# Planning Evinrude 88 Outboard Conversion



## JasonWilsonAUX (May 30, 2008)

Hello everyone, 
Well I'm new here and I'm pretty much new to everything involved in electrical conversions. I'm a fast learner but I've got a load of time for this project.

I have a 90HP Gasoline outboard with a blown powerhead. The lower unit and most other components are working but there is no compression on two of four cylinders due to this damage:



Seeing as I wasn't looking forward to filling the tanks anyway, I'm considering an electric conversion.

I know the setup couldn't get much simpler, batteries, a controller and a motor on an adapter plate. I'm sure I'll need help with the details of those installations but what I'm really racking my brains over are the numbers.

I'm looking to be able to get about 8 to 10 hours of run time at planing speeds (not sure what that is for this boat) and I'd like to try to fit in (if weight/space permits) a small generator to give me an additional reserve. I'd also like to try and get the performance I could expect out of 100HP motor. I have absolutely no idea how to translate that into size/type of motor and size/number/type of batteries.

I don't even know if it is possible. Any ideas?


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## xrotaryguy (Jul 26, 2007)

I don't know of any vehicle that can run for 8 hours without refueling... outside of a military vehicle of course. I doubt that such a thing was possible with gasoline. It is very improbably with batteries. You'll need lithium ion batteries to even get remotely close to what you want. Sorry for the skeptical reply.


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## JasonWilsonAUX (May 30, 2008)

xrotaryguy said:


> I don't know of any vehicle that can run for 8 hours without refueling


Not a problem being skeptical at all. I'm a bi skeptical too. I came up with my eight hour figure by looking at the performance data for a boat of similar size and power. I may have done it wrong though. 

http://www.gradywhite.com/208/

If you look at the performance data for the 150 hp version, the fuel capacity is 82 gallons an the fuel consumption at optimal cruse is 7.7 Gph. That gives about 10.7 hours of operating time. I think it is simply the size of the tanks that allow this, on a car you'd have to refuel the full tank every hour and a half.


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## onesojourner (May 6, 2008)

Is there any chance you could run solar panels? If you have a pontoon with a big area up top you could get a good chunk of power from that.


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## JasonWilsonAUX (May 30, 2008)

So looking at this, http://www.griffinleisureboats.com/Battery%20Configuration.htm if I had a 72 HP Motor (http://www.go-ev.com/ImPulse.html) and wanted 300 Ah, I'd need 24 batteries?

Would I get the same amount of power if I had the 300 Ah/48 Volt setup with 2 48 volt motors with a gearing or chain setup?

I don't have the space for solar panels unfortunately. I've got a 20 foot cuddy cabin cruiser. 


(are the photos coming through?)


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## onesojourner (May 6, 2008)

I think you are going to just make things complicated by doing that. I would stick to a single motor if you can.


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## JasonWilsonAUX (May 30, 2008)

So how does horsepower compare between EV and IC? Does it take 100HP in an Electric Motor to do the same work as 100HP on an IC?

What about determining operating time, if I'm drawing 200 Amps on a 100Ah system does that mean I have 1/2 an hour of operating time?

Why'd I give away my physics books?


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## mattW (Sep 14, 2007)

For a mainly constant RPM application like a boat motor you just compare power to power. You'll just want to match your existing ICE's running power.

Your operating time is determined by your energy divided by power i.e Watt-hours / Watts = hours. Luckily the volts is the same for Watts and Watt-hours so dividing amp-hours by amps does the same thing. So 1/2 an hour is right.


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## JasonWilsonAUX (May 30, 2008)

Crap... so I'm looking at needing 90-100 HP and about a ton of batteries. 

The motor I had looked at so far can get up to 43HP but they burn nearly 500 amps to do it. Since they need 72 volts, I'd be looking at 72 batteries to get half the power I need and that for only one hour . 

I've got to be doing something wrong here. Are batteries really that inefficient compared to gas?


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## mattW (Sep 14, 2007)

Its not inefficiency, its the energy density. Gas contains 36.7kWh per gallon which is the same as a 72V 500Ah battery pack. Luckily electric motors are 4-6 times more efficient than ICEs but you still need a lot of batteries for comparatively less liquid fuel. Do you really run at the full 100hp for the whole 8 hours? I'm trying to imagine the activity...


