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I am back with more questions for the group. As you may recall I did this build,? /g/electricboats/message/31909?with your help and wanted to let you know that this system is still working great.? Now for the electric outboard idea/question. The boat is used for fishing on the Potomac River utilizing the 1997 150 HP 2 stroke (that left me stranded the other day for the first time) and it is also used in some electric-only lakes utilizing the 36-volt trolling motor (thread above). Being stranded the other day was not a great feeling and I was too far away from the marina to get home with the trolling motor and battery setup I have. This got me thinking... an electric outboard could serve as an emergency kicker motor and allow me to venture further into the electric-only lakes.? Distance: on Google Maps I plotted out a distance from my furthest fishing point back to the marina I frequent. I ended up with approx 8 miles, let's round that up to 10 miles.? Speed: my 36-volt trolling motor pulls me along at an average speed of 3.5 MPH according to my GPS...? If I could get 6 MPH that would be great but distance is more important than speed for a self-rescue.? Boat specs: Hull Material: Fiberglass, Beam: 7'7", Length: 20', Net Weight: 2250 lbs. I think a 48-volt setup would be better than 36 volt but I am open to all suggestions. If I go 48 volts then eventually I could replace my trolling motor with a 48-volt setup and have maybe 30 or 40 extra Ah of capacity in an emergency.?
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I think the motor I have would meet those requirements well.? ePropulsion Navy 6.0 Evo.? With the low-pitch prop, 6mph should be achievable on your boat.
They make a smaller version (3.0), but I think it would be close on hitting 6mph.? Given that they are close in price and weight (closer than the 2x power difference), going for the higher-powered model is easy to justify.
Other than a Hangkai electric outboard motor (2.2kW), that's the only model I have direct experience with.? But I do look over Golden Motor's offerings from time to time.? Their EZ-X05 motor might be a better fit for your needs (and more cost effective):
And of course there's Torqeedo, but I feel that they are overpriced for what they deliver.
One good resource for this type of question is??... they also have an 'under 5kW' guide ... your requirements seem to put you right on that line.? But I could be off on that estimation as I have a semi-displacement hull and yours is a planing hull.
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I've played with electric outboards a little bit.
One experiment was using a 48V Torqeedo on a Catalina 22 (compared to your boat, a little longer, maybe about the same weight?).? ? From my notes, I was able to do about 6.3mph at 3300 watts (wide open throttle), with 4 AGM 12V batteries.? ?For 3300 watts, to go 20 miles (round trip of your rounded up 10 miles), you should plan for at least 200Ah of battery.? If you don't use lithium, you will need to plan twice as much for lead's 50% depth of discharge.
The 24V Torqeedo did a fine job of pushing the Catalina 22, but max speed was only about 4.5mph - and that was at close to 2000W.
I agree with the comment that the Torqeedo's seem very high priced.? I'm also reluctant to leave such an expensive motor in salt water!
For my 10' West Marine RIB dinghy, I did an experiment with a 48V Hangkai against a 24V (not 48V) Torqeedo. Note that a 10' RIB dinghy is not as svelt as a sailboat!!! The 24V Torqeedo could only push the dinghy to 4.3 knots at 1200W (47.5A, 24.8V). The 48V Hangkai pushed the dinghy to a very modest 3.4 knots at 1000W (17.6A, 56.6V)
My experience so far has been that the Torqeedo is a MUCH more robust outboard, and seems to put out a lot more thrust - largely due to the much larger prop.
The 48V 1000W Hangkai is a "cute little motor" for puttering around in the dinghy.? You won't go anywhere fast!? ?But it will easily run 2 hours on a 60AH 48V ebike battery, and at $350 - it's cheaper than the ebike battery!? ?Motors will die, especially in the salt environment I'm in.? ?I'll be feel a LOT better about replacing a $350 Hangkai than a $4000 Torqeedo.? ?But it won't push you to 6mph.
