Sailboat conversion from 14 hp Diesel to 10 Kw 48V electric motor

[jwelter99]

Here is a basic wiring diagram. Probably not enough detail. Please let me know and I'll get more from the supplier.

That works, the LEV200 is the contactor and one that is broadly used in the marine community, for both disconnects like in your motor system as well as for BMS applications.

I am very certain that the BMS can share control of that contactor so you get a simplified system. The hookup depends on which BMS you use.

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[keimor85]

Sorry, you interpreted what I wrote not as I intended.

Using common port BMS (which use FET's as the switching device) is not a good solution for high power electric motors as they tend to fail quite quickly. Most BMS manufactures specifically state they are not suitable for high current motors.

This then leads you to a BMS that uses contractor(s) for control. These usually have the contactor external to the BMS so you can use readily available high power contactors, and easily replace them. In these systems the main power does not flow via the BMS, but the BMS controls the contactor which enables/disables that flow.

Batrium, REC, and several others work this way. For a 12V marine pack like yours I would do a REC Active as it's easy and reliable but a bit higher priced than the China sourced units.

Thanks for the quick response. I have a 48V 16S 3.2V 202Ah pack not a 12V. Is the Batrium, REC still the answer?

 

[jwelter99]

Thanks for the quick response. I have a 48V 16S 3.2V 202Ah pack not a 12V. Is the Batrium, REC still the answer?

Batrium yes but REC I don't like their >4S units as they have a habit of cooking their balance resistors.

With 48V it is a bit more limited selection. Let me ask one of the electric conversion gurus at work tomorrow what's a reasonable 48V BMS for such an application.

 

[keimor85]

Batrium yes but REC I don't like their >4S units as they have a habit of cooking their balance resistors.

With 48V it is a bit more limited selection. Let me ask one of the electric conversion gurus at work tomorrow what's a reasonable 48V BMS for such an application.

Fantastic, thanks for the help

 

[jwelter99]

Fantastic, thanks for the help

No worries, I love electric boat conversions! Really cool to see these older boats get a new life.

 

[keimor85]

No worries, I love electric boat conversions! Really cool to see these older boats get a new life.

J,

Any info on the BMS that I should use on my application?

 

[jwelter99]

J,

Any info on the BMS that I should use on my application?

Sorry!

Two recommendations:

Orion Jr 2 BMS will do up to 16 cells.
Rec Q BMS will do up to 16 cells.

Both are good reliable products, but the Orion was better recommended. Some issues in the past with the balance resistors in the REC burning up but supposedly that has been solved.

 

[keimor85]

Sorry!

Two recommendations:

Orion Jr 2 BMS will do up to 16 cells.
Rec Q BMS will do up to 16 cells.

Both are good reliable products, but the Orion was better recommended. Some issues in the past with the balance resistors in the REC burning up but supposedly that has been solved.

Thank you I'll look into them

 

[keimor85]

I launched on May 5th with just 4 79Ah group 24 AGM batteries in series to provide 48 V. I already had three that were new last year so rather then delay my launch waiting for the 3.2V cells to arrive from China I bought the 4th battery. I waited to long to order my 3.2 cells from china. I was nervous with only 79Ah and being AGM's only about 45 Ah usable. As it turns out the AGM's actually work just fine for my use which is motoring 1/2 mile in and out of my harbor. I was even able to motor a few miles as well. This is how ever like running your car with just a few gallons in the tank and was a bit nerve racking especially when one day I had to motor into a 30 Knot wind which really sucks up the Ah.

The cells arrived mid may and I charged them up in 4 groups of 4 to 3.5V then put them in parallel and top end balanced to 3.65 and describe by Will. While I was charging the batteries I designed and constructed the battery box and platform. As mentioned on this site cell movement is a critical issue so I designed pressure plates with jack screws to load the batteries in the X and Y direction. see pics below. The box was epoxied, screwed and then glassed on the edges. My speed vs Amps has exceeded the manufactures estimates for my boat/hull design. Which means my range expectations have also been exceeded. The torque of the electric motor is incredible vs the diesel.

I went with 4 70W solar panels and a Victron 48V controller 110V/20A. Unfortunately the solar panel are exceeding the manufactures specs (I hate it when that happens ) and at max V are seeing 118V which faults out the controller so I had to use just three panels. The three panels have brought the batteries to full charge every day with the most Ah produced/replaced being 22Ah. The only problem with the solar panels is shading form the boom when on morning. So I have to move the boom to port or starboard when I leave the boat and depending on if the weather service was correct or not with there wind direction prediction I may not get max production out of the panels. I may get two more panels to ad to the one that I already have and another controller and set the two arrays up as port and starboard that way at least one will always be producing to the max and I won't have to worry about the weather service accuracy and moving the boom around.

