Going full electric on a Montgomery 17 sailboat

[IGBT]

I know, I know, you never go full electric

But anyway...

We decided to convert the 2013 Montgomery M17 we recently purchased into full electric, with the hope of using it to do the Great Loop. Took a few days and a few (dozen) trips to the stainless steel hardware aisle but we have the boat wired up and ready for the electric outboard when it arrives.
The system is comprised of two 48V banks, each consisting of four LiFePO4 12.8V 100AH batteries wired in series. Each of these batteries has a bluetooth BMS for user monitoring and also several protections including over current, over charge, and low temp charge protection. They are 22 pounds each, which makes the port and starboard banks 88 pounds each. There is no house battery anymore, rather we are using a Victron 48V to 12V 20AH DC-DC. We used 1/2" marine ply and teak sides to make battery trays with stainless steel holddowns to contain the four batteries on each side. These just screwed into the existing plywood trays on the M17.
Each bank has its own 120 amp breaker and its own 58.6V 18AH charger. There are Victron 450 amp rated switches to control which bank is active and another 450 amp switch going to the stern connections for the outboard. These connections are Amphenol Surlok bulkhead 200 amp 1500V connectors which are IP67 rated when connected.
The motor we have chosen is overkill, but we are planning to try it out on some other boats as well. It is a E-propulsion Navy 6.0, 2024 version. It weighs 66 pounds and has the equivalent output at full throttle of about a 7 to 8 hp gas outboard. A bit more thrust than a 9.9hp gas outboard. From our experience using a Torqeedo 1103 at full throttle (1100 watts), we know we should be able to achieve about 4.5 kts at that level. Thus we should have about a 40nm range at roughly 1000 watts input. Alternatively, we can leave the running lights on the boat lit for about a year lol.
I am thinking 2000 to 3000 watts is going to get us at full hull speed, for going against a current or really heavy wind and chop. This would give us 3.5 to 5 hours of running on the 10kWh battery bank.

Now we are just waiting for ePropulsion to ship some more motors to their dealers.

 

[Bluedog225]

Great loop in a 17! That’s going to be awesome. And no gas motor. I love this.

How are you going to recharge? Do you think the marinas will have some arrangement? Seems like you will be pretty dependent on finding plugs.

 

[IGBT]

Great loop in a 17! That’s going to be awesome. And no gas motor. I love this.

How are you going to recharge? Do you think the marinas will have some arrangement? Seems like you will be pretty dependent on finding plugs.

We thought about solar, but with 10kWh of battery and really not a lot of deck space on a 17 foot sailboat, I think it would be more trouble than it was worth. *maybe* you could sneak 200 to 300 watts of panels onboard and not be in the way of the sails, but figure the sails and mast are going to shade them at times, so best you could hope for is what...half a kilowatt-hr per day? Not worth the hassle.

That leaves marinas and our portable YETI power station. I figure we will want to shower twice a week at least, so hopefully we can plan out stops at a marina that has shore power, and if they don't have at least 20amp or 30 amp shore power, we would recharge the 3000 watt YETI at a hotel, then bring it back to the boat to dump in the power to the main bank. That is not ideal so I am really thinking it will have to be marina stays.

We have set up the banks as two independent banks, each with its own 58.6V 18amp charger, powered by 120V at 12 amps max. Thus 30 amp shore power with a splitter should be able to charge both banks at once, easily putting in 10kWh over a single night stay.

Still kind of in the planning stage on that part (how to recharge). I absolutely do not want a generator. I am willing to consider flexible panels or something if they can stow easily.

 

[IGBT]

Here are some example legs I found for part of the Great Loop. It does seem like marina charging (if our bank is large enough) could be possible. We technically do have a bit more room forward of this 10kWH and could sneak a 5kWh Epoch 48V in there

If we are lucky, maybe we could be on a beam reach or a run for parts of these legs and save on the motoring...

"

LEG 1. HARBORSIDE MARINA​

WILMINGTON, ILLINOIS​

Estimated Mileage: 55 nmWhen departing Chicago, two routes continue your Great Loop cruise. Route one via the Chicago River is a scenic cruise through downtown to the Chicago Sanitary and Ship Canal. There are more than 40 bridges within five miles. The lowest bridge has a fixed vertical clearance at 18.5 feet.Route two via the Calumet River to the Calumet-Saganashkee Channel is the only option if vessels cannot clear the lowest bridge.

Regardless of which route is taken from Lake Michigan, boaters eventually arrive at the lowest fixed bridge on the Great Loop. At Mile 300.5 on the Illinois River is a fixed railroad bridge that is charted at 19.6 feet. Reaching Mile 288, many cruisers on the Great Loop opt to tie up overnight at Joliet City Dock which offers complimentary power and dockage.Brandon Road Lock and Dam is located at Mile 286.

Reaching Mile 273.33 near the mouth of the Kankakee River southwest of Joliet, dockage is available at Harborside Marina, which offers a full-service facility for any type of vessel.

LEG 2. STARVED ROCK MARINA​

OTTAWA, ILLINOIS​

Estimated Mileage: 48 nmShortly after departing Wilmington, boaters reach the Dresden Island Lock and Dam at Mile 271.5.At Mile 240, directly adjacent to Starved Rock State Park in Ottawa, is Starved Rock Marina, a full-service port with on-site bar and grill, boutique and water-sport rentals.

If the cruise from Ottawa to Peoria Heights is too lengthy to complete in one leg, consider docking at Henry Harbor Marina in Henry, Ill. at Mile 196.

 

[ThaiTaffy]

Probably not cheap but I'd guess solves the solar panels issue.

