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**organic farmer** · 03-15-2022, 03:19 PM

Often at the power meter is a 'mains breaker'.

If you shut off that breaker you are no longer connected to the grid.

**SunEagle** · 03-15-2022, 04:19 PM

Originally posted by C.R.J.

Hi All, Advice required.
i have a grid tied 2.5kw system. No batteries, although my inverter is equiped to connect them. Due to several grid failures in the area, i need my solar to work during the day when the grid fails.
Obviously I have to disconnect my system from the grid when it fails, before I could connect my solar to the house supply. I do have zero grid injection device to prevent power going to the grid in normal operation.(The supplier won't pay for it, so is not having it!). However it is obviously not instantaneous, and would injur those nice electical workers trying once again to fix the grid.
My inverter requires to sample and match the grid frequency before it connects. I am not planning on purchasing a bank of batteries for power at night or during low sunlight, its just not affordable.
i guess what i am asking is how can i temporarily become 'Off grid'.
I do have access to a small generator now, and a true sine wave static inverter. Both are relatively low power.
Thoughts?

Once you have disconnected your panel from the grid the only way I know of being off grid is to use either batteries or a generator. Unless you have a hybrid inverter your solar is useless.

**Mike 134** · 03-15-2022, 04:27 PM

I saw you're not having any batteries. So, the grid only loses power during the day with the sun shining? See where I'm going? Buying a bigger generator would be a more reliable solution.

**solardreamer** · 03-15-2022, 05:06 PM

Originally posted by C.R.J.

Hi All, Advice required.
i have a grid tied 2.5kw system. No batteries, although my inverter is equiped to connect them. Due to several grid failures in the area, i need my solar to work during the day when the grid fails.
Obviously I have to disconnect my system from the grid when it fails, before I could connect my solar to the house supply. I do have zero grid injection device to prevent power going to the grid in normal operation.(The supplier won't pay for it, so is not having it!). However it is obviously not instantaneous, and would injur those nice electical workers trying once again to fix the grid.
My inverter requires to sample and match the grid frequency before it connects. I am not planning on purchasing a bank of batteries for power at night or during low sunlight, its just not affordable.
i guess what i am asking is how can i temporarily become 'Off grid'.
I do have access to a small generator now, and a true sine wave static inverter. Both are relatively low power.
Thoughts?

Conventional solutions require hybrid inverters and batteries.
You can check out other recent threads like "Usable A/C output question" for more info.

**nomadh** · 03-18-2022, 12:04 PM

I bought my sunnyboy 5 years ago because it had daytime energency power. My 5 kw system can give me 1500 watt during the day to an emergency outlet. Even near dusk I could still run a fridge or small ac off grid. I hated not having per panel monitoring but that was the trade off. My inverter was the 7000 tl-us. Iirc. I just heard they now have per panel off grid daytime power. Brand new optimizers. The Israeli company. Sorry been out of the loop a few years but when I saw an ad for the product recently I triggered.

it's possible so keep looking

**bcroe** · 03-18-2022, 05:39 PM

Some time in the previous century, I wanted backup power, so I spent
some $500 on an electric start gen set. So far have only used it 4 times,
less than 10 hours total.

9 years ago, I decided to stop using fossil fuels at home, by going solar.
Net metering allowed me to collect energy credit when the sun was shining,
and to use it at a different hour or season when it was not. Lots of devices
including mine are not happy to run from a power source that is subject
to frequent power dropouts. So not much effort has gone into panels
supplying general loads with no energy buffer. I would not want to have
to stand and watch, making sure my fridge finished running before the sun
faded. I already covered that issue with the gen set.

In 9 years I have had some wiring issues, a couple burned out MC4s, and
a blown AC breaker (probably conterfeit from across the Pacific). Per
panel monitoring would not have helped me track down any of the above
faults. Meanwhile the 100 plus original panels are ALL still in service, no
faults among them. Bruce Roe

**C.R.J.** · 03-20-2022, 04:48 AM

Originally posted by Mike 134

I saw you're not having any batteries. So, the grid only loses power during the day with the sun shining? See where I'm going? Buying a bigger generator would be a more reliable solution.

I lose the power during the day and night. Right now i cannot afford a bank of batteries or a bigger generator. Hence the reason to at least try get some power while the sun is shining when the grid is down.

**SunEagle** · 03-20-2022, 09:31 AM

Originally posted by C.R.J.

I lose the power during the day and night. Right now i cannot afford a bank of batteries or a bigger generator. Hence the reason to at least try get some power while the sun is shining when the grid is down.

Just be careful with the Sunny Boy. While it can provide some power when the grid is down it is subject to the amount of sunlight hitting the panels. If you load can't handle even momentary outages (when clouds pass) then you could be damaging them. With batteries providing a cushion the load can ride through a moment of sunless sky. I wouldn't leave the house during a down grid day and hope my panels provide constant power through the SMA inverter continuously.

**Will792** · 03-22-2022, 05:49 PM

Originally posted by C.R.J.

I lose the power during the day and night. Right now i cannot afford a bank of batteries or a bigger generator. Hence the reason to at least try get some power while the sun is shining when the grid is down.

you need some transfer device, automatic or manual. Output from the inverter cannot be injected back into panel. You can probably use regular generator transfer panel that is wired to your inverter output, instead of a generator. Overall it is too much hassle and you would be better off using conventional NG/LP or gas generator with a transfer switch. It will also give 240V, unlike SB emergency output.

