carterjohnsons25
New Member
- Joined
- Mar 26, 2021
- Messages
- 41
Starting this thread to document the full Solar Boat Conversion Project. Always looking for good advice.
The Concept
1) I will eventually be converting a nice 40 Cat from Gas to Electric. Needed a project boat to experiment on first.
2) I found this 23 foot boat for $1800 + Trailer delivered to my house. It is a 1971 Uniflight. The early versions of the Uniflight are know for rock solid Fiberglass hulls. It will be stripped down to the Hull and Completely remodeled.
Requirements
50 to 100 mile range min at Cruise Speeds.
Charge from Solar when Moored or at sea. Targeting 2kWh array.
Charge from Shore Power when docked – utilizing full capacity of a standard 30amp RV/Marine hookup. No reason to go above this.
Initial Research
This got interesting very fast. Here are some basics.
With current technology, you will not get a larger boat up on plane. This would require about 200hp for a 4300lb 23 foot boat.
1kW of electric motor appears to = ~1.34 HP Gas. However we need to acknowledge that Gas HP at the Prop is fractional of what most gas motors are rated for.
We would need a 149kWh motor (200hp) to get this on plane. if I did the math correct.
I had to learn about displacement max. Radically simplified. At a certain speed, a boat will just push water out of its way. This is your displacement hull speed. Above that speed the boat is trying to lift out of the water and get onto plane. Until on plane you only get 2ish miles per hour faster every time you double your current power. Very depressing. And this boat is not a displacement hull. I will be pulling lots of water behind me. May modify it. Found info on how to do this.
Found this calculator which let me start some calculations https://vicprop.com/displacement_size_new.php
My 23 foot long boats Hull Speed is ~7mph. Assuming I would need a battery the size of a standard Electric Vehicle, did the math below with an 85kWh battery using the info from Vicprop.
Decision time – 48v, 96v, 144v motor
Basic research shows that 48v, 96v and 144v EV motors are quite common the web. They come in Permeant Magnet and AC Induction.
One motor that kept on surfacing over and over was the Montgomery Motor 1616 (ME1616). It is a 55lb Beast that can run water cooled continuously at 250 amps up to 96v. This would get me a 24kWh motor (32hp). The same motor could be ran at 48v, 250amps for 12kWh (16hp)
There were several AC induction motors such as the AC50/51 that run at 144v. At 250amps continuous I could get 36kWh.
48v
PROS
PROS
PROS
The Concept
1) I will eventually be converting a nice 40 Cat from Gas to Electric. Needed a project boat to experiment on first.
2) I found this 23 foot boat for $1800 + Trailer delivered to my house. It is a 1971 Uniflight. The early versions of the Uniflight are know for rock solid Fiberglass hulls. It will be stripped down to the Hull and Completely remodeled.
Requirements
50 to 100 mile range min at Cruise Speeds.
Charge from Solar when Moored or at sea. Targeting 2kWh array.
Charge from Shore Power when docked – utilizing full capacity of a standard 30amp RV/Marine hookup. No reason to go above this.
Initial Research
This got interesting very fast. Here are some basics.
With current technology, you will not get a larger boat up on plane. This would require about 200hp for a 4300lb 23 foot boat.
1kW of electric motor appears to = ~1.34 HP Gas. However we need to acknowledge that Gas HP at the Prop is fractional of what most gas motors are rated for.
We would need a 149kWh motor (200hp) to get this on plane. if I did the math correct.
- At 48v = 3000amps
- At 96v = 1552amps
- At 144v = 1034amps
I had to learn about displacement max. Radically simplified. At a certain speed, a boat will just push water out of its way. This is your displacement hull speed. Above that speed the boat is trying to lift out of the water and get onto plane. Until on plane you only get 2ish miles per hour faster every time you double your current power. Very depressing. And this boat is not a displacement hull. I will be pulling lots of water behind me. May modify it. Found info on how to do this.
Found this calculator which let me start some calculations https://vicprop.com/displacement_size_new.php
My 23 foot long boats Hull Speed is ~7mph. Assuming I would need a battery the size of a standard Electric Vehicle, did the math below with an 85kWh battery using the info from Vicprop.
- 6.8kw motor -10hp = 7mph, 86 miles, 12 hours run time (more like 5mph to 6mph since not displacement hull)
- 12kw motor - 16hp = 8.4mph, 60 miles, 7 hours run time (more like 6mph to 7mph since not displacement hull)
- 24kw motor - 32hp = 10.4mph, 37 miles, 3.5 hours run time. (more like 7mph to 9mph since not displacement hull)
Decision time – 48v, 96v, 144v motor
Basic research shows that 48v, 96v and 144v EV motors are quite common the web. They come in Permeant Magnet and AC Induction.
One motor that kept on surfacing over and over was the Montgomery Motor 1616 (ME1616). It is a 55lb Beast that can run water cooled continuously at 250 amps up to 96v. This would get me a 24kWh motor (32hp). The same motor could be ran at 48v, 250amps for 12kWh (16hp)
There were several AC induction motors such as the AC50/51 that run at 144v. At 250amps continuous I could get 36kWh.
48v
PROS
- Lots of Proven high end standard equipment for solar / shore charge / Inverter..
- Safer
- Will get almost any 30 foot boat up to Hull Speed
- May be under power in wind or chop
- No ability to blow thru battery for faster short trips
PROS
- Extra Power when needed in wind or chop
- Ability to burn battery for short trips at faster speeds
- You still can run at Hull Speed for long trips
- May be necessary to get my final 40 foot boat to even Hull Speed
- Smaller wires
- Less Safe, Higher Voltages
- Significantly more thought needs to go into Safe factor.
- Very Little proven standard equipment
PROS
- Power…
- Getting dangerous
- Even with the extra power. Would still only be at 12mph Max
- At max power only 1.5 hours to kill full 85kWh battery
- While there are EV parts to charge the 144v. Could not find any Solar equipment or inverters to hook up to the battery. Became apparent fast this would be a Shore Power only charging boat.
- 48v – While it will get me to hull speed, it will be underpowered and not safe in anything but flat water. I would not feel confident for bigger trips on open water. I do believe this would be the no brainer choice for many though due to all the options available.
- 144v will make going solar extremely complicated. I am also not willing to go this voltage in a marine environment
- 96v - I have to figure out how to make 96v Work. It is the happy middle ground and will also be scalable for my final 40 foot boat. Sadly, I could not find any blogs about this. Hence this thread.
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