Grid tie inverter wiring with battery 5 ways (just curiousity and experiment)

[JOS77]

mywiring.png


Hi guys, I just registered this site and want talk about best efficient solar PV wiring grid tie inverter and battery.

I have bought and set my solar system few weeks ago and I found it is not good enough. I think I can do something more.

As a picture ,

1 is my actuall PV now. 300W panel and 300W GTI inverter. And I have 12V battery , so I want to wire it to my PV

2 is the best way I found from internet website and googling, but I'm not sure about battery and inverter wiring and how it will working (In my thinking , controller will lose mass electric power)

3 is wrong way. Some sites recommended it and I considered, but I searched more sites and found out that the charge controller load connect to inverter will make serious damage to controller by inverter pulling out more power from controller. (But in my thinking, with controller, separating time for charging battery and load current is attracting point.)

4 is wrong way (but I doubt). Charge controller and inverter are both MPPT machine so they make conflict for searching maximum point and do infinite loop , so they are not working - is main opinion. But somebody said PWM controller can work.

5 is just curious. What will happen if 5 ? my battery is 12V 80Ah and my 300W panel produce about 800Wh~900Wh per day. (And I use 10kwh per day average) I think it can't be overcharged. (And If it works , I don't need to buy controller)

If no response , I'll try myself to 2,4,5 and upload the experiment result Have a nice day~!

[SunEagle]

Unfortunately that 300W grid tie inverter is illegal to use anywhere in the US due to it not being UL listed or approved by any POCO. So none of the 5 examples will work.

Although #4 will work as an off grid system if you eliminate the 300w inverter connected to the house.

[JOS77]

Unfortunately that 300W grid tie inverter is illegal to use anywhere in the US
Although #4 will work as an off grid system if you eliminate the 300w inverter connected to the house.

Oh, I'm not in US, and I'm using #1 for two weeks now. Is it illegal US ? so strict , then just forget about 300W. I just want better wiring method.
What I want is just like #4 - 2 ways to use solar panel - sometimes charging battery , sometimes using in house. (of course it is possible when I on/off switch manually but I want automatic)
Is it no conflict between controller and inverter #4 ? Many opinions from other sites, they two will conflict by mppt mechanism.

[littleharbor]

When your battery bank is full any potential power from your solar panels will be available for loads. Obviously daytime only. It basically bypasses the battery and would be available for whatever load you present it. If your system is as shown then you cant expect a lot of power, especially later in the day. If you have a sizable array then of course, you will have more power available.

[Mike90250]

My question is - does the inverter actually operate off 12VDC ? A 12V panel for charging a battery produces about 19v in normal conditions

[JOS77]

My question is - does the inverter actually operate off 12VDC ? A 12V panel for charging a battery produces about 19v in normal conditions

That's one of the problem. (but not serious)
My inverter is operating 22V-55V voltage , (if lower voltage , it off itself) and my 300W panel produces 35V , 3~6A current.
I think I can upgrade my battery to 24V if necessary.

[jflorey2]

1 is my actuall PV now. 300W panel and 300W GTI inverter. And I have 12V battery , so I want to wire it to my PV

2 is the best way I found from internet website and googling, but I'm not sure about battery and inverter wiring and how it will working (In my thinking , controller will lose mass electric power)

3 is wrong way. Some sites recommended it and I considered, but I searched more sites and found out that the charge controller load connect to inverter will make serious damage to controller by inverter pulling out more power from controller. (But in my thinking, with controller, separating time for charging battery and load current is attracting point.)

4 is wrong way (but I doubt). Charge controller and inverter are both MPPT machine so they make conflict for searching maximum point and do infinite loop , so they are not working - is main opinion. But somebody said PWM controller can work.

5 is just curious. What will happen if 5 ? my battery is 12V 80Ah and my 300W panel produce about 800Wh~900Wh per day. (And I use 10kwh per day average) I think it can't be overcharged. (And If it works , I don't need to buy controller)

4) is your best option - but add a DPDT switch or relay so you run one or the other off the solar panel. Ideally if you can get a charge controller that will give you "charge complete" then use that to flip the relay.

5) generally won't work because the voltages the grid tie inverter wants vs the voltages the battery wants are quite different.

[JOS77]

4) is your best option - but add a DPDT switch or relay so you run one or the other off the solar panel. Ideally if you can get a charge controller that will give you "charge complete" then use that to flip the relay.

5) generally won't work because the voltages the grid tie inverter wants vs the voltages the battery wants are quite different.

My thought is same.
At first , my imaginary #5 was inverter drains power from panel at day , and from battery at night. But on the other point, battery may not be charged at all.
Now I'll try it myself , thank you!

[JOS77]

I tested system by myself at home , and I found out 2,4,5 working fine

[JOS77]

My solar controller load is 10A and gti inverter is also 10A (22~50V) , so I tested wiring #3 . And it works fine! Now I use #1 or #3 by manual switch change

#2 is not good because inverter do not properly low level voltage cut.
#4 #5 is not good because battery do not be charged or work properly.
I set up for few months now but controller or inverter has not been broken. I think it is safe now

[JOS77]

My inverter has broken with PV system #3 after 3 months.
I don't know why, but guess both inverter and solar controller have not been working good at same time simultaneously.
I changed inverter and now my PV system is #1 and #2 . Those 2 are stable.