Solar cells / panels

[Mads-Ejnar]

Hey.
I working on solar cell / panel project. Just for fun and to see how much power i can get. And in the end see if i can run my pc or something else on solar
But i can't find any info on what will be better:

1 big solar panel (12v) or

many small (12v) and set them in parallel?

I will think many small will be better, because if the shadow blocks some of them, the rest still makes power. Where on the 1 big, if some of it have shadow it wont make any power.
Well this is what i think but i don't know, and my google skills is not good enough to find any info about what is better.

 

So do any of you know what will be best?

And again, it's just a project for fun

[Thunderpup]

question, 

 

How far apart would these panels be from each other and/or the charge controller & power inverter?

 

If they are close together then having multiple ones would be pointless as they would each be affected from the same shadow at the same time.

If they are far apart then you run into problems where the power generated decays as it is being transferred along the cables.

While i am by no means an expert on solar, or electrical engineering in general, i am going to guess that having a single panel would be best and most likely most affordable when you take into account not needing as much wires and other components.

[cluelessgenius]

well im also no expert on solar panels but i can say more smaller ones would allow you to switch them out if some break or something. very similar to hard drives. getting 4x1TB drive instead of one huge 4TB drive allows you to account for failure. but again thats just my take on it.

[dalekphalm]

6 hours ago, Mads-Ejnar said:

Hey.
I working on solar cell / panel project. Just for fun and to see how much power i can get. And in the end see if i can run my pc or something else on solar
But i can't find any info on what will be better:

1 big solar panel (12v) or

many small (12v) and set them in parallel?

I will think many small will be better, because if the shadow blocks some of them, the rest still makes power. Where on the 1 big, if some of it have shadow it wont make any power.
Well this is what i think but i don't know, and my google skills is not good enough to find any info about what is better.

 

So do any of you know what will be best?

And again, it's just a project for fun

So just to clarify a few things:

 

1. Partial shadows will only block Solar Panels that don't have "bypass diodes" - these diodes (equipped on some panels, but not all) allows electricity to flow around cells that are blocked by shadow.

2. If you wire the entire array in parallel, small panels will work to bypass any shadows, but if you use any serial wiring, each "string" may be blocked or affected by even one shadowed panel - again, assuming "non-bypass" models.

 

I would try and set them up in an area not affected by shadows. I would also get as many and as big panels as you can get. If shadows are really a concern, then plan around shadow size. You want the largest panel size you can get away with that will cause the smallest number of panels to be blocked.

[Mads-Ejnar]

15 minutes ago, Thunderpup said:

question, 

 

How far apart would these panels be from each other and/or the charge controller & power inverter?

 

If they are close together then having multiple ones would be pointless as they would each be affected from the same shadow at the same time.

If they are far apart then you run into problems where the power generated decays as it is being transferred along the cables.

While i am by no means an expert on solar, or electrical engineering in general, i am going to guess that having a single panel would be best and most likely most affordable when you take into account not needing as much wires and other components.

Well not that far, less then ½ meter i think. and to the charge controller a few meters i think.

I have some big cables that should be ok for the task.

 

I will make the panels myself from cells, so i think the price will be close to the same. it's just if a need a few big cells to make 12v and 1 big solar panel og many small cells to make more panels at 12v.

8 minutes ago, cluelessgenius said:

well im also no expert on solar panels but i can say more smaller ones would allow you to switch them out if some break or something. very similar to hard drives. getting 4x1TB drive instead of one huge 4TB drive allows you to account for failure. but again thats just my take on it.

Thats right, did not think of that. easy to replace 1 small panel and cheaper, then 1 big, if for some reason 1 will get damage

[Mads-Ejnar]

1 minute ago, dalekphalm said:

So just to clarify a few things:

 

1. Partial shadows will only block Solar Panels that don't have "bypass diodes" - these diodes (equipped on some panels, but not all) allows electricity to flow around cells that are blocked by shadow.

2. If you wire the entire array in parallel, small panels will work to bypass any shadows, but if you use any serial wiring, each "string" may be blocked or affected by even one shadowed panel - again, assuming "non-bypass" models.

 

I would try and set them up in an area not affected by shadows. I would also get as many and as big panels as you can get. If shadows are really a concern, then plan around shadow size. You want the largest panel size you can get away with that will cause the smallest number of panels to be blocked.

I make the panels myself and i have bypass diodes i can add on them. 

i have around 4 small places where i can have solar panels. i in the morning 1 will be block by shadow and in the afternoon another will be block by shadows for some time before the rest will get in shadow. 
It's because i live in an apartment where i can use 4 windows that get alot of son.

[Thunderpup]

29 minutes ago, Mads-Ejnar said:

It's because i live in an apartment where i can use 4 windows that get alot of son.

You going to be mounting them inside the windows or outside?

If outside make sure you consult your apartment's rules and regs cause they may frown upon such things. 

[xentropa]

7 hours ago, Mads-Ejnar said:

Hey.
I working on solar cell / panel project. Just for fun and to see how much power i can get. And in the end see if i can run my pc or something else on solar
But i can't find any info on what will be better:

1 big solar panel (12v) or

many small (12v) and set them in parallel?

