Hybrid system inverter keeps restarting

[Theone964]

Hello,

This is my very first post and I'd like to start of by saying that I'm really glad there exists a forum for solar related stuff to help us advance.

My equipment
3 1000w on grid inverters
10 300w panels
2.5kw inverter
4 150ah batteries

Inverter 1=4 panels
Inverter 2=3 panels
Inverter 3=3 panels
All of these inverters plug into one strip of outlets on the 2nd floor attic.

I plug the 2.5kw inverter with the 4 12v batteries into a wall outlet closest to the main panel in the garage.
I don't have permission to tie up to the grid yet so I've been turning off the power to the mains and then plugging in the inverter and turning it on. Everything was working just fine. I then realized that my batteries weren't lasting as long as I expected, so I looked at my wires and realized that my wires were too thing and upgraded them to 8AWG.

Now this is where my problem started. The inverters were pumping out power like they should according to a few DC power meters that I picked up. The problem was that they seemed to be pumping too much power because the inverter in the basement which is acting to fool the on grid inverters on the roof keeps "flickering" when it's really sunny outside. I measured the voltage of the battery bank and it was 60 to 62V. I measured individual batteries and they were around 15.77V. I turned off a single inverter and the flickering stops, doesn't matter which one so I know it's not an issue with a faulty inverter. After I do this anD measure the battery bank it's 50V and individually around 12.66V.

The 2.5kw inverter is plugged up with only one plug that is connected to the output.

Can anyone help, because right know I have to climb into the attic and play flip the switch to control my solar output. I know my system is designed to be hooked up to the grid so the excess will be sold, but if you think about it, if the grid goes down for a day then the system will function exactly like it is right now and will "flicker" (the inverter will keep starting and stoping).

Thank you
Chuck

[ButchDeal]

Are you in the US?
you upgraded your DC wire to 8awg? on a 48V 150Ah bank connected to a 2.5kw inverter? what is the model of the inverters?
you have apparently three pluggin inverters connected to an extension cord to connect to the 2.5kw bimodal inverter?
you are wondering why the 2.5kw inverter with just 150ah battery bank and thin 8awg wire is acting up when you feed 3kw of PV into ?

If you think about it, (to use your words) it is a wonder you haven't killed yourself yet.

[Raul]

What you try to do is a hibrid system ,to achieve that your 2.5kw inverter needs to be a bimodal inverter charger and to accept the grid inver connectivity.
Some very knowledgeable people in here will sink in to assist you properly . I think you should stop feeding from the grid inverters to the 2.5kw inverter till you are clear that you got the right gear to do that.

[Raul]

Sorry Butch beat me to it.

[Theone964]

I thought 4x150ah battery's was a good enough size that's about what 5kW worth of power. And the 8AWG is from the panels ran in parallel it's only 42v 36A Max on the 4 panels and 42V 27A on the 3 panels.

[Theone964]

The distance the 8AWG wire is ran is 5 meters one way. No I'm not in the USA right now which is frustrating. I came to India to visit my parents who thought it'd be fun to retire there, an availability of decent goods is rather on the poor side so I'm having to make do with what I can get my hands on. That's why the panels are wired in parallel and not series, the grid tie inverter rated at 1000W can only accept between 20-45v which is stupid in my opinion.

[Mike90250]

Fire about to happen to clueless.
Shut that system OFF
There are no safe plug in inverters legally permitted to be connected in the USA (or most of north america)
You should have utility permission before you feed power into the grid. Otherwise, most meters will BILL you for power you export.
most homes need a permit to install solar panels, both a construction permit, and an electrical permit. Otherwise your homeowners insurance is void.
You are installing gear you don't understand, and it can burn you.

[Theone964]

I am not in the USA, in in India right now, no building permits or anything required, only permit required is to connect to the grid. And I understand that I will be billed for power that I export with a bi-directional meter, which is why I haven't connected it to the grid. Whenever power is big generated by the panels I flip the mains to the house so I'm not longer on the grid. I trick the grid tie inverters with my regular 2.5kw inverter, just like an AC coupled system.

As for the wire size can someone recommend the correct wire size, because I punched in my cable length and my volts and amps and it's saying that 6mm2 wire which translates to 8AWG is ok with a 3% loss

[Sunking]

If you think about it, (to use your words) it is a wonder you haven't killed yourself yet.

Amend, the world needs a lot less stupid people.

[huge]

How is the 2.5kw inverter being powered? Just from the batteries?

[ButchDeal]

It is AC coupled to three 1k inverters

[cebury]

Theone964,

It is unlikely you will get any further assistance by the key contributors to this board. The "you know just enough to be dangerous" is applicable here.

You are missing basic components and design to allow your system to work, not to mention working safely. While it may seem novel to "fool the grid tied inverters" with a supply from a main inverter, that won't work. You feel like you are close to getting this system working (just stop having to flip the switch) but it is a illusion.

[herrydas]

Home UPS that delivers both AC & DC output.
Solar Panel wattage = Daily Power requirement / (Average Sunlight hours in a day * efficiency of the system)
Let’s say, daily power requirement = 1000 Watt /hour
Average sunlight hour = 5 hrs
Efficiency of the system = 35%
Now the solar panel wattage requirement = 1000 Wh / (5 hrs*0.35) = 600 Watt
Battery you can use upto 24V/(135 Ah – 180Ah)