Converting CD30C from Diesel to Electric propulsion

[Keith]

This winter I finally made the decision to replace the MD7A due to raw water in the oil last season. The next decision was to replace with another diesel or go electric. I have been thinking about electric for several years. The two main factors that swung the decision to electric were cost and the fact that I mostly used the diesel to charge the batteries. Out of 3000 Nm logged last season I would estimate that only 25 or so were actually motoring. The cost of a new diesel with the v-drive is around $14K. The cost of electric I estimated to be $8-9K with many variables. It now looks like it will be just about $9K as almost everything is purchased. I have been working on the project since the start of March when the weather permits. Here is the documentation of the process.

The first pic is the existing engine bay

MD7A and Walters V-drive.jpg (116.89 KiB) Viewed 983 times

First I removed the muffler, exhaust manifold and then V-drive and trani. Both were easily removed, loaded into my trunk and put in my cellar. If anyone is interested in either please let me know. I will also be posting all diesel related parts on another thread for sale. I will be very reasonable with price just want them to go to a good home and not the scrap pile.

Trani and v-drive removed.jpg (118.83 KiB) Viewed 983 times

Next came the engine. I removed every thing from the engine that I could to reduce the weight. The fly wheel was incredibly heavy. I would guess 75 or more lbs. I used my boom vang/preventer with a 4/1 advantage attached to my mast that is vertical to haul the engine then fly wheel up through the companion
way, through the cockpit and down to the ground. It was surprising easy. Just moved the boom vang in increments aft until I was at the transom.

engine on cockpit floor.jpg (113.16 KiB) Viewed 983 times

[tjr818]

Keith, I am very interested in this. We plan to go electric this summer/fall. Which brand of motor did you go with?

[Keith]

Keith, I am very interested in this. We plan to go electric this summer/fall. Which brand of motor did you go with?

I went with Electric Yacht QT10 sport.

[Keith]

Next task was to remove everything else from the engine bay. I removed all of the plumbing from the engine bay side wall to provide space for the new electronics and electrical connections. I also removed both seacocks. The one for the raw water intake is no longer needed as the 10Kw motor is air cooled and the sink drain seacock is being moved from the starboard to port. I'm not sure why CD put it on the starboard side when the sink is on the port side. The drain hose had to cross over the V-Drive. The newer CD30C came from the factory with the sink drain seacock on the port and they added a small door to access it. I have added the door which you will see later in the project. I also moved all of the plumbing under the sink to keep it away from the new electrical hardware and motor. The new access door made all of this possible.

Engine Bay cleaned up.jpg (73.39 KiB) Viewed 946 times

Then I test fit the electric motor with some 2x4's to get the rough location and see how much I needed to cut down the prop shaft. It need to be shortened by 8" along with the stuffing box hose.

10Kw motor test fit.jpg (107.89 KiB) Viewed 946 times

Next I cut and shaped pressure treated 4x4's to fit the contour of the engine bay pan. This was the most difficult part of the project. I ended up with a good fit on the outside but needed to epoxy in wedges on the inside of each stringer. The stringer extensions were held in place with fixturing for the fiberglass work to come.

new stringer fixtures.jpg (67.76 KiB) Viewed 946 times

[Keith]

Next I glassed in the 4x4's on the sides and end but left the top open. Once the sides and ends cured I poured thickend epoxy down into the structure so that the stringers and wedges were all bonded together as well as to the pan. Once the pour cured the top was glassed over.

Fisrt layer of glass on new stringers.jpg (94.31 KiB) Viewed 942 times

Then another layer of glass was added all around including tabbing out another inch or so to provide even more strength. Finally two coats of primer and two coats of white finish 2 part paint were added. I also painted up the surrounding areas with bristle beige. It's looking very spiffy indeed.

New stringers complete .jpg (68.11 KiB) Viewed 942 times

While waiting for the paint to cure I am planning out the electrical component placement on the side wall.

Electrical wall test layout.jpg (57.98 KiB) Viewed 942 times

As soon as the paint is cured I will mount and align the motor.

[ghockaday]

Keith, I am very interested in this. We plan to go electric this summer/fall. Which brand of motor did you go with?

We did too! 2 years ago, we have had no regrets.

Engine to Motor.JPG (556.56 KiB) Viewed 924 times

[tjr818]

That looks like the Electric Yacht Motor. What is the big yellow box on the left?

[ghockaday]

That looks like the Electric Yacht Motor. What is the big yellow box on the left?

Charger

[Keith]

The motor is mounted, aligned and I had the prop spinning for a few second just to make sure everything was good before mounting the rest of the components and managing wires. The cardboard box represents the LiFePO4 battery that I am building. As you can see it will mount aft of the motor basically where the MD7A sat. I'll explain the battery decision in the next post.

motor installed.jpg (96.54 KiB) Viewed 890 times

mockup for LiFePo4 battery placement.jpg (103.83 KiB) Viewed 890 times

planning for wiring.jpg (115.68 KiB) Viewed 890 times

[Keith]

The three biggest issues with converting to electric are what range do you need, what type of batteries to use and how to keep the batteries charged.

1. I day sail Nantucket sound and very seldom used my diesel except to charge the batteries. The most range that I would ever need is 23 mile to get me back from Nantucket if there was no wind as a side note there has never been no wind in the 9 years that I have been sailing Nantucket sound. So that answers the range question. Here is a graph showing the estimated range in Nm, Hrs and Ah used. The X axis is range in Nm and the Y axis is Amps and hours. The graph does not take into account the Ah that are being added during sailing. On a sunny day I could in theory motor all day at 2 knots with the sun providing all the Ah needed. These are all estimates from Electric Yacht which take into account our full keel boats. I will post updates in the future as to what numbers I actually get. Other users of Electric Yacht motors have actually achieved better then the estimate. Time will tell.