Battery backed micro grid mode is nice to have but starting price is very high. I have 3 Tesla PowerWalls with Tesla Gateway (ATS) which can provide 70A max in battery only mode and 125A max in battery + PV production limit. My recollection is that it was about 16K, after federal tax credit. A couple of weeks after installation was completed my neighborhood had blackout for 6 days. I kept monitoring battery charge level but it never went down below 50% and I did not have to change devices (AC, oven, cooktop, microwave, electric dryer) usage pattern. It was business as usual.

**nomadh** · 03-23-2022, 11:00 AM

Originally posted by SunEagle

Just be careful with the Sunny Boy. While it can provide some power when the grid is down it is subject to the amount of sunlight hitting the panels. If you load can't handle even momentary outages (when clouds pass) then you could be damaging them. With batteries providing a cushion the load can ride through a moment of sunless sky. I wouldn't leave the house during a down grid day and hope my panels provide constant power through the SMA inverter continuously.

In testing my sunnyboy I think that issue came down to headroom. I have a 5kw system but my standby power is o ly 1.5 kw. I did a test at sundown where even when full output was less than 2k I was still powering up my fridge and iirc the fridge ran until system output was below 1.5k. Then I shut down in case I was risking something. The newer inverter model can now do 2 or 2.5k if anyone can confirm?
it's a manual switchover. Is it a pain and a compromise? Of course. In 4 years only had 2 outages and didn't switch over for either. But if the outage would have gone into the next day I would have flipped the switch and ran my fridge wifi and charged my laptop.
I find it maddening and in fact insulting this feature isn't included or as a low cost option on every solar. this issue kept me from buying solar for years. Im glad to hear optimizers are finally offering it. There is no reason this shouldn't be a near zero cost option except the laziness of designers.

**solardreamer** · 03-23-2022, 12:03 PM

Originally posted by nomadh

In testing my sunnyboy I think that issue came down to headroom. I have a 5kw system but my standby power is o ly 1.5 kw. I did a test at sundown where even when full output was less than 2k I was still powering up my fridge and iirc the fridge ran until system output was below 1.5k. Then I shut down in case I was risking something.

That's the problem with with sunlight only backup. You have to monitor loads and solar power closely. Not so practical.

Of course, you also have no nighttime backup power.

Originally posted by nomadh

I find it maddening and in fact insulting this feature isn't included or as a low cost option on every solar. this issue kept me from buying solar for years. Im glad to hear optimizers are finally offering it. There is no reason this shouldn't be a near zero cost option except the laziness of designers.

Enphase iQ8 offers it as an included feature but it costs about 20% more than the iQ7 which is same except for sunlight only backup and also requires other add-on equipment. What did you pay for the SPS?

**SunEagle** · 03-23-2022, 12:51 PM

Originally posted by nomadh

In testing my sunnyboy I think that issue came down to headroom. I have a 5kw system but my standby power is o ly 1.5 kw. I did a test at sundown where even when full output was less than 2k I was still powering up my fridge and iirc the fridge ran until system output was below 1.5k. Then I shut down in case I was risking something. The newer inverter model can now do 2 or 2.5k if anyone can confirm?
it's a manual switchover. Is it a pain and a compromise? Of course. In 4 years only had 2 outages and didn't switch over for either. But if the outage would have gone into the next day I would have flipped the switch and ran my fridge wifi and charged my laptop.
I find it maddening and in fact insulting this feature isn't included or as a low cost option on every solar. this issue kept me from buying solar for years. Im glad to hear optimizers are finally offering it. There is no reason this shouldn't be a near zero cost option except the laziness of designers.

I doubt the issue is the "laziness" of the designers. More like what the Bean Counters think is going to get them a profit.

If you have ever worked in a company that spends their time and money on new inventions you would understand why new products cost so much. The company wants to get back all of their research funding along with a profit to keep the investors interested.

As of now the market for a grid tie inverter that works 100% when the grid is down and has isolated itself automatically is just not big enough to build them. Once solar comes way down in price and the POCO's stop playing with the Net metering option more people will want solar and then maybe that type of inverter will become desired by a lot more people.

**SunEagle** · 03-23-2022, 12:52 PM

Originally posted by solardreamer

That's the problem with with sunlight only backup. You have to monitor loads and solar power closely. Not so practical.

Of course, you also have no nighttime backup power.

Enphase iQ8 offers it as an included feature but it costs about 20% more than the iQ7 which is same except for sunlight only backup and also requires other add-on equipment. What did you pay for the SPS?

Why do you think the IQ8 took so long to be available in the US? Maybe the price was a limiting issue.

**solardreamer** · 03-23-2022, 04:17 PM

Originally posted by SunEagle

Why do you think the IQ8 took so long to be available in the US? Maybe the price was a limiting issue.

My feeling is that Enphase had some technical compliance issues since it's a fully automated solution (unlike SB SPS) and their sales management probably didn't want to eat into their home battery business. Pricing may have been a factor but I think the delay was so long that more people (including me) started to realize sunlight only backup just isn't that practical after seeing how much smoke limited solar power production for days in the California wildfires.

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Grid tie, no batteries, connection required during grid failure

Grid tie, no batteries, connection required during grid failure

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