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18 kWh System Realistic? Liveaboard / Workaboard

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svmare

New Member
Joined
Apr 17, 2024
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8
Location
Coastal
Currently the plan is eight 400W+ Panels. Three 460Ah batteries. Beyond this I'm hoping for guidance on what inverter, charge controller, other parts. I might need for a reliable system.

Past utility bills show monthly utilization from 300 kWh to 500 kWh, daily estimate 9.68-16kWh

High power draw items include,
Cooktop - 1800 watts. Probable use, two to three hours max daily.
1000W PC - Graphics and design + Monitor 300W Estimate three to five hours high load use.
Laptop + Monitor x2 400W estimate = Used for the full 9 to 5
Starlink 75-100W = Continuous
Air Conditioning, small instant waterheater (These two are unknowns at this point, unpurchased - Efficient recommendations welcomed)
 
Voltage and chemistry of the battery? Voltage, hz, and phases of your grid, or what you want. On grid or off grid? Do you want to export to grid? Cheap or high quality?
 
This system will be entirely offgrid, other than potential charging via the boats engine alternator. Preference to high quality, the system needs to generally just work and not require troubleshooting of gremlins.

LiFePO4 12.8 V, was looking at these https://www.litime.com/products/litime-12v-460ah-lifepo4-lithium-battery-250a-bms-5888wh-energy and https://www.epochbatteries.com/prod...4-battery-ip67-heated-bluetooth-victron-comms

Panels https://signaturesolar.com/canadian-solar-400w-mono-crystalline-solar-panel-black-cs6r-400ms-hl/
  • N-type TOPCon Bifacial
  • Solar Cell: 108-Cell Mono Crystalline
  • Pmax: 400W
  • Operating Voltage: 30.8V
  • Operating Current: 13.85A
  • Open-Circuit Voltage (Voc): 36.8V
  • Efficiency: 20.5%
As far as voltage, hz, and phases of the grid, I would assume single phase since its such a small system... but three phase might work out better with panel groups potentially being shaded by sails underway. Hz, i know that starlink requires a pure sinewave.. other than that its completely new territory to me.
 
Not sure what size boat this is, but 8 400wt panels will cover about 170-190 sq ft. Will also weigh about 400lbs plus panel mounting hardware. And an alternator is not going to supply more than limited "boost" to this system. If you have room for that many cells, you likely have room for a portable generator. In dock I would consider an ATS and using the shore grid to keep the batteries above 50-70% when in dock - at least early on while you are working out the bugs and testing your actual capacity.
 
Sail or power?
I ask as two different issues come to mind that you need to consider.
Shading is difficult on a power boat, more so on a sail. Need to consider in design. Could almost end up with a CC per panel.
Not really economical to run a power boat engine to charge (hours, fuel, etc). A sailboat ehhhhhhhhhhh.

3200w is going to be hard to keep up that load. Either more panels or a small generator to supplement. If the water heater and air-conditioner are not in your daily totals now.... not even close for 3200w. Seat of the pants, your daily load stated seems high for the usage you detailed.

Hard to find nowadays. but if you are flat mounting the bifacial will not give you any benefit, only an increase of weight. Some say worse that the extra heat created will reduce efficines.

At 1300+ AH any reason you are not looking at 24v or 48v?
 
This is a 35 foot sailboat with a raised pilothouse, the panels will essentially be on hard davits, bimini, dodger, below the boom situation. There's potential for expansion if I get creative with some kind of folding mounting hardware @SparkyGage I could probably swing a generator if needed. @MrThisIsME daily load is estimated from previous power bills and could be complete BS. I am all ears to 48v ideas, just have to plan for dc to dc converters down to 12v for the blue sea systems panel and instruments. And an inverter for the 110-120 v gadgets.
But of course I don't want to over purchase on the battery end when there's no chance that the array will charge them efficiently.