Jwelter 99 - I am using the Dailey BMS and so far it is working fine but I have it designed so if/when if fails I can jumper around it until I get a new Orion or rec BMS. I also can just flip the switch and use the AGM batteries.

I am ecstatic about this conversion it has exceeded my expectations in so many ways.

 

[keimor85]

Possibly a bit when I get over 6 kts. My hull speed is 6.4 kts and there is almost always a stiff breeze in Nantucket Sound so I'm at hull speed often. We will see and I'll report after some time sailing. I will hopefully launch in early May.

Bubba thanks for the thumbs up. As far as regeneration I do get it in spurts but it is not enough to offset the amps needed to keep the contractor closed. I have a 2 bladed prop maybe with a 3 bladed prop it would work but I think that you really need a bigger boat with higher hull speed but then you would have a higher Kw motor so I'm not sure.

 

[nonoceb]

Nice setup guys!
If im doing same on my boat i will use the BMS as switch off only for charging/discharging when propulsion system is off then use BMS only as alarm when propulsion is ON.

Only put a big and very common rotative switch A, A+B, B, OFF switch :
- bms service wire on A (automatic disconnect by bms)
- LifePo4 gnd on B (manually switched ON)
- EV motor controller on common

Then put an alarm to surveil the GND presence in A, the user will catch an alarm when the bms triggered a low cell voltage but keep the ability to slow down the power on EV propulsion, safer! No need to buy a monster bms that handle inductive load at 400A

Just my 2ct

 

[Groscout]

Nice setup guys!
If im doing same on my boat i will use the BMS as switch off only for charging/discharging when propulsion system is off then use BMS only as alarm when propulsion is ON.

Only put a big and very common rotative switch A, A+B, B, OFF switch :
- bms service wire on A (automatic disconnect by bms)
- LifePo4 gnd on B (manually switched ON)
- EV motor controller on common

Then put an alarm to surveil the GND presence in A, the user will catch an alarm when the bms triggered a low cell voltage but keep the ability to slow down the power on EV propulsion, safer! No need to buy a monster bms that handle inductive load at 400A

Just my 2ct

Hey nonoceb, if I understand your idea correctly you would also be bypassing the loss one would get through a bms by connecting the propulsion system directly to battery? This makes me think of Will's video talking about using a relay or whatever and a small bms to turn off an inverter allowing large loads to be powered directly from the battery bank.

 

[keimor85]

Nice setup guys!
If im doing same on my boat i will use the BMS as switch off only for charging/discharging when propulsion system is off then use BMS only as alarm when propulsion is ON.

Only put a big and very common rotative switch A, A+B, B, OFF switch :
- bms service wire on A (automatic disconnect by bms)
- LifePo4 gnd on B (manually switched ON)
- EV motor controller on common

Then put an alarm to surveil the GND presence in A, the user will catch an alarm when the bms triggered a low cell voltage but keep the ability to slow down the power on EV propulsion, safer! No need to buy a monster bms that handle inductive load at 400A

Just my 2ct

OK I understand the theory. So I would run the motor with the switch in the A+B position and if the BMS shuts off the motor will still run on the B connection correct? How do I detect that the BMS (A) has discounted?

 

[nonoceb]

OK I understand the theory. So I would run the motor with the switch in the A+B position and if the BMS shuts off the motor will still run on the B connection correct? How do I detect that the BMS (A) has discounted?

you can drive a relay with normaly closed contact and wired the coil (12 or 48vdc) like this :
ground coil on A
positive coil on 48vdc battery+ (or +12vdc converter) or ignition contact

then normally closed contact of the relay like that :
one pin the B (rotative switch)
one pin on the alarm buzzer ground

alarm buzzer positive on a 48vdc battery+ (or +12vdc converter)

alarm buzzer will only working if switch is on B position and bms cutoff

 

[solarbot]

Yes, charging a DC battery with DC power input is exactly what solar charge controllers do, and they must be the most common DC charging application, so we have plenty to choose from, with history and reviews. The charge controller wouldn't care or know whether the 48V comes from a PV panel or a battery. But I wouldn't pay extra for MPPT for this application. That's Maximum Power Point Tracking and is a feature that takes advantage of PV panels being constant current devices; the charge controller varies the panel voltage to find the max power output in varying light conditions.

