Conversion project - documented

[sailorxyz]

Originally Posted by sailingharry

But low RPM produces exceptionally small torque from the propeller. A propeller only achieves maximum torque at maximum rpm, which closely aligns with a diesel engine's maximum torque. At 100 shaft rpm, you could probably turn the propeller by hand! Probably not really, but close. At idle rpm, a diesel engine can deliver many times more torque than a propeller requires, as evidenced by the fact that when you shift into gear at idle, the engine doesn't load up. An electric motor's high torque at zero RPM makes for stunning 0 to 10 in electric cars but is of no value in a propeller.

Explain why a prop with a lot of pitch will stall a diesel. This is a typical problem with a Kiwiprop on small diesels. Kiwiprops have lots of pitch when they flic into reverse mode and often stall the diesel that they are attached too. I've never seen one stall an electric motor.

[SaylorMade]

Originally Posted by GrowleyMonster

Let us know when you actually motor 50nm at 4.2kts, will you please? Extrapolation from using a small percentage of your stated power capacity is valuable data but not as conclusive as a full discharge test of the system. I like EP. I like it a LOT. But I am also about halfway between being a cynical realist and a pessimist even on things that I like. Worst case scenario and results are better design waypoints than pie in the sky, even if a particular limited data set supports it.

Congratulations on your test run, anyway. You have a good system there and it should serve you well for many years of trouble free use. But I would keep quiet about how many kwhrs of juice you use from shorepower! They might decide to throttle or meter you!

I don't expect I ever will motor 50 nm, so can't promise you that.
It is perfectly fine to extrapolate in this setup, it has been demonstrated over and over and over again, how you can get the exact KWh's from a LiFePo4 battery as stated on the tin. No need to doubt that.

To refill the the bank today took about 1.5 kwh, still a good deal for the harbour. So no need to hide anytying.

Most places power is metered, and so is it in our home marina, it was just a bit of fun that it was a free ride here today

[SaylorMade]

Two more days on the water, not much new to report.
Still the same figures

Yesterday we went through a patch of completely calm, and the autopilot gave up, so I just put in 100 watt of propelllor which was completely silent but still gave us 1+ kts and steering capability. 10 minutes later wind came back.

Today was windy, so just out of the harbour, and back in with the motor.
Battery at 99 percent when we were in our home berth.

[JBP]

Come on, get out there! Work that motor! Drain those batteries! We want more info!

[Bullshooter]

Originally Posted by GrowleyMonster

That's one sweet looking battery! Hate to think what it costs compared to my golf cart batteries, but that is a tidy little package you got there. I would have gone for a pair of them, funds permitting. Maybe three of them! You could electro-motor all day and all night and into the next day! Maybe even pull a shrimp trawl! Okay, a small one, yeah.

Hahaha! Shrimp trawl! That's about what a guy from Louisiana would say! I'm from New Orleans too, so it sounds reasonable to me. I don't know how much trawling they to in Denmark...

[Shaneesprit]

Originally Posted by SaylorMade

I don't expect I ever will motor 50 nm, so can't promise you that.
It is perfectly fine to extrapolate in this setup, it has been demonstrated over and over and over again, how you can get the exact KWh's from a LiFePo4 battery as stated on the tin. No need to doubt that.
:

It’s your system and it sounds like your having a lot of success, must be great to be silent, and the weight was ok too. Maybe one day we will all have to have a marina with shore power. and they will charge us the Earth for it.

First I am not complaining, but would just like to point out something about testing the system. Draining down the batteries and hard use is really something you should be doing. Not just so the wonderful people can enjoy your data, but because doing so proves the safety and operation of your system.

Now as I said before part of my job involves testing of various systems including batteries for clients. Last year I would expect the replaced batteries to be 2 - 3% based on general experience, of that figure I am removing the loss of 1 section of a system to fire 🔥 that was over 100 batteries (not lithium) so the fire service were able to cool it, and extinguish. now cause of the fire May of been a battery but far more likely to of been a cable fault, when I say cable I really mean the battery or a terminal (I wasn’t personally present) well no one was at the start, the high load discharge test is dangerous if your near the batteries, so it’s always done with the door closed.

the rest of the battery failures were a mixture of issues - high temperature when discharged, this temperature was not excessive but enough that we had them replaced, there also would of been a few that gassed off and fewer still that ended spewing acid.

If it were me I would decide what a test should be performed and do that, I would probably include.
1) include a course that goes in a square. To give the most rounded results. 😂
2) Run the course at 25%
3) Again at 50%
4) Again at 75%
5) Normally I might say run a full power but that would be a final test. If was to decide it would leave the battery almost drained, you may decide that if you were to do this, you stop at a certain % of life or battery voltage. I would go until it stops.

This would give the opportunity not only to assess the system but also to thermal image the entire installation, Battery Cables Motor.

Then I could check the recharge and be very happy.
It’s basically a sea trial.

What it sounds like you have done (I am not criticising) at the moment is turn it on and hope it works. and for you that maybe ok, but the more people that install either themselves or professionally, the more likely that we will hear of the one that was lost because, they didn’t test it properly and it failed when needed.

PS an emergency connection to the house bank might just get you home one day.

Anyway I am glad you’re happy with the change to EV, I got out of EV in about 1982, but that was my go kart. Not ready to go back until it fits my lifestyle. Presently cannot see a way to make it work on land or sea.

[AKA-None]

I agree it would be nice to know the limits of the system

[SaylorMade]

The thread was meant to document the install, and post real-life figures of consumption later on.

Still is the point, and it will be used for that.
But it will be data from real life usage as it happens over time It's not a science project.
There is nothing special about this simple setup, with a load of up to 6KW on a quality and over-specced LifePo4 Battery from a builder known for quality.

