One thing I confirmed during the blackout : the inverter stops when the grid doesn't provide power. This is a requirement by European norms : the time between grid's power loss and inverter switch off must be lower than 200ms.

Does your inverter has the same behavior ?

In some regions, the power provided can have perturbations. Some inverter take some times to reset the mpp (max power point) tracker and resynchronize with the grid : up to a couple minutes. Some inverter are very quick to disconnect : 20-50 ms.
From time to time I can have several microcuts per day, so some appliances are resetting. My inverter wait as much as possible (200 ms) before powering off when there is perturbations/power loss. Since my panels are connected I don't remember having any microcut, but 2 months 1/2 isn't significant enough to be able to say that my inverter "erases" these small perturbations.

Denis.

mine also shuts down if the grid voltage or frequency falls outside of certain parameters. It can disconnect as fast as .16 seconds for certain frequency and voltage issues, or up to 300 seconds for certain mildly low frequency problems.

Here are the whr #s from the last 7 days (Jan 28 - Feb 3)

Wed 720
thurs 180
fri 500
sat 520
sun 1300 :)
mon 440
tues 780

I've been looking over the specs of the Enphase stuff and read about the grid failure-system shutdown test.
It seems like a reasonable test that should be preformed once in a while to insure that no PV power gets sent out on the grid during a power failure.


I wonder if the Enphase minis can be used off-the-grid, by tricking them
with a portable AC source? (Like an UPS(APC) or a gas generator)?

Cheers,
Rich

Digital meter might explode??? ;)
 

Wow! After watching the installation video, this 700 watt system looks like it would be a snap for a DIY project.
GTe .7


But, when the home use was less than 700 watts, what would the meter do?
(Mine looks kinda like this).
http://www.griffmonster.com/miscella...tric_meter.gif

Would it stall? Count backwards? :rolleyes: Or maybe read outgoing power
as incoming power and add more to your bill??

Thanks,
Rich

I've heard if you have a digital meter they have to come back and install a second meter as they can not count backwards. Maybe things have changed in recent years, but that is one thing I heard.

If the meter is using an inductive pickup, I wonder if it can even tell the direction of power flow?
If it can't, and I fed my surplus power into the grid, the meter might actually go UP and I would be billed, as if I was the user, not the producer of that (backwards moving) power.

Having two 'dumb' meters wouldn't help much, unless you piped all your PV power out of your house via the extra meter, and onto the grid. Not using any of it in your home, except via your regular meter.

How they calculate the 'net' difference and deduct from your bill is another thing I'm wondering about..

That kind of two 'dumb' meter system wouldn't really work well, once people saw how easy it would be to steal some power. The more you steal, the more money you get back.. LOL!



I think the old style mechanical meter would be the best way to go. It seems like a good Net meter should work like the old style mechanical meters!

Edit:
Just found this: Electric Meter for Net Metering ? - Solar Electric Discussion Forum by Northern Arizona Wind & Sun
"This is bad - I'm being charged for power I'm making!"

I have a mechanical meter on my house and it will run backward when backfeeding the grid.

We have had a huge warm-up here the last couple days. It was 60f yesterday (we were around -20f only a week ago) so the ground was soft enough for me to screw in a mobile home type anchor to help hold my array in place. It's a good thing too, we Are supposed to get high winds when the cold air moves back in tonight.

Edit; conditions are almost nonexistant to allow backfeeding with my puny system.

I forgot to write down my weekly #s :o. I'll update later, I'm at work now. I did have some good days though :). I'll try to get a # for a full month too.

Here are some watt hour #s for wed feb 4th thru wed feb 11th;

wed 1320
thurs 820
fri 1360
sat 800
sun 1080
mon 400
tues 1080
wed 20