First 3kw DIY solar with PowMr split phase inverter10kw

[sunshine_eggo]

What I tried to say in my last statement is I want an inverter that can utilize the PV power I am actually producing which is closer to 12 amps instead of this thing that barely pulls 40% from the array capacity and needs a battery in order to compensate for what it lacks in pulling from the PV array.

One of four things is happening:

1) Your used panels are not performing anywhere near specification. Confirmation of Voc and Isc are NOT guarantees of proper panel function.

2) your MPPT is insufficient for the size of your array.

This seems unlikely as the subject implies you have a 10kW PowMR with 2X MPPT capable of 5500W each.

3) Your charging + loads are insufficient to draw max power from the array.

You seem to understand this.

4) Your AiO MPPTs are defective.

#1 is the most likely by far and I'm assuming you understand that your maximum power output is going to be at high noon with all other times being lower and that panels RARELY output rated power. Additionally, panels flat on the ground can't produce max power for two reasons, 1) they're going to get hotter than normal and 2) they're not optimally tilted.

If you attach those panels to a different MPPT under the same conditions, they will perform no differently (unless your AiO is defective).

1. Are these strings in parallel on 1 MPPT, or are they each on their own?
2. Your panels seem to have white sand on them, but in the pictures where they are vertical, it is still visible. What is this? If this isn't debris, I would question if the panels have been damaged. Further support that #1 is the issue.

IMHO, you need to find your bad panels.

I recommend you pick five of the most perfect looking panels and put them 5S on a single MPPT and confirm output at high noon. If you get 70-80% of rated power and the array voltage is close to the calculated Vmp, you have 5 good panels. If not, you have one or more bad panels. Go through the rest of them one at a time adding a 6th panel and confirm you get a 20% boost to power and Vmp. If you fail to get that level of increase, the 6th is bad.

When you buy used panels, you're rolling the dice.

 

[Rconce01]

Power out (<or=) to power in. Your unit is not capable of taking in more power than it is consuming unless there is a problem like a short.

Amps in from panels at one voltage will never equal amps out to battery and load at another but the watts have to balance out.

You do not produce any PV power without load. It is also true that without a battery your system just functioning on PV will be erratic because at any moment that load exceeds PV supply things stop working.

You will never find an inverter* that will output what your panels could produce. Your panels must output what your inverter demands based on loads.

* Exception of grid tie. That is because the grid is an infinite load.

Understood the point I was trying to make with the amps is that the inverter doesn't pull the amps I register as short circuit current at the PV input cables even under full load.

For example If I take both cables that I would feed from the PV into the inverter and check the shortcircuit current I'm at more than 50% over what the inverter pulls while connected to the PV panels With a full load on the AC output.

I would like an inverter that can use the grid to supplement the load if needed and have the battery as optional.

This one goes crazy if you don't put a battery on it. It throws all sorts of error codes.

I'm thinking if my PV array produces the 3kw it should I can always get a smaller inverter closer to that capacity and see if under the same loading conditions and with this PV array it will pull more KW.


Is there no logical test or device other than the Inverter that can load the PV circuit to assess PV power output?

 

[Rconce01]

One of four things is happening:

1) Your used panels are not performing anywhere near specification. Confirmation of Voc and Isc are NOT guarantees of proper panel function.

2) your MPPT is insufficient for the size of your array.

This seems unlikely as the subject implies you have a 10kW PowMR with 2X MPPT capable of 5500W each.

3) Your charging + loads are insufficient to draw max power from the array.

You seem to understand this.

4) Your AiO MPPTs are defective.

#1 is the most likely by far and I'm assuming you understand that your maximum power output is going to be at high noon with all other times being lower and that panels RARELY output rated power. Additionally, panels flat on the ground can't produce max power for two reasons, 1) they're going to get hotter than normal and 2) they're not optimally tilted.

If you attach those panels to a different MPPT under the same conditions, they will perform no differently (unless your AiO is defective).