Going back and rereading this informative thread... my reason for suggesting MPPT is that they use an efficient buck converter as opposed to inefficient pwm for a cheap controller that generated extra heat and eats watt hours. Caveat: I am not an EE so my free advice is worth what you paid for it.

 

[Wibla]

Going back and rereading this informative thread... my reason for suggesting MPPT is that they use an efficient buck converter as opposed to inefficient pwm for a cheap controller that generated extra heat and eats watt hours. Caveat: I am not an EE so my free advice is worth what you paid for it.

I don't think he meant that you should use a PWM controller for this voltage conversion, but rather a dedicated DC-DC charger like a Victron Orion-Tr or similar. A 48/12-20 is $120, a 100/20 MPPT is $160, so it makes sense.

 

[solarbot]

I don't think he meant that you should use a PWM controller for this voltage conversion, but rather a dedicated DC-DC charger like a Victron Orion-Tr or similar. A 48/12-20 is $120, a 100/20 MPPT is $160, so it makes sense.

Understood. The question I raised is, would a solar controller make a decent substitute for a dedicated dc/dc converter for this particular use case, and maybe have advantages, such as a familiar interface, maybe manufactured in higher volume, therefore cheaper, more featureful and perhaps even more reliable. And maybe you already have one sitting around doing nothing, or soon will after the 48v system is built. I understand that both kinds of device are buck converters at heart.

 

[Wibla]

Sure, and there might even be some upsides to using a spare MPPT for that job, as a backup solar charge controller. As for the rest of your arguments, have a look at the Orion Tr compared to a SmartSolar MPPT. They're almost identical

 

[keimor85]

Just a quick update. After 3 months everything is working great. The 10Kw motor pushes the boat along fine with great torque right from the get go unlike a diesel or gas engine where you have to build up the rpm's to get into the good part of the torque curve.

The 202Ah LiFePo4 battery is performing well. The most Ah that I have used at one time in 80 which took the battery down to 60%. It took me 3 days to full charge it with the 3 70W panels. If you remember from earlier in the thread I decided to go with 4 70W panels but they were so efficient and exceed the manufacturers specs that they were going up to 117V and faulting out the Viltron 100V 30A controller so I had to eliminate one panel. I have since purchased a Viltron 150V 35A controller which allows me to add the 4th panel and increase from 210W to 280W. This of course makes charging a bit quicker. I'm still considering going with 2 solar arrays. I would set them up as one on the port side of the boom and one on the starboard side of the boom. I currently have to move the boom to port or starboard every evening dependent on the wind direction for the following morning. This eliminates the boom shading the array and maximizes the output. With a port and starboard array one side would always be maximized without me having to move the boom around. I would also dedicate one array to the 202Ah LiFePo4 battery and the other array to the 79Ah AGM battery. The array that goes to the 79Ah battery would be capable of switching to the 202Ah LiFePo4 battery when needed.

The Daly BMS is still working (no FET failures). I have only 32 hours on the motor and usually only run it at 40 or 50 A and I always rump up the Amps slowly. So we will see if the BMS holds up.

 

[pete c]

Keimor,

There's a "free" CD 30 sitting on a slip in Constitution Marina in downtown Boston that I went and looked at.
I know, nothing more expensive than a free boat, but she looks pretty solid. Although the interior is scary looking.
It has a shot Volvo and I was thinking, it would be perfect for what you've done.

Trouble is, it's a 100 miles away. Probably cost me over a grand just to get it in my yard. Then more than that for the divorce i'd likely go through for dumping that thing in my yard!!!

I have a friend with a Pearson 27 that may need repower. Am looking into cobbling together a system on the cheap rather than the nice Quiet torque setup you went with.

Did you look at going this route?

My guess is that such a system would work but might not give regen, which given his use, mostly LI sound daysails, shouldn't really matter.

One other question.

I have a nearly inexhaustible supply of 48v UPS battery packs. These packs consist of (4) 12v 7ah SLA batteries. I regularly replace these packs at work and my experience is that "bad" packs typically have 2-3 useable batteries, so I can cobble together complete packs. 8 of these packs in parralel would provide 230 ah were they all new batteries, which they aren't. So, maybe they have 150ah. I could add more packs, to get back to 200ah.

Do you think this is feasible or should I just break down and go LiIon? Are you familiar with the used Nissan Leaf packs?

If we do go edrive on the Pearson, I will likely give the UPS packs a try, since they cost me nothing more than wiring them all together.

