Reasonable Expectation for Solar Pv

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Ishisheean

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Hi All, I want to ask if my expectations are out of whack with reality.
My Setup:
4x120Ah deep cycles
1 5KW inverter (Kodack VMIII)
6x330w solar panels on the roof (WNW facing) (Set up in series)

The inverter has a data output that allows me to track the outputs (there is also a mobile app and a PC app, but you need a network connection for that)

On a good clear SA late summer day my Inverter reports only 500wh were generated (NOT KWh)
at at any one time my PV input to the inverter never tops
230v
400w
I am not that hot with the match for electronics, but I was expecting a lot more watts from the 1800w installed capacity.

Please help me understand if I am misunderstanding or if I might have a challenge in terms of the installation.
 
I have 3300W installed capacity, Joburg, facing ENE.

My peak daily generation in Joburg in summer has been 21kwh.

Tell me about the charge controller you have - PWM or MPPT? Integrated into the inverter? Are you cycling the batteries daily? What is your electricity usage profile during sunny hours?
 
T
Sinbad said:
I have 3300W installed capacity, Joburg, facing ENE.

My peak daily generation in Joburg in summer has been 21kwh.

Tell me about the charge controller you have - PWM or MPPT? Integrated into the inverter? Are you cycling the batteries daily? What is your electricity usage profile during sunny hours?
Click to expand...
Thanks, Sinbad, it is an integrated MPPT charge controller. (https://solaradvice.co.za/product/kodak-solar-off-grid-inverter-vmiii/)
I am not cycling the batteries daily.
The inverter has been set up as a UPS in case of Eskom failover, rather than a semi off-grid Eskom replacement.
The load on that circuit is currently very low, around 300 - 400 w (keeps the office, internet and TV running)

My expectation was that the panels would take over the load during the day as well as charge the batteries if they have been depleted. (hence the over specced system for my load)

If this adds any further insight, the inverter fan runs all the time when Eskom is available but only intermittently when there is load shedding.
 
Ishisheean said:
T

Thanks, Sinbad, it is an integrated MPPT charge controller. I am not cycling the batteries daily.
The inverter has been set up as a UPS in case of Eskom failover, rather than a semi off-grid Eskom replacement.
The load on that circuit is currently very low, around 300 - 400 w (keeps the office, internet and TV running)

My expectation was that the panels would take over the load during the day as well as charge the batteries if they have been depleted. (hence the over specced system for my load)

If this adds any further insight, the inverter fan runs all the time when Eskom is available but only intermittently when there is load shedding.
Click to expand...
SO your panels are only going to provide the load that you pull off them. Seems that the numbers you're seeing are close to your load - which is what I would expect if they're not charging batteries.
Not familiar with the inverter - it may be charging the batteries from grid power, not solar - reinforced by the fans running when there's grid.
 
Sinbad said:
SO your panels are only going to provide the load that you pull off them. Seems that the numbers you're seeing are close to your load - which is what I would expect if they're not charging batteries.
Not familiar with the inverter - it may be charging the batteries from grid power, not solar - reinforced by the fans running when there's grid.
Click to expand...
OK, so just to make sure I get it.
the panels on the roof have the CAPACITY to deliver 1800w into the circuit but they limit what they put in based on consumption. That makes sense (bit of a doh! moment for me).
What still flummoxes me is that while the PV input roughly tracks the circuit load, it seems to sit at around 50% of the load.
So for e.g. when the inverter reports a load on the circuit of 214w, the solar input at that time is around 102w. Or another example 220w load 152 w from the Pv.

what could I be missing?
 
Ishisheean said:
T

Thanks, Sinbad, it is an integrated MPPT charge controller. (https://solaradvice.co.za/product/kodak-solar-off-grid-inverter-vmiii/)
I am not cycling the batteries daily.
The inverter has been set up as a UPS in case of Eskom failover, rather than a semi off-grid Eskom replacement.
The load on that circuit is currently very low, around 300 - 400 w (keeps the office, internet and TV running)

My expectation was that the panels would take over the load during the day as well as charge the batteries if they have been depleted. (hence the over specced system for my load)

If this adds any further insight, the inverter fan runs all the time when Eskom is available but only intermittently when there is load shedding.
Click to expand...
I think I have a reasonable explanation, I have some experience with the Axpert Inverter, that wattage you see on the screen is not the total power produced by the panels but the power drawn by your load, and on top of that it is not accurate, there is something about that in the manual, it's not the actual power draw but some formula they devised, something like anything from 0 to 300 would be displayed as 300 regardless if it's 50 or 70W.

Your expectation of the solar taking over during the day cannot work because you have set the priority to utility first, there are options if you want the solar to earn its keep, you would have to change the priority and put it on solar first, but it will drain the battery because solar is sort of bundled together with the battery so it's not advisable if your battery is small.
 
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A 330W at STC Pmax. You have to look at the NOCT value of your panel's datasheet to get a more realistic output value per panel. The orientation can deteriorate that further.
 
thechamp said:
I think ....
Click to expand...
Thank you. I am going to go back to the manual and take a look. I have read elsewhere on MBB that these Kodaks are rebadged from another make. Do you happen to know what these might be, then I can dig into those manuals too.
Your explanation does make sense as the two graphs do track, so they must be related.
 
Ishisheean said:
Thank you. I am going to go back to the manual and take a look. I have read elsewhere on MBB that these Kodaks are rebadged from another make. Do you happen to know what these might be, then I can dig into those manuals too.
Your explanation does make sense as the two graphs do track, so they must be related.
Click to expand...
Voltronic (Axpert type)
 
Ishisheean said:
Thank you. I am going to go back to the manual and take a look. I have read elsewhere on MBB that these Kodaks are rebadged from another make. Do you happen to know what these might be, then I can dig into those manuals too.
Your explanation does make sense as the two graphs do track, so they must be related.
Click to expand...
They are all Voltronic, just like the Axperts, Mecer, RCT and other brands, there could be a couple of differences here and there but they are basically the same thing.

To prove the power thing you can plug stuff on while monitoring the power figure, you will see it rise and go down as you add or remove appliances.
 
Ishisheean said:
One question, the datasheet says the Voc is 43v, am I right in thinking that as these are in series they are adding their volts, to get to around the 240v mark (6x43)?
Click to expand...
It depends on the strings you have. I suspect yours are two, so it would be 3 panels connected in series and parallel to the other 3.
 
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