Introducing myself and my project: 33ft cruising monohull to electric drive+LiFePo4+solar

[shrspeedblade]

Hi all,

I'm a longtime lurker/reader, but finally got around to actually signing up as I'm sure all need some experienced tips for the project I'm undertaking.

I've had my 1978 Nor'West 33 sailboat for about 3 1/2 years now. When I first bought it, I had in mind to go electric conversion 'someday' as it still had the 50 year old original Yanmar 2qm20 diesel. However, the old lump had proven to be so (relatively) reliable I'd swung over to deciding to just "ride it until it dies" including starting full time cruising about two years from now. I'm VERY dedicated to sailing, so I'd burn a whopping 15 gallons or so of diesel every year and put about 30 hours of run time. I'm probably underway about 200 hours a year. I'll happily cruise under 1/2 ounce spinnaker at 2 knots or bust out 20+ tacks in a river channel before I'll turn the motor on. I'm also a gondolier (sadly not in Venice LOL!) and have toyed with the idea of developing a sculling system if that tells you anything.

I had a big haulout planned for this April in which I would install the 460ah Vatrer RV battery for the house, renogy dc-dc converter and keep my 2 group 24 AGMs for the starter, and install (finally) the two 195ah bifacial solar panels over the back of the cockpit with a MPPT controller I got a long time ago. Everything got upended a month ago, when I had a chance to purchase a never installed Thunderstruck 10kw kit for a good price. I'd even gone over to Thunderstruck to talk to them a couple years ago but then decided it would more conscientious to just ride the diesel as little as I motored anyway.

So as I'm want to do I'm my own worst enemy and I've turned my big haulout (doing bottom and nonskid paint as well) into an absolutely monstrous one. I'm prepping to get the Yanmar out now, but my plans for the rest of the system are:

10kw Thunderstruck kit
2x 48v 135ah TCB Worth golf cart batteries (either can power the system, so redundancy)
Victron 48-12v converter (don't have yet)
Vatrer 460ah RV LiFePo4 house battery (it fits perfectly into the boat's existing well-protected battery box)
2x Ecoworthy 195ah bifacial solar panels with MPPT controller (this is a starter kit I got over a year ago, I haven't done solar before)
3000w Giandel pure sine wave inverter
replacing old CNG oven with induction cooktops, small microwave, and toaster oven (have LPG camp stove back up)
I plan to get a 100ah 12v LiFePo4 trolling battery for my trolling motor I could use in a pinch for the house battery

Obviously fuse everything. Assuming wire sizes are apropriate, I'd like to use 300 amp fuses and a 250 amp breaker which would be the 'weak link' in the system and could easily cut power to the motor.

Our boat has pretty modest power loads, and I don't intend to add anything much bigger except maybe 12v starlink mini down the road. It does have a small chiller in the icebox that IIRC only draws about 10 amps.

Some questions:
In reading the forum, it sounds like my best choice for solar charging will be to charge the 48v bank then convert down to charge the 12v house? Any cons to this? Atom voyages designed a fancy switch system but for starters I want to follow the KISSS principal:
Keep It Simple and Safe Stupid

I assume the Renogy DC-DC charger I got to work with the alternator/AGMs/LifePo4 is now unusable? Please confirm.

In reading how to ground the 48v system I'm in the early stages, but still a little flummoxed. Back to the 48v bank or the 12v bank?

Will I need to add more solar panels already to be able to charge the 48v bank, or do I need a boost controller?

Thank you for reading my long winded info. I look forward to interacting with the forum in the future and your tips/advice.

FYI my boat is 12k lbs displacement, sloop rigged with a moveable inner staysail, and calculators estimate I can do about 4 knots at 2kw, which is sufficient for me. If the wind is blowing it can point at 30 degrees to apparent wind and claw out a good VMG with its modified full keel. I carry a big modern anchor and lots of rode for when it's not.

 

[yabert]

10kw Thunderstruck

What is the exact motor and controller for this kit?

Will I need to add more solar panels already to be able to charge the 48v bank, or do I need a boost controller?