These are estimated numbers for an AC unit
  • Model: ECD16K-410A part number: 207500316
    • Voltage: 115V AC
    • Frequency: 60 Hz
    • Full Load Amps - Cool: 10.5 @ 115V
    • Full Load Amps - Heat: 13.7 @ 115V
    • Locked Rotor Amps: 62.0 @ 115V
    • Dimensions: 13.50" H x 20.00" W x 11.25" D
    • Net weight: 64 lbs

      Model: ECD6K-410A part number: 207500306
      • Voltage: 115V AC
      • Frequency: 60 Hz
      • Full Load Amps - Cool: 4.6 @ 115V
      • Full Load Amps - Heat: 5.9 @ 115V
      • Locked Rotor Amps: 36 @ 115V
      • Dimensions: 11.25" H x 16" W x 9" D
      • Net weight: 38 lbs
 
svmare said:
This is a 35 foot sailboat with a raised pilothouse, the panels will essentially be on hard davits, bimini, dodger, below the boom situation. There's potential for expansion if I get creative with some kind of folding mounting hardware @SparkyGage I could probably swing a generator if needed. @MrThisIsME daily load is estimated from previous power bills and could be complete BS. I am all ears to 48v ideas, just have to plan for dc to dc converters down to 12v for the blue sea systems panel and instruments. And an inverter for the 110-120 v gadgets.
But of course I don't want to over purchase on the battery end when there's no chance that the array will charge them efficiently.
Click to expand...

Ok, so are you planing to:
1) Live aboard? Solo? Couple? Family?
2) 2-3 days out of port?
3)1-2 weeks out of port?
4) I'm sailing away, set an open course for the virgin sea, cause I've got to be free, free to face the life that's ahead of me..... (and are you old enough to get that reference?)

I doubt "over buying" battery will be be a problem (available space on a sailboat will keep you in check). The consensus here seems to be that for any large load, higher voltage=greater efficiency. There is also some savings as most 100ah 48v batteries I've priced cost less than 4 100ah batteries.

Think of your battery usage like this:
Day 1) Leave port fully charged 100% (FC) from solar and shore power. During the day, the solar may keep it topped up if your needs underway are minimal. If the motor runs and feeds the system, then you get that as well.
Day 2) You wake up with batteries down by whatever you used over night. Is that down 10%? 25%? 50%? Depends on the bank size and your usage. Sun starts charging (hopefully) and if you are using less than you are collecting, state of charge goes back up. You run the engine some and have it boost it as well. Was it an overcast day? Were the panels shaded by the sails part/most of the day?
Day 3) See day 2.
....
Day ??) Batteries flat. You do without and/or you find a charging source. How long out this is will depend on how many batteries, and what YOUR loads are. If you optimize your usage and charging, you may never see this day.

24v-48v to 12v:
Whatever system you go with, you can add DC to DC converters (note I used the plural). Put one near the fuse panel for the helm that is rated for the draw of the helm. Put an AB switch between the fuse panel and the the (A)DC-DC and the (B)12v main system from the motor batteries. Put a separate DC-DC at the galley. Remember: anything you can run/charge/use DC will have less of a loss in most cases.

I hope this doesn't you. My dad had a houseboat and we would go down Sunday night, or on the 4th of July, go out the next morning, and park on a island on the lake. We would run the generator for an our in the AM, an hour around noon, and an hour at 7ish. That would top up the batteries (FLA), cool down the fridge (AC Only) let us run the microwave if needed, AND run the AC if needed (July in Arkansas, it was always needed). We would come back in Friday-Saturday noon after having been there 3-5 days. I wondered back then about building a solar canopy and how much we could run off of it.

(and what boat is this? The only one in this class I've been on was a really nice Costa Rica 38')
 
Seems you need 1 system to run the 120vac loads of your office, kitchen and A/C. Then another to run the 12vdc of a live aboard boat. You didn't mention anything about refrigerator/freezer, electric head, water pump and ect. All usually are 12vdc and run off the house bank. Then there is the engine start and possibly windlass, bowthruster, and electric winch(s). Those are ususally 1 or multiple dedicated battery bank.
We need to know the existing systems of the boat.

Without those details initial thought is 3500w inverter generator and 48vdc battery bank into a dual victron 3k inverters (or single 5k). This will power all the 120vac. You will have to run the generator when the A/C is needed.
Run whatever config of panels and SCC to to the 48vdc battery. Then 48-12 dc to dc charger to a 12vdc house bank to run boat stuff. Leave the engine and alternator alone with a dedicated FLA batter.
 
Very quick math here(I might have made a mistake, but I think not):
1800W cooktop, 3 hours per day, / 12V = 450 Ah
1300W PC, 5 hours per day = 541 Ah
400W Laptop, 9 hours = 300Ah
Starlink 24/7 = 100Ah
Excluding AC and hotwater for now.
That is 1391Ah. To get that need at least 4100W of solar on a typical bright day. You are planning 3200W of solar, so right there, your plan won't work. And that is not counting rain days, or A/C and hot water, which are both very large draws. Especially A/C.
So what do you need?
I would want to plan for at least 3 days of extra battery to get through rain days. So the minimum battery is going to be 4173Ah, or 8-9 480Ah batteries. And solar should be enough to power 24 hrs worth of your use, plus extra to be able to bring the batteries back up after some rain days. So, while the minimum solar not including rain days would be 4100W, you should really be looking at 8kW.