Good luck! John
On Friday, October 6, 2023 at 08:30:27 PM CDT, Kelly R. <kelly@...> wrote:
I am back with more questions for the group. As you may recall I did this build,? /g/electricboats/message/31909?with your help and wanted to let you know that this system is still working great.? Now for the electric outboard idea/question. The boat is used for fishing on the Potomac River utilizing the 1997 150 HP 2 stroke (that left me stranded the other day for the first time) and it is also used in some electric-only lakes utilizing the 36-volt trolling motor (thread above). Being stranded the other day was not a great feeling and I was too far away from the marina to get home with the trolling motor and battery setup I have. This got me thinking... an electric outboard could serve as an emergency kicker motor and allow me to venture further into the electric-only lakes.? Distance: on Google Maps I plotted out a distance from my furthest fishing point back to the marina I frequent. I ended up with approx 8 miles, let's round that up to 10 miles.? Speed: my 36-volt trolling motor pulls me along at an average speed of 3.5 MPH according to my GPS...? If I could get 6 MPH that would be great but distance is more important than speed for a self-rescue.? Boat specs: Hull Material: Fiberglass, Beam: 7'7", Length: 20', Net Weight: 2250 lbs. I think a 48-volt setup would be better than 36 volt but I am open to all suggestions. If I go 48 volts then eventually I could replace my trolling motor with a 48-volt setup and have maybe 30 or 40 extra Ah of capacity in an emergency.?
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I have used a Torqeedo Cruise 2.0 for the last 6 years. I have it pushing an 18' home built catamaran with solar panals on a canopy. I find the Torqeedo is very efficient for a cruising speed of 5 knots. I also have an Elco 20 hp motor and it works well but does not have the same efficiency for cruising.
Phil Boyer
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My friend has a Torqueedo on his Macgregor 25 and it does well. It might do 10 miles at mid throttle.
I have an epropulsion spirit Evo on a small pontoon boat on a lake in Canada. It’s great . We do the leisurely evening ‘wine tour’ of the lake at lower speeds. ?Its probably 3 miles and we return with 95% battery. If needed, we can push along at a good clip - maybe 5 mph?
I have the basically the same motor on my 15’ Pocketship which I just launched last week, so I don’t have good numbers on it, but I probably went a mile and hardly used any battery. This one has regen, but you’d have to go over 5 knots to get much output.?
Yes they are expensive, but they are trouble free, and have good thrust.? -Steve
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On Oct 6, 2023, at 11:51 PM, Phil Boyer via groups.io <philaboyer@...> wrote:
? I have used a Torqeedo Cruise 2.0 for the last 6 years. I have it pushing an 18' home built catamaran with solar panals on a canopy. I find the Torqeedo is very efficient for a cruising speed of 5 knots. I also have an Elco 20 hp motor and it works well but does not have the same efficiency for cruising.
Phil Boyer
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My max range requirement would be 10 miles total one way in a rescue situation and that range would be more than enough for the electric lakes.? The speed is not a big concern, reliability and range is the driving factor so if that 6MPH number is pushing me over a line I would be happy with 4 or 5 MPH, I just want to know I can get home. I can always fish along the way ;).?
The golden EZ-x10 is about $3500 with no additional controllers needed.
The Navy 6 would be $3500 plus an additional $350 for the basic controller.?
Option 2:
Stick with 36 volts and put the money into batteries. I already have the 36-volt trolling motor up front with autopilot for steering and when needed I could add a second 36-volt motor to the rear. Would a second motor on the rear of the boat work? This gives me even more redundancy.??
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One thing you should know is trolling motors are designed, not for primary propulsion, but to control the boat at slow speeds.?
Their props are pitched for slower speeds and more torque, not higher speeds you might be able to achieve with the same motor.
The stock props that come from the motor manufacturer are usually low pitch, like 3 - 4".
You might consider changing the prop on your existing electric motor to gain additional speed.
Identifying which pitch/diameter of prop you would use depends on how much power you are consuming now when your motor is at wide open throttle. You would need an in-line or clamp on amp meter to take these measurements.
Specific motors have an upper limit to how many amps they are designed for.? That specification should be in the motor's documentation.? The gap between your current power consumption and the rating of the motor will give you how much power you have to play with trying new props.
I use model airplane props to "dial in" the pitch/diameter choice, paying close attention to how they affect speed and power consumption.
You may need to make minor modifications to the prop hubs or use nylon spacers to get them to fit on your motor's prop spindle and match your shear pin.
Don't expect miracles with this approach.? You might gain a 0.5 mph increase in speed, or, perhaps some additional efficiency because the model airplane props are thinner and slice through the water with less resistance.
Physics is a tough taskmaster.? There is an exponential relationship between additional speed and power consumption.
With my 26 foot, 4000 pound cruiser, I can go 2.5 miles per hour on 400 watts, 3 miles per hour on 700 watts and 4 miles per hour on 1200 watts (zero wind, no current, no chop)? I literally have to triple my power consumption for that extra 1.5 mph.? 6 mph is possible, (My hull speed is 6.4 mph) but would consume over 3kw.