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## JasonWilsonAUX (May 30, 2008)

No, I'd doubt we'd be at full power often, and certainly not for that long. I'm just asking questions out of a very limited knowledge of this boat and motor; I just got them a week ago. The motor on there now is 90HP, that's about all I know.

The boat will mainly be used as an Auxiliary Patrol boat, I'm not going to be going fast all the time but could occasionally have need to get up and run for an hour or more. When I need to run it's going to be for something important and could be life or death for someone. I will have to ask the previous owner if he remembers what it took to get it to plane or, better yet, if he has an RPM to Speed curve.

Another question on the numbers, should I be more concerned about matching torque rather than horsepower? If so, how would I find out what I have now?


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## mattW (Sep 14, 2007)

Torque is dependant on gearing but HP stays the same no matter what gearing. So HP should be the thing you match. I'd be curious about how high power/rpm the ICE actually cruised at... I'm sure that is a 90hp peak which would be at pretty much the highest rpm, I assume that you would use that for accelerating and then drop back a bit when cruising.


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## xrotaryguy (Jul 26, 2007)

Your performance goals have lithium ion written all over them. Running all day on one charge is a pretty tough to do on a normal person's budget.

That electric outboard site stated that their setup could run for 30 hours at trolling speed, six hours at medium speed with 100lbs of thrust, and only 2 hours at top speed with 200 lbs of thrust. I am fairly impressed by their 6 hour claim. Still, that's assuming that no one ever does anything but putter around at 12 knots or so. Obviously that's not an option for a patrol boat. You'd be stuck at trolling speed to conserve energy for the times when you need it. That's bad. You need Li Ion.


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## Manntis (May 22, 2008)

My associate Monty Gizborne successfully builds and sells LiIon / solar panel powered pontoon boats, so it can be done


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## JasonWilsonAUX (May 30, 2008)

Well I got two bits of info today.

1.) My powerhead is done, there is not going to be any way to repair the damage to it.

2.) The previous owner didn't have an RPM curve but estimates 3800 RPM was what got the boat on plane. They originally had a 55hp motor but it took full throttle for him to plane and stay up. He doesn't recommend anything under 90hp, but I think it would do alright on 75+. I was also told she's sensitive to weight in the stern so to keep the weight about the same.

It still seems like my biggest concern is power storage. I don't really have a lot of space to run a generator and I can't rely on spending most of my time putting around at 5-10 knots either. Even the Li batteries I have seen would add a gross amount of weight to get the Ah capacity I've been looking at. 

When I mentioned torque earlier we said it depends on the gearing. What does it mean then when an electric motor sports a torque number? Would it be possible in my application to get the same torque out of a smaller motor or is the advice still to match horsepower for horsepower. 

When I start looking at a 75+ horsepower motor and 36+ batteries it starts sounding impractical.


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## xrotaryguy (Jul 26, 2007)

I don't want to come off as discouraging. On the contrary. I think that you've got a neat project if you can find a way to pull it off. 

So getting on plane is going to be a challenge because the weight of the boat will probably need to go up regardless of whether you use Li ion, Pb A, Nicads, MiMH, etc. I still say that you are firmly stuck with Li ion. Or have I beat that horse to death already? 

The idea of using solar panels to extend the boat's range is an interesting one... 
How much to solar panels cost? 

You could possibly get away with a smaller motor if you could keep it cool... and if you can keep the com from arcing. You're going to be on the water... Does anyone make a water cooled DC motor? I don't think so, but it's an interesting idea. Has anyone ever successfully modified an air cooled DC motor to be water cooled? Perhaps by adding a water jacket to the outside of the motor... I don't know. That's getting kinda complicated and unconventional.

Just a couple of ideas


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## fshagan (Jun 4, 2008)

Historically, electric boats have been picnic boats, pontoon boats, or bass-type boats. Its hard to get a boat up on plane because of the power requirements. Because of this, most of the people looking at electric or hybrid systems for boats are doing so with sailboats, since getting up on plane is something you simply don't do with them.