Yes, this is always a tricky one for a boat.
Charging 48V LFP at 55-57V almost always imply 2 panels in series or more. Some solution for this:
1-Find the perfect solar panel with 60-75 Vmp (rare)
2-Put two panel with 35-45Vmp in series (can be affect by shade)
3-Two (or more) panels in parallel with a boost MPPT (can be limited in current)

What the spec of your 195W panels. There is many chance that your best bet will be to select other panels.
Fortunately those are affordable those days, even in the 400-500W format.

 

[singlehander]

Hi all,

I'm a longtime lurker/reader, but finally got around to actually signing up as I'm sure all need some experienced tips for the project I'm undertaking.

I've had my 1978 Nor'West 33 sailboat for about 3 1/2 years now. When I first bought it, I had in mind to go electric conversion 'someday' as it still had the 50 year old original Yanmar 2qm20 diesel. However, the old lump had proven to be so (relatively) reliable I'd swung over to deciding to just "ride it until it dies" including starting full time cruising about two years from now. I'm VERY dedicated to sailing, so I'd burn a whopping 15 gallons or so of diesel every year and put about 30 hours of run time. I'm probably underway about 200 hours a year. I'll happily cruise under 1/2 ounce spinnaker at 2 knots or bust out 20+ tacks in a river channel before I'll turn the motor on. I'm also a gondolier (sadly not in Venice LOL!) and have toyed with the idea of developing a sculling system if that tells you anything.

I had a big haulout planned for this April in which I would install the 460ah Vatrer RV battery for the house, renogy dc-dc converter and keep my 2 group 24 AGMs for the starter, and install (finally) the two 195ah bifacial solar panels over the back of the cockpit with a MPPT controller I got a long time ago. Everything got upended a month ago, when I had a chance to purchase a never installed Thunderstruck 10kw kit for a good price. I'd even gone over to Thunderstruck to talk to them a couple years ago but then decided it would more conscientious to just ride the diesel as little as I motored anyway.

So as I'm want to do I'm my own worst enemy and I've turned my big haulout (doing bottom and nonskid paint as well) into an absolutely monstrous one. I'm prepping to get the Yanmar out now, but my plans for the rest of the system are:

10kw Thunderstruck kit
2x 48v 135ah TCB Worth golf cart batteries (either can power the system, so redundancy)
Victron 48-12v converter (don't have yet)
Vatrer 460ah RV LiFePo4 house battery (it fits perfectly into the boat's existing well-protected battery box)
2x Ecoworthy 195ah bifacial solar panels with MPPT controller (this is a starter kit I got over a year ago, I haven't done solar before)
3000w Giandel pure sine wave inverter
replacing old CNG oven with induction cooktops, small microwave, and toaster oven (have LPG camp stove back up)
I plan to get a 100ah 12v LiFePo4 trolling battery for my trolling motor I could use in a pinch for the house battery

Obviously fuse everything. Assuming wire sizes are apropriate, I'd like to use 300 amp fuses and a 250 amp breaker which would be the 'weak link' in the system and could easily cut power to the motor.

Our boat has pretty modest power loads, and I don't intend to add anything much bigger except maybe 12v starlink mini down the road. It does have a small chiller in the icebox that IIRC only draws about 10 amps.

Some questions:
In reading the forum, it sounds like my best choice for solar charging will be to charge the 48v bank then convert down to charge the 12v house? Any cons to this? Atom voyages designed a fancy switch system but for starters I want to follow the KISSS principal:
Keep It Simple and Safe Stupid

I assume the Renogy DC-DC charger I got to work with the alternator/AGMs/LifePo4 is now unusable? Please confirm.

In reading how to ground the 48v system I'm in the early stages, but still a little flummoxed. Back to the 48v bank or the 12v bank?

Will I need to add more solar panels already to be able to charge the 48v bank, or do I need a boost controller?

Thank you for reading my long winded info. I look forward to interacting with the forum in the future and your tips/advice.

FYI my boat is 12k lbs displacement, sloop rigged with a moveable inner staysail, and calculators estimate I can do about 4 knots at 2kw, which is sufficient for me. If the wind is blowing it can point at 30 degrees to apparent wind and claw out a good VMG with its modified full keel. I carry a big modern anchor and lots of rode for when it's not.

I just did a small conversion of my house AGM to LFP. Much smaller effort than yourself but I plan to expand this system at some point to eliminate propane on the boat. I am on that California Delta about 10 NM from sailing and 45 NM from SF Bay. Consequently I do a lot of motoring. Electric drive does not work for me right now.

