HP and you say that will move your 8,900 pound boat at 2.4 knots? How can that occur? My Milwaukee drill ( 660 watts or 0.88 HP) is geared for 0 to 950 RPM and I am pretty sure it cant move an 8,900 pound boat at 2.4 knots.

Dave Gerr is a very well respected Naval Architect and has published a great deal of technical professional information about calculating power to move vessels. Here is a link to an article about the formula and its application in the professional journal published by the Westlawn Institute of Naval Technology.
http://www.westlawn.edu/news/Westlaw...d06_June08.pdf

Gerr says you need 2.06 Kw (2.76 HP) or 43 amps at 48V to move the boat at 2.4 Knots rather than the 0.63 HP your data reports.

You claim to move the boat at 5.5 knots using 3.84 Kw (80 amps) but the Gerr formula says you need 7.11 Kw.

How do you propose to overcome the formulas used by professional boat designers? Those formulas predict you need more than four (4) times the shaft horsepower to move the boat as you are citing.

I am not making up any numbers! I am just applying the numbers you provide to standard formulas. Are you saying that you and the other electric boat advocates know how to overcome the power issues that have plagued naval architects since the first propeller driven ship?

I have reviewed the E-Boat modeling spreadsheet used to calculate power needed to move a boat thru the water. I see that sheet predicts the same power requirements you cite above.

Looking at the E-boat formula for hull drag I see a simple linear function that seems to ignore the exponential characteristic of drag as a function of speed.

So a fundamental difference I find in our positions is the calculation of power requirements.

A big difference I see in the formulas are probably the cause of our vastly different estimations of required power.

The Gerr formula is exponential in respect to drag increase with speed increase. The E-boat formula for drag is linear and specifically excludes calculations below an S/L of 1.0 or 5 knots in your case.

The E-boat spreadsheet also assumes a fixed 55% efficiency factor the transmission of power to the water by the prop. But, we know that most prop curves are cubic in nature and the prop puts very little power into the water at low RPM. For example, a 20HP Yanmar 3GM makes 9 SHP at 1800 RPM but the prop only puts 2.5 HP into the water for an efficiency of 28%. At 2200 RPM those numbers are 12, 3.5 and 29%. The engine has to be turning 2900 RPM for the prop to put 50% of the 14 SHP into the water.

As far as I know electric motors turning a propeller in the water suffer the same cubic prop curve. The E-Boat model ignores the inefficiency of the prop at low RPM compared to total RPM.

The results of the spreadsheet equate shaft horsepower in a direct and linear fashion to propulsion power. I am pretty sure than is not the way it works.

Is there something unique about the new motors and controllers that allow them to move boats thru the water with less power than all previous boats powered with diesels?

I have applied the Gerr and Bebe formulas to my Caliber 40 and find them, when using the Yanmar prop curve charts, to be very accurate at predicting boat speed in still water. That is - the Gerr prediction for a given HP needed agrees almost exactly with the prop HP delivered at a particular RPM and a measured speed. I would be totally gob-smacked if someone told me the Gerr, or Bebe, formulas are incorrect.

Those formulas also work very well with a Tartan 42/Perkins 4-108 that I operated for several years and thousands of miles.

That is the reason I am so curious about the predicted HP needed to move electrically powered boats - it differs by a factor of 3 or 4 from what I measure in my real life.
I have a GREAT idea. You are in San Diego, I am in Mission Bay. When I get this Electric Yacht Systems 10Kw PMAC/Sevcon package installed and the monitoring completed (Victron 700, Junsi Cell Log8's x2 data logging with alarms, and Electric Yacht CAN buss readout at the helm), then I will be able to dial in the pulley ratio and the prop pitch as best I can to see if I can hit my numbers. Then you come over to the boat and we can take 'er for a spin and see some REAL numbers! This will either make me very happy and satisfied, and you going away scratching your head, or you very happy and satisfied, and me still very happy and satisfied even if I don't meet my numbers exactly...
Sound like a plan? I'm up for it. How 'bout you?
__________________

__________________
s/v "Bamboleo" - Freedom 32 (Hoyt)
Farrier Trimaran -- Morgan 41 Classic,
Rawson 30
Wireless1 is offline   Reply With Quote
Old 22-08-2015, 16:28   #78
Registered User

Join Date: Apr 2013
Posts: 4,876
Re: Electric Inboard

Quote:
Originally Posted by Stumble View Post
SolarWave is actually a pretty good example of how good design can change the numbers.

