My Solar System has a problem and need suggestions from pros

[DANISH RAZA]

Dear all,
I hope everybody is safe and sound in this Pandemic and i pray for the fast recovery of patients.
I am using a Solar Inverter, It is based on MPPT VFD system, Made by Chinese, Its a Battery Less System with a Solar Input of around 6000 Watts DC, to an out put of 220VAC at around 5000 Watts, the inverter unit works fine, but i am having an issue , it shuts down (showing Short circuit ) whenever:
1- i plug in my Power Adapter ie any 12vdc adapter or say a laptop adapter, the unit shows Short Circuit ans shuts down, sometimes it automatically restarts, but sometimes it just haults to a short circuit screen.
2- Whenever i shift from Solar power to Utility power, its shows same symptoms as above, I shift it from an automatic MCC, Magnetic contactor setup ( Solar magnetic contactor switches on and utility contactor switches off and vice versa) or using manual Changeover switch, it shows the same screen and freezes.
3- I have noticed that the small spark that you see whenever plugging in any AC to DC device causes it to Go to short circuit mood.

The Solar System has one 5KVA Inverter ( MPPT VFD Min Solar Voltage 200VDC, MAX Solar Voltage 400VDC, out put 220VAC,
20 x 150 Watts Solar Panels, The output on a Sunny day is around 2.2K Watts, (Photos Attached for reference, also internal components are similar as in photo)
I need your suggestions about, How to avoid these frequent restarts, and inconvenience of your Solar Inverter getting shutdown on a mare 12VDC adapter.
Kindly help me, and suggestions/ideas to improve the situation. My email address is sdaniraza@gmail.com
My name is Syed Danish Raza, I am from Islamabad Pakistan, and an Architect by profession, thanking in anticipation, and once again i pray that everybody is safe and things may get to normal ASAP.

 

[gnubie]

A lot of power adaptors effectively put a reasonable size capacitor direct across the mains when you plug them in. That causes a momentary high draw of current. Your inverter may be incorrectly reacting to that draw and declaring a short.

When you are changing over the manual or automatic cut over switch, are there any loads connected, not necessarily on, just connected? You could be seeing the same thing happening - capacitors charging up and the unit falsely reacting to that.

If any of the load items are actually on and they contain AC motors, older style fridges, vacuum cleaner, etc, and the motor is running it could be due to phase mismatch causing a high load.

Ideally you don't change back to inverter power unless everything is off, and preferably this means off at the wall outlet if it has a switch. If things are on when you change back to inverter the inverter will go from 0 to what ever power level the loads are using and that may also trigger the short warning.

If those pictures are of the inside of your inverter, I can't say I'm surprised you are having these problems.

 

[RCinFLA]

I agree it is likely caused by momentary load spike. A refrig or any induction motor would likely also cause it.

It should not be that sensitive but that is what happens with a lot of cheap equipment.

Try to make the inverter connection as close to incoming house feed. Preferably at the main circuit breaker box to minimize impact of internal wiring drop.

 

[DANISH RAZA]

Thank you Dear gnubie and RCinFLA, What I understand from your solution to the problem is:
Install the Inverter next to the main DB / Circuit breakers of the house, Currently it is installed on Roof top Mumty Room, 220VAC wire comes down at a distance of 20-25 Meters or so. so if i Install it next to the Circuit breaker then the DC Power coming from the Roof top will come through the same wires, @ 360 VDC, would not that be risky? DC wires on very high voltage?

Is there another solution? like maybe install an AC Capacitor of high capacitance next to Inverter on roof top to avoid any voltage spike ( as the inverter turns on changing over from Utility with Appliances already turned on? Kindly guide me through.

 

[DANISH RAZA]

Please note that the problem occurs on even very small load and only on AC to DC Adapters/ Transformers/ Chopper type power supply, as in Laptop or other DC fan power supplies.

 

[DANISH RAZA]

Also i have tried to install an extension cord directly to output of the inverter without connecting to mains, and tried to plug in my laptop charger or other AC to DC charger ( a very light load) to that extension socket, yet it shows shot circuit , so i guess length of wire is not an issue, because an extension cord was merely 1m in length with load not more than couple of hundred watts or even less. Induction motors, Universal motors like in Air Blowers, run fine and it does not show any shots.

Is there another solution that i do , as Install an external AC Capacitor of high capacitance, so capacitor can supply power during changeover or when a Charger is plugged in ( during power spikes as mentioned in your messages)

 

[gnubie]

There's really not a lot anyone here can do about your problem. Its probably a modified sine wave inverter so it is not possible to use an AC line filter to smooth out the kick from inductive and capacitive loads being applied to it.

 

[asder]

Where did you buy PM solar inverter from? Did you buy this so that you wouldn't have to install batteries to run the solar set up with? If you don't mind my asking, whom did you buy the solar inverter from? Most good companies sell their inverters at the 5kw range around 80k~100k these days. If you paid around 30k~60k, there is a reason for that. If possible, speak with your seller and ask them to change it for a better (a reputable company) inverter as this one is faulty . Just keep a rough estimate, 1kw set up costs roughly 100k.

6,000W dc, would be either 18 panels at 330W or 15 panels at 400W. Take an average price of about 17,000 per panel (330W panel). Installation cost of about 4,000~7,000 per panel (inclusive of wires, stands, labours, circuit breakers and everything). Let's assume the inverter at 100,000. That should cost 315,000 (15 panels, 4k install cost, i put the average price of a 330W panel, not a 400W panel) to 432,000 (18 panels at 7k install cost). Inverter is around 100,000. Since we are doing 48v systems, would require 4 lead acid or tubular, that would be an extra 80,000 to 170,000 for a 2~4 hour backup.

Total cost would be about 415,000 without batteries to 532,000 without batteries. Assuming the panels are grade A. The inverter is a hybrid inverter with net metering options.

If the inside of the complete inverter is the 3rd picture, I am sorry buddy, someone ripped you off greatly. That looks like a UPS system that people make here (to me, I am no expert at these things). That is what gnubie is reffering to as a modified sine wave inverter (UPS in the local lingo). You can watch videos, and people have opened up their inverters and shared the photos and videos here. An inverter is a bit more complex than that.