1. Are these strings in parallel on 1 MPPT, or are they each on their own?
2. Your panels seem to have white sand on them, but in the pictures where they are vertical, it is still visible. What is this? If this isn't debris, I would question if the panels have been damaged. Further support that #1 is the issue.

IMHO, you need to find your bad panels.

I recommend you pick five of the most perfect looking panels and put them 5S on a single MPPT and confirm output at high noon. If you get 70-80% of rated power and the array voltage is close to the calculated Vmp, you have 5 good panels. If not, you have one or more bad panels. Go through the rest of them one at a time adding a 6th panel and confirm you get a 20% boost to power and Vmp. If you fail to get that level of increase, the 6th is bad.

When you buy used panels, you're rolling the dice.

Thanks, it's not white sand on the panels is the cracked glass. It may appear as sand but is the cracks.

I will give your troubleshooting tips a shot and I'll start looking for a new set of panels. For now I'm going to slow things down and try to get my $1800 back on this inverter since definitely doesn't give me the outcome desired.

 

[sunshine_eggo]

Thanks, it's not white sand on the panels is the cracked glass. It may appear as sand but is the cracks.

Okay, so you have known damaged panels. Obviously, they are the most likely issue if you don't get the output you expect.

I will give your troubleshooting tips a shot and I'll start looking for a new set of panels. For now I'm going to slow things down and try to get my $1800 back on this inverter since definitely doesn't give me the outcome desired.

Again, the inverter is almost certainly NOT your issue. In case you've missed it the two other times I've said it, Voc and Isc measurements on a panel or string in no way confirm they will perform properly.

Your desired outcome is almost certainly associated with the panels you have.

 

[Rconce01]

Okay, so you have known damaged panels. Obviously, they are the most likely issue if you don't get the output you expect.



Again, the inverter is almost certainly NOT your issue. In case you've missed it the two other times I've said it, Voc and Isc measurements on a panel or string in no way confirm they will perform properly.

Your desired outcome is almost certainly associated with the panels you have.

Thanks for your patience! I'll start looking for some new panels and hopefully I'll have better luck. Any guides on here on the best value on inverter for Approx 240v 3000watt ?

 

[42OhmsPA]

Thanks for your patience! I'll start looking for some new panels and hopefully I'll have better luck. Any guides on here on the best value on inverter for Approx 240v 3000watt ?

It's not the inverter.
Are the longi panels cracked or damaged at all?
Try your longi panels in 4s configuration with no other panels hooked up and see what you get, angle them for your latitude.

 

[Mattb4]

Understood the point I was trying to make with the amps is that the inverter doesn't pull the amps I register as short circuit current at the PV input cables even under full load.

...

The current your panels can deliver when fully loaded is the Imp rating not the Isc. Short circuit amperage is a bit of a fictional amount. Yes tehre are testers for panels. Image below for one on Amazon for $90

It sounds like you want a full grid tie hybrid AIO if you are going to use grid and PV only with a small backup battery. Although some hybrid AIO's will run batteryless this way they tend to be a bit flaky.

 

[gotbeans]

The max pv input voltage is 500v on the inverter. I figured the higher the better. Should I string them up as 7s 2p? I figured 14s is more effective use of the power.

14 in a string? so their VOC is 34volts?
Are you sure they're not 37.6 VOC because those look identical to the 250 watt ones santan solar sells

480Voc is VERY high unless you have a 600Voc MPPT. The MPPT voltage is a NEVER EXCEED value.

All panels in the same string must face the same direction. All panels will perform no better than the worst orientation panel.

Shading may also challenge the MPPT's ability to find the max power point.

I think you are guessing at the 480 being VOC. I'm pretty sure the 480 is running voltage. I'm guessing the VOC is actually 526.4

The current your panels can deliver when fully loaded is the Imp rating not the Isc. Short circuit amperage is a bit of a fictional amount. Yes tehre are testers for panels. Image below for one on Amazon for $90

It sounds like you want a full grid tie hybrid AIO if you are going to use grid and PV only with a small backup battery. Although some hybrid AIO's will run batteryless this way they tend to be a bit flaky.