We're used to thinking of the drag caused by 4 tires, and a lot of electric vehicles use 3 wheels to reduce drag. A boat doesn't have tires, so think instead of the amount of energy required to drive a car if the entire bottom of the car was sliding along the pavement. Every square inch of the hull in contact with water creates drag. Once you are up on plane, the situation changes, but getting there will be a problem.

The maximum theoretical speed for a boat that doesn't plane is 1.34 x LWL (length at water line), so a 22' boat is going to have a hull speed of no more than 6.29 knots. I think you might be able to design something for cruising along at hull speed, but getting up on plane is going to be troublesome.

The added weight will also be a problem in that boat. Unlike a sailboat, where the batteries can be used in place of ballast, you will be adding hundreds of pounds in extra weight. The good news is you can locate it where it can help trim the boat. The bad news is every pound you add changes the amount of energy it takes to get it up on plane.

Because you are going to patrol with this boat, and lives may depend on it, I would recommend going with a gas outboard. You can add a smaller electric outboard for axillary use and cruising in the no wake zones.


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## marke1952 (Jul 24, 2008)

HOw is your research going....I have a similar project in the works and cannot find anyone who had actually done this....very confused about power requirements ... Thanks
mark e


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## marke1952 (Jul 24, 2008)

I think Metricmind has a liquid cooled elec motor....pricey though.


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## fish-a-holic (Jul 6, 2008)

Here is a quote I got from:

ELECTRIC VEHICLES OF AMERICA, INC. 
16 LEHNER STREET PO BOX 2037 
WOLFEBORO, NH 03894 
(603) 569-2100 
FAX (603) 569-2115 
[email protected] <mailto:[email protected]> 

I want to get the same performance as I have with my 85 HP Johnson. 
total is about $6,000.00 but in line with the cost of a new outboard and a couple of years of gas.

VEHICLE: 1976 Ranger Bass Boat - 144V 

QTY DESCRIPTION PRICE PRICE 
DRIVE SYSTEM 
1 FB1-4001A Advanced DC Motor with dual shaft $1,550.00 $1,550.00 
( 72V - 144V ) 18HP - 30HP 
1 1231C-8601 Curtis Controller $1,495.00 $1,495.00 
96V - 144V 500 Amp Limit 
1 Aluminum Plate/ heat sink compound/ 12V fan $50.00 $50.00 
1 Pro-4 Joystick with friction brake $250.00 $250.00 
2 Albright Contactor SW-200 (12V coil) $150.00 $300.00 
1 Albright F/R Contactor SW-202 (12V coil) $360.00 $360.00 

BATTERY SYSTEM 
1 PFC-3000 110 VAC / 230 VAC 144VDC Sealed Charger $1,030.00 $1,030.00 
Batteries to be determined later 
24 2/0 Battery Terminal Protective Covers (Red & Black) $1.50 $36.00 
50 ft 2/0 UltraFlex Cable (Orange) $5.00 $250.00 
40 2/0 lugs - Magna lug ( includes 6 90 degree ) $2.50 $100.00 
5 ft Heat Shrink with sealant $6.00 $30.00 

INSTRUMENTATION 
1 ElCon Fuel Gauge 144VDC $85.00 $85.00 
1 80-180 Voltmeter (Westberg 2in Black) $65.00 $65.00 
1 0-400 Ammeter (Westberg 2in Black) $65.00 $65.00 
1 50 mV Shunt - 400A $30.00 $30.00 

SAFETY 
1 Littelfuse L25S-400 $55.00 $55.00 
1 Littelfuse holder $25.00 $25.00 
1 KLK Fuse & Holder - HV Control Wiring $20.00 $20.00 
1 Pair Anderson connectors SBX-350 (Red) $64.00 $64.00 
1 Fuseholder (4) - Control Board $15.00 $15.00 
1 First Inertia Switch - Auto Shutoff (12V Sys) $45.00 $45.00 
1 ElCon DC-DC Converter 132-168VDC Sealed Unit $250.00 $250.00 
Recommended for headlights, wipers, etc.


