300w solar panels low voltage reading

[jenevers]

Sunny day here but only getting 14.2v this morning from my 3 x 100w, in series, wired panels, normally about 57v in good sunshine.

12.1v and only 4.8A going into batteries,usually around 17A, and only 32% state of charge.

Batteries (720Ah) don't need topping up.

What's going on???

[Paul's Nulife4-2]

check rhe connection between the first and second pannal,

Have you got your inverter on with a load being drawn,

[Phil Ambrose]

check rhe connection between the first and second pannal,

Have you got your inverter on with a load being drawn,

I'd go one step further than Paul and check all your connections. (Donut anybody?)

Phil

Edited June 28, 2015 by Phil Ambrose

[jenevers]

Panic over.

Now reading

47v

13.1v 15.4A

61% SOC

I haven't done anything. Strange.

[Paul's Nulife4-2]

It's the Mischievous Pixies at work !.

Glad it seems ok now.

[Nightwatch]

The wrong type of sun,perhaps.

[jenevers]

The wrong type of sun,perhaps.

Yes. Early morning sun. It was gloriously sunny but maybe too low in the sky.

[pearley]

My 4 panels are semi flexibles screwed flat to a cream roof. They normally give just over 80 volts but the last few days it has been between 80 and 62. I've put this down to the roof being rather warm.

Edited July 3, 2015 by pearley

[jenevers]

My 4 panels are semi flexibles screwed flat to a cream roof. They normally give just over 80 volts but the last few days it has been between 80 and 62. I've put this down to the roof being rather warm.

Are they 100 w panels?

[jenlyn]

Sunny day here but only getting 14.2v this morning from my 3 x 100w, in series, wired panels, normally about 57v in good sunshine.

12.1v and only 4.8A going into batteries,usually around 17A, and only 32% state of charge.

Batteries (720Ah) don't need topping up.

What's going on???

They lose a bit of efficiency when it's hot.

[pearley]

Are they 100 w panels?

No, 4 x 80 watt

[jenevers]

No, 4 x 80 watt

So that's 320w and you can get 80v.

Is that wired for 24v?

Cos I've got 300w 12v and never had anywhere near 80v!

[bottle]

Check the labels on the panels and look for Voltage at P max probably in the region of 19.3v for a 100 watt panel.

 

So three panels (100 watt each) wired in series will give a maximum voltage , at the controller of 3*19.3 = 57.9v

 

Looking back you are getting this (almost) so your panels are OK.

 

So the low voltage was probably an outside influence as to what that was...

Pearley probably gets a higher voltage as his panels are possibly in the region of 36v P max. per panel depends on type.

I have 400 watts (19.3v Pmax) wired in series. parallel and the max. voltage at the controller is 38.6 v

[jenevers]

Check the labels on the panels and look for Voltage at P max probably in the region of 19.3v for a 100 watt panel.

 

So three panels (100 watt each) wired in series will give a maximum voltage , at the controller of 3*19.3 = 57.9v

 

Looking back you are getting this (almost) so your panels are OK.

 

So the low voltage was probably an outside influence as to what that was...

Pearley probably gets a higher voltage as his panels are possibly in the region of 36v P max. per panel depends on type.

I have 400 watts (19.3v Pmax) wired in series. parallel and the max. voltage at the controller is 38.6 v

Yes max Power voltage on mine is 17.8v

 

Low voltage was because it was early morning although it was gloriously sunny!

[bottle]

Then that will be the outside influence all that pollution the sun was trying to shine through.

 

[Neil Smith]

If max power is 17.8 x 3 that's 53.4v so at 57v your panels are over performing, happy days.

 

Neil

[Dinz]

Strangely had 2 separate peeps come up yesterday and ask basically the same question as the OP.

Remember Volts isn't Amps.

Need both for Watts.

You can have the potential but little power behind it.

[pearley]

Check the labels on the panels and look for Voltage at P max probably in the region of 19.3v for a 100 watt panel.

 

So three panels (100 watt each) wired in series will give a maximum voltage , at the controller of 3*19.3 = 57.9v

 

Looking back you are getting this (almost) so your panels are OK.

 

So the low voltage was probably an outside influence as to what that was...

Pearley probably gets a higher voltage as his panels are possibly in the region of 36v P max. per panel depends on type.

I have 400 watts (19.3v Pmax) wired in series. parallel and the max. voltage at the controller is 38.6 v

For some reason I haven't take a note of the panels spec but the sellers website states maximum OPEN CIRCUIT voltage is 21v. With 4 of them wired in series that is, theoretically, 84 volts. But less when the batteries are actually charging, ie under load. Edited July 4, 2015 by pearley

[Jess--]

just a quick (possibly silly) thought about solar panels on hot roofs...

 

has anyone thought of trying to put the panels on some form of heat exchanger with canal water pumped through (via a small pump run from the panels)?

 

I wonder whether the performance increase from the panels would more than offset the load of running the pump.

 

of course another possible advantage would be that at least one area of the roof would be cool

[bottle]

If max power is 17.8 x 3 that's 53.4v so at 57v your panels are over performing, happy days.

 

Neil

 

That is how they guarantee them to be 80% efficient after 10 years.

For some reason I haven't take a note of the panels spec but the sellers website states maximum OPEN CIRCUIT voltage is 21v. With 4 of them wired in series that is, theoretically, 84 volts. But less when the batteries are actually charging, ie under load.

 

Yes and that voltage should be in the v Pmax range if all things are correct, panels cool and the panels aligned with the sun correctly.