Thanks Lenny and friends, - but now more controller confusion !

[Marauder]

Hi Folks,

Thanks all for wind turbine feedback - it seems like a longer term investigation than I initially anticipated. First step will be to get it up and turning in some clean air, see if any power comes out . . . But clean air wont be till I get to Scotland in April.

One comment that stuck in my mind was Lenny HB - something like "you cant beat loads of Solar".

So that convinced me to buy more before I leave home. But the people I bought original panels from are saying that power outputs from different panels "have different profiles", and so I can't just buy one big controller and put all the power into it.

They are saying that each panel set needs to have it's own dedicated controller - and all controllers should feed direct onto the battery(s) independently of the others.

So there's my question - is that true ? must all the panels have separate controllers ?

I kinda have a feeling that folks with multiple roof panels probably don't have multiple controllers ( or a merangue? )

How can electricity have different profiles ?

Here's hoping someone can put me straight . . . .

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[stevewagner]

With domestic PV you have a controller for each array of panels.

 

[Lenny HB]

Providing all the panels are the same voltage you can connect them in pararell. If you need to use more than one controller the outputs can be paralleled but the inputs must remain seperate so you would have to arrange the panels in seperate banks.

 

[autorouter]

How can electricity have different profiles ?

For a battery, the voltage stays almost constant as the amps increases. So as you try to take more amps from the battery, the power increases too, until the fuse blows or the battery is damaged.

A solar panel isn't like that. As you increase the amps, the voltage stays almost constant at first, and the power increases. However beyond a certain point the voltage starts to drop quickly, and the power decreases. There is a point where the amps and voltage is 'just right', and the maximum possible power is being delivered.

The point of maximum power also depends on the sunlight power, which varies throughout the day, especially if it's cloudy. Some solar controllers can sense the volts and amps, and can track the maximum power point as it varies. They are called Maximum Power Point Tracker (MPPT) controllers. Different models of panel have different maximum power points, so if you connect two different panels to the same MPPT controller it will compromise, and some power will be wasted.

If the panels are the same make and model, they will have more or less the same maximum power point, so can be connected to the same controller.