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## Robyj (May 28, 2008)

fshagan said:


> Historically, electric boats have been picnic boats, pontoon boats, or bass-type boats. Its hard to get a boat up on plane because of the power requirements. Because of this, most of the people looking at electric or hybrid systems for boats are doing so with sailboats, since getting up on plane is something you simply don't do with them.
> 
> We're used to thinking of the drag caused by 4 tires, and a lot of electric vehicles use 3 wheels to reduce drag. A boat doesn't have tires, so think instead of the amount of energy required to drive a car if the entire bottom of the car was sliding along the pavement. Every square inch of the hull in contact with water creates drag. Once you are up on plane, the situation changes, but getting there will be a problem.
> 
> ...



Hello to all,

just in response to what was written here above (just for discussion, no offence):
most of it is true, but in an EV conversion like this you are not adding hundreds of punds in extra weight (for sure you are not subtracting weight, but you are replace the weight of ICEngine and fuel tank);
drag cx in the water aren't the same as on road;


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## Harold in CR (Sep 8, 2008)

2 cycle engines are rated at max HP. When you mash the throttle, they are under powered, until they get to rev up. 

The boat in question will squat when the power is thrown to it. Trim tabs will make a big difference. 

Electric motors are rated at roughly 2½ times gas engines, so, an 88 HP outboard at WOT would be equal to a 25-30 HP electric. Outboards run 4000 RPM's or so, according to what is required for the application, for efficiency. More RPM's usually won't gain more speed, only waste fuel. Racing is a whole nother thing, using modded engines.

Changing props to match the performance of the electric motor, will make a huge difference. 

Weight of gasoline for that 6 hours is pretty heavy, IN the BEGINNING. Boat gets lighter with usage of fuel. Batteries will stay the same weight.

I've had boats and built and raced boats for over 45 years.


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## SinkTip (Jul 21, 2008)

I work for a company who is designing and manufacturing Li-ion batteries for marine propulsion. We are talking about heavy boats with displacement hulls like tugboats and ferries - series hybrid systems mostly with a few full electric as well. 
Our Group 8D battery is rated at 29v and 240ah. It can discharge at huge rates and weighs about 120 pounds.
I am researching a demo boat for testing and display at trade shows etc. 
I am thinking of a 20 foot or so Zodiac RIB with the equivalent of about 100hp ICE outboard. 
How do I figure out what the run time would be, the voltage needed, how many batteries etc? I would like to get about 40 mph out of it.
I have been searching but I can't find anyone who is converting outboards other than a few backyard guys.
Any links or info anyone?
Grant Brown
Vancouver, BC


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## esoneson (Sep 1, 2008)

Sorry for the red herring question, but..........

240 AH, 29V, 120lb in about 20x11x10 inch box sounds pretty darn interesting to me. 5 of these would give 145 volts with three boxes under the hood and two in the trunk. Built in BMS or what?

Do you have more info about these batteries and the company that makes them? How about a pointer or two?

Thanks,

Eric




SinkTip said:


> I work for a company who is designing and manufacturing Li-ion batteries for marine propulsion. We are talking about heavy boats with displacement hulls like tugboats and ferries - series hybrid systems mostly with a few full electric as well.
> Our Group 8D battery is rated at 29v and 240ah. It can discharge at huge rates and weighs about 120 pounds.
> I am researching a demo boat for testing and display at trade shows etc.
> I am thinking of a 20 foot or so Zodiac RIB with the equivalent of about 100hp ICE outboard.
> ...


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## dragster (Sep 3, 2008)

Hi
You need to get in touch with the town of Menemsha on the island of Martha's Vineyard MA
They have been running a big all electric outboard that pushes a barge to delever passangers from one side of the river to the other in a very very strong carrent. It has been running for years.


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## SinkTip (Jul 21, 2008)

esoneson:
We are in final prototyping stages. The battery works just as the Tech guys said and yes it uses an onboard BMS. It's all proprietary stuff, one of the founders of the company hold something like 70 patents in BMS technology.
I am not at liberty to disclose the name yet but it's coming soon.
Cost is about $9k per unit...
dragster:
Thanks for the tip.

I will be sure and let the group know more when I can.


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## Robyj (May 28, 2008)

Very nice SinkTip,

for "unit" you intend your "Group 8D" battery pack?