Solar panel sails

www.hallberg-rassy.com

 

[SparkyGage]

Awesome! For a lake, that motor might be overkill, but for a long haul on salt water it's hard to argue with overkill. On the ocean, I want as many options, as much reliability, and as much power as I can reasonably fit, as well as many tools as I can carry. Once I use a tool, it doesn't leave the boat.

Good luck and happy sails to you! I'll be following along.

 

[AnarchyJet]

What is going to power your dinghy? I would go gas and be setup to use it as a backup on the sailboat. Going up the Ohio against the current is going to be a challenge with your setup. Get another 12v 100ah battery to be your house bank. This can be pulled to replace one of the propulsion batts if it fails. If 1 of 8 bms fail, you are at 1/2 capacity.
I know you don't want one but get a generator since you won't have solar. You can store a lot of back up energy in 10 gallons of gas.
I've done Milwaukee to St. Louis on a 35' sailboat. That took a week motoring down the rivers 10hrs per day at 6-7kts with the current.
Our boat had a gas inboard and burned around 1 gal/hr. With 40 gals on board it still took some planning and walking into towns with jerry cans to make sure we had comfortable range. I couldn't imagine trying it with 40nm range an no alternative.

 

[OzSolar]

I know, I know, you never go full electric

Tropic Thunder?

 

[IGBT]

What is going to power your dinghy? I would go gas and be setup to use it as a backup on the sailboat. Going up the Ohio against the current is going to be a challenge with your setup. Get another 12v 100ah battery to be your house bank. This can be pulled to replace one of the propulsion batts if it fails. If 1 of 8 bms fail, you are at 1/2 capacity.
I know you don't want one but get a generator since you won't have solar. You can store a lot of back up energy in 10 gallons of gas.
I've done Milwaukee to St. Louis on a 35' sailboat. That took a week motoring down the rivers 10hrs per day at 6-7kts with the current.
Our boat had a gas inboard and burned around 1 gal/hr. With 40 gals on board it still took some planning and walking into towns with jerry cans to make sure we had comfortable range. I couldn't imagine trying it with 40nm range an no alternative.

Someone else mentioned the 9th battery and I agree it is a good idea, it really reduces the chance of losing one of the two banks from BMS failure. am not sure I would bother wiring it in as the 12V house bank since we have already wired in the Victron 48 to 12 dc-dc and it works fine. I would probably just keep the spare battery in the forward compartment in its padded shipping box or something.

My wife wants to use our Portland Pudgy as a dinghy and that boat can support a small gas outboard but I am waffling if I want to drag it along. I think it would be a fairly large drag on the M17 on days where we actually do get to sail. Maybe we could take it on parts of the trip and not others. We also have a Achilles inflatable that we have used before (it stores in the port cockpit locker, just).

I'd really like to go without gas, as I hate gas. If this means more frequent stops, or going slower, I am ok with that. Our draft is a lot less than a 35 foot sailboat...we can even beach our M17 when needed. Perhaps we could find less current on the Ohio section by sticking closer to a shore. It looks like the distance you have to go upriver on the Ohio (from Cairo, Il to Paducah, KY) would be one of the more difficult sections. About 40nm and some friggen big barges!

 

[AnarchyJet]

I've mostly sailed the great lakes and been down to St Louis once. Just living on a 17' boat seems very challenging let along only having 40nm of aux. range. I'm sure you can step the mast by yourself on your boat. Still there isn't much opportunity to sail until you get on the Tenn-Tom. It's narrow, constant tow traffic and low bridges.
Your location says Seattle, where to you plan to start the Loop from? The issue I see on the upper rivers is a lack of places to charge. There simply isn't a lot going on in Illinois west of Chicago. Its either farmland or industrial.
My opinion is to at least triple your battery. I'd look at prebuilt 48v options or build yourself from 280ah cells. Then have some means to recharge. Maybe mount panels on the rails that can fold out. Build a bimini or arch off the back with some panels. Tow the dinghy with a rack and panels on it?

 

[IGBT]

I've mostly sailed the great lakes and been down to St Louis once. Just living on a 17' boat seems very challenging let along only having 40nm of aux. range. I'm sure you can step the mast by yourself on your boat. Still there isn't much opportunity to sail until you get on the Tenn-Tom. It's narrow, constant tow traffic and low bridges.
Your location says Seattle, where to you plan to start the Loop from? The issue I see on the upper rivers is a lack of places to charge. There simply isn't a lot going on in Illinois west of Chicago. Its either farmland or industrial.
My opinion is to at least triple your battery. I'd look at prebuilt 48v options or build yourself from 280ah cells. Then have some means to recharge. Maybe mount panels on the rails that can fold out. Build a bimini or arch off the back with some panels. Tow the dinghy with a rack and panels on it?

I just found out CIGS panels have gotten a lot cheaper and somewhat more efficient than a decade ago when I last looked. Now we are considering having about 600 watts of those onboard, to drape over whatever when the sun is out and the wind is dead. You can roll them up in a pretty tight bundle and toss them in the bilge area. A 200 watt panel only weighs 6 pounds. I watched a video where a guy shot one six times, put it in his swimming pool, then several months later gave it to a friend. It was battered and still putting out 195 watts (amazing for a 200 watt panel anywhere)

 

[yabert]

From our experience using a Torqeedo 1103 at full throttle (1100 watts), we know we should be able to achieve about 4.5 kts at that level.

Here some data I keep from experiment found online.
39' boat on the left and 25' + 32' boat on the right graph.
Based on this you could reach more than 5 knots with your motor.
I really like full electric sailboat
Thanks to share.