Solar Panel Output verse rating

[newhaul]

SV third day come on rich you want to ruin my winter entertainment. This debate is much more fun than last years mmgw thread.

[noelex 77]

Originally Posted by SV THIRD DAY

Now go back to debating calculations and I'll boil it down to reality:
If you have more room on your Boat for it...then add more Solar leave the calculations and BS for those that never leave the dock.

If you have room, more solar is always better.

Where these calculations help is deciding if your solar panels and controller etc is working satisfactorily. This was the OP's original question. Theoretical calculations also help predict how much power you will have when moving to a new location, although solar insolation figures (which is different to peak output) are more useful for this.

PS. I almost never tie to a dock. Solar provides 99% of our power and has done so for the last 8 years.

[rom]

Originally Posted by noelex 77

20th of June is the solstice so this is about when the peak output will occur.

Both of your tables are corrected for the latitude of Palm Beach, but one is for a tilted panel and one for a flat panel.

ok, we may not be talking about the same thing. I am trying to understand why you say that Stu's geometrical correction shall not be applied. Hence the two calculations I posted which actually show that if the panel stays horizontal today at Palm Beach we shall apply quite precisely the 87% correction coming from cos(z)...

[newhaul]

Becides all, that really matters is that my battery is in float (14.8 v or so) by about noon for about 9 months a year and shows the same by sundown the rest of the year.

[Paul L]

The good thing about absolutely maxing out the amount of solar that will squeeze onto your boat is that it will then not sail worth crap - so you motor and have plenty of power. Problem solved

[newhaul]

Originally Posted by Paul L

The good thing about absolutely maxing out the amount of solar that will squeeze onto your boat is that it will then not sail worth crap - so you motor and have plenty of power. Problem solved

I have maxed my boats solar and I have not noticed any difference between before the solar panel and now with it

[Paul L]

Originally Posted by newhaul

I have maxed my boats solar and I have not noticed any difference between before the solar panel and now with it

Maybe you need a bigger arch then to add another 1kw. Like that back of a Porsche.

[newhaul]

Originally Posted by Paul L

Maybe you need a bigger arch then to add another 1kw. Like that back of a Porsche.

I dont have an.arch I have a 100 watt panel mounted on the pushpit a full 1kw of panels has as much surface area as my whole deck.

[chala]

Originally Posted by sailorboy1

Still seeing 210-220W from my 290W panel under good conditions

I have a 40W solar panel. The power output of that panel is 2.31A at 17.3V as specified by the manufacturer.
The regulator output can reach at best 2.2A at 14.5V = 31.9W.
The heat losses, that contribute to global warming , between the output of the panel and the output of the regulator, include the heat losses of the blocking diode at the solar panel, of the wiring between the panel and the regulator, of the regulator and
equal 40 - 31.9 = 8.1W or 20.25 % of the panel output.
The heat losses in the wiring between the regulator output and the battery getting charged are negligible.

Originally Posted by sailorboy1

Still seeing 210-220W from my 290W panel

290W – 220W = 70W or 24.138 %.

Monitoring the output of the solar panel at the solar panel will give a good indication of how well the solar panel is performing.

Originally Posted by newhaul

float (14.8 v or so)

14.8V float?

[newhaul]

Originally Posted by chala

I have a 40W solar panel. The power output of that panel is 2.31A at 17.3V as specified by the manufacturer.
The regulator output can reach at best 2.2A at 14.5V = 31.9W.
The heat losses, that contribute to global warming , between the output of the panel and the output of the regulator, include the heat losses of the blocking diode at the solar panel, of the wiring between the panel and the regulator, of the regulator and
equal 40 - 31.9 = 8.1W or 20.25 % of the panel output.
The heat losses in the wiring between the regulator output and the battery getting charged are negligible.



290W – 220W = 70W or 24.138 %.

Monitoring the output of the solar panel at the solar panel will give a good indication of how well the solar panel is performing.



14.8V float?

Sorry 13.8v my thumbs are not working right today

[rom]

Originally Posted by epiic

I often get in the upper 680-690w range on my 700w array but I have the most expensive solar panels on the market (Solara S560M43 140w Power-M).

It's usually on a windy day so that keeps the solar panels nice a cold.

Hey, I just realized you were in florida like the OP and getting close to 100% out of your panels while the OP was only getting 60% ! That is a useful comparison, can you confirm your latitude ? I have the same sunpower cells and I am having excellent results too.

At least this thread could be useful to the community by showing which panels are good...

[a64pilot]

Originally Posted by sailorboy1

At the end of this first year of cruising I'll be deciding if it is worth it to add another panel. Right now it appears it is at least a 2 year pay back over running the generator.

Do you mind explaining the method you used to determine the payback?
Just curious, to me I think there are so many variables that it just isn't possible to calculate.
I'm attempting to get to a point to where day to day electrical needs are met by Solar, and the generator will be run in a perfect world only to make water and wash clothes and any other power intensive chores at one time.

[SV THIRD DAY]

Originally Posted by newhaul

SV third day come on rich you want to ruin my winter entertainment. This debate is much more fun than last years mmgw thread.

Lets really have some fun...

Amp * Hours

[newhaul]

Dont know his calcs but here is how it would do for me it costs 3 bucks per day to plug into power.in a guest marina. I paid 150 aprox for my entire solar panel and.controler setup so 50 days in a guest marina without plugging in. Not to mention that with the.panel I dont even need to go to the guest marina at all to charge batts. Which costs 25 bucks per day for my boat. ( you get the idea.) My system paid for itself in less than a month for my boat.

[newhaul]

Originally Posted by SV THIRD DAY

Lets really have some fun...

Amp * Hours

Ok I.figure I use less than 15 ah per day in the winter and even less.than that in the summer.