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diy solar

Not getting what I expected...getting way more...

T

That Dog Guy

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Aug 9, 2020
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I have 6 of these panels in 2S3P...the 2S are putting out about 95v and over 20A...I was expecting a bit less.

Can someone explain this to me...I am confused. Is the bifacial producing at that efficiency?

Thanks in advance.

Cheers,
Mike


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I have seen a max of 713 Watts from my two 330 W panels. It was a cool, cloudy day here in Phoenix, with wind blowing. When the sun came out, the panels were cool and making more power than standard.
 
Good catch. I was looking for his power. I expected a more prominent display for it and so missed it.
 
With the 2S3P wouldn't it produce less? I was expecting far fewer amps...Why would I get over 20 amps from two connected in series? So the panels will produce the watts in terms of the voltage and amps are variable based on the watt...yep...thought I was understanding as I was putting it together but realize I am not...can each series string produce up to 25 amps based on the sticker? I was going off the calculation of VxA=W...but it is more W/V=A

The control box has 20 amp fuses...I am likely pushing it with those? It is actually only advertised for 10 amps but has 20 amp fuses?
 
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3P means 3X the rated panel current, so you may see nearly 30A incoming from the array at max output.
 
So then you're pushing 63 Amps into a bank that's probably at 26 ish Volts. 63 x 26 = 1638 Watts to the batteries.
 
But according to the specs shouldn't each panel produce about 10amp based on Imp (getting readings of over 20amps per panel)? I guess I don't understand how I am getting as many amps as I am according to the specs....I realize there is some gain from the cold weather but way more than I expected.

I measured at several points along the circuit (from panel to inverter) and always got about 60A once reading was close to 70...2 panels connected in series was at 95 volts and 20 amps

THanks for the help
 
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You're making a similar mistake in your conceptual thinking to the one I made. Which is why I sent you the link to the thread about MPPT charge current.
 
Are you getting more watts than your panels' rating? What? Power (watts) equals volts times amps. Only thing that really matters is watts, or watt hours, collected by your panels.

The MPPT does it's thing ... doesn't matter how.
 
Q-Dog said:
Are you getting more watts than your panels' rating? What? Power (watts) equals volts times amps. Only thing that really matters is watts, or watt hours, collected by your panels.

The MPPT does it's thing ... doesn't matter how.
Click to expand...
Yeah thinking in Amps without Voltage will confuse.
His 380w x 6 panels is 2280w
His readout says 1710w input.
That's 75% which is pretty good.
 
Q-Dog said:
Are you getting more watts than your panels' rating? What? Power (watts) equals volts times amps. Only thing that really matters is watts, or watt hours, collected by your panels.

The MPPT does it's thing ... doesn't matter how.
Click to expand...
Not more watts...more amps than I expected and had designed the system for...I was assuming I would get about 10-15 amps from each string of 2 panels with three strings in parallel keeping it below 45amps...I completely misunderstood.
 
You're still not getting it. The Amps that come out of the panels are not directly related to the Amps that go into your battery. Think of the MPPT as a variable transformer. It takes the voltage and current from your panels and "transforms" them to the proper values for your battery bank. (As the panels and the batteries determine.)
 
That Dog Guy said:
Not more watts...more amps than I expected and had designed the system for...I was assuming I would get about 10-15 amps from each string of 2 panels with three strings in parallel keeping it below 45amps...I completely misunderstood.
Click to expand...
What design?
How many feet of wire between your panels and SCC?
What gauge wire?
 
Forbisher said:
Yeah thinking in Amps without Voltage will confuse.
His 380w x 6 panels is 2280w
His readout says 1710w input.
That's 75% which is pretty
Click to expand...

pmikep said:
You're still not getting it. The Amps that come out of the panels is not directly related to the Amps that go into your battery. Think of the MPPT as a variable transformer. It takes the voltage and current from your panels and "transforms" them to the proper values for your battery bank. (As the panels and the batteries determine.)
Click to expand...
When I take a multimeter and plug it directly into the panels I am getting the larger than expected amps...that does matter and is to be expected? ....I measure two panels in series at the panels and get ~90volts and ~23amps about the same measurement 125' away at the electric panel. 6AWG ....I just don't understand the 23amps...that would be over 2kw at 90 volts for 2 380 watt panels?? Am I still confused. Yep.

Thanks for your patience...
 
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That Dog Guy said:
When I take a multimeter and plug it directly into the panels I am getting the larger than expected amps...that does matter and is to be expected? ....I measure two panels in series at the panels and get ~90volts and ~23amps about the same measurement 125' away at the electric panel. 6AWG ....I just don't understand the 23amps...that would be over 2kw at 90 volts for 380 watt panel?? Am I still confused. Yep.

Thanks for your patience...
Click to expand...

This is what happens with MPPT:

PV volts * PV Amps = Battery Volts * Battery Amps.
Panel input power = battery charge power

Are you saying that you took only two panels in series, and shorted their (+) to (-) leads together and measured 23A?
 
snoobler said:
This is what happens with MPPT:

PV volts * PV Amps = Battery Volts * Battery Amps.
Panel input power = battery charge power

Are you saying that you took only two panels in series, and shorted their (+) to (-) leads together and measured 23A?
Click to expand...
I tested across the leads in full sun like I did with voltage changing the setting on my meter to DC Amps...at the combiner box with all panels I get up to 70amps...I am likely doing something wrong?...I get the same readings from the Growatt
 
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