If I understand correctly, you want to use the design of long tail boats like this, but you want to switch from a gas engine to an electric motor:

If you want the same performance, you want to go with around 1/3 the rated hp of the gas motor. So for example, if you had a 20 hp gas motor you would want to have around a 6 hp electric motor, which is about 5KW electric motor.

The problem you will have, is that you will need a very large battery bank, unless you are only going on short rides. It is possible though.

On Tue, Feb 27, 2024 at 4:39?PM Phil Boyer via <philaboyer=[email protected]> wrote:

Hi,?
Sounds like you have a sail boat and you need to have an extra long shaft to reach below the water. All motors? are standard long shaft or short shaft. Or you can buy a pod type that mounts under your boat. You may need to design a mount that can extend down when you wish to motor. If you have a picture you could send? I would have a better idea. Or post it on the Facebook page and ask for ideas.

Regards

Phil

On Tuesday, February 27, 2024 at 02:00:50 p.m. EST, mogjibs@... <mogjibs@...> wrote:

Hi,

I was wondering what would be the best electric motor for "long-tail boats" (in replacement for gasoline, diesel etc. motors; these are outboard motors altered to extend their propellers far from the rest of the motor)!

Thank you in advance for your comments, suggestions and tips.

Best,
M

Hi,?
Sounds like you have a sail boat and you need to have an extra long shaft to reach below the water. All motors? are standard long shaft or short shaft. Or you can buy a pod type that mounts under your boat. You may need to design a mount that can extend down when you wish to motor. If you have a picture you could send? I would have a better idea. Or post it on the Facebook page and ask for ideas.

Regards

Phil

On Tuesday, February 27, 2024 at 02:00:50 p.m. EST, mogjibs@... <mogjibs@...> wrote:

Hi,

I was wondering what would be the best electric motor for "long-tail boats" (in replacement for gasoline, diesel etc. motors; these are outboard motors altered to extend their propellers far from the rest of the motor)!

Thank you in advance for your comments, suggestions and tips.

Best,
M

I expect it only a remote possibility, but if anyone has interest in DIY-level floatovoltaics, I will report after two seasons of experience with my battery charging system. To review: This is a 100-watt semi-flexible panel bonded to an exercise mat that floats next to my sailboat while in its marina slip. Control is via Victron Energy MPPT 75/15 Solar Controller to 2X100Ah AGMs. The solar panel is partially shaded by the floating pier in early morning. Latitude DD is 46.677 N.

The components have held up well and the batteries continue to be charged to float level – at least whenever I have observed the status later in the day. There is no evidence so far for any delamination or degradation of the panel. There is also no evidence of stray electrical potential. The closed-cell foam pad has proved surprisingly durable and even seems to have some resistance to algae deposits and cleans off at season’s end better than most things left submerged. The charging duty decreased during the second season because I no longer use the AGMs for propulsion. ?It becomes overkill for house needs, but the weight is equal to the lead ingot ballast that was removed, so they will stay for now.

Occasionally there can be flotsam that settles on top – as cpcanoesailor warned – but a good rain or a bit of hosing solves that easily. The main problems I faced were missed in the advice from this group. The floating panel just proved irresistible to critters. In the first season, a mallard gave a new meaning for poop deck. This duck was quite persistent and possessive. It paid little attention to the dogs on the dock or interested onlookers. Scaring it off with the hose was only a brief interruption to its sunning and defecating activities. Amazingly, even with a large deposit of duck poop, the panel kept producing.

For the second season, I fashioned a protective cover of bird netting. This successfully kept the ducks off, but late in the season, a (suspected) otter got curious and broke through the netting. I do not know whether it was the same otter or not, but I also found the rope that tethered the panel to the pier cleat to be severed on two occasions. This year, there will be new bird netting and a cut-resistant line.

I have queried the journalist who covered some of the efforts of students at Michigan Tech and the university to find out whether they ever progressed to field tests for their floating system. In the article, the students were performing tests in a swimming pool. I was curious about successful deterrents if my critter condition is common. No reply received. I would imagine this critter invasion could be a serious drawback to small or large arrays.?

On Jan 29, 2024, at 3:27 PM, Stew <stewart.reed@...> wrote:

?Makes total sense. Really helpful post, thanks. I currently run my 12V off the 48V bank but your solution ring-fences the 48V for motor energy. I think I’ll do the same.

Stewart

+33 6 87 96 66 80

On 29 Jan 2024, at 17:43, Fabien Letourneau <fabien.letourneau@...> wrote:

?

I have a 48V battery bank and a 12V house.? Been running?this setup for 4 years now and no issues.

I use an MPPT (Victron SmartSolar 100/20).? Connect your 48V battery to the MPPT PV input.? The MPPT sees your 48V or 52V bank as solar and it outputs proper?charging voltage for your battery type.? You can set charge?voltages, and all the charging parameters.? MPPT's are designed to do exactly that, so much better than a converter.? Chances are you already have a Victron unit for your solar arrays, if so you can use the same Victron Connect app to read the house battery unit as well.

Additional?tip.? I charge the 48V bank at the dock (shore power) as well as solar when cruising (using another? MPPT).? To prevent our 12V loads discharging our 48V bank when at sea or dock and end up?without a motor, we use a switch to the victron unit remote connector.? This is not very well documented or understood, but the VE. Direct connector can be used to turn the unit on or off without requiring the VE.Direct cable or unit.? Connect Pin 2 to GND will switch the MPPT charger off.? Switch that connection to open and the unit starts charging.

Keep in mind that the 48V whether connected through a DC-DC or MPPT, the 12V battery is being maintained all the time from your 48V hence draining your 48V bank, unless you have a 12V disconnect or a charger disconnect.??

In my case, at the dock, a relay opens when we have shore power, and allows the MPPT to charge the house battery.? When shore power is removed (when at sea), the relay closes and the MPPT for our 2V house is off.? We use minimal 12v loads and monitor?the?house battery level.? I also installed a bypass switch that I can manually through open if needed (after confirming sufficient reserve in the 48V bank).? So at sea, if the 12V is starting to get low, we flip the switch?and the MPPT starts charging our house battery from?our?48V.? Very nice and peace of mind, no worries about the house loads draining?our?48V bank while sleeping, anchor light staying on, etc..

I use a Victron mppt smart solar controller from the 48V main bank to the 12V house bank. It’s smart, switchable and has a configurable charge profile with bluetooth control and monitoring.?

I use a Victron mppt smart solar controller from the 48V main bank to the 12V house bank. It’s smart, switchable and has a configurable charge profile with bluetooth control and monitoring.?

I have a 48v battery charged from solar and a 12v AGM battery in the bow for windlass and local 12v needs. I use a DC/DC charger. Works perfectly. If interested I can get you brand and info.?