No Grid Power = No Solar Power

I was looking into buying a solar system and was told by the sales person that here in California PG and E requires your panels to cut off power to your house if there is a grid failure. One of the main reasons I was going to get one was so that I have a backup for the Leaf. She said that since we only use 60$ a month in electricity that leasing doesn't really make sense. Anyone have any similar experiences or stories to share? Is there a way around this? This seems like the most backwards system to me. If your going to have distributed power then why kill one of the major advantages of having one? (During a catastrophic failure)

For safety reasons, this is true of most-all grid tied solar systems. Two solutions are a battery float system or, if you are technically suave, you can trick the solar system by using a small inverter to tickle it and trick in to coming on. The latter is NOT for those who do not fully understand what they are doing and the ramifications of it!

esounds said:

I was looking into buying a solar system and was told by the sales person that here in California PG and E requires your panels to cut off power to your house if there is a grid failure. One of the main reasons I was going to get one was so that I have a backup if the grid power goes out since even with our Leaf we only use 60$ a month in electricity. Anyone have any similar experiences or stories to share? Is there a way around this?

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esounds said:

I was looking into buying a solar system and was told by the sales person that here in California PG and E requires your panels to cut off power to your house if there is a grid failure. One of the main reasons I was going to get one was so that I have a backup for the Leaf. She said that since we only use 60$ a month in electricity that leasing doesn't really make sense. Anyone have any similar experiences or stories to share? Is there a way around this? This seems like the most backwards system to me. If your going to have distributed power then why kill one of the major advantages of having one? (During a catastrophic failure)

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That's correct, unless you go off-grid altogether, your PV must shut down if the grid goes down.
Some parts like Enphase micro-inverters are designed only for grid-tied installations, not off-grid.
Off-grid installations are much more expensive due to battery costs.
You will pay a very high price for the batteries. Said batteries will have to be replaced over time also.

At $60/month in electric charges, you likely won't benefit financially from a solar system.

If you are only looking for a backup for your Leaf, it would be far cheaper to own another car (ICE car).
If you are looking for a backup for your house, then the off-grid solar install may be for you, but that will be very pricey.

If you have outages on rainy days like today , your solar PV would not generate much power. So you may still run out anyway. Unless you significantly oversize your PV system and your batteries so you can hope to never run out. We are talking a lot of $$$.

WHy so many just get a generator. quick , cheap, runs day or night ( with fuel of course). can charge the car as well, backfeed into your breaker box with right setup and switches/hardware. Solar is nice tho.

esounds said:

If your going to have distributed power then why kill one of the major advantages of having one?

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Simply put, grid-tied PV systems with no battery backup cost less money, produce more electricty and last longer than other types of PV systems. The differences in the three areas mentioned can be substantial.

RegGuheert said:

Simply put, grid-tied PV systems with no battery backup cost less money, produce more electricty and last longer than other types of PV systems.

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It is just money. For catastrophic events, you could design a system that does not even need batteries. The system would be designed were it works as grid connected until a pilot signal from a transfer switch will make all the "Enphase" modules switch to off grid mode. Any extra power could be used to heat water or the ground. Not enough power the system shuts down. It will be up to the owner to keep only the emergency loads on, watch the clouds and decide if a slice of bread can be toasted. I do not believe it would even be a lot more expensive once the designed is done.

As EV owners, a proper design would use the EV battery in conjunction with the PV system, no additional large battery cost.

There is just not enough demand for such systems, but I am sure there are people that can build them. Like ... Phil.

TomT said:

For safety reasons, this is true of most-all grid tied solar systems. Two solutions are a battery float system or, if you are technically suave, you can trick the solar system by using a small inverter to tickle it and trick in to coming on. The latter is NOT for those who do not fully understand what they are doing and the ramifications of it!

esounds said:

I was looking into buying a solar system and was told by the sales person that here in California PG and E requires your panels to cut off power to your house if there is a grid failure. One of the main reasons I was going to get one was so that I have a backup if the grid power goes out since even with our Leaf we only use 60$ a month in electricity. Anyone have any similar experiences or stories to share? Is there a way around this?

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I'll add to what Tom says. I've spoofed our 2 PV inverters back to life - once we disconnect our main service panel from the grid (we have a safety interlock that prevents back feeding). One can't simply use any old gen set. However our honda eu6500 DOES have pure sine wave power. so besides the know-how, you need an inverter to deliver grid quality power back to your PV inverter(s). PV inverters are looking for wave form prior to entering start up ... not voltage/amps.

A

camasleaf said:

RegGuheert said:

Simply put, grid-tied PV systems with no battery backup cost less money, produce more electricty and last longer than other types of PV systems.

Click to expand...

