EcoRenovator - View Single Post - Off-the-grid with grid-tie inverter?

Xringer · 10-30-11, 05:43 PM

depdevil1 is using a MSW inverter + batteries. But, I'm not sure what kind of waveform his MSW inverter is generating.
It might be a small step type waveform that looks very much like a sine-wave.

Plus, his Island grid might have a pretty large load on it, most of the time.
That solid load might be what's keeping his GTI's from putting out high voltage.

IIRC, In my test configuration, I had a 1200 PJ GTI connected to a light load(300-500w),
and a 48v 1500w TSW inverter to simulate the grid.
Not sure what happened, but my guess is the high voltage came from the GTI.
It was working great, then I saw some smoke and heard a pop from the TSW unit and shut down the test.
I think the PJ GTI was connected to the 800w PV array.

~~~

The way I think of GTIs, is a large one might able to provide all the power needed for your loads.
But, if it is connected to a large battery or PV, it will try to run at full power, to it's max rating!
How does it get rid of that excess power (that your loads aren't using)???
It tries to dump it out on the grid.. That's what it was designed to do..

But, how does it dump to the grid? There is only one way it can make
current flow into the grid. It increases it's output voltage. slightly.
Because the GRID is so powerful, it only needs to raise the voltage a small amount.

BUT, if you are running an Island, with limited loads..?. Well, that's a difference story.
The GTI will pump up it's output voltage! It wants to move some kWh onto the grid.. (The real grid)!
My old 1200w PJ tried to smoke my tiny grid!!

My loads were too light.

10-30-11, 05:43 PM	#58
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	depdevil1 is using a MSW inverter + batteries. But, I'm not sure what kind of waveform his MSW inverter is generating. It might be a small step type waveform that looks very much like a sine-wave. Plus, his Island grid might have a pretty large load on it, most of the time. That solid load might be what's keeping his GTI's from putting out high voltage. IIRC, In my test configuration, I had a 1200 PJ GTI connected to a light load(300-500w), and a 48v 1500w TSW inverter to simulate the grid. Not sure what happened, but my guess is the high voltage came from the GTI. It was working great, then I saw some smoke and heard a pop from the TSW unit and shut down the test. I think the PJ GTI was connected to the 800w PV array. ~~~ The way I think of GTIs, is a large one might able to provide all the power needed for your loads. But, if it is connected to a large battery or PV, it will try to run at full power, to it's max rating! How does it get rid of that excess power (that your loads aren't using)??? It tries to dump it out on the grid.. That's what it was designed to do.. But, how does it dump to the grid? There is only one way it can make current flow into the grid. It increases it's output voltage. slightly. Because the GRID is so powerful, it only needs to raise the voltage a small amount. BUT, if you are running an Island, with limited loads..?. Well, that's a difference story. The GTI will pump up it's output voltage! It wants to move some kWh onto the grid.. (The real grid)! My old 1200w PJ tried to smoke my tiny grid!! My loads were too light.