5kw Inverter absurd performance

[Rogli]

Dear Solar enthusiasts,
I get straight to the point and share the technical details below.
Recently, I installed Smart Solar system of 3000 W capacity. Five panels each of 600 W connected in series by giving a total output of 3000 WFive panels each of 600 W connected in series by giving a total output of 3000 W DC. Each panel is 55v at 13.3 A roughly 600watt manufacturer rated (bifacial module).

Hi, I am unable to draw even 700 W of power during the peak and hours. I checked the connections are done correctly and voltage of the string is also correct. 275 VDC.

The inverter however, is a 5 kW inverter made by Chinese Voltronics company.

This is an off-grid inverter and has the capability to share the grid power and solar power to run the load.

The problem is that when I give it grid power supply, it goes on bypass mode and runs the load from the grid despite that Solar is availabl and runs the load from the grid despite that Solar is available and it is peak sun hours time. I even checked the settings, which are set toI even checked the settings, which are set to SUB as priority meaning that first is Solar then is utility and then the battery.

Another major problem is that when I put a load on this inverter, meaning that when I run an air conditionemeaning that when I run an appliance above 600 W, the output voltage drops suddenly from 230VAC to 200VAC even during the peak sun hours. Is this normal?

When I put the iron on, the inverter trips immediately there by cutting the power supply.

I am wondering why this is happening when in fact, I installed threI am wondering why this is happening when in fact, I installed 3000 W of solar panel panels as input source and why they cannot even give 700 W of power as output?

Generally, speaking with all things and losses combined, we should get at least 70% of the power of solar panel in AC form. From this calculation, we should get at least 2000 W of powerFrom this calculation, we should get at least 2000 W of power in AC format, but maximum I am able to draw is 600 W and sometimes 700 W and if I increase the load to let’s say 800 or 900 W the inverter will trip.

For comparison, there has been an air conditioner 2 Tons being sold in the market, which has 3 kW inverter built into the air-conditioning system. The inverter is in the outer unit of the air conditioner. The company has demonstrated that it can run on just five solar panels of 600 W each. The power of the air conditioner is 2000 WThe power of the air conditioner is 2000 W AC.

Now here I am stuck and cannot figure out why I cannot run even 1.5 ton air conditioner with 3000 W of solar panels on a 5 kW inverter, when there is a 2 ton air conditioner in the market which has a 3 kW inverter inside and it just needs five solar panels??

Could it be that my 5 kW inverter is not performing well because I did not connect enough panels to eais not performing well because I did not connect enough panels to it? But then why a small 3 kW inverter easily handles five solar panels and even runs a 2 ton air conditioner?

I am attaching a picture of the data sheet of the inverter for your reference.
Thank you so much. I look forward to your answers.

 

[Mattb4]

Do you have a battery? If so what is its rating?

 

[Rogli]

Do you have a battery? If so what is its rating?

The inverter advertises as working without battery. Therefore I did not connect batteries. As well, there were YouTube demonstrations of this inverter working efficiently without battery.

 

[rogerheflin]

The inverter advertises as working without battery. Therefore I did not connect batteries. As well, there were YouTube demonstrations of this inverter working efficiently without battery.

The inverters "work" without a battery, so long as you define "work" as "work badly" if the solar has any issue (cloud, someone walking in front of the panels, a big bird or any other shade cloud issue).

If this was a grid connected inverter then it would work ok because the grid acts to pick up the load when the solar cannot handle, if it is an off-grid and/or a hybrid with loads on the load side(UPS side) of the inverter then that works badly.

I made the mistake on my eg4-18kpv of turning off the battery breaker at about sunrise, it flipped back and forth to grid a bunch of times until I threw my transfer switch to move the load back to the 100% grid (off the load/ups lugs). EG4's manual used to say it worked without batteries, now it says "will not work stably without batteries". And that is what is expected of most of the inverters, without a battery it is just about impossible to make it work ok.

The YouTube demonstrations were likely short tests with full sun and excessive solar panels to load needed, and even with that they may have had to do several takes to get it to look stable.

For your 3000w of solar panels, what time of day is it and is it fully sunny and do you have the panels aimed optimally with absolutely no shade on any of the panels? And at best you will only get about 75% of the rated power in the middle of the day. With my 395w/495w bifacial panels on a 10F day (-5 to -10C) I have gotten 415w/panel sustained at peak for 20-30 minutes, but as it gets warmer power output goes down (with the same sun intensity).

 

[Rogli]

hello, thank you very much for your reply. I do understand the consequences of not connecting a battery in case the cloud or sudden she appears on the panels in which case the water would just trip and the Lord will be cut off. There is a setting in the inverter which continues to beep, but does not turn the inverter on again. This can however, be disabled, but then it can be disastrous for the load of inverter trips and restarts continuously.

To answer specifically to your question, I did this test in peak hours that is at 12 to 1:48 PM. I gave the second sourceI gave the second source input (grid connection) to the inverter but the inverter does not draw any power from the gribut the inverter does not draw any power from the solar then and straight goes to bypass mode. this is terrible because there is sun available with peak hours better than inverte draws all the load from the grid.

As you can see from the specifications in the picture, the water is 5 kW and I have attached a total 3000 W panels to it. In other words, the total voltage of the Solar Panels equals to 265 V DC.

when I turn on the load as low as 300 W the inverter output 230VAC drops to 200 V AC.

 

[Glock24]

I've seen many people complain about these "battery less" inverters in other forums, especially from Spain and South America. From what I've read you need at least 250VDC from the panels just for the inverter to work, probably need the nominal voltage on the spec for it to work stable. As for the output, I don't think you'll get the same out of the panels as if you had butteries. When there are batteries the excess energy goes to then, with no batteries I guess the inverter is way more conservative and slow to react because it has nowhere to dump excess energy.
If I were you I would get a battery, even a small one just to account for drops in sun from clouds, etc.

 

[chamilun]

gotta have batteries