I have one of these, they're pretty cool. Powered by the panels themselves too
$50-60 on aliexpress

 

[Rconce01]

It's not the inverter.
Are the longi panels cracked or damaged at all?
Try your longi panels in 4s configuration with no other panels hooked up and see what you get, angle them for your latitude.

Yes the deal i got was on cracked panels. My dumb mistake I guess to think that voltage and the current confirmed watt output.

I am still going to return the inverter because it was nearly $1800 and I will never need 10k output.

 

[Rconce01]

14 in a string? so their VOC is 34volts?
Are you sure they're not 37.6 VOC because those look identical to the 250 watt ones santan solar sells


I think you are guessing at the 480 being VOC. I'm pretty sure the 480 is running voltage. I'm guessing the VOC is actually 526.4



I have one of these, they're pretty cool. Powered by the panels themselves too
$50-60 on aliexpress

So those testers have more technology than the clamp on amp meter and voltage tester? It can actually confirm the true power out of each panel?

 

[42OhmsPA]

Yes the deal i got was on cracked panels. My dumb mistake I guess to think that voltage and the current confirmed watt output.

We are all learning everyday.

I am still going to return the inverter because it was nearly $1800 and I will never need 10k output.

Let us know how the return goes.
That's quite the markup. If you ever do need the 10k output you can order it from SRNE directly for ~$1400 delivered.

 

[1201]

Yes I measured each one VOC is good and short circuit amps are within 4-6 amps on all.

The entire string is producing the power it's measuring out 300voc out of the 9s2p with short circuit current at 6 amps. That's roughly 100w a panel for all 18.

Short circuit current is at 0 volts. In actual Operation you may never see that. The mppt is going to find the spot where voltage and current result in maximum output, so the ssc doesn't really tell you anything

 

[Rconce01]

We are all learning everyday.

Let us know how the return goes.
That's quite the markup. If you ever do need the 10k output you can order it from SRNE directly for ~$1400 delivered.

Awesome thanks, I ordered the tester and checking out some new panels to buy. I'll post their info for guidance. I think I'll get this right the second time around!

 

[Rconce01]

Short circuit current is at 0 volts. In actual Operation you may never see that. The mppt is going to find the spot where voltage and current result in maximum output, so the ssc doesn't really tell you anything

So the handheld tester mimics the mppt to get an actual value of power output in watts?

 

[1201]

So the handheld tester mimics the mppt to get an actual value of power output in watts?

I haven't used one of those but looking at it it looks like it can find the true power output

 

[gotbeans]

So those testers have more technology than the clamp on amp meter and voltage tester? It can actually confirm the true power out of each panel?

kind of yea.
With a clamp meter you can short out the single panel to itself and read the amps
you can also read the VOC
but you can't read all of them at the same time, and can't read the operational amps + voltage under max panel load
These devices allow you to do that

So the handheld tester mimics the mppt to get an actual value of power output in watts?

the handheld tester is an MPPT, that is what it's internals are

 

[Rconce01]

kind of yea.
With a clamp meter you can short out the single panel to itself and read the amps
you can also read the VOC
but you can't read all of them at the same time, and can't read the operational amps + voltage under max panel load
These devices allow you to do that


the handheld tester is an MPPT, that is what it's internals are

Nice I get it tommorow and I'll post pics of the results.

I can get new Trina panel or Zn shine 360w for 95 each. Are those any good ?

 

[G00SE]

Nice I get it tommorow and I'll post pics of the results.

I can get new Trina panel or Zn shine 360w for 95 each. Are those any good ?

They are both well known brands. I’m not an expert but I believe Trina has a pretty stellar rep

 

[sunshine_eggo]

They are both well known brands. I’m not an expert but I believe Trina has a pretty stellar rep

I think all panel reputations go out the window when their glass is cracked...

 

[G00SE]

I think all panel reputations go out the window when their glass is cracked...

Well, he did say “new” for the next ones so I was being optimistic hah