I currently sail a Freedom 30 at just short of 4 tons loaded but have owned a Beneteau 235 in the past. She weighed in at around a ton fully loaded. The Beneteau was delivered with an oarlock installed on the transom and one could make a good two knots in calm water when sculling. I though it was pretty cool auxiliary power, good exercise too.

 

[shrspeedblade]

What is the exact motor and controller for this kit?


Yes, this is always a tricky one for a boat.
Charging 48V LFP at 55-57V almost always imply 2 panels in series or more. Some solution for this:
1-Find the perfect solar panel with 60-75 Vmp (rare)
2-Put two panel with 35-45Vmp in series (can be affect by shade)
3-Two (or more) panels in parallel with a boost MPPT (can be limited in current)

What the spec of your 195W panels. There is many chance that your best bet will be to select other panels.
Fortunately those are affordable those days, even in the 400-500W format.

Motor and controller:
Motenergy ME1115 Dual-Stator Brushless Motor.
Controller: 48V Sevcon Gen4 G4845

Part of the reason I picked the panels I did was the fit over the cockpit dimensions are pretty ideal. The boat narrows near the stern being a more traditional design and the beam is only about 5 feet. Granted, I did this before I ever planned to go electric propulsion. I was originally just planning the 2 panels, dc-dc charger, and lifepo4 house battery. I'm inclined to go with what I have currently, but then upgrade down the road if unsatisfied. The panel's vmp is 19.8v; voc is 23.7v. Adding two might be my best option on the rails on the sides of the cockpit, which I thought I might do anyway.

I like you #3 option of two with a boost MPPT possibly as well.

With my sailing/motoring ratio being about 10:1, I'd really like to see how the regen performs and build up from there.

 

[shrspeedblade]

I just did a small conversion of my house AGM to LFP. Much smaller effort than yourself but I plan to expand this system at some point to eliminate propane on the boat. I am on that California Delta about 10 NM from sailing and 45 NM from SF Bay. Consequently I do a lot of motoring. Electric drive does not work for me right now.

I currently sail a Freedom 30 at just short of 4 tons loaded but have owned a Beneteau 235 in the past. She weighed in at around a ton fully loaded. The Beneteau was delivered with an oarlock installed on the transom and one could make a good two knots in calm water when sculling. I though it was pretty cool auxiliary power, good exercise too.

I'm your neighbor, my boat is at Napa Valley Marina. Yeah, in the Delta a boat would have to be very small (and nimble!) not to motor a lot.
Usually I motor the first mile then start tacking all the way into San Pablo Bay. It sounds like your conversion was very close to what I originally planned to do.

I think I'd be doing well to get my 6 ton keel boat up to 1 knot sculling, but it would sure be good exercise!

 

[yabert]

Motenergy ME1115

Sadly, it's not a sealed motor. I hope it will do well in salty air.
What kind of gear ratio/belt ratio do you plan?
Do you know the pitch and diameter of the prop?
Also, do you plan to have a shore charger?

I'm inclined to go with what I have currently, but then upgrade down the road if unsatisfied.

If you do you job right, electric powertrain will be so nice that you will need more and more
You will be addicted to no noise and no fume!
13 kWh of energy is not a lot, but based at the fact I push our 38' monohull at 3 knot with only 1 kW, you should be good for a while at low speed in light wind condition.

I like you #3 option of two with a boost MPPT possibly as well.

It's your only choice if you use the 19.8Vmp panels. Here an example: https://ebikes.ca/adjustable-400w-boost-mppt.html

Personally, if I would do all that job once, I would add more solar power as it's the most complicated part (good/rugged fixation design) and use a Smart Victron mppt as it will show all the details about energy harvest (this is so nice to see/understand). Victron 100/20 is affordable and can supply over 1 kW.
I was planning 1600W over our 38' (pic), but now the plan is fully solar: https://diysolarforum.com/threads/wetdream-solar-100-electric-catamaran.90518/

 

[fuzzmunky415]

Welcome, and hope you can update this thread like a blog...I'm interested in your experience with Thunderstruck, as well as your whole process. Cheers!