It is just money. For catastrophic events, you could design a system that does not even need batteries. The system would be designed were it works as grid connected until a pilot signal from a transfer switch will make all the "Enphase" modules switch to off grid mode. Any extra power could be used to heat water or the ground. Not enough power the system shuts down. It will be up to the owner to keep only the emergency loads on, watch the clouds and decide if a slice of bread can be toasted. I do not believe it would even be a lot more expensive once the designed is done.

As EV owners, a proper design would use the EV battery in conjunction with the PV system, no additional large battery cost.

There is just not enough demand for such systems, but I am sure there are people that can build them. Like ... Phil.

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I am glad you brought up the money issue. I think if your going to drop 2000-3000 dollars for a back up system. Why dont you just leave. spend that money on gas, airplane ticket, hotel or food. Go some where else for the week. I understand if there is no warning but every major disaster outside of earthquakes you have the heads up. I yelled at my brother in Houston for staying after the last hurricane and he didnt have power for 10 days. About day 4 he traveled 2 hrs away to my house finally. why suffer and go crazy fighting crowds and possible looters. come back when things are back up and running. 600-700.00 per event you would have 5 major disasters before you break even and alot less fustrations. Solar as a cost savings and green energy is a different bird.

I think a great system would be one where I could charge up the car and use its batteries as backup for the house. (Maybe the system wouldn't work unless the car was plugged in and was able to feed a certain amount of amps back into the house) It seems like if we want to move away from a centralized power system to a decentralized system making each home a power plant would be the best way to go. At any rate thanks for all your input, it looks like I wont be getting solar anytime soon.

esounds said:

I think a great system would be one where I could charge up the car and use its batteries as backup for the house. (Maybe the system wouldn't work unless the car was plugged in and was able to feed a certain amount of amps back into the house) It seems like if we want to move away from a centralized power system to a decentralized system making each home a power plant would be the best way to go. At any rate thanks for all your input, it looks like I wont be getting solar anytime soon.

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There are some portable backup/battery assist solar setups that could do what you want, has like 1 125AH battery with a single 45 watt or 65 watt solar panel and inverter. you pull it out when needed but it would need 12hrs of sunshine to be able to fully charge your car(maybe). I dont see a simple system for what you want. if you want a system to charge the car it would take a large solar system costing at least 3-4 thousands dollars. if you did a smaller system with some batteries , then why do you need the leaf. I was in you same predicament and my 5000 watt gas generator will charge the car, and supply power to the house when needed . costing only 500.00. it is not the most efficient way to charge the car but works and is low cost. portable, but noisy, seems like the best bank for the buck.

Glad this topic came up, 'cause I just happen to be digging around for this type of information/discussion (now that our house has grid power again and we are no longer rationing generator use thanks to hour+ waiting lines at the gas stations).

I came across this after digging through some ancient posts on other forums. To quoth:

This inverter can also be utilized as a back-up system in grid-tied applications. Its seamless transfer allows existing Sunny Boy inverters to be utilized during daytime grid outages.

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So what I get from this is, this "Sunny Island" inverter will take in and put out both AC and DC power, all at the same time, and since it's agnostic about where the AC input comes from it will have no problem if the grid goes out. However it does not appear to be something you can connect your PV panels into directly as the example riser diagram shows solar PV inverters as part of the system.

But maybe that's a good thing - you could use a mircoinverter system just as easily, which has a lot of advantages.

esounds said:

I think a great system would be one where I could charge up the car and use its batteries as backup for the house. (Maybe the system wouldn't work unless the car was plugged in and was able to feed a certain amount of amps back into the house) It seems like if we want to move away from a centralized power system to a decentralized system making each home a power plant would be the best way to go. At any rate thanks for all your input, it looks like I wont be getting solar anytime soon.

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That's all fine and good until you need the car for something. We were without power from Monday afternoon to Thursday night, and my Thursday would have been very interesting if I had a pure EV and had been using the battery to keep the basic stuff going instead of a generator. That's why I'm interested in grid-tie PV that will continue to work during an outage... THEN I might be able to get away with using the car's battery as a buffer! (I'd still opt for a battery bank if I can afford it, though)
=Smidge=

esounds said:

I think a great system would be one where I could charge up the car and use its batteries as backup for the house. (Maybe the system wouldn't work unless the car was plugged in and was able to feed a certain amount of amps back into the house) It seems like if we want to move away from a centralized power system to a decentralized system making each home a power plant would be the best way to go. At any rate thanks for all your input, it looks like I wont be getting solar anytime soon.

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You can do it in Japan, if you have Nissan Leaf.

The new ad for Leaf shows this and I guess US will have the same available in near future

http://venturebeat.com/2012/06/18/nissan-leaf-power-station/" onclick="window.open(this.href);return false;

Got power and internet at the office now, so that's nice. Power still out at home though. :?

