Electric Conversion

[HillbillyMatt]

I am converting an American Mariner 26 to an electric SAILOR. I bought it gutted with a trailer. While im restoring it I figured why not do it right and install a sizable battery bank, solar array, and run electric propulsion.

my vision is a SAILBOAT THAT IS USED FOR SAILING, that can do longer hauls with a fully capable electric propulsion backup.

after a year i am still in the R&D phase (because there isn't much out there as far as products and information that i want to risk my life on)

the conclusions i have come to:

1. a set of golf cart batteries will be the cheapest and most proven idea for a battery bank and will be easily upgradable. this should provide enough reserve power ALONE to power for ideally 6hrs for emergency situations. i will split the set of six batteries into two separate banks of 3 batteries. i will most likely charge the off service one while depleting the other.

2. one 55lb thrust saltwater trolling motor will provide enough propulsion to get in and out of port. i plan on upgrading propulsion with a second 55lb thrust trolling motor for longer trips and/or in case i need more thrust in a sticky situation. i plan on mounting one on my drop down motor mount and one directly to the rudder with a quick release.

3. my solar panels will be the main means of power with, ideally, enough RATED power provided to run the motors continuous without any draw on the battery. i have one 45w panel set (like the ones found at most bargain tool stores) that i will use to build a dodger. i will be making custom hatches and companion way door to be imbedded with solar cells which should provide around 200w. the companion way door will be mounted at sea to provide power while frequent access is needed. i may build other multiple panels to mount on the cockpit rail if necessary for more power. ideally i would like to have 1000w of rated solar power available.

4. all lighting will be LED. i will be making an icebox with equivalent performance to a yetti cooler. this will save loads of power for nav and coms equipment, random hotel loads, and necessary and/or emergency propulsion

5. the electrical system will be designed to incorporate multiple sockets and connections for solar panels, and a socket for shore power in the cockpit. i am a submarine nuclear electrician for the navy so the rest of the system will be set up similarly to how i know its done. it will have all the necessary protective devices, switching devices, and power conversion equipment with safety and duel reliability in mind.

my question to you guys:

Any USEFUL suggestions?

also, i will be documenting this project on my youtube channel HillbillyMatt ExtremeDIY

[GordMay]

Greetings and welcome aboard the CF, Matt.

[HillbillyMatt]

thank you GordMay


My main question for now is where to get a reliable saltwater trolling motor for less than the cost of my boat.

I considered building my own out of an old outboard and a 1-2hp motor...which may be much cheaper. but ive never done it and I would definitely want some advice from someone who has built and used one reliably.

[lonesoldier0408]

I have an electric scooter, with a 36 volt motor and controls, that I plan to use for a boat motor, when not under sail. The scooter was second hand but ran. Good torque for around town but short battery life. Add this to a weed eater, lower section, and off I go with all the others in my head.🤔🤔🤔😁😁😁


Still surrounded by anchors.

[seandepagnier]

Originally Posted by HillbillyMatt

I am converting an American Mariner 26 to an electric SAILOR. I bought it gutted with a trailer. While im restoring it I figured why not do it right and install a sizable battery bank, solar array, and run electric propulsion.

my vision is a SAILBOAT THAT IS USED FOR SAILING, that can do longer hauls with a fully capable electric propulsion backup.

after a year i am still in the R&D phase (because there isn't much out there as far as products and information that i want to risk my life on)

the conclusions i have come to:

1. a set of golf cart batteries will be the cheapest and most proven idea for a battery bank and will be easily upgradable. this should provide enough reserve power ALONE to power for ideally 6hrs for emergency situations. i will split the set of six batteries into two separate banks of 3 batteries. i will most likely charge the off service one while depleting the other.

What? 3 batteries = 18 volts.

Don't do that, their efficiency drops off considerably at higher currents so it's better to use all of them together.

2. one 55lb thrust saltwater trolling motor will provide enough propulsion to get in and out of port. i plan on upgrading propulsion with a second 55lb thrust trolling motor for longer trips and/or in case i need more thrust in a sticky situation. i plan on mounting one on my drop down motor mount and one directly to the rudder with a quick release.

I used a 40lb and 30lb motor together on my bristol 27 and could go 3 knots, but the range wasn't great. I had 8 golf batteries a the time. I could go 10 hours at 2 knots on only one motor though and only drain the batteries half.

trolling motors are cheap and quiet but less than half of efficiency possible with other systems.

3. my solar panels will be the main means of power with, ideally, enough RATED power provided to run the motors continuous without any draw on the battery. i have one 45w panel set (like the ones found at most bargain tool stores) that i will use to build a dodger. i will be making custom hatches and companion way door to be imbedded with solar cells which should provide around 200w. the companion way door will be mounted at sea to provide power while frequent access is needed. i may build other multiple panels to mount on the cockpit rail if necessary for more power. ideally i would like to have 1000w of rated solar power available.