 

[shrspeedblade]

Sadly, it's not a sealed motor. I hope it will do well in salty air.
What kind of gear ratio/belt ratio do you plan?
Do you know the pitch and diameter of the prop?
Also, do you plan to have a shore charger?


If you do you job right, electric powertrain will be so nice that you will need more and more
You will be addicted to no noise and no fume!
13 kWh of energy is not a lot, but based at the fact I push our 38' monohull at 3 knot with only 1 kW, you should be good for a while at low speed in light wind condition.

It's your only choice if you use the 19.8Vmp panels. Here an example: https://ebikes.ca/adjustable-400w-boost-mppt.html

Personally, if I would do all that job once, I would add more solar power as it's the most complicated part (good/rugged fixation design) and use a Smart Victron mppt as it will show all the details about energy harvest (this is so nice to see/understand). Victron 100/20 is affordable and can supply over 1 kW.
I was planning 1600W over our 38' (pic), but now the plan is fully solar: https://diysolarforum.com/threads/wetdream-solar-100-electric-catamaran.90518/

I had actually looked at/considered the sealed motors when I visited Thunderstruck. I agree it would have been the best option, but getting this kit, unused, at 1/4 the price of retail was what lured me into ditching the diesel in the first place! I've considered a small, 12v fan mounted to blow right at the motor when the boat is sitting might keep corrosion to a minimum. Heck, I run an air dryer in the boat all winter so why not?

I have the 2:1 gear reduction that you can add with the kit.

I don't know prop specifics, but it's the 3 blade that probably came with the boat in '78 and likes to start spinning at 5 knots so I hope it's great for regen as well. (And one less expensive thing to have to replace, too!)

Yes, I'll be able to plug in/charge off shore power when in the slip. The nice thing is I still have about 2 years before I plan to go cruising so it gives me plenty of time to work out bugs and get an idea about performance of systems while still sailing out of a slip. I definitely would like to get to the point I don't plug in at all, though. That will show me the boat is ready for cruising.

I'm already addicted to something: sailing. One reason I'm posting this thread here rather than Cruisers Forum, which I also really enjoy, is it avoids all the fanatics that will post arguments like they think burning diesel is a religious right or something. I find it encouraging that you could push your 38 footer at 3 knots with 1kw. I'll probably see similar performance being a modified full keel.

 

[shrspeedblade]

Welcome, and hope you can update this thread like a blog...I'm interested in your experience with Thunderstruck, as well as your whole process. Cheers!

Thanks, I certainly intend to. I also want to show if you treat sailing like a sport, and the sails are the primary drive system of the boat, a modest electric drive system is very doable now. Hell, Lin and Larry Pardey circumnavigated the planet TWICE with no motor at all!

I'm anticipating having challenges and lots of questions along the way, which from my reading this forum will be and already is good for!

 

[yabert]

One reason I'm posting this thread here rather than Cruisers Forum, which I also really enjoy, is it avoids all the fanatics that will post arguments like they think burning diesel is a religious right or something

Hahahahahhahahaaaaa!!!
I can't understand you more
I have read too often sentence like: ''You will die without a big diesel''.

I definitely would like to get to the point I don't plug in at all, though.

That my thoughts about adding more powerful solar panels.
300ich W is nice, but around 1000W will be better.
Solar panels continuously improve and year after year they output more watts for same surface as cells efficiency increase.

I had great expectation about regen under sail when I start to search about boat electric propulsion.
But after looking at many place like E-Propulsion and Ocean Volt regen graphs, it look like there is very little power (100-200W) to recover on a typical monohull at 5-6 knot.
Over 24h that a relatively large energy quantity, but for me it how I end to ditch the sails to have a lot of solar on a Cat.

 

[shrspeedblade]

A Cat is great with all that surface area for panels, to be sure!

With the Yanmar you put it in neutral when it's off, so I KNOW my prop spins early and often. Even 200w would be like another hard panel that can't be shaded for me, and I intend to keep my energy needs modest.

 

[yabert]

so I KNOW my prop spins early and often

Last year, I tried to put the engine of our monohull on neutral to watch the prop shaft spinning during sailing.
I was almost able to stop the shaft with my hand (read here very low torque, so low power available).

I intend to keep my energy needs modest.

This is key

 

[shrspeedblade]

Well, the Yanmar diesel is finally out of the boat. It's amazing how long all the little things can take to do- but it is a boat after all!