Throw A/C in there, and your utility bill seems close. But your 3.2kW solar is far from it. Generally when living on a boat, power usage needs to be kept very minimal. Consider what you really need, vs what you want. Graphics design, while really great on a big machine with lots of GPU and a fancy monitor, can also be done on a modest laptop, with no external monitor. Consider not having extra laptops working as well. Consider cooking and hot water with propane. Starlink has a standby mode for when not actively using it, and humans are capable of acclimating to the heat an not needing A/C, at least in the popular cruising areas.
 
SparkyGage said:
Ok, so are you planing to:
1) Live aboard? Solo? Couple? Family?
2) 2-3 days out of port?
3)1-2 weeks out of port?
4) I'm sailing away, set an open course for the virgin sea, cause I've got to be free, free to face the life that's ahead of me..... (and are you old enough to get that reference?)

I doubt "over buying" battery will be be a problem (available space on a sailboat will keep you in check). The consensus here seems to be that for any large load, higher voltage=greater efficiency. There is also some savings as most 100ah 48v batteries I've priced cost less than 4 100ah batteries.

Think of your battery usage like this:
Day 1) Leave port fully charged 100% (FC) from solar and shore power. During the day, the solar may keep it topped up if your needs underway are minimal. If the motor runs and feeds the system, then you get that as well.
Day 2) You wake up with batteries down by whatever you used over night. Is that down 10%? 25%? 50%? Depends on the bank size and your usage. Sun starts charging (hopefully) and if you are using less than you are collecting, state of charge goes back up. You run the engine some and have it boost it as well. Was it an overcast day? Were the panels shaded by the sails part/most of the day?
Day 3) See day 2.
....
Day ??) Batteries flat. You do without and/or you find a charging source. How long out this is will depend on how many batteries, and what YOUR loads are. If you optimize your usage and charging, you may never see this day.

24v-48v to 12v:
Whatever system you go with, you can add DC to DC converters (note I used the plural). Put one near the fuse panel for the helm that is rated for the draw of the helm. Put an AB switch between the fuse panel and the the (A)DC-DC and the (B)12v main system from the motor batteries. Put a separate DC-DC at the galley. Remember: anything you can run/charge/use DC will have less of a loss in most cases.

I hope this doesn't you. My dad had a houseboat and we would go down Sunday night, or on the 4th of July, go out the next morning, and park on a island on the lake. We would run the generator for an our in the AM, an hour around noon, and an hour at 7ish. That would top up the batteries (FLA), cool down the fridge (AC Only) let us run the microwave if needed, AND run the AC if needed (July in Arkansas, it was always needed). We would come back in Friday-Saturday noon after having been there 3-5 days. I wondered back then about building a solar canopy and how much we could run off of it.

(and what boat is this? The only one in this class I've been on was a really nice Costa Rica 38')
Click to expand...
@ SPARKYGAGE I’m (Liveaboard couple) sailing away, to see the entire east coast of the USA on anchor throughout. Shooting for only marinas when there’s an emergency. And while I knew the song (Reminds me of times driving with my dad on the oldies channel in the 90s :D I’d never actually paid attention to the lyrics)

Honestly the boat has room for 8+ 48v 100AH batteries (CAL 35 CRUISE) has an elevated floor with huge diesel tanks, so I’ve debated removing one for the batteries to keep the weight lower to offset my apparently potential 10 400w panels which is just ridiculous :D My wallet of course prefers to not do 8 batteries.

Currently have an isolating switch for the AGM starter battery and the old house bank. Have a little auxiliary solar charger for it, I might just keep it isolated until I’m more aware of what I’m doing.

https://www.bluesea.com/products/8086/AC_3_Sources_+_12_Positions_DC_Main_+_19_Position

This panel controls all of the DC and AC connections on the boat, they’re all breakers. So I’d imagine I’d need one DC to DC to supply load to the DC side of the panel. If I’m off tell me.