I had 500 watts of solar, and despite losses, and partial shading, I could travel 2 knots while also putting 10 amps into the batteries.

4. all lighting will be LED. i will be making an icebox with equivalent performance to a yetti cooler. this will save loads of power for nav and coms equipment, random hotel loads, and necessary and/or emergency propulsion

5. the electrical system will be designed to incorporate multiple sockets and connections for solar panels, and a socket for shore power in the cockpit. i am a submarine nuclear electrician for the navy so the rest of the system will be set up similarly to how i know its done. it will have all the necessary protective devices, switching devices, and power conversion equipment with safety and duel reliability in mind.

If you use more motors (say 3 motors) and use controllers to spin them slower you will get more efficiency than only 1 or 2 with the same power input.

my question to you guys:

Any USEFUL suggestions?

Build a sculling oar first. I can travel 1 knot with the same effort as walking at 1.5 knots with the effort of running (like I could run 5 miles not a sprint).

[HillbillyMatt]

lonelysoldier, thank you. I am often surrounded by nay sayers myself. lol.

I thought about converting all of the electrical bits of a golf carts to use in my boat. the only problem was the cost of a used golf cart is still way more than I want to spend and the motor may be too much power for a sailboat hull...but it would all be there.

[HillbillyMatt]

boat_alexandra, also thank you.

I may be mistaken about the individual cell voltage (ICV) of golf cart batteries but I do understand that I need to and how to hook them up to provide 12vdc. I would like two separate banks for dual reliability while also not over loading my boat.

I also understand that motor power consumption increases exponentially by a power of 3 as you increase speed. N(speed)^3=Power. This is another reason why I would like to get two motors and run them at lower speed when I need more thrust vice running one at full speed.

most people don't know these things. that's very commendable of you. you would make an excellent submarine nuclear electrician for the navy and an excellent battery petty officer. lol

I did look at other systems like the torqueedo systems but the reviews were so negative as far as reliability and potentially fraudulent claims on the part of the advertisement...not to mention the astronomical cost. I decided that a trolling motor would be extremely easy to set up and very inexpensive, especially considering I pretty much do it for a living. I figured didn't really need the fancy expensive gear to make up for lack of user knowledge. I can and pride myself on being able to fix, build, operate, and maintain pretty much anything.

ABOVE ALL,

I really appreciate the input about your experience using 500w of solar while motoring and putting 10amps into the battery. that is exactly the data I have been collecting and treasuring.

also, I have been toying with the idea of a sculling oar. my concerns are...
1. I don't yet know how to build one but I have been amassing a workshop full of tools to be able to do such things.
2. I don't understand how they work mechanically/hydro dynamically. I have watched one working in a video so I can see how they work, but I imagine its like building a boomerang and it looks easy but...(my boomerang did not come back. lol)
3. im not sure how I would mount one or where to get the special swiveling mount.
4. im trying to trailer sail to avoid unnecessary slip fees so I need enough power to seat the boat on the trailer whilst maneuvering and possibly fighting currents. although I like the idea (and will most likely adapt it) to assist my first solo motor getting to the launch ramp or any other case when I cant be under wind power (like narrow ICW passages)
5. I was a little confused by that last bit but I am assuming you meant to say that its really quite effortless to use one. lol

[HillbillyMatt]

so I have figured that having 1000w of solar may be a little over ambitious. I was a little concerned as to where I was going to fit all the panels. lol

I planned on making my own custom multicrystaline plexiglass and poly resin hatches and a companion way door using the Dan Rojas (youtube user) GREENPOWERSCIENCE (youtube channel) method. I figured while I have to make new ones that I might as well make custom ones that incorporate solar cells and allow some solar light to pass through for cabin lighting.

has anyone done this or something similar?

my main concern is that you need about 36 cells in series to make 12vdc. I most likely will not be able to put that many cells into each hatch/door.

how could I get that to pair with a 12vdc battery charging regulator? maybe I could 12 cells on each of the three panels and wire the panels in series before connecting them to the charging circuit?

that should give me, combined, about 200-300w.


Im talking about something like this...but home made.
http://www.sailmagazine.com/gear/mai...y/solar-hatch/

[Stumble]

Mat,

Just a few things...

1) one large bank will provide more usable power than two smaller ones. Battery output capacity drops as a function of how quickly you pull power out see Pukerts laws.

2) the efficiency of trolling motors at all speeds is very high. Wether you use two smaller ones or one large one will have minimal effect on power needed to hit a particular speed. Is anything multiple small motors may negatively impact range because of the added drag of the multiple motors.

3) a range of six hours is meaningless. You need to know the range in miles, preferably miles and time. You maximum range will be somewhere in the 20 hour range, but you would need to slow down to .5kn or so to get there.

4) seriously invest in a small gas generator. This will have more effect on range than anything else you could do.

