diy solar

diy solar

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

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
 
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.
 
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?
 
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
 
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.
 
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.
 
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.
 
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 ;)
 
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.
 
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.
 
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
 
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.
 
Keimor,
Fantastic job, and updates were appreciated. When did you calculate or adjust for trim after removing the engine and fuel?
 
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
 
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?
 
"Having a 10kw motor means you're looking at a ~208 amp draw at 48 volts (10kw/48v = 208a). With that, you'd draw down a 200Ah 48V battery in about 45 minutes of operation, or about 65 minutes for the 280Ah pack. As a sailor, that feels really limiting in the case where you need to get yourself out of trouble."

I always try to stay out of trouble. Good planning and diligently watching conditions pays off. Having a boat that can sail around the world also helps. I even sail my 30 ft 10,000 lb boat for 8 week with no motor one year.

Yes, you are correct but no sailor ever runs their diesel at max RPMs as no Tesla owner ever runs in ludecrist mode for very long besacue the battery will die in minutes or possibly the driver. As an example my diesel redlined at 2750 but the rule of thumb is run a diesel at ~75% or 2050 with would push my boat at 4.5-5 kms depending on current and relative wind direction. So to push my boat to hull speed (6.5 kms) it would use about 180Ah but if you look at the speed to power consumption curve I will only use about 60 A at 4.5-5 kts. Drop the speed to 3 kts and it only draws 20 A Which means I could run about 10 hours or 30 km. Throw in the solar again and it just increases the hours and distance.


What is your planned use for your boat with this electrical system?

The bottom line is I'm a sailor and the mechanical propulsion is an auxiliary. Last season I logged about 3,000Km less then 30 of those Km were motoring. On an average day I will run the electric motor 10-15 minutes at 5 kms which will use 15-20 Ah. My solar system with array 1 will provide about 32 Ah per day on average if I add the array 2 the average daily Ah will increase to 52. Also my electronic, stereo, etc... will consume about 10-15 Ah per day. So I will see if array 1 will be sufficient or if I need to add array 2.

I will update in the spring.
I installed an Electric Yachts System 10Kw PMAC motor and Sevcon controller in my Freedom 32 several years ago. Something I don't hear many mention when they talk about how much range you can get, and that is motor-sailing. When the wind dies and you're doing 1.5 to 2 knots and the boom and main are flopping around, and it's getting aggravating -- just add in tiny bit of motor. This is a game changer. You will now be moving your apparent wind forward of the beam and you have the best of both worlds. You'd be surprised that all of a sudden you're doing 3 to 4 knots now! If I had to hazard a guess I'd say you're doubling your motoring range.
 
Great explanation and with that boat is stiffer with a little self produced wind
Yes! Thank you for reminding me of that. As the boat starts moving slightly faster, you will get just enough apparent wind to stabilize the rolling and it feels very nice! Plus, you are still moving through the water quietly with the soft humming sound of the motor. One more funny thing. When you have an electric motor propelling your boat, with other engine-powered boats around you, you will realize that your entire engine-powered life you have been talking VERY loudly on your boat to get your voice over the engine sound. You will definitely hear a lot of loud conversations from people on the engine-driven boats.
 
Yes! Thank you for reminding me of that. As the boat starts moving slightly faster, you will get just enough apparent wind to stabilize the rolling and it feels very nice! Plus, you are still moving through the water quietly with the soft humming sound of the motor. One more funny thing. When you have an electric motor propelling your boat, with other engine-powered boats around you, you will realize that your entire engine-powered life you have been talking VERY loudly on your boat to get your voice over the engine sound. You will definitely hear a lot of loud conversations from people on the engine-driven boats.
Hey! I just noticed you're in Kenwood. Have a good friend that lives up there; Tommy Smothers! :)
 
Hey! I just noticed you're in Kenwood. Have a good friend that lives up there; Tommy Smothers! :)
Small world. He went to Redondo High with my older sister. I saw him last summer at a local event. I was just a kid when he and his friends would come over to our house and crack jokes. I thought that was what being a teenager was going to be like. Are you in the area?
 
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