Solar Panel On-Grid System not producing as Rated

[Baggs]

Hi All,

This is my first post in the Community and I hope someone can shed some light for me as I'm new to the solar game. I have purchased and installed 6 - 180 watt panels (24V 7.7 amp) and have tied them in parallel with each other. (I have also tried series with two panels) The systems longest run is 20 feet back to the bus bar. I'm using 10 gauge wire and the bus bar is rated for 100 amps. I have connected the system to various inverters a 600 watt MPPT and a 1200 watt MPPT grid tie inverters. The 600 watt unit will produce about 400 watts from the 1000 watt system and the 1200 watt inverter does 250 watts. I have another small test system with two 180 panels and they are producing 260 watts with a 300 watt inverter. I guess my question is What can be going wrong that I'm only getting 40% of the rated output? I realize about transformation losses but the book on the inverters say they are 92% efficient. I have measured the output open circuit and they panels are doing what they are rated. Any ideas?

By the way this is a grid tie system. I also have pictures if anyone is interested.

[Wy_White_Wolf]

Make/model of the inverters and panels?

[Baggs]

Panel and Inverter Specs

Panels are

2 x Canadian Solar CS6P230P (230W Poly – Black Back Sheet, Silver Frame)
5 x Schueten Solar P6-54C (185W Poly – Black Back Sheet, Silver Frame)

Inverter

PSWGT-1200
Rated 90-130V AC - 50-100 VDC (used series connection for this since two panels connected in series gives 60 + volts)

SUN-600G
Rated 90-110 VAC - 22-60 VDC (Parallel connection I'm currently using)

Thanks

[SkywaveTDR]

Maybe I am getting confused or asking additional question but isn't a MPPT unit for charging batteries and not an inverter by itself?
On the inverter (parallel one) would it not be better to put a higher voltage in rather than a lower one?

[Baggs]

Maybe I am getting confused or asking additional question but isn't a MPPT unit for charging batteries and not an inverter by itself?
On the inverter (parallel one) would it not be better to put a higher voltage in rather than a lower one?

MPPT Max Power point tracking is used in grid tie inverters.

The voltage question if I put two cells together is gives more that the allowed 60VDC and therefore saturates the inverter causing a fault.

So I do believe you may be a little confused

[SunEagle]

Panels are

2 x Canadian Solar CS6P230P (230W Poly – Black Back Sheet, Silver Frame)
5 x Schueten Solar P6-54C (185W Poly – Black Back Sheet, Silver Frame)

Inverter

PSWGT-1200
Rated 90-130V AC - 50-100 VDC (used series connection for this since two panels connected in series gives 60 + volts)

SUN-600G
Rated 90-110 VAC - 22-60 VDC (Parallel connection I'm currently using)

Thanks

Ok. I am a little confused. You first stated that you have 6 - 180watt panels that produce 7.7amp at 24v. Plus two more 180watt panels for your smaller system. Now you state you have 2 - 230watt and 5 - 180watt panels.

Before we can determine why your systems are not producing you need to confirm exactly what your panels are.

... deleted suggested wiring ...

Wait. I just checked your inverter models and the 1200 watt only accepts up to 52 vdc and the 600 watt is good for a max of 60vdc.

And lastly both of these inverter are the type you plug into a wall outlet. They are dangerous and can cause an electrical fire. DO NOT USE THEM.

[Baggs]

Ok. I am a little confused. You first stated that you have 6 - 180watt panels that produce 7.7amp at 24v. Plus two more 180watt panels for your smaller system. Now you state you have 2 - 230watt and 5 - 180watt panels.

Before we can determine why your systems are not producing you need to confirm exactly what your panels are.

... deleted suggested wiring ...

Wait. I just checked your inverter models and the 1200 watt only accepts up to 52 vdc and the 600 watt is good for a max of 60vdc.

And lastly both of these inverter are the type you plug into a wall outlet. They are dangerous and can cause an electrical fire. DO NOT USE THEM.

Not trying to confuse anyone just trying to simplify the situation so I can get the help. The 1200 watt unit is a 50VDC to 100VDC unit not just a 52 VDC. Not really sure why you say that the inverters are dangerous as I have used them for two years now on panels I built and in my test system. Can u please explain?

[russ]

Like SunEagle noted - If those inverters are the plug in the wall socket type they are not legal to use in the US and most of the civilized world.

They are junk and dangerous junk. If you value your family or home do not use such things.

[Baggs]

Thanks for your input. So if these things are junk what type of inverter do you suggest? I would like to keep the cost down.

No Boom necessary either. I take exception.

[SunEagle]

Not trying to confuse anyone just trying to simplify the situation so I can get the help. The 1200 watt unit is a 50VDC to 100VDC unit not just a 52 VDC. Not really sure why you say that the inverters are dangerous as I have used them for two years now on panels I built and in my test system. Can u please explain?

Basically those type of units do not have the proper fuse or over-current protection that is required by Code. They also do not perform per their specifications which is maybe why you are not getting the full expected output that first brought you to ask your question.

Your 1200 watt unit may have the 50 to 100vdc input range but I was unable to find one with that specification. All the ones I found with the model number PSWGT-1200 stated a max 52vdc input.

I again caution you about the use of those type inverters. They have been known to overheat and cause fires. Please do not use them.

[inetdog]

I again caution you about the use of those type inverters. They have been known to overheat and cause fires. Please do not use them.

And while you are not using them, please be sure that they are plugged only into receptacles that go directly to a dedicated breaker in your main panel and that circuit does not contain receptacles that can be used to power any other equipment.
The reason for this is that if a plug-in GTI produces 15 amps output and the circuit has a 15 amp breaker, together they could feed 30 amps into a defective load or cord plugged in somewhere else. That would overload the equipment and the wires and no circuit breaker would even see an overload.

[russ]

Anyone dumb enough to use the plug in type units is also the one to connect it to an already overloaded circuit in an old home.

[Baggs]

Anyone dumb enough to use the plug in type units is also the one to connect it to an already overloaded circuit in an old home.

Russ,

Please do not reply to any of my posts, even though you are a mod your input is unnecessary and seems to be rather opinionated.

Baggs

[russ]

Russ,

Please do not reply to any of my posts, even though you are a mod your input is unnecessary and seems to be rather opinionated.

Baggs

No problem at all! Bye