Good advice. Regarding the panels, my poorly worded question was what size of panels and their arrangement. I was simply thinking of three large panels, say 350-400W each, arranged in series. Unfortunately finding a 400W panel that is under 72” long is a challenge. I understand the concept of matching the V and I of the controller to the panels. But is there an advantage to choosing more smaller panels and arranging them in series/parallel to maximize the wattage output? I can reasonable go 5.5’ x 12’ total and still have some walking space around the panels.
Solar enthusiast trying to replace diesel generator on yacht
- Thread starter Awsmits
- Start date
It is a trade off....
Small panels will allow you to maximize the coverage of whatever area you have available.
Big panels will get you more power as less wastage of space with frames, etc, etc.
Ideally your area is the right shape to take several large panels and cover it 100%, but if not then smaller panels might be the ticket.
With 66 * 144 you can probably get several REC Alpha 380's in a row which would work. They are about 66 inches long.
The 380W's are 67.5" by 40", so you can fit 3 in 67.5" by 120". If you can go to 13' and some change, you can fit 4 of them, which would give an "easy" 2s2p configuration for most MPPT controllers at <100Voc and 22A Isc. This also allows you to run a 48V battery bank without having to worry about your array voltage.
If you are concerned about shading and you can't stretch it to 4 panels, you'd probably find yourself in a 3p configuration, and then your Vmp is under Vbat (at 48V), which means going to a boost MPPT controller, those are not as common. For a 24V battery this won't be a problem.
If you are concerned about shading and you can't stretch it to 4 panels, you'd probably find yourself in a 3p configuration, and then your Vmp is under Vbat (at 48V), which means going to a boost MPPT controller, those are not as common. For a 24V battery this won't be a problem.
That depends on:
1) The battery voltage you decide on. You want panel voltage at least 5V above battery voltage or a Victron SCC will not start charging.
2) The SCC you select (to stay inside voltage limit).
Or 3S using a 150V input SCC.
Simi 60
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If it at all helps with sizing we have been living aboard constantly cruising for over 5 years now - never been into a marina so no shore power.
Main 240v loads come from 3 fridge freezers one 550 litre 2 door, a 120 litre bar fridge and same size freezer all running 24/7.
Occasional use of 240v pressure cooker - once a week for an hour
Very occasional use of 240v microwave - once a month for 10 minutes
2 Lenovo tiny PC running 24/7, screens turned off when not in use.
Daily we manually turn on and off the 240v 180 litre hot water system - we do that either with Genset running or plenty of sun
In the future, I would like to consider a 240v induction cooktop.
Everything else, pumps, lights are 24 or 12v
To power this we currently have.
Cheap 8 X 220ah AGM @ 12v joined into 24v
Charging is provided by.
9 x 250 watt Jinko solar panels on flat roof running through a Midnite classic 150 mppt
A victron 5000va 120 amp inverter charger
A 7.5 diesel Genset only used on cloudy days and for a short head start in winter
According to the Victron Battery Monitor the batts never got below 80% SOC (20% used)
And on a sunny day were at 100% again by midday
After 5 years the cheap AGM are showing signs of fail so now going LFP bank at same size ( 3 x 24v @ 280ah each)
Main 240v loads come from 3 fridge freezers one 550 litre 2 door, a 120 litre bar fridge and same size freezer all running 24/7.
Occasional use of 240v pressure cooker - once a week for an hour
Very occasional use of 240v microwave - once a month for 10 minutes
2 Lenovo tiny PC running 24/7, screens turned off when not in use.
Daily we manually turn on and off the 240v 180 litre hot water system - we do that either with Genset running or plenty of sun
In the future, I would like to consider a 240v induction cooktop.
Everything else, pumps, lights are 24 or 12v
To power this we currently have.
Cheap 8 X 220ah AGM @ 12v joined into 24v
Charging is provided by.
9 x 250 watt Jinko solar panels on flat roof running through a Midnite classic 150 mppt
A victron 5000va 120 amp inverter charger
A 7.5 diesel Genset only used on cloudy days and for a short head start in winter
According to the Victron Battery Monitor the batts never got below 80% SOC (20% used)
And on a sunny day were at 100% again by midday
After 5 years the cheap AGM are showing signs of fail so now going LFP bank at same size ( 3 x 24v @ 280ah each)
Out of curiosity what is your 240V loads like for the 3 refrigerators?
From what you've given it seems you are using about 180Ah a day which seems very good.
Simi 60
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- Jul 10, 2021
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- 159
From sunset to sunup is usually about 180ah @ 24v so says the Victron device.
Haven't done an accurate refrigeration load check but
Full party mode at night there is no more than 20amp draw
Get up in the AM for any reason and there is around 4 amp draw, a fridge cuts in and it'll bounce up for a few seconds and drop back to 8 amp, if a second one cuts in it bounces up again but drops back around 12 amp
I'm new here, and I want to go outside the box a little. The argument about solar panels not generating rated capacity because of poor orientation is very valid. What about adding into the mix a small wind generator that you could set up while at anchor? I'm thinking about something in the 500W range, that would be easy to handle.
Where would you put it? Wind needs height to function, and height on a boat can be an issue.
Good idea, wind generator, but I’ve never been keen on them. Models I’ve seen make a lot of noise, but maybe this aspect has been improved upon. I think for my modest AC loads needed, 1200W of solar plus a high output Balmar generator should keep my batteries happy.
newbostonconst
Solar Enthusiast
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- Sep 24, 2019
- Messages
- 1,004
I hear the wind generators on sail boats are loud and don't produce....but, let us know how it works.
We've installed a few even with strong recommendations against doing so, and in 95% of the cases they get removed within 2 years of being installed.
They are noisy (even if working well, but tend to start to squeak after a few months in the salt air), an eye sore, tend to kill birds that end up splattered across your deck/hull, and do not produce enough to warrant these issues.
They are noisy (even if working well, but tend to start to squeak after a few months in the salt air), an eye sore, tend to kill birds that end up splattered across your deck/hull, and do not produce enough to warrant these issues.
Common knowledge of the issue, on land or sea.
Study: Wind Farms Kill Off 75% Of Buzzards, Hawks And Kites That Live Nearby
Wind turbines are the world’s new ‘apex predators’, wiping out buzzards, hawks and other carnivorous birds at the top of the food chain, say scientists. A study of wind farms in India found that pr…
wattsupwiththat.com
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