Good morning forum.

I recently went out and got a couple of solar components to help with the constant outages experienced in our area.

This is what I have now:

2 x 450W/10A solar panels. They're connected in series and they each output about 50V. The inverter picks up around 89-94V from the panels when the sun is out. 

1 x Skyking(Seems to be an Axpert clone)24V 3KVA/2.2KW Hybrid inverter.

2 x 200ah 12V Batteries connected in series.

So far everything is working fine. The inverter charges batteries from the grid and I can use the batteries to power my home office quite nicely. 

My question is this. When there is no grid power, I would expect the inverter to start charging the batteries using the panels right? but it doesn't. What could this be? 

Well, that depends on a couple factors.

So first there are the relevant priorities, I would recommend setting solar as your charging/load support priority. Otherwise, the panels will fall back and grid will be used first saving you nothing on your power bill.

Then, with many inverters there is a fallback mechanism that forces the unit to run off grid or batteries if the load is too small. So if you see periods where solar is disconnected on loads under like 200W its pretty normal depending on what inverter you have.

@Psy Thanks for your response.

I followed your advice and checked my configuration on my inverter.

Currently it's set to use solar first for charger source as well as solar first as output priority. But still nothing.

I also tried to add a more substantial load to the inverter as you can see in the attachment but I still am not seeing the PV being used at all.

Any ideas?

 

It looks like an Axpert VM II, if that's correct the PV voltage may be a little low. The following has been taken from the VM II manual:

If I am right, the VM II needs a little more voltage to operate as you intend. Double check the manual for your inverter to see if it mentions the minimum PV voltage and try getting info from the app if you can since it does offer a couple more details.

29 minutes ago, Psy said:

Double check the manual for your inverter to see if it mentions the minimum PV voltage

I think the sticker on the right hand side on the inverter gives the relevant details also...

Thanks. I looked at that section in my manual and this is what I see, this is what it says:

It seems that it's providing more than the minimum. Unless I'm reading it wrong

 

Edited January 10, 20232 yr by JasonDK
Wrong image

If this is correct, the MPPT in your unit is much weaker than expected and you might have exceeded the MPPT max...

Can you send us a picture of the sticker on the side? It'll confirm the model etc.

Sure thing, here it is:
 

If the Voc of the panels are 50V your voltage is to high. You will need to connect the panels in parallel.

 

Edit: Posted a moment after J.E. Can only echo what he said.

 

You are providing more than the maximum Voltage, not the minimum.

Could be you are exceeding the Voltage by placing your panels in series. Please try to install the panels in parallel.

Side note, this is a PWM inverter, it does not have an MPPT, so your power generation will probably be lower than the panel rating.

Edited January 10, 20232 yr by GreenFields

Oh that makes sense.

So what you guys are saying is I will be keeping the voltage at around 50v and the amps will go up to 20, so I won't lose any power generation?

Brilliant, I'll do that today and I'll see of it makes a difference.

Also, @GreenFields, you mentioned that this is a PWM inverter. Is this less efficient than MPPT?

8 minutes ago, JasonDK said:

Also, @GreenFields, you mentioned that this is a PWM inverter. Is this less efficient than MPPT?

Basically yes. Some info in the link below, or you can google search a bit more.

https://www.solar4rvs.com.au/buying/buyer-guides/choosing-the-right-solar-charge-controller-regulat/#:~:text=The crux of the difference,smart DC-DC converter”)

23 minutes ago, JasonDK said:

So what you guys are saying is I will be keeping the voltage at around 50v and the amps will go up to 20, so I won't lose any power generation?

Brilliant, I'll do that today and I'll see of it makes a difference.

I really hope you come right and this helps... There is a small chance the PV board is damaged so if you don't get any PV after re-arranging the the panels it's not completely odd, sadly the capacitors on the PV boards can be rather sensitive and don't do well with excessive voltage...

25 minutes ago, JasonDK said:

Also, @GreenFields, you mentioned that this is a PWM inverter. Is this less efficient than MPPT?

Yeah @GreenFieldsgot you a great article there, MPPT is becoming the industry standard because it gives more control over charging etc. I haven't seen a PWM board in ages so it's likely you have an Axpert clone.

It looks like I may be in luck, I covered up part of the panel and it looks like it's charging! 

I'll rewire it into parallel to be sure but this is progress!