I've been using my access to do a bit more research on keeping grid-tie PV producing during a grid failure. This link is chock full of interesting discussion:

http://community.enphaseenergy.com/...oinverters_grid_tie_only?page=1#reply_6991635

There are apparently multiple ways to accomplish it, all of which involve at least some battery capacity (no revelation there!). Those Magnum Power inverters look pretty dang sexy and appear to work fine with Enphase microinverters per the above thread. Good stuff IMHO - have your grid-tie and backup too!
=Smidge=

mksE55 said:

I am glad you brought up the money issue. I think if your going to drop 2000-3000 dollars for a back up system. Why dont you just leave. spend that money on gas, airplane ticket, hotel or food. Go some where else for the week.

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None of which helps you in the event of the Mayan apocalypse, or other such disaster, when there is no more grid. That's my use case scenario. I consider it unlikely enough that I'm not willing to spend large amounts of money on an off-grid battery system, but in the event of such a scenario, I would *at least* like to be able to generate power while the sun in shining.

Can anyone point me to some low cost options to kick-start my system (Enphase Microinverters) in such a situation?

Smidge204 said:

So what I get from this is, this "Sunny Island" inverter will take in and put out both AC and DC power, all at the same time, and since it's agnostic about where the AC input comes from it will have no problem if the grid goes out. However it does not appear to be something you can connect your PV panels into directly as the example riser diagram shows solar PV inverters as part of the system.

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If you already have grid-tied PV with an SMA "sunny boy" inverter, the "sunny island" is an turnkey solution to run the grid-tied sunny boy locally when the grid is down via "AC coupling." The sunny island inverts from a battery pack (48VDC lead-acid) and it handles the load management and syncing by communication with the sunny boy to turn down the PV generation from max available to match the load plus charging requirement, or it can meet extra load from the battery when PV is not sufficient. This system automatically manages the microgrid load matching that custom solutions address with excess power dumping controls, etc. The down side is that the sunny island will run you close to $5000 with a modest ~4kWh capacity battery pack (can't be directly connected to the LEAF because it wants 48VDC, not 400VDC).

A curiosity where the LEAF is concerned, is whether you can add a second sunny boy coupled to the 400VDC battery bus (within the input range of a PV inverter, if the MPPT circuit doesn't get confused and trip and error) allowing a connection to the 20kWh LEAF pack on the sunny island managed microgrid. Unless you choose to hot wire close to the LEAF battery, the only custom part to work out is devising a solution to talk to the chademo interface and close the high voltage contactor, etc., which is manageable (Phil showed it could be done with his range extending trailer). Of course, now your're probably north of $9000 for two inverters, batteries and a chademo plug (assuming you already had the PV and a sunny boy installed). It would be seriously questionable to spend this money for infrequent outages, however it is still a technical curiosity and perhaps not that much more expensive than Nissan's LEAF to home product without PV management.

However, the sunny island with its lead-acid pack is redundant when you have an EV battery, it just offers an expedient off the shelf solution. Short of needing off grid power at the house during periods when the LEAF is away, the only place it makes sense to spend money on battery storage is in a vehicle where that capacity is regularly used. Unless the grid is really unreliable, a stationary battery back-up will sit there doing nothing (apart from presenting a parasitic load) most of the time. Ultimately, most of the necessary hardware is already there if you have a grid-tie PV inverter and an electric vehicle. It is mostly about software, safety and integration issues, but really it shouldn't cost much to provide the solar/EV home power backup solution at little to no additional cost if the manufacturers of these various products were coordinated and designed with this application in mind.

Howdy

hgoudey said:

Unless the grid is really unreliable, a stationary battery back-up will sit there doing nothing (apart from presenting a parasitic load) most of the time.

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Interesting stuff, hgoudey, though if you have selected a Time of Use rate schedule it is conceivable that a battery pack adds savings by letting you use stored off-peak power for peak-time loads. How profitable that scheme is depends entirely on the cost difference and actual demands, of course
=Smidge=

Smidge204 said:

hgoudey said:

Unless the grid is really unreliable, a stationary battery back-up will sit there doing nothing (apart from presenting a parasitic load) most of the time.

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Interesting stuff, hgoudey, though if you have selected a Time of Use rate schedule it is conceivable that a battery pack adds savings by letting you use stored off-peak power for peak-time loads. How profitable that scheme is depends entirely on the cost difference and actual demands, of course
=Smidge=

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You'll also need to add in the cost of replacing the batteries more often as you cycle them more.

Select batteries that are suited for the application.

Nickel-iron, for example.
=Smidge=

http://climatecrocks.com/2012/11/09/in-sandys-wake-a-nissan-powered-fridge/

As millions of people fired up generators and burned candles in the wake of superstorm Sandy, some EV owners hacked their cars to keep their lights on and refrigerators humming.

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With a bi-modal system like Xantrex XW (Schneider) or SMA Sunny Island, no mater the power outage, your house will always have power for your tv, lights, even your Leaf

Using a grid-tie no backup system is non sense, at any event with the power company like over voltage, under voltage, Hz, etc... the system will shut down and you stop producing power