Going off the grid with a grid-tied system

Xringer · 03-14-09, 09:27 AM

I've been looking at the idea of using a grid-tied PV system, and it seems one of the draw-backs is,
the system is useless in a power failure..
It's designed to drop off-line and play dead, while the main grid is down.

Assuming the power fail occurs during a nice sunny day. At night, it would
make no difference.

http://i46.photobucket.com/albums/f1...roInverter.jpg

If you go to your main breaker box and flip the main supply breakers open,
you are still out of luck.

BUT, if you opened the breakers and then applied 230V to your in-house circuit using your own battery backed-up inverter,
that should re-start your PV system and allow you to turn on some low powered items you might want to use during a power failure.

I'm sure that doing this would be in violation of regulations..

I guess a more legal way to doing this would be to disconnect your PV system from everything, and plug it into a big Back-Up box.
The Box would supply 230VAC voltage to the PV system, allowing it to turn on.
The Box would have eight 120VAC outlets on it, that you could use
during the power failure.
You would unplug your radio etc from the grid, and plug it into the Box..

If the battery back-up inverter in your Box was large enough, it might be able to handle the load while clouds were passing..

I'm just thinking back to the days after the recent ice storms and the Blizzard of 78 when the power was off for many days, sunny days.

03-14-09, 09:27 AM	#1
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Going off the grid with a grid-tied system I've been looking at the idea of using a grid-tied PV system, and it seems one of the draw-backs is, the system is useless in a power failure.. It's designed to drop off-line and play dead, while the main grid is down. Assuming the power fail occurs during a nice sunny day. At night, it would make no difference. http://i46.photobucket.com/albums/f1...roInverter.jpg If you go to your main breaker box and flip the main supply breakers open, you are still out of luck. BUT, if you opened the breakers and then applied 230V to your in-house circuit using your own battery backed-up inverter, that should re-start your PV system and allow you to turn on some low powered items you might want to use during a power failure. I'm sure that doing this would be in violation of regulations.. I guess a more legal way to doing this would be to disconnect your PV system from everything, and plug it into a big Back-Up box. The Box would supply 230VAC voltage to the PV system, allowing it to turn on. The Box would have eight 120VAC outlets on it, that you could use during the power failure. You would unplug your radio etc from the grid, and plug it into the Box.. If the battery back-up inverter in your Box was large enough, it might be able to handle the load while clouds were passing.. I'm just thinking back to the days after the recent ice storms and the Blizzard of 78 when the power was off for many days, sunny days.