Drag is proportional to the L/B ratio (leingth/beam) or more technically the froude's number. Basically as a hull gets longer and thinner it produces less drag. On a monohull there is a practical limit to this since the hull also has to contain the living space. On a multihull the living space can be pushed to the bridge deck and the hulls can be made very long and very narrow.

This is exactly what SolarWave has done. Where a typical monohull has a L/B of about 2.5:1 SolarWave is about 7:1. This means the hulls are incredibly easily driven compared to a monohull, thus needs less power for the same speed. To use it as a comparison we would need a 45' monohull that is about 6' wide at the waterline. You could certainly design such a boat and it would take very little power to move, but it would be a pain to sleep on.

This is why all the prop-speed formulas have a disclaimer that they don't work for catamarans BTW. but there are separate formulas that do.
Actually solarwave is more an example of trading off load carrying ability and accommodations to reduce the drivetrain power needs. Take that same boat and put in a couple 5hp diesels and limit the throttle setting to 4kts and you are probably getting 30-40 MPG negating most of the assumed fuel saving benefits. 50gal tanks is ocean crossing range.

They are willing to sacrifice comfort (relative to more comfortable boats of the same length) to reduce the force needed to drive the boat. That comes with it's own set of costs but doesn't prove the viability of electric drivetrains for typical cruising boats.

Also don't forget the replacement cost of batteries. I've yet to come across a battery that doesn't wear out after a few years and when you are talking thousands of dollars for a battery bank, that's a lot of fuel that could be purchased.
__________________
valhalla360 is offline   Reply With Quote
Old 22-08-2015, 17:06   #79
Registered User
 
Terra Nova's Avatar

Join Date: Apr 2007
Location: Marina del Rey, California
Boat: Freya 39 cutter- Terra Nova
Posts: 3,645
Re: Electric Inboard

Unsubscribed.
__________________
1st rule of yachting: When a collision is unavoidable, aim for something cheap.
"whatever spare parts you bring, you'll never need"--goboatingnow
"Id rather drown than have computers take over my life."--d design
Terra Nova is offline   Reply With Quote
Old 04-03-2017, 04:13   #80
Registered User

Join Date: Sep 2009
Posts: 331
Re: Electric Inboard

Let say I want about 16kw LiFePO4 batteries to run an electric inboard.
Can I put 15 batteries 3.2v 400Ah in serie....like these ones?https://www.ev-power.eu/Winston-40Ah...-2V-400Ah.html

when it comes to LiFePO4, what decides which maximum voltage and bank size it can handle? I have seen limitstions stated on some batteries but not all. Is it the built in BMS?
__________________
andreas.mehlin is offline   Reply With Quote
Old 04-03-2017, 09:33   #81
Marine Service Provider

Join Date: May 2012
Location: New Orleans
Boat: We have a problem... A serious addiction issue.
Posts: 3,940
Re: Electric Inboard

Quote:
Originally Posted by andreas.mehlin View Post
Let say I want about 16kw LiFePO4 batteries to run an electric inboard.
Can I put 15 batteries 3.2v 400Ah in serie....like these ones?https://www.ev-power.eu/Winston-40Ah...-2V-400Ah.html

when it comes to LiFePO4, what decides which maximum voltage and bank size it can handle? I have seen limitstions stated on some batteries but not all. Is it the built in BMS?
If you have to ask questions this basic then lifepo is probably not a reasonable option for you yet. They take a good bit of technical ability to keep working right and if something goes wrong you just bricked tens of thousands of dollar worth of batteries.

But to answer your question, yes you can connect multiple batteries in series then parallel to get the voltage then Ah you need from a bank.
__________________
Greg

- If animals weren't meant to be eaten then they wouldn't be made of food.
Stumble is offline   Reply With Quote
Old 04-03-2017, 12:21   #82
Registered User

Join Date: Oct 2015
Posts: 144
Re: Electric Inboard

Quote:
Originally Posted by andreas.mehlin View Post
Let say I want about 16kw LiFePO4 batteries to run an electric inboard.
Can I put 15 batteries 3.2v 400Ah in serie....like these ones?https://www.ev-power.eu/Winston-40Ah...-2V-400Ah.html

when it comes to LiFePO4, what decides which maximum voltage and bank size it can handle? I have seen limitstions stated on some batteries but not all. Is it the built in BMS?
Andreas what type of Cat are you running now still a 38'? You have so much sailing experience. I'll answer your questions.