I went the easy route and hired the marina to use a crane to pluck it out, and I'm glad I did! The thing weighs nearly 500 lbs and I reasoned if I broke something on the mast or boom (or me!) trying to get it out it would make hiring the crane look cheap. It was still a bit difficult, even then.

I hit my first big snag of the project yesterday, as I finally have the prop shaft out and accessible and doing some eyeball measurements I can tell my two 8D 135ah LiFePo4 batteries will NOT fit in front of the electric motor in the old engine bed. So I either have to have a machine shop chop off 3 or 4 inches of shaft or reposition the batteries by modifying (read: cutting and refiberglassing-ugh!) the engine bed.

I'm leaning towards the bed modification, because although it will be harder it means they will rest side by side rather than one over another lowering the center of gravity, making them a bit more secure, and easier to cover. Doing this in my spare time, it also means probably almost another week of work, too!

 

[shrspeedblade]

On a different note, a little side project I've wanted to do for some time is to modify the old CNG stove on board. So far I've disassembled it and have the burner section off the top. So I'll mount brackets to hold a 2 burner induction cooktop down in the top and the space below where the oven was will hold a small microwave I got for free. I'll post a picture of that as well once it's done. I got the inspiration from James of Sailing Triteia who did something similar, and it allows you to keep everything gimbaled and securely in place for cooking at sea.

 

[yabert]

Yanmar diesel is finally out of the boat

Interesting! Pictures?
Brainstorming, help, advice or been inspire without picture is tough

 

[shrspeedblade]

Good idea.
In my defense, this is before a WHOLE lot of scrubbing yesterday!
I'm thinking at this point since the motor with its reduction gear will sit just forward of the aft mounts, I saw out a section of the right side (port side of the boat) motor motor pan and mount the 8Ds sideways on their sides with the battery posts to the right as I'll have to mount the Sevcon motor controller on that solid bulkhead.

Any inputs/brainstorms greatly appreciated!
And yes, I many break down and rewire the whole damn boat now, too.

 

[yabert]

Yeah, nice! It look really more compact that my 38' Beneteau.
But if this is effectively your gear reduction unit, you can probably modified it a bit and fit motor in the rear and allow all the place in front, over the motor mount, for batteries.

 

[shrspeedblade]

Yeah, nice! It look really more compact that my 38' Beneteau.
But if this is effectively your gear reduction unit, you can probably modified it a bit and fit motor in the rear and allow all the place in front, over the motor mount, for batteries.
View attachment 294880

That is my gear reduction. I think in the picture I took I already had the prop off so the shaft is a bit further aft than it normally sits.

I need to get the old coupler off the end (ugh!) and the cutless bearing out and replaced (double ugh!), remount the prop, and put the shaft exactly where it will sit to bolt to the chain coupler pictured. However, I'm almost certain once that is down that it will intrude 3 inches too far forward for the batteries to be mounted longitudinally.

I *could* have a machine shop shorten one of the shafts by several inches as well once I have exact measurements.
At this point, however, I'm leaning towards taking a section of the pan out where that red motor mount was as it's the perfect length to fit the 8D batteries sideways on their sides. This is probably more difficult but will make them easier to secure and cover.

The more traditional designs don't carry their beam as far aft, so you're right I'm working with a lot less space than a Beneteau 38.

 

[yabert]

the old coupler off the end (ugh!)

I have a solution to keep the flange coupling if really it's impossible to remove and if you have to rework chain coupling hub anyway.
I the know it can be complex, but if I can do, I bet most machine shop can do. You can weld a 4 holes flange (in blue) on the chain coupling hub and then it will fit you original coupler.

If it's an interesting solution, don't forget to weld inside and outside to pass the torque by two large weld.
It's best to rework the face in contact with the coupler after welding.
If you want simple flange drawing to have this laser cut by send cut send (by example) don't hesitate to ask.

 

[shrspeedblade]

Got delayed by a couple of days battling a cutless bearing that refused to come out.

I ended up having to buy a reciprocating saw if that tells you anything!

Ahhh.....boat work.

 

[fuzzmunky415]

Honestly, if only one power tool were allowed on an island, it would be my hand-held DeWalt sawzall. With a selection of blades, of course.