SinkTip said:


> esoneson:
> We are in final prototyping stages. The battery works just as the Tech guys said and yes it uses an onboard BMS. It's all proprietary stuff, one of the founders of the company hold something like 70 patents in BMS technology.
> I am not at liberty to disclose the name yet but it's coming soon.
> Cost is about $9k per unit...
> ...


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## esoneson (Sep 1, 2008)

I was thinking for a BMW 318i conversion (144 volt), but at $45K for the pack, I can do a lot better for a lot less. Granted, they are convenient and reduce the complexity of the battery system, but not for $45K. I can replicate the same storage capacity for half that price, easy.

Eric



Robyj said:


> Very nice SinkTip,
> 
> for "unit" you intend your "Group 8D" battery pack?


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## SinkTip (Jul 21, 2008)

esoneson: you'd be way farther ahead with a bunch of thundersky cells that you can wire up yourself. 

Thanks to everyone for all the help. It looks like the boat conversion project will be on the back burner awhile. Other marketing related duties seem to be much more important these days.


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## SinkTip (Jul 21, 2008)

So now I have approval to talk about the battery. This stuff is ground breaking, game changing and you heard it here first.

Our company is called Corvus Energy (www.corvus-energy.com). We are finally building the battery I was talking about in earlier posts. It is called the Corvus Energy AT6200.

They are 6.2 kWh each and discharge at 10C continuous until 100% DOD with no damage. They will charge at about 2C. Our standard group 8D module weighs about 132 pounds, is about 24"x11"x12", is 14.8V at 420ah. At 10C you can discharge this in about 6 minutes with no ill effects (you would need to be careful though) . If you had an 840 amp charger you could charge it in 1/2 an hour. Again no ill effects. We are using the same cells as in the White Zombie. Except we have a special difference: Yes, it has a state of the art onboard BMS that is patent pending and developed in house.

Because of the way we configure the bus bars in the module we can have a 100v 70ah module, a 4.2v 1680ah module or any of a multitude of combinations in between.

It will cycle more than 3000 times at 100% DOD and if the pack is sized for 60% DOD we are estimating more than 300,000 cycles. 

Due in part to the advanced BMS, we are able to scale the battery modules into packs sized up into mega-watt sizes. We are actively looking at grid support and renewable energy production storage. 

However the battery was designed for marine propulsion and basically as a replacement to diesel fired ICE's. Almost any industrial machine that uses diesel can be made more efficient using our batteries in a diesel-hybrid form. In some cases we can get ROI on fuel savings alone in less than 3 years...

So I guess you can say I found my dream job. Don't tell anyone, but I'd probably work for batteries! The only downside is that I'm now so busy that I won't have time to build my EV for at least another year...

These are not a "made-in-china-by-an-unskilled-workers-bare-hands" type of thing. They are the real deal, and made in the US and Canada. Limited lifetime warranty.


Grant Brown
Director of Marketing
Corvus Energy Limited
www.corvus-energy.com


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## esoneson (Sep 1, 2008)

SinkTip said:


> In some cases we can get ROI on fuel savings alone in less than 3 years...



If you know ROI is less than 3 years, you must know the battery costs.

So, what is it?

Thanks,

Eric


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## SinkTip (Jul 21, 2008)

It is meant for a commercial marine application. Reliability and safety are paramount. Cost is a distant second. I am not at liberty to discuss specifics but I will tell you it is less than $1600 per kWh, all engineering included with a limited lifetime warranty.
Not cheaper than cylindrical Lithium Phosphate cells, no.


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## JRP3 (Mar 7, 2008)

Just saw this article on the Corvus Battery:
http://www.energy-daily.com/reports/World_Most_Powerful_Industrial_Lithium_Ion_Battery_999.html

I don't understand the discharge rating on this sheet:
http://www.corvus-energy.com/pdf/corvus_power_and_energy_formats.pdf

There are various AH capacities all showing the same discharge amps, which would be different C rates.


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## david85 (Nov 12, 2007)

Like the boat posted earlier - we have one like it (even have the same evenrude V4!)

I'd like to see some testing before I can believe claimed cycle life though.


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