The maximum voltage is derived on a per cell basis. Nominally 3.2v per cell of lithium to a max of 3.6v per cell with the ideal charged rate being 3.45 volts per cell. In your case a bank of 16 of the winston cells will provide 20kwh of energy and is a great bank. I have one.

Electric motors will have an acceptable voltage range in which they will operate. That can vary by motor type. In the case of the electric yacht motors I would imagine they operate from 40v to 60v range. This is well suited to the battery chemistry.

The motors themselves are governed by a controller - typically a sevcon controller or a curtis controller for example. This allows the operator to control the throttle and the current.

On my 26' catamaran I use 16 400ah cells in series tied to dual rayeo electric outboards at 4kw each. I can use up to 7500 watts of power when running at top speed - which is wildly inefficient but still doable for a 6.6 knot speed. My displacement is < 6000lbs.

Otherwise my best efficiency occurs at 65% of my hull speed around 4 to 4.3 knots and I can motor at this speed forever considering my final design layout. I had the option to install light sails, aluminum mast, rigging but opted not to.

I instead covered the topside with 2160 watts of flexible solar panels. 12 panels in series 79.60voc and 32.88amps STC. 2160 Watts of panels mounted to the catamaran weighs 120lbs. I will see over 20 amps of solar input on a nice sunny day.

I can motor using 30 amps against current back upriver of 1-2 knots and still maintain 8.2 km/h on the chartplotter and 4.1 knots from the sensor on the hull. Port and starboard motor are using 20amps each and solar is kicking back in 10 amps. From my 320ah (conservative) usable amp hours I could do this for 10 hours.

Otherwise I simply opted to have on board two alphagen dcx3000 generators that are load bearing up to 50amps dc and maintain my bank at 52.5 volts. If ever I were to run low on energy I would simply start my generators and keep on motoring. You could accomplish the same with a a couple honda 3000 generators plugged into two 120v battery chargers.

I think you will be very happy with 16 400ah Winston cells. For me it was the bare minimum starting point for an electric boat and likely the best considering the weight 565lbs was about equal to the mast rigging sails and associated gear. I even figured the weight right down to every component when starting from the empty hull.

https://www.facebook.com/media/set/?...1971275&type=3

At that point I could only estimated that she weight about 3200lbs anchors rode chain included. I then added the batteries, chargers, inverters, solar panels, outboards, induction cooktops, heaters, dehumidifiers, washing machine, 2 quick boilers, pressurized hot water pump, tools, electric incinerating head, and all the wiring plus state of the art ais, radar, sounder, dual autopilots and electronics.

At the same time I removed all the redundant sailing gear, winches, cleats, rudders. At least 300 lbs worth or more didn't weigh it just happy to have it off the boat.

When we finally put the boat on the travel lift it came in at 5600 lbs. The boat electrical draw is from 4-8 amps depending on which systems we have running. We run it all from one bank and invert from 2 3000w 48v inverters. We convert to 12v with a converter.

Maneuvering is almost instant and it easily turns on it's length.

Attached Files
File Type: gpx track.gpx (19.2 KB, 5 views)
File Type: gpx track1.gpx (12.8 KB, 6 views)
File Type: gpx track2.gpx (13.0 KB, 3 views)
__________________
PacificGreen is offline   Reply With Quote
Old 04-03-2017, 13:22   #83
Registered User

Join Date: Sep 2009
Posts: 331
Re: Electric Inboard

Quote:
Originally Posted by PacificGreen View Post
Andreas what type of Cat are you running now still a 38'? You have so much sailing experience. I'll answer your questions.

The maximum voltage is derived on a per cell basis. Nominally 3.2v per cell of lithium to a max of 3.6v per cell with the ideal charged rate being 3.45 volts per cell. In your case a bank of 16 of the winston cells will provide 20kwh of energy and is a great bank. I have one.

Electric motors will have an acceptable voltage range in which they will operate. That can vary by motor type. In the case of the electric yacht motors I would imagine they operate from 40v to 60v range. This is well suited to the battery chemistry.