It’s wild to imagine how far technology could go without too much intervention, we need another new world :D
 
AnarchyJet said:
Seems you need 1 system to run the 120vac loads of your office, kitchen and A/C. Then another to run the 12vdc of a live aboard boat. You didn't mention anything about refrigerator/freezer, electric head, water pump and ect. All usually are 12vdc and run off the house bank. Then there is the engine start and possibly windlass, bowthruster, and electric winch(s). Those are ususally 1 or multiple dedicated battery bank.
We need to know the existing systems of the boat.

Without those details initial thought is 3500w inverter generator and 48vdc battery bank into a dual victron 3k inverters (or single 5k). This will power all the 120vac. You will have to run the generator when the A/C is needed.
Run whatever config of panels and SCC to to the 48vdc battery. Then 48-12 dc to dc charger to a 12vdc house bank to run boat stuff. Leave the engine and alternator alone with a dedicated FLA batter.
Click to expand...
@AnarchyJet You’re right I did forget a few load items, we’re looking at a
Fridge 12v 60Wh potentially two of them.
Manual Pump head.
Manual Windlass for now
Water pump 12V 5A.
Watermaker 12V 9A infrequent use
Navigation Lights 4.5W
Anchor light 12V 1.5W
Navigation Instruments
Autopilot 12V 18-36W
VHF Radio 12V 5A
Radar
House Lights
Hella fans
Engine battery is AGM isolated with separate auxiliary solar charger.
 
wholybee said:
Very quick math here(I might have made a mistake, but I think not):
1800W cooktop, 3 hours per day, / 12V = 450 Ah
1300W PC, 5 hours per day = 541 Ah
400W Laptop, 9 hours = 300Ah
Starlink 24/7 = 100Ah
Excluding AC and hotwater for now.
That is 1391Ah. To get that need at least 4100W of solar on a typical bright day. You are planning 3200W of solar, so right there, your plan won't work. And that is not counting rain days, or A/C and hot water, which are both very large draws. Especially A/C.
So what do you need?
I would want to plan for at least 3 days of extra battery to get through rain days. So the minimum battery is going to be 4173Ah, or 8-9 480Ah batteries. And solar should be enough to power 24 hrs worth of your use, plus extra to be able to bring the batteries back up after some rain days. So, while the minimum solar not including rain days would be 4100W, you should really be looking at 8kW.

Throw A/C in there, and your utility bill seems close. But your 3.2kW solar is far from it. Generally when living on a boat, power usage needs to be kept very minimal. Consider what you really need, vs what you want. Graphics design, while really great on a big machine with lots of GPU and a fancy monitor, can also be done on a modest laptop, with no external monitor. Consider not having extra laptops working as well. Consider cooking and hot water with propane. Starlink has a standby mode for when not actively using it, and humans are capable of acclimating to the heat an not needing A/C, at least in the popular cruising areas.
Click to expand...
Yep, it's looking like I'll try to squeeze ten panels onto this boat :D and a generator to supplement for the rain. There's just no way to fit 20 panels AT ALL lol. Yeah, AC might have to wait.
 
The 18Kpv is serious overkill for that amount of load.
Also the tiny bit of PV is mismatched for that inverter.
I don’t know the panel specs or how your string configuration will be done but make sure the Vmp is enough to start the inverter.
 
https://static.csisolar.com/wp-cont...131418/CS-Datasheet-HiKu6_CS6R-MS_v2.0_EN.pdf spec sheet for the panels. I figure two series of four and one series of three. The calculator is spitting out MPPT 250/85 Tr VE.Can

Money is not really an issue so if a certain charge controller gives more capability for different string combinations it might be preferable.

Orion-Tr 48/12-30 (360 W) for the DC to DC https://signaturesolar.com/victron-energy-orion-tr-48-12-20a-240w-isolated-dc-dc-converter/

Am I missing anything and do these look like good choices? Open to the best recommendations
 
How do you think you can install that much solar on a 35ft sailing boat and still have a viable sailing boat? 1000w is about as much as you see on most sailing yachts up to about 45ft. My 44ft sailboat has 920w.
Your loads are also nothing like reality. Why do you think you will be cooking for 3 hours per day? We use lithium batteries and induction cooking. The cook period for 2 liveaboards is nothing like 3 hours per day. The induction cooker load is not continuous either. Below 1000w, most induction cooker cycle between nothing and power. You will not be running the cooker flat out.
 
@TimE so I seem to be way off base with my assumptions of use. Can you let me know your hardware setup so I can wrap my mind about something realistic.
 
Think energy audit - you desperately need to perform one before you spend a dime.
 
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