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

Xringer · 05-27-11, 11:40 PM

Well, long story short, the little pure sine wave inverter didn't hold sync with the 1200w PJ GTI.
It would work for a while, but then drop out randomly, 1 to 3 times a minute. (IIRC).

So, I have not done anything with the 1200w GTI for months..

Then this week, I figured that two of my new Canadian panels in parallel might supply
200 or 300 watts, even with their low voltage (28v). In series, the open voltage (72v) is too high.

So, today I hooked up the panels to the GTI, and connected the AC output
to the AC output of my 2500w MSW inverter, that was running this PC.
(and a few other small loads).

At first, there were 3 to 4 amps of DC going into the MSWI from the batteries (48v).
But within 15 seconds, the GTI started pulling in PV power.
It took over running the 300w house load (this PC too).
I checked the MSWI again, the current was 0.07 amps. (That's it's idle draw).

So, it does work. The MSWI was providing a master AC signal to a GTI
and it was producing pretty good power into a medium load.

After about an hour with the MSWI & GTI tied together without any smoke,
I figured the GTI's pure sine wave was filling in the gaps in the MSW waveform..
And then, I connected the O-scope.. WT heck? It was still a MSW!!
The GTI is copying the MSW waveform perfectly!!

I was hoping that some of that Sine wave would show up on the AC line, but no luck.
I just ended up with a really powerful MSW system (2.5 + 1.2 = 3kw)

When I added another 150w to the load, the panels weren't up to it.
They were doing their max, so the MSW started using amps (to make AC)
and the extra load was fed.
I assume that up to 3kw of load could have been connected..

If someday, I do get a larger PSWI, then I'll be able to connect the
1200w GTI with it, and it should sync up and make some nice sine waves.

I'm also thinking of hacking the 1200w GTI, by adding a 60hz sine wave
source signal that would trick it into becoming a stand-alone solar PSWI.
Likely need a schematic for that hack.

05-27-11, 11:40 PM	#29
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Well, long story short, the little pure sine wave inverter didn't hold sync with the 1200w PJ GTI. It would work for a while, but then drop out randomly, 1 to 3 times a minute. (IIRC). So, I have not done anything with the 1200w GTI for months.. Then this week, I figured that two of my new Canadian panels in parallel might supply 200 or 300 watts, even with their low voltage (28v). In series, the open voltage (72v) is too high. So, today I hooked up the panels to the GTI, and connected the AC output to the AC output of my 2500w MSW inverter, that was running this PC. (and a few other small loads). At first, there were 3 to 4 amps of DC going into the MSWI from the batteries (48v). But within 15 seconds, the GTI started pulling in PV power. It took over running the 300w house load (this PC too). I checked the MSWI again, the current was 0.07 amps. (That's it's idle draw). So, it does work. The MSWI was providing a master AC signal to a GTI and it was producing pretty good power into a medium load. After about an hour with the MSWI & GTI tied together without any smoke, I figured the GTI's pure sine wave was filling in the gaps in the MSW waveform.. And then, I connected the O-scope.. WT heck? It was still a MSW!! The GTI is copying the MSW waveform perfectly!! I was hoping that some of that Sine wave would show up on the AC line, but no luck. I just ended up with a really powerful MSW system (2.5 + 1.2 = 3kw) When I added another 150w to the load, the panels weren't up to it. They were doing their max, so the MSW started using amps (to make AC) and the extra load was fed. I assume that up to 3kw of load could have been connected.. If someday, I do get a larger PSWI, then I'll be able to connect the 1200w GTI with it, and it should sync up and make some nice sine waves. I'm also thinking of hacking the 1200w GTI, by adding a 60hz sine wave source signal that would trick it into becoming a stand-alone solar PSWI. Likely need a schematic for that hack.