Range Graph.png (34.92 KiB) Viewed 887 times

2. What type of batteries do I get? Lead acid batteries can only be safely discharged to 50% so with 100 Ah batteries you only really have 50 usable Ah. LiFePO4 batteries can be safely discharged to 10% so with a 100Ah battery you have 90 usable Ah. The problem is they are incredibly expensive. After extensive research I discovered that you can get the cost down to at or below lead acid costs. The first option that I found was used medical equipment batteries. They must be replace at certain frequencies per standards independent of how many charge cycles they have actually had. Most of them that I found had seen less then 1000 charge cycles (many only 300-500 cycles) and they are good for 4000-5000. These batteries were 40-50 percent of the cost new LiFePO4 batteries but they are hard to find and they are scooped up fast. Next I found that you can build your own LiFePO4 batteries from 3.2V cells that you get from China. They are less then 25% the cost of new LiFePO4 and less then lead acid batteries as well. I purchased 16 3.2V 202Ah cells (48V in series) at $56 each for a total of $896 plus shipping from China $400. I also needed to buy the BMS (battery management system) for $220. So my total cost for 202Ah is $1516. 202Ah of Battle Born LiFePO4 batteries is around $8000. Note: I have to build the battery case, balance the cells and connect the BMS. If you bought off the shelf LiFePO4 batteries the BMS is already buried in the package. For anyone that is interested the BMS manages the voltage of all cells. If one cell goes high it will limit the voltage until it is even with the other cells if one cell goes low it will increase it's voltage until it is even with the other cells. I forgot to mention the other advantage of LiFePO4 over lead and is weight my 202 Ah battery will weight 160lbs plus the 1/4 inch plywood and glass epoxy that I plan on building it with. 210 Ah with lead acid group 31's (8 needed) would be over 500 lbs and remember only 105 of those Ah are usable.

In addition to 202 Ah of LiFePO4 batteries I have 79 Ah from my group 24 AGM's. I already had there group 24 AGM's that were new last year. So I bought one more and hooked them insures to give me 48V. I bought a 48-12 V DC DC converter which is hooked to the AGM's. My plan is to only use the AGM's for 12V use but I have wired them so that they could power the electric motor in an emergency.

3. I'm on a mooring so how do I charge the batteries? The only two option were solar cell and wind turbines. I didn't want the noise and visual distraction of a wind turbine so I am going with 4 70W semi-flexible solar panels. According to the manufacturer on average they should generate about 32 Ah per day. Three will mount on the dodger and the forth on the sea hood. Visually that should not distract from our beautiful Alberg lines because I'm not adding any new structures to mount them. On an average I will use less then 20Ah which includes electronics, stereo and motoring in and out of my harbor (I usually sail out and motor in depending on wind direction). If I motor one way the Ah will decrease. I took the cover off yesterday so I will show some pics of the new dodger and solar panels in a day or two. Getting my second moderna shot today so no work on the boat. Here they are in my basement.

Solar Panel Layout.jpg (87.24 KiB) Viewed 887 times

[John Stone]

Very cool Keith. You are doing some neat work. Very interesting. Hope the vaccine goes well. I received the second dose of Moderna last Friday. Sat was not fun. I was sore and felt like I had a very mini flu for about 24-36 hours. My wife had no symptoms other than a sore arm. Weird.

[Keith]

Thanks John,

Both my wife and I received our second shot today. Neither of us had a problem with the first shot. It's been about 6 hour and so far so good for both of us.

Keith

[Keith]

Well that didn't last long! Both my wife and I were really hurting today after our second Moderna shot yesterday a 5PM. Chills, aches and shakes all day. I'm starting to feel a bit better now but still not good. I went to the boat rather then whining in the house. I was at a bout 25% or less.

Hopefully tomorrow will be better. I plan to add all the snaps to the new dodger now that the cover is off. Then I'll figure out how to mount the 3 solar panels on the dodger (Sailrite has some suggestion) and one on the sea hood. I did wire the 4 panels in series and they are incredible efficient. The manufacturer list them at 25 V max each so it should be 100V for the 4 in series. I was reading 113.2V in the sun and when I moved them under the mast with partial shading they only dropped to 109V. I called Tom at Custom Marine Products let him know how well they were performing. If you are looking for solar panels I suggest that you give them a look. https://www.custommarineproducts.com These are grade A+ panels but not much more expensive then Grade B or lower grades.

Keith

[John Stone]

I hope you and yours are feeling better today. It took me a couple days to get sorted out. The day after was the worst.

I have visited custom marine products web site a couple times over the past year as I researched my way ahead. I called them not too long ago and they were helpful. I liked the A+ panels but they are too big for my boat. I am looking for a 50 watt about 25” x 25” I can put on a flexible power cord so I can move it around and keep it in the sun. Kind of like my 30 watt Getz which is no longer available.

Sun Power makes an inexpensive 55 watt but it’s a flexible panel and I’d have to mount it on a piece of poly carbonate or 1/8” aluminum. I don’t think it would last more than a couple years. I’m still looking.

[Keith]

Hi John,

Thanks for asking. I'm feeling much better maybe 80% but my wife is still the same as yesterday. Hopefully she will perk up tomorrow.

The 70 watt panels that I have are 22x28 and they make the 22x23 that are the 55watts that I think you were referring to. They are called semi-flexible but are actually quite stiff. I'll see If I can come up with a way to demonstrate how stiff they are. If you wanted to go with a long and thin semi-ridged walk on panel (with aluminum backing) they have some new ones that aren't on the web site yet. I think that they are 13x33 and 13x48. They are around 55 or 60 watts.

As a side note they told me that walking on my semi-flexible panel that will be mounted on the sea hood would not be a problem.

Food for thought.

Keith