The motors themselves are governed by a controller - typically a sevcon controller or a curtis controller for example. This allows the operator to control the throttle and the current.

On my 26' catamaran I use 16 400ah cells in series tied to dual rayeo electric outboards at 4kw each. I can use up to 7500 watts of power when running at top speed - which is wildly inefficient but still doable for a 6.6 knot speed. My displacement is < 6000lbs.

Otherwise my best efficiency occurs at 65% of my hull speed around 4 to 4.3 knots and I can motor at this speed forever considering my final design layout. I had the option to install light sails, aluminum mast, rigging but opted not to.

I instead covered the topside with 2160 watts of flexible solar panels. 12 panels in series 79.60voc and 32.88amps STC. 2160 Watts of panels mounted to the catamaran weighs 120lbs. I will see over 20 amps of solar input on a nice sunny day.

I can motor using 30 amps against current back upriver of 1-2 knots and still maintain 8.2 km/h on the chartplotter and 4.1 knots from the sensor on the hull. Port and starboard motor are using 20amps each and solar is kicking back in 10 amps. From my 320ah (conservative) usable amp hours I could do this for 10 hours.

Otherwise I simply opted to have on board two alphagen dcx3000 generators that are load bearing up to 50amps dc and maintain my bank at 52.5 volts. If ever I were to run low on energy I would simply start my generators and keep on motoring. You could accomplish the same with a a couple honda 3000 generators plugged into two 120v battery chargers.

I think you will be very happy with 16 400ah Winston cells. For me it was the bare minimum starting point for an electric boat and likely the best considering the weight 565lbs was about equal to the mast rigging sails and associated gear. I even figured the weight right down to every component when starting from the empty hull.

https://www.facebook.com/media/set/?...1971275&type=3

At that point I could only estimated that she weight about 3200lbs anchors rode chain included. I then added the batteries, chargers, inverters, solar panels, outboards, induction cooktops, heaters, dehumidifiers, washing machine, 2 quick boilers, pressurized hot water pump, tools, electric incinerating head, and all the wiring plus state of the art ais, radar, sounder, dual autopilots and electronics.

At the same time I removed all the redundant sailing gear, winches, cleats, rudders. At least 300 lbs worth or more didn't weigh it just happy to have it off the boat.

When we finally put the boat on the travel lift it came in at 5600 lbs. The boat electrical draw is from 4-8 amps depending on which systems we have running. We run it all from one bank and invert from 2 3000w 48v inverters. We convert to 12v with a converter.

Maneuvering is almost instant and it easily turns on it's length.

Wow, that was a long reply
Impressive setup you have!


No, the 38 ft Helios catamaran was sold in Australia....but now looking for boat again to go on adventures with. Who can get enough?



What kind of electric engines do you have? I have looked at torqeedo, but also green marine system (if I go inboard). One thought I had was to use two outboards an a catamaran and use one of them as dinghy engine. Green star marine system offers charging when sailing. Otherwise maybe a separate hydro gen

Another question
Let say I have one bank 48V and one 12V. I put all charging to 48V bank. Is thete a DC to DC charger which can charge the 12V from the 48V bank?
__________________
andreas.mehlin is offline   Reply With Quote
Old 04-03-2017, 18:25   #84
Registered User

Join Date: Oct 2015
Posts: 144
Re: Electric Inboard

Quote:
Originally Posted by andreas.mehlin View Post
Wow, that was a long reply
Impressive setup you have!
Thanks, it is a work in progress for sure.

Quote:
Originally Posted by andreas.mehlin View Post
WowNo, the 38 ft Helios catamaran was sold in Australia....but now looking for boat again to go on adventures with. Who can get enough?
Can't wait to get started again on mine. Have a 36v gps trolling motor/anchor/autopilot to install.


Quote:
Originally Posted by andreas.mehlin View Post
WowWhat kind of electric engines do you have? I have looked at torqeedo, but also green marine system (if I go inboard). One thought I had was to use two outboards an a catamaran and use one of them as dinghy engine. Green star marine system offers charging when sailing. Otherwise maybe a separate hydro gen
I have Ray Electric Outboard most powerful, durable, not plastic underwater trolling motor. We don't troll, we motor. Made in the U.S.A. two year warrenty! and they are probably the most robust motor you will ever find on the market. I really lucked out getting mine. I quickly ruled out the rest simply based on material construction and ability to diagnose and fix underway. I can tear the Rayeo 48v outboards down and trace every wire if need be. No impellers for water cooling to worry about either.

