420: What size and number of solar panels needed

[StuM]

How much solar do you need? - None, you can always use other sources such as wind, generator, engine charging.

How much solar would save you from having to fire up a generator or your engines all the time? Depends on your power usage, but personally I would install as much as can fit.

On a Lagoon 420, you should be able to fit 1000 Watts or so fairly easily. To live and cruise in the tropics, that should be enough to largely avoid stuffing around with the alternative sources and not have to be a power miser all the time.

[casablanca]

We have 1000W on our 420. Good thing about the 420 is the space available on the bimini. When one day I replace the existing panels I will add as much as room permits.

Can't have too much solar. Panels are cheap. Power is free. But in winter and adverse conditions you are still going to need to supplement the solar input. That means motoring, shore power or a generator. The more solar you have the less frequently you have to turn to other sources.



Bob
CASABLANCA L420 #86

[PaulinOz]

I believe the factors that effect the size and qty of solar that you put on your cat are more to do with in no particular order.

1: How much space do I have to place the panels.

2: How many panels can I afford, remembering that the solar controllers, protection devices, cable, mechanical frame and inverter will cost more than the panels cost. Not to mention installation if you can not do it your self.

3: Am I going to live on the boat or just camp for short periods. Power equals comfort, you do not have to listen to noisy generators of any kind. You want a coffee turn the coffee machine on, slice of toast with that sir put the bread in the electric toaster and throw that gas stove top bread burner away. A hot shower perhaps, once we are back up to 100% SOC we then use the 240 volts from the inverter to heat up the water 60 liters approx 1 hour. Then sit down and watch a movie on the 46" Screen.

4: The electrical load on your boat will not decrease over time it will increase as you add more things.

5:The out put of the panels at mid day in full sun is not as relevant as is the output you still have at 0830 or 1630 on an overcast day. (I still see 20 to 40 amps @ 12 volts) My system in theory is capable of 150 + amps but the panels are not tracking the sun and are mounted horizontal so the reality is the best I have ever seen is 132 amps but the normal range is in the 60 to 100 amp range . Time of year, time of day, cloud cover and shadows will all degrade the output nothing will increase it other than more or bigger panels.

[EllisElectric]

Originally Posted by PaulinOz

The out put of the panels at mid day in full sun is not as relevant as is the output you still have at 0830 or 1630 on an overcast day. (I still see 20 to 40 amps @ 12 volts) My system in theory is capable of 150 + amps but the panels are not tracking the sun and are mounted horizontal so the reality is the best I have ever seen is 132 amps but the normal range is in the 60 to 100 amp range . Time of year, time of day, cloud cover and shadows will all degrade the output nothing will increase it other than more or bigger panels.

Are you saying that the 60 to 100 amp output of the solar translates to 60 amp-hours to 100 amp-hours of replaced battery capacity?

[PaulinOz]

Originally Posted by EllisElectric

Are you saying that the 60 to 100 amp output of the solar translates to 60 amp-hours to 100 amp-hours of replaced battery capacity?

No the 60 to 100 amp is the output current of the 2 x Flexmax 80 controllers going into the battery bank, that I typically see if I check the charge rate.

The 6 x panels are 327 watt each and rated output from them is 5.98 amps at 54.7 volts.

[Sailmonkey]

Originally Posted by EllisElectric

Are you saying that the 60 to 100 amp output of the solar translates to 60 amp-hours to 100 amp-hours of replaced battery capacity?

That's a spot quantity. Not amp hours


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[EllisElectric]

Originally Posted by PaulinOz

No the 60 to 100 amp is the output current of the 2 x Flexmax 80 controllers going into the battery bank, that I typically see if I check the charge rate.

The 6 x panels are 327 watt each and rated output from them is 5.98 amps at 54.7 volts.

I'm having a hard time understanding the solar system. From solar output to each Flexmax 80 controller (what does the controller do to the input from solar panels? What is the output from each the Flexmax 80 controller to battery bank?) How many amp-hours of capacity does 6 X 327 watt panels normally replace in spent capacity daily?

[Sailmonkey]

Originally Posted by EllisElectric

I'm having a hard time understanding the solar system. From solar output to each Flexmax 80 controller (what does the controller do to the input from solar panels? What is the output from each the Flexmax 80 controller to battery bank?) How many amp-hours of capacity does 6 X 327 watt panels normally replace in spent capacity daily?

What "electric" does your username refrence?


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[PaulinOz]

Originally Posted by EllisElectric

I'm having a hard time understanding the solar system. From solar output to each Flexmax 80 controller (what does the controller do to the input from solar panels? What is the output from each the Flexmax 80 controller to battery bank?) How many amp-hours of capacity does 6 X 327 watt panels normally replace in spent capacity daily?

what does the controller do to the input from solar panels?
The Panels output in round figures 50 volts DC at 6 amps
The controllers convert this into 12 volts at 25 amps.

How many amp-hours of capacity does 6 X 327 watt panels normally replace in spent capacity daily?

This question is like asking how long is a bit of string.

How much sun? winter or summer makes a large difference.
How long a day?
How much shading?
What is the temperature?
What angel are the panels to the sun?

All of the above will effect the output of a solar Panel array.

So to come up with a typical output, first you need to specify a normal day.

[EllisElectric]

Originally Posted by Sailmonkey

What "electric" does your username refrence?


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Electric that does not work with solar, batteries and associated equipment

[Sailmonkey]

Originally Posted by EllisElectric

Electric that does not work with solar, batteries and associated equipment

Ok,
An array that outputs 100 amps for an hour will put 100 ah into the batts.
200 amps for 30 mins is also 100 ah.

Controller answered above.


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[EllisElectric]

Originally Posted by Sailmonkey

What "electric" does your username refrence?


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What "monkey" does your username reference? The monkeys I see at the zoo always want show their behinds

[Sailmonkey]

Originally Posted by EllisElectric

What "monkey" does your username reference? The monkeys I see at the zoo always want show their behinds

The questions you're asking are pretty basic, so I thought I'd see if elliselectric was a band name before I explained ohms law.
This monkey won't fling poo unless repeatedly jabbed.


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[Bulawayo]

Originally Posted by 1tviere

I am putting solar panels on my 420 which I intend to live aboard and cruise in the Caribbean. How much solar do I need and where is a good place to get what I need?

We added 3x 345 watt Kyocera panels to our cat which already had 2x110w panels when we bought the baot. These power the whole boat very comfortably and we are fairly well kitted out. I would suggest over size your solar array as you'll be adding equipment from time to time and you have no way of knowing, at this time, of how shading shall affect the panels or of how much sun you'll actually be getting. Solar panels are not an exact science as there are so many variables.

[Bulawayo]

Originally Posted by 1tviere

I am putting solar panels on my 420 which I intend to live aboard and cruise in the Caribbean. How much solar do I need and where is a good place to get what I need?

Last posting vanished..........we have 3x 345 watt Kyocera panels plus the boat came with 2x 110 watt BP panels. This runs a pretty well kitted out cat. There is no exact science involved despite what may be claimed. There are mounting location issues which may lead to shading, plus you have no way of knowing just how much sun you shall receive - and obviously geographical location is important. You need to consider also that your batteries are big enough and to have a decent MPPT controller. Also, how shall you wire the panels - series or parallel - we always opt for parallel to reduce potential losses from one panel being shaded etc.