Your mileage/speed/power consumption will vary depending on your boat hull design and water/wind/current conditions.
I vote for using your existing motor, adjusting your props to use all its power, and be happy with 3.5 mph and invest in better batteries.? New LiFePO ones are an interesting option if you can get the right charge controller for them and keep them reasonably dry.
Ken Cooke Solar Six
If you
On Sat, Oct 7, 2023 at 12:17?PM Kelly R. < kelly@...> wrote: My max range requirement would be 10 miles total one way in a rescue situation and that range would be more than enough for the electric lakes.? The speed is not a big concern, reliability and range is the driving factor so if that 6MPH number is pushing me over a line I would be happy with 4 or 5 MPH, I just want to know I can get home. I can always fish along the way ;).?
The golden EZ-x10 is about $3500 with no additional controllers needed.
The Navy 6 would be $3500 plus an additional $350 for the basic controller.?
Option 2:
Stick with 36 volts and put the money into batteries. I already have the 36-volt trolling motor up front with autopilot for steering and when needed I could add a second 36-volt motor to the rear. Would a second motor on the rear of the boat work? This gives me even more redundancy.??
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I was just watching some YouTube vidieos on this. I fly R/C giant scale and 2 meter pattern planes so I’m familiar with the APC props and have a few different pitches in 10 and 13 inch.?
looking at the rear of my boat I don’t have much space on iether side of the main motor. As you can see the rear slopes upward at approximately 30° on both the left and right side of the transom. Those sections sound hollow to me and I do not think the main transom board is underneath of that fiberglass so that leaves me with a very narrow area to mount anything. That narrows my selection of motors significantly.?
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Does your current bow trolling motor mount on deck? Maybe you could do something similar for a second motor at the rear. Or maybe you could find or fashion a kicker bracket to mount on the sloped aft area. It only has to handle 20 or 30lbs of motor and 100lbs of thrust.
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Something like this might work:
Granted most of that style of motor are just for trolling.? But possibly a 'pod'-style
electric motor, mounted on something attached to the transom (one a side) that
can be flipped up when not in use:
Or combine the two ideas and see if a smallish pod motor can be mounted like
shown in that picture?
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Yes the current trolling motor is deck mounted on the front and used for boat positioning when fishing.?
Your ideas of a pod type motor or another deck mount in the rear seem to be the best option.
?
After assessing all the power option I think I need to stick with 36 volts. Unfortunately they don’t make 48 volt trolling motors with the features I need up front and I don’t want three separate systems, 48v, 36v, and 12v.
What are you thoughts on twin 36 volt motors vs a single in regards to efficiency?
?
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Two motors versus one wins on redundancy.? But you're already going to at least one additional motor to get some redundancy... three/four motors is easily past a point of diminishing returns.
Downsides of two versus one motor (same total power) is more more cost, more weight and more drag.? The last two are probably not that large of a consideration given the actual numbers involved.
Possibly you could run a 24V or 48V motor from 36V with an appropriate DC-DC converter.? Downsides being some loss of efficiency (~10%) and an additional point of potential failure.? And those are harder to find at higher power levels, and costs go up beyond 1kW.
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Overall efficiency depends on several factors, including the motor controller(s), the amount of drag in the water, and the propeller. It's really helpful if you can measure the power used by your motor(s) in different circumstances, and when trying out modifications.
Trolling motor controllers vary widely in efficiency. The new electronic ones are a huge improvement over the old-school resistors and switch type.
When you start using trolling motors for cruising instead of just positioning, then the drag of the motor and shaft becomes a significant factor in the overall efficiency. I use a 600W Haswing Protruar with my little trimaran, and I was able to reduce the energy needed to go 5mph by nearly 20% by adding an airplane fairing (for landing struts on kit planes) around the motor shaft, a nose cone, and an 11x6 APC propeller. You might want to look at sturdier after market trolling motor propellers for your heavier boat.
Another advantage of two electric motors is that you can have one that works best for fishing, and the other that is adapted for cruising. The fishing motor can also be a backup or augment the cruising motor. It sounds like you'd like them to share the same battery, so I think other things being equal, using one motor is more efficient than using two. But the benefits of having two motors available have already been stated.
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The outboard cavitation plate should be even with the bottom of the boat. Mounting a motor above the plate will not work as intended since water flow will be turbulent.?
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Kelly Regan
bobkart
cpcanoesailor
Reuben Trane