I will think many small will be better, because if the shadow blocks some of them, the rest still makes power. Where on the 1 big, if some of it have shadow it wont make any power.
Well this is what i think but i don't know, and my google skills is not good enough to find any info about what is better.

 

So do any of you know what will be best?

And again, it's just a project for fun

"1 big solar panel (12v) or

many small (12v) and set them in parallel?"

 

If you put many small "12 volt" solar panels in parallel, that's still going to be just 12 volts.

 

"I will think many small will be better, because if the shadow blocks some of them, the rest still makes power. Where on the 1 big, if some of it have shadow it wont make any power.
Well this is what i think but i don't know, and my google skills is not good enough to find any info about what is better."

 

I am sorry, that's incorrect.  If a portion of a solar panel is blocked, the unblocked portions will continue to produce power.

 

[dalekphalm]

Just now, xentropa said:

"1 big solar panel (12v) or

many small (12v) and set them in parallel?"

 

If you put many small "12 volt" solar panels in parallel, that's still going to be just 12 volts.

 

"I will think many small will be better, because if the shadow blocks some of them, the rest still makes power. Where on the 1 big, if some of it have shadow it wont make any power.
Well this is what i think but i don't know, and my google skills is not good enough to find any info about what is better."

 

I am sorry, that's incorrect.  If a portion of a solar panel is blocked, the unblocked portions will continue to produce power.

 

Only correct for certain types of solar panels - as I noted above, if they include bypass diodes for each cell, then yes, you are correct.

 

However, not all panels will necessarily have them. You'd of course need to check any manufacturer specifications to be sure.

[Mads-Ejnar]

3 hours ago, Thunderpup said:

You going to be mounting them inside the windows or outside?

If outside make sure you consult your apartment's rules and regs cause they may frown upon such things. 

It will be on the inside  so should not be any problem there
 

 

3 hours ago, xentropa said:

"1 big solar panel (12v) or

many small (12v) and set them in parallel?"

 

If you put many small "12 volt" solar panels in parallel, that's still going to be just 12 volts.

 

"I will think many small will be better, because if the shadow blocks some of them, the rest still makes power. Where on the 1 big, if some of it have shadow it wont make any power.
Well this is what i think but i don't know, and my google skills is not good enough to find any info about what is better."

 

I am sorry, that's incorrect.  If a portion of a solar panel is blocked, the unblocked portions will continue to produce power.

 

Yes i know, i need a 12v system, so have to be parallel  

3 hours ago, dalekphalm said:

Only correct for certain types of solar panels - as I noted above, if they include bypass diodes for each cell, then yes, you are correct.

 

However, not all panels will necessarily have them. You'd of course need to check any manufacturer specifications to be sure.

Well i thought a big panel will stop making power if there is shadow on it, because the voltage will drop. 
See the picture, If that's 1 big panel, if there is shadow on 1,A,B,C,D,E and 2,A,B,C,D,E that will be 40% of the panel and think the voltage will drop below 12v and stop making power.
But if you had 5 panels like every number is a panel, you lose 1 and 2 because of shadow, but 3-4-5 will still make power because each is making 12v.

Maybe i'm completely wrong and 1 big panel will still give power, just 40% less? 

[dalekphalm]

19 hours ago, Mads-Ejnar said:

It will be on the inside  so should not be any problem there
 

 

Yes i know, i need a 12v system, so have to be parallel  

Well i thought a big panel will stop making power if there is shadow on it, because the voltage will drop. 
See the picture, If that's 1 big panel, if there is shadow on 1,A,B,C,D,E and 2,A,B,C,D,E that will be 40% of the panel and think the voltage will drop below 12v and stop making power.
But if you had 5 panels like every number is a panel, you lose 1 and 2 because of shadow, but 3-4-5 will still make power because each is making 12v.

Maybe i'm completely wrong and 1 big panel will still give power, just 40% less? 

There certainly is a "useful cutoff" where the panel can't generate enough power to deliver useful voltage. Most panels will list this in their specs, often as a curved graph. You'll have to do research and see what the specs are for the ones you're intending on using.

 

But yes, if shadow is a concern, smaller panels *may* be somewhat useful. Again, though, it depends on shadow size, blockage, etc. There's no clear cut answer, it depends on your exact situation, which you'll have to measure out, etc.

[Thunderpup]

have you tried measuring exactly how much light each window gets on average during a day?

 

Reducing the problem down to cold hard numbers on a data table should help you resolve the quandary you are having.

 

 

[Mads-Ejnar]

15 hours ago, Thunderpup said:

have you tried measuring exactly how much light each window gets on average during a day?

 

Reducing the problem down to cold hard numbers on a data table should help you resolve the quandary you are having.

 

 

Not every window. but it's a good idea, i will try to set some solar cell in every window and log how much sun they get over 1 week and then see
I had only tried 1 window to see if i will get any sun or not, and i get alot of hours of good sun. But i will try and see how big the difference is between every window.