I experimented with a new but old 9.9 yamaha hight thrust long shaft remote on my Craig Cat catamaran as a motor but it really is too problematic the whole 400lbs of it.

I'm going porte bote tender with an electric 12v outboard. You can see videos of a Ray Electric outboard mounted to a Craig Cat on my you tube channel. Because they are remote steer models the idea of simply taking one off the dingy and replacing it back on the big catamaran becomes a bigger problem than it solves. The actual solution with the Rayeo Electric outboard would have been to just purchase another throttle controller and have that mounted on the dingy. Still doesn't account for having to disconnect the steering rod and undoing the bolts.

Quote:
Originally Posted by andreas.mehlin View Post
WowAnother question
Let say I have one bank 48V and one 12V. I put all charging to 48V bank. Is thete a DC to DC charger which can charge the 12V from the 48V bank?
Simple. I have a 12v charger that came with the boat. I plug it into the inverter to charge the 12v battery for the dingy when needed. Otherwise I use 120vac to 12v converters to power all my electronics. The ones I use produce 200w and 15 amps.

Lets be clear with what you can do with a 20kwh lithium battery bank. Over six months it ran 1 or 2 heaters that ran anywhere from 10-24 amps. It would always amaze our 12v friend that would come visit. He would say your running that all night cooking supper on your induction cooktop and making hot water all from your batteries!!! Eventually he understood but was convinced in some other drop in replacement 12v lithium battery that is good at making press releases.

When I went to look at that same 12v lithium battery of his I laughed because it was dying already and there was no way to check the voltages of any of the cells inside because it was a sealed unit.

6000w (2 3000w 48v inverters) of inverted power is easily handled by a 20kwh bank. I could in a few respects use one more but we make due cycling between running the hot water tank which we only turn on when we want to make hot water (for dishes/showers) and other things like using the electric head. The former would draw 50 amps and the later around 42 amps. Induction cooking can be done easily on a 2 or 3 setting for around 20 amps.

Waste is burnt in a cycle of 40amps on to 18amps blower for about an hour - no plumbing issues or discharge hassles. Water heats up in under an hour with the 120v quick bx16 boiler elements and they quickly stop the 50amp draw at which point there is 9 gallons of water and when showering they kick back on and warm up the tank. I could shower on the deck in the middle of winter for 10 minutes with steam everywhere.

For what it's worth you can no doubt find a dual inboard catalac in your area that could be easily converted to electric inboards. If you choose to keep the sails and mast would be another decision. If you could find one without the dog house on top you would have room there for 1440 watts of unobstructed solar. A bimini on the back would give you a nice look and another 1000 watts.

I doubt it would ever compare to what I've read about some of your trips but I'm sure you could still get her surfing at 18 knots without a sail. Under power diesel or otherwise your still only around 5 knots which would be hassle free with electric. With outboards you have to wonder about getting hit by a wave but with electric they will still run. Inboards no worries.
__________________
PacificGreen is offline   Reply With Quote
Old 04-03-2017, 19:45   #85
Registered User

Join Date: Dec 2015
Location: USA
Boat: O'Day DSIII
Posts: 19
Re: Electric Inboard

I use one all the time on my pontoon boat. It works great.
__________________
Time Theory is offline   Reply With Quote
Old 04-03-2017, 20:08   #86
Registered User

Join Date: Oct 2015
Posts: 144
Re: Electric Inboard

Quote:
Originally Posted by Time Theory View Post
I use one all the time on my pontoon boat. It works great.
An electric inboard or a Ray Electric Outboard? They seem to have sold many in the southern USA. 99% of their motors since 1973 are still running today.
__________________
PacificGreen is offline   Reply With Quote
Old 17-03-2017, 04:12   #87
Registered User

Join Date: Sep 2009
Posts: 331
Re: Electric Inboard

Quote:
Originally Posted by Stumble View Post
If you have to ask questions this basic then lifepo is probably not a reasonable option for you yet. They take a good bit of technical ability to keep working right and if something goes wrong you just bricked tens of thousands of dollar worth of batteries.