[HillbillyMatt]

stumble

1. I can see your point about one large bank. there being that my loads will only work in a certain range of the asymptotic discharge of the batteries voltage as the pixies grow weaker. if that makes sense. im seeing the graph in my head.

2. I do not agree with your number vs power assessment for the trolling motors. at least, in my training from the navy, (and it may be wrong)

power consumption of a motor (P), is proportional to, speed of the rotor(N) cubed(^3)

therefor if N=2, then P=8
if N=3, then P=27
if N=4, then P=64
if N=5, then P=125
and so on...

where as two motors with N=2 would only require P=16, and three motors...P=24

in the navy we operate with this in mind to save electrons when we are on the battery and also to save some core life. it also goes without saying that it is much better for health of the motor windings to run them at the lowest amperage possible. hence your final sentence in your item #3.

the individual motors mechanical efficiency doesn't change but its efficient use of pixies as speed is increased drops exponentially.

about the hydro dynamic drag factor I will absolutely agree with you. that is why I plan on pulling them out of the water whenever I don't need them. one motor will be on a drop down motor mount and the other attached to my rudder via quick release.

and once I get them im going to see if I can get a more efficient screw 3d printed.

3. my 6hr battery time is based on a theoretical engineering estimation of the worst case average longest time I should either be motoring into unsailable water or in an emergency situation in which I no longer have sail power (wind squall, mast gone), with a current. if I can get 6hrs reliably out of my battery bank, at or near hull speed, then I know I should never have any problems.

4. I did forget to mention I have two small coleman gas generators for backup (solar) to the backup (battery) to the backup (batteries all fried) scenarios. I want to convert one of them to bubble fuel tank vapor power for extreme fuel economy.

[HillbillyMatt]

stumble

also now that im thinking about it and again I may have been taught wrong but

flow work (F) added by a motor/pump if proportional to N^2...if I am remembering correctly (im an electrician not mechanic)

so if N=2, then F=4 and P=8
if N=3, then F=9 and P=27
if N=4, then F=16 and P=64

with two motors with N=2, F=8 (so you got me there by 1 "F" unit) and P=16(but not here)
and three motors with N=2, F=16 (and definitely not here) and P=24

[Twidget]

Welcome aboard HillbillyMatt.
Very interesting concept. Good opportunity to learn something.
I will be following along. Carry on....

[HillbillyMatt]

twidget,

I will also be doing some garage experiments on salt water (galvanic corrosion) "batteries". the concept I have in my head is to have an array of these hanging off the back end of the boat in the turbulent wake to minimize drag and possibly power at least one trolling motor.

they would just be a stack of dissimilar metals with fiberglass matting sandwiched between them (just like in a real battery but the sea water would be allowed to permeate through the glass matting.

this would meet the requirements for a battery (two dissimilar metals in an electrolytic solution) and should provide some pretty substantial voltage FOR FREE...well the price of lost metal oxides. so I would probably use stainless steel and something else that is really cheap and relatively corrosion resistant.

[Stumble]

Matt,

A single properly sized motor and prop will always be more efficient than multiple engines turning multiple props. This is why all cargo ships operate with single screws. In fact almost all endurance vessels operate with one screw, the efficiency gains are substantial.

There might be an argument that for a particular motor slowing the revs down to its design rpm will gain something, but the gain is going to be minimal compared to all the drag of a second drive unit.


As for your formula... I have no idea what if anything that describes. The power produced by an engine is given by the formula. Hp = rpm X torque, it is possible to find the efficency of the motor by measuring the input power and seeing the loss at the output, but for most electric motors this is pretty constant across all designed rpm ranges. At least until you start overheating the windings when efficiency drops off a cliff.

Now the HP demands to maintain a given speed go up exponentially wh speed. Gerr's formula works quite well for a displacement hull.

Hp = Disp in lb/(10.665/S/L)^3

This assumes a clean hull, and a prop at 55% efficency (good, not exceptional). Add a second prop and you have to account for the excess drag by assuming a dirty bottom.

[Waterrat10]

Hillbillymat

Your enthusiasm and curiosity will over come many of your challenges though it can't over come the physics. There are some great threads on this forum regarding going electric where others illustrate their trials and tribulation with going electric. No need to make the same mistake as others when you can make new ones all on your own. Check out this website with lots of great electrical and sailboat maintenance advice. Welcome To MarineHowTo.com Photo Gallery by Compass Marine How To at pbase.com

Your galvanic corrosion battery you describe above is not going to produce enough juice to power one of your outboards. Save your time and money. No such thing as free energy. Though many people have tried to sell the idea of free energy.

Have you considered traditional (2) oars. You won't be fast but lots of power, good exercise and much less expensive. If you search yuloh oar in google you will find lots of great info and plans for various methods of construction.

Stumble knows his stuff and if I recall correctly he has converted a small sailboat to electric propulsion. Good luck and have fun with the process.