 

[keimor85]

Keimor,

There's a "free" CD 30 sitting on a slip in Constitution Marina in downtown Boston that I went and looked at.
I know, nothing more expensive than a free boat, but she looks pretty solid. Although the interior is scary looking.
It has a shot Volvo and I was thinking, it would be perfect for what you've done.

Trouble is, it's a 100 miles away. Probably cost me over a grand just to get it in my yard. Then more than that for the divorce i'd likely go through for dumping that thing in my yard!!!

I have a friend with a Pearson 27 that may need repower. Am looking into cobbling together a system on the cheap rather than the nice Quiet torque setup you went with.

Did you look at going this route?

My guess is that such a system would work but might not give regen, which given his use, mostly LI sound daysails, shouldn't really matter.

One other question.

I have a nearly inexhaustible supply of 48v UPS battery packs. These packs consist of (4) 12v 7ah SLA batteries. I regularly replace these packs at work and my experience is that "bad" packs typically have 2-3 useable batteries, so I can cobble together complete packs. 8 of these packs in parralel would provide 230 ah were they all new batteries, which they aren't. So, maybe they have 150ah. I could add more packs, to get back to 200ah.

Do you think this is feasible or should I just break down and go LiIon? Are you familiar with the used Nissan Leaf packs?

If we do go edrive on the Pearson, I will likely give the UPS packs a try, since they cost me nothing more than wiring them all together.

Pete sorry for the late response. I haven't been on here for some time now.

I started out looking at the cobbling together route but was quickly overwhelmed with all of the options and had little to no knowledge of what I was doing at that time. The electric yacht was a good all in one solution. basically just add batteries and you are good to go. I also knew of another CD30 owner that have converted to Electric yacht and was very happy. One other supplier like Electric yacht is Thunderstruck. they are similar to Electric yacht but it appeared to me to be lower quality but was I think 30% or so less money.

I would absolutely give the UPS battery pack a try.

No knowledge of the Nissan packs

 

[keimor85]

Just a quick update. After 3 months everything is working great. The 10Kw motor pushes the boat along fine with great torque right from the get go unlike a diesel or gas engine where you have to build up the rpm's to get into the good part of the torque curve.

The 202Ah LiFePo4 battery is performing well. The most Ah that I have used at one time in 80 which took the battery down to 60%. It took me 3 days to full charge it with the 3 70W panels. If you remember from earlier in the thread I decided to go with 4 70W panels but they were so efficient and exceed the manufacturers specs that they were going up to 117V and faulting out the Viltron 100V 30A controller so I had to eliminate one panel. I have since purchased a Viltron 150V 35A controller which allows me to add the 4th panel and increase from 210W to 280W. This of course makes charging a bit quicker. I'm still considering going with 2 solar arrays. I would set them up as one on the port side of the boom and one on the starboard side of the boom. I currently have to move the boom to port or starboard every evening dependent on the wind direction for the following morning. This eliminates the boom shading the array and maximizes the output. With a port and starboard array one side would always be maximized without me having to move the boom around. I would also dedicate one array to the 202Ah LiFePo4 battery and the other array to the 79Ah AGM battery. The array that goes to the 79Ah battery would be capable of switching to the 202Ah LiFePo4 battery when needed.

The Daly BMS is still working (no FET failures). I have only 32 hours on the motor and usually only run it at 40 or 50 A and I always rump up the Amps slowly. So we will see if the BMS holds up.

Another update after 1 1/2 years everything is working great. I did add the second solar array of 4 60W panels so I now have 520W. I have taken the LiFePO4 batteries down to 20%DOD and everything works great.

The Daley BMS is still working fine after 82 hours on the motor clock and many thousands of hours on solar charging.

 

[Bbbbrass]

Keimor,
Fantastic job, and updates were appreciated. When did you calculate or adjust for trim after removing the engine and fuel?

 

[keimor85]

My final calculations showed that I was about 225 pounds lighter with the electric motor, batteries, panels, etc. She sits up about an inch higher in the stern because of this. I have been planning to put maybe 150lbs of lead in the bottom of the bilge but just never got to it. The weight in the bottom of the bilge should make her a bit stiffer due the the weight being significantly lower then the diesel, train and v-drive. Maybe i'll get some lead one of these days

 

[keimor85]

I have a new question. In several videos that I have watched lately I noticed that they are using a two pole breaker (one pole positive and the other pole negative) between the solar panels and the controller. I currently just have a single pole breaker on the positive wire. Should I be concerned?