The EG4 6500EX-48 appears to only have a 60amp max current charge setting, but it appears that refers to max for the unit, with a separate setting to control utility charge setting...
Unimpressed by PV production, what am I doing wrong?
- Thread starter 30362
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The EG4 6500EX-48 appears to only have a 60amp max current charge setting, but it appears that refers to max for the unit, with a separate setting to control utility charge setting...
My browser wasn't showing the links to download results, switched browser and it's there... thanks!
It's cloudy today, so no good data available, however I am combining strings today and my battery is down to 60% so if we get sun tomorrow I should have enough of a load to get more data points... That csv shows 967w for 8am today, so hoping there's sun and I can compare tomorrow.
page 8 bottom
Your panels point on South so second string input is useless in your case.
Second input can be used in case of East / West roof strings.
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I'm looking at the bottom of page 8, solar input, and I'm not sure what info there says that my second string of 4 panels are useless. When I discussed this with SS it was recommended 8 panels in series on PV1 and 8 panels in series on PV2, then the same on the 2nd inverter, for a total of 32 panels. 8 panels max per string so the input voltage didn't exceed 500v per PV input...
zanydroid
Solar Wizard
? Does your analysis still hold keeping in mind that the I-V curve varies by irradiance? Generally speaking if the bypass diodes do not activate the maximum power point voltage won’t vary that much.
MPPT working process and solar panel working process are independent element no matter formula is same
zanydroid
Solar Wizard
Can you show your logical derivation for the claim that the MPPT won’t activate? My understanding is that this primarily happens when enough bypass diodes activate due to shaded cells. You lose slightly over 1/3 voltage of each panel’s Voc per diode.
Moreover there is power being generated, and no shutdown of MPPT in the power output graph anyway.
@30362
Just to confirm, there is definitely room in your batteries to take the power being made by the panels ?
If not drain them down, then see what happens. If your batteries are at 100% your panels won't be making anything, sunshine or not
Also are your charge voltages set correct for the batteries you're using ?
Just to confirm, there is definitely room in your batteries to take the power being made by the panels ?
If not drain them down, then see what happens. If your batteries are at 100% your panels won't be making anything, sunshine or not
Also are your charge voltages set correct for the batteries you're using ?
MPPT have startup voltage (~200v) then start to consume more Amps and this bring voltage to 120v to take as much as possible amps.
No diodes evolved in this.
4 panels voltage is on lower limit of string capacity.
Yesterday, no, they were at 100%, so I was only getting enough from the solar to power the inverters.
Overnight I ran my heat pump and drained the batteries to 59% and they're charging a bit this morning, but only about 11w because it's cloudy and I'm barely over 200w coming from all 8 panels (in 2 strings).
I plan to disconnect everything today, wire all 8 panels in series (instead of 4 on each PV input) and see if I can get more. Alternatively I will leave the bank as-is and hope for sun tomorrow to see if I can get a higher input PV value....
zanydroid
Solar Wizard
Solar panel specs:
String specs
From the IV chart at different irradiance there is always over 40V Voc (look at the lower lines for lower irradiance. Voc goes down but not by much. also this part of the derivation assumes no bypass diodes active due to hard shading). With 4s that gives 160Vdc which is above the 80Vdc startup voltage.
Now each bypass diode that activates will translate to losing 50/3 = 16V (Voc). So activating like 5 or 6 out of the 4*3=12 bypass diodes on the string will indeed drop the string below startup voltage.
Roughly where abouts are you in the world?
Here in the UK , the rule of thumb is panels make 1x their rated output per day in winter , 5x in summer
So 250w panel averages roughly 250w a DAY total in winter . 1250w a day in summer
. We have very short days in winter
zanydroid
Solar Wizard
Where did these numbers come from?
The MPPT optimized for the maximum power by sweeping the IV curve for the string in the physical conditions, to find the global peak. This may be oddly shaped depending on what is going on. Anyway the voltage and current can be more complex than what you said. Usually max amps means pretty low voltage (this corresponds to the left part of the IV graph, when you push to Isc voltage goes to 0, so power approaches 0)
Huntsville Alabama, 34deg latitude. That's a good rule of thumb, thank you. I know someone had a calculator in their signature for simulating output \ load to go off-grid, I just need to find that so I can figure out how many more panels I need to add.
zanydroid
Solar Wizard
Are the two strings oriented in the same angle (altitude and azimuth)? Same shading? Do you have separate power info for each string? Probably you can get this if each string goes to a separate inverter.
Anyway what I am getting at is the two inverters and strings have a combination of common and independent failure modes from installation mistakes. If the strings are expected to generate the same power but don’t, that tells you something.
Also, is this your first solar system at this site/overall?
As many as you can afford lol can't have too much solar
You're a LOT further south than me (I'm 52deg lat) so you won't get as big of a swing as we do in Britain. We get 7hrs of day light in winter, 18hrs in summer
Personally I would leave it up and running for a few days and see what happens, what have you got to lose?
zanydroid
Solar Wizard
How do you ever have enough space/money to go off grid in the winter with that kind of seasonal swing?
give them as example
Different Conventional and Soft Computing MPPT Techniques for Solar PV Systems with High Step-Up Boost Converters: A Comprehensive Analysis
Solar photovoltaic (PV) systems are attracting a huge focus in the current energy scenario. Various maximum power point tracking (MPPT) methods are used in solar PV systems in order to achieve maximum power. In this article, a clear analysis of conventional MPPT techniques such as variable step...
www.mdpi.com
Since each PV input can only support max 500v, I'm maxxed out with 32 panels across the 4 inverter inputs. I have space to add more, but I'd need to add another inverter or two...
Haha yes very good point... With great difficulty! (And an LPG generator), little wind turbine to make some power would help, it's windy here
What most people do is cut their power use to the bone ,
it's only really Oct, Nov, Dec, Jan, Feb, that are a problem.. . The rest of the year is brilliant lol
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