Where does the power go

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Where does the power go

Postby Hastings » Wed Jan 09, 2019 3:17 pm

Lets say I have a CB between my array and the regulator. If I turn the breaker on, where does the power from the panels go?
Does it just go into space?
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Re: Where does the power go

Postby Gordon-Loomberah » Wed Jan 09, 2019 4:38 pm

It doesn't go anywhere if you turn it off (it goes to the load when on), because there is no power.

Open circuit = infinite (or close enough for the purposes here) resistance, so current is zero.
Zero X 45V or whatever panel voltage you have) = zero power.

All you have is a voltage potential, no power.
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Re: Where does the power go

Postby jaahn » Sat Jan 12, 2019 6:01 am

Hi Hastings :)
To expand on Gordons explanation. If you have your normal 240 power points and you do not plug anything into them,there is no power used even if switched to ON. The voltage is available but does not produce any flow of current unless there is a load connected to it.
A solar panel is the same. It can produce the voltage while the sun shines on it, but no current flows until you put a load there to allow the current to flow.
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Re: Where does the power go

Postby Solar@wind » Sat Jan 12, 2019 9:52 am

Important...

You should also always remember , the outlet or exposed cables from the panels or house supply are always energised and just waiting for a load . You must be aware, that YOU may be that unsuspecting LOAD !!!.

Always ,always, treat cables and power points,Etc as live ....

Just a gentle warning ,as the poster would not have asked the question ,if aware of the circumstances,,

I've been bitten 2 times,,,, first and hopefully ,last time.

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Re: Where does the power go

Postby australsolarier » Sat Jan 12, 2019 3:30 pm

Solar@wind
i am utterly amazed
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Re: Where does the power go

Postby Solar@wind » Sat Jan 12, 2019 4:05 pm

Australsolarier,

I am utterly amazed

please explain what you mean ?

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Re: Where does the power go

Postby australsolarier » Sat Jan 12, 2019 4:30 pm

Solar@wind,

well, to me, this might be different to other people, to me, when fiddling around with wires, i mean any kind, solar DC or mains AC, when doing work on the wires, it is common practice to isolate the power.

or if this is not possible, like connecting a battery, then one cable at a time with the other end of the cable fixed.

solar DC in particular you want to isolate, as that stuff arcs when shortened.
so yes, i either work on it after sunset. (caveat here, some grid inverters and charge controllers reverse and put dc out on the input) or climb up on the roof and unplug the particular string, after turning the breaker off for that particular string. and using the voltmeter to confirm 0 Volts for good measure. and instinctively do not touch both blank wire ends at the same time, no matter what.

so my amazement is that you got bitten twice. and then own up here openly. with hindsight maybe a good thing for newbies. and considering the title "where does the power go" maybe to your hands? (joke)
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Re: Where does the power go

Postby Hastings » Mon Jan 14, 2019 10:32 am

Thanks to everyone again. Great answers and I don't mind if someone admits "on here" that they made a mistake. I will when I do, so others can either take pleasure in scolding me or take advise not to do it again.
I really didn't know that its waiting for a load........which of course could be me ha ha.
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Re: Where does the power go

Postby Solar@wind » Mon Jan 14, 2019 11:04 am

Thanks Hastings,

It was supposed to be a polite safety message for the original poster and fellows like him..

I'm 74 , been in telecoms and radio for 55 years, since tech training school (PMG) in the 60,s...

Done possibly hundreds of safety courses + first aid. We worked on many live boards and equipment,-at times ..Yes, we had all the safety personal gear .

I might have got tickled once or twice or more, cannot remember ,and don't want to..

If you were to know me , I'm the most safety aware person ,,and actually was an instructor in safety ....

Once again , my message was polite,and highlighted to reinforce the safety of working on equipment that we here talk about to many unknown friends, and I want to keep it that way..

yep, 74, 55 years in the same industry,,, ,, not a bad innings?.

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