But to answer your question, yes you can connect multiple batteries in series then parallel to get the voltage then Ah you need from a bank.
haha
Well, now when I read my question again, I understand it might have sounded very dumb/simple. The thing is that I have seen some Lifepo4 batteries where it was stated a maximum of Ah to be parallell connected. My question was more or less if these batteries had any limitations when it comes to bank size. But I guess these ones doesn't have that limitation. Is it the BMS having that kind om limitations?

LifePo4 is pretty new to me, that is why I ask questions. Otherwise I would say Im very good at electrical systems.
__________________
andreas.mehlin is offline   Reply With Quote
Old 17-03-2017, 07:47   #88
Registered User

Join Date: Oct 2015
Posts: 144
Re: Electric Inboard

Stick with large format prismatic cells. In your area you should be looking at 123smartbms product sellers

There are many different types of BMS systems. Some can only handle a certain amount of cells in series or parallel. Some are very basic and some are more advanced. Some people manage cells without a BMS.

Configure a simple series only based approach to prototyping a designed system. That being said if you want 400ah battery bank make it with 400ah cells. Making a 400ah battery bank from 100ah cells results in a far more complex configuration that you don't want on a boat.

Select a pack voltage greater than 12v for redundancy and efficiency. 48v is optimal. Practice making your own based on this both above and below in cell size and voltage https://www.ev-power.eu/Sinopoly-40A...rotection.html

I see a trend especially by boat manufacturers going with just small banks that are pretty much insufficient for propulsion of any length and usually pushing big boats. They end up overbuilding on huge generators with huge solar arrays and miss the point of energy storage completely usually going with way to small of batteries for their now heavy catamarans, bon voyage 440.
__________________
PacificGreen is offline   Reply With Quote
Old 17-03-2017, 13:54   #89
Registered User
 
denverd0n's Avatar

Join Date: Jun 2008
Location: Tampa, FL
Posts: 3,949
Images: 6
Re: Electric Inboard

Well, here's my take on the diesel vs. diesel/electric issue...

It now officially goes into the same category as discussions about anchors and guns. In other words, everyone has made up their mind, and only wants to tell everyone who disagrees that they are wrong.

My prediction is that this "discussion" (argument, really) will get more and more contentious until the moderators will eventually have to lock it.

Now I can add one more subject to those that, when I see it in a subject line, I just ignore the whole thread.

Have fun, y'all!
__________________
denverd0n is offline   Reply With Quote
Old 17-03-2017, 15:45   #90
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 12,374
Re: Electric Inboard

Quote:
Originally Posted by denverd0n View Post
Well, here's my take on the diesel vs. diesel/electric issue...

It now officially goes into the same category as discussions about anchors and guns. In other words, everyone has made up their mind, and only wants to tell everyone who disagrees that they are wrong.

My prediction is that this "discussion" (argument, really) will get more and more contentious until the moderators will eventually have to lock it.

Now I can add one more subject to those that, when I see it in a subject line, I just ignore the whole thread.

Have fun, y'all!
Gee Don, are you just figuring this out? I thought you were usually pretty quick on the uptake.

Not only are you told you are wrong if you disagree with the go electric group but also accused of being a Luddite, refusing to accept innovation and "new" technology, ignoring their facts and proofs, and belong in the same group as those who told the Wright brothers man could never fly and claimed the earth was the center of the universe.

I cannot recall a single one of those that claimed all these miracle results with electric boats that have ever come back to report on their successful project for large boats with long range and lots of power. Yes there are a number of cruisers that have successfully converted to electric but to date all of them have done so within those limitations IE small to moderate size boats with limited range or have had to add a large diesel generator.
__________________

__________________
The water is always bluer on the other side of the ocean.
skipmac is offline   Reply With Quote
Reply

Tags
electric

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale: Sailboat inboard electric motor system for sale lazystar@aol.com Classifieds Archive 9 12-03-2015 10:01
For Sale: PAR Electric System Water Pump and JABSCO Electric Bilge Pump hanks Classifieds Archive 3 05-03-2014 20:03
For Sale: Electric Motors and hydraulic electric lifter arms 4 sale Sea Shoes Classifieds Archive 0 25-03-2012 08:46
Replacing Inboard Engine with Electric Motor boat_alexandra Engines and Propulsion Systems 10 30-12-2009 21:50
Electric consumption of Inboard autopilots. Tonick Monohull Sailboats 7 10-01-2009 05:21



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 20:40.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.