Of course I monitor temperatures during motoring. After about an hour of motoring with 4-5 knots everything was cool as strawberry ice.
The battery has several temperature sensors inside, and none of them rose by any significance.

I know that some are so much against EP that any facts posted about usage and range, will be doubted and they will find an angle to make it somehow invalid.
It's fine

@shaneespirit good points. I am considering adding temperature sensors on the terminals with readouts in the cockpit (need something for the old engine panel space ) Would that be a useful thing to monitor, combined with the batterys internal sensors (it has two in between cells, and one on the BMS) ?

[SaylorMade]

Another typical trip today - just sailing on the fjord, so motoring in and out of harbour.
A fresh easterly took some toll against the wind.
It took 1.5 KW to motor at 4 knots, but it was just for getting out to hoist the sails and back in.
Battery left when docked again was 98 percent

Due to some good advice in the thread I am designing a cover for the old engine panel, where I am going to put in a temperature monitor for the battery cables.
Mostly for when we are motoring for a longer time, to be able to spot any trouble early on.

[SaylorMade]

I don't have much to post regarding the consumption, it all seems to be accurate from the intial postings, so I am kind of getting why not many of us electric boaters post more about consumption.
It just seems to be what it is, and I can already feel that I am starting to pay less attention to the remaining "fuel".

I did however notice the other day, when I motored for a bit against a fresh breeze that it does lower the range remarkably. No suprise, but something to have in mind, if you are inclined to motor against any significant wind.

For my purpose it seems absolutely fine, and I am happy that I went with a big bank, and room to add another if ever needed.

LifePo4 batteries are fantastic though. The BMS (Bluetooth app) is in complete agreement with the throttle display, and it is great to have an exact reading of the SOC and remaining distance.

It is also fun to see on the app how the battery accepts all 25A from the charger, just shortly until full. The last couple of minutes it goes down to 8 amps and then shuts off at cell high voltage setting.
So much more amazing than Lead Acids.
There are 16 cells in the battery, and they are within 0.005 volts shortly after end of charge and the balancer decides that we are all good

Now, as mentioned earlier on, I have a gaping hole where the old engine panel was, and I am in the process of designing a cover plate.

I want to put something on there, and the current idea is to mount a dual temp readout, with sensors connector to the battery poles, to monitor if they get hot.
Is that a meaningful thing to monitor?

And please, feel free to comment if you have other ideas for readouts to put in the panel

The first image is my current design idea for the panel, and the other one, is one I did a few years back in the cabin.

[SaylorMade]

It was a nice very calm morning, so I decided to go out for some motoring and collect a larger set of consumption data.

I even made graphs

There was zero current (which is almost always the case here), and only very light wind, but even so I meassured speeds while having the wind from the side only.

After changing throttle-setting I allowed the boat to stabilitze the speed for 2 minutes before noting the speed.
There were some tiny fluctuations (0.1 up and down) so the numbers I've used is the average on each leg (not the highest not the lowest).

I have included a couple of graphs, and also links to two videos, so you guys can see that I am not just making it all up

YouTube video - 200 watt - slow

YouTube video - Steaming with 2 KW

There seems to be a sweet spot around 1,5 KW which I already had a feeling about. But honestly - most calm days, we can just go 5,2 knots as we did with the diesel and still have plenty of range for what we normally do.

The motor can go at 6 KW, so there is still a nice reserve if it is needed to go up against a bit of nasty wind. I was at 4,5 KW today, pushing the boat at 5,8 to 5,9. It was the same pattern with the diesel it took a lot of effort to get it to 5,8 let alone 6 kts. (Which would be WOT, so the same as the electric, which I am sure would also reach 6+ knots at 6 KW)

[Statistical]

Nice additional data. All in all looks like you have a pretty sweet setup. Curious how long you can go and still have steerage. With high flat torque curve you should be able to creep at speeds like when docking that would not be possible with traditional engine.

[SaylorMade]

Originally Posted by Statistical

Nice additional data. All in all looks like you have a pretty sweet setup. Curious how long you can go and still have steerage. With high flat torque curve you should be able to creep at speeds like when docking that would not be possible with traditional engine.

Thank you Stat,
I am not sure what you mean (English is not my firs languague, which I am sure everybody is aware of by now )

The boat steers well down to 1 knot, it has a big transom hung rudder, which I love (especially in sporty conditions with a downwindsail)
It can certainly creep along in the harbour (in calm) with just 100 watts on the prop. That gives 1+ knot. Crazy.

Could not even do that with the diesel, in and out of gear, while it was still pumping dinojuice, even out of gear

[SaylorMade]

A few years back I had a quote from OceanVolt, and they included their calculated range for my boat with their system, with 3 different battery options.
They were quite a bit more optimistic, BUT they used 3.000 kg as weight for my boat, but I have later found out that it actually weighs 3.900 kg (crane dude says so).

So with that in mind it is probably very close to what I see with my setup.

[Statistical]

Originally Posted by SaylorMade

Thank you Stat,
I am not sure what you mean (English is not my firs languague, which I am sure everybody is aware of by now )

The boat steers well down to 1 knot, it has a big transom hung rudder, which I love (especially in sporty conditions with a downwindsail)
It can certainly creep along in the harbour (in calm) with just 100 watts on the prop. That gives 1+ knot. Crazy.

Could not even do that with the diesel, in and out of gear, while it was still pumping dinojuice, even out of gear

Oops I had a typo "long" should have been "low". As in how slow can you go and maintain steerage which you answered. I imagine docking is a lot nicer (and quieter) with electric.