Going from Grid Tied to Off Grid

BobK · April 2015

A year ago we had a grid-tied system installed at our house. We have 24 panels and two Sunnyboy grid-tie inverters. At times in the spring and fall our panels provided all the power that we needed and our electricity bill was the minimum ($8.00). Our bill in January of this year was the highest that we've had in 10 years. I suspect that the electricity company is 'getting even with us' for going solar.

Anyway, we are thinking about adding more panels and a battery bank so that we can go off grid. My question is whether we can add more panels, charge controller(s), the battery bank and non-grid-tie inverter(s) and then use battery power through the new inverters to provide the 120 volt power to keep the grid-tie inverters working as if the grid was still connected? I'd rather not dispose of perfectly good inverters just because they want the grid. Thanks for any suggestions.

Photowhit · April 2015

No, they won't work without an existing wave to match up with.

Off grid is more expensive than grid tied electric, you may just have a problem with your system. Do you get a breakdown of your utility bill? How much you produced and how much you used?

It may be that January was very cold and not very sunny. I know at one point this winter we had a 2 week period with just and hour or 2 of direct sun during the whole period.

It will cost you more in the short and long term to try off grid solar and during those cloudy cold Januaries, you might be running a big generator around the clock, first though you have to buy a big generator and a whole lot of fuel!

BobK · April 2015

I checked the weather for my area going back a few years. The temperatures were pretty similar to what I had for January 2015. It was not the difference in temperatures that caused the differences in the electricity bill. No, the electricity company does not give a breakdown of how much electricity came from them versus how much came from my PV on the bill.

Are you saying that the electricity coming from my battery pack, through a new non-grid-tie inverter to the grid-tie inverters has the wrong wave form to activity the grid-tie inverters?

Alaska Man · April 2015

You can't run from one inverter to a grid tie inverter. No, it's a different critter all together. That would mean Two Inputs they aren't built for that. It can't be done (reasonably) it doesn't make sense to do it anyway. You have to get away from the grid and store power in a battery bank or use the Grid as your battery bank or just feed the Grid.

Personally I don't want to be "Grid-Tied", I hate those bastards. However, I do realize that my dislike comes at a cost. The Southern Grid has power that is much, much cheaper than my power.

Generators are needed to be off grid I don't care how big your array is. That means oil, gas and maintenance. Battery Banks only last 7-10 years in most cases and that is if you know what your doing. Electrical components have to be replaced. Solar panels age, It takes monitoring and baby sitting, Yada, Yada..... It's a lot easier and ten's of thousands cheaper to throw a breaker and squeak about it from time to time for most people.

cupcake · April 2015

Generators are NOT needed to be off grid...

I'm off grid... never had a generator as I live in the mojave where it's 325 days of sun.

The best way to manage power is to use less of it.

The other best way is to live where there is sun!

I'm on 3 panels 800watts no generator
Fridge is on now as is a load of laundry...

My point is work with solar not against it..

If you are using solar in Seattle or in a rainforest it's time to realize that solar works better with SUN.

froggersix · April 2015

BobK wrote: »

A year ago we had a grid-tied system installed at our house. We have 24 panels and two Sunnyboy grid-tie inverters. At times in the spring and fall our panels provided all the power that we needed and our electricity bill was the minimum ($8.00). Our bill in January of this year was the highest that we've had in 10 years. I suspect that the electricity company is 'getting even with us' for going solar.

Anyway, we are thinking about adding more panels and a battery bank so that we can go off grid. My question is whether we can add more panels, charge controller(s), the battery bank and non-grid-tie inverter(s) and then use battery power through the new inverters to provide the 120 volt power to keep the grid-tie inverters working as if the grid was still connected? I'd rather not dispose of perfectly good inverters just because they want the grid. Thanks for any suggestions.

you have sunnyboy gt now they can be ac coupled to sunnyisland battery inverter just as you want costs money but works really good just be sure you want to do this because grid is cheaper.

generator is always a good idea for backup you can have power out with any system.

sub3marathonman · April 2015

BobK wrote: »

At times in the spring and fall our panels provided all the power that we needed and our electricity bill was the minimum ($8.00). Our bill in January of this year was the highest that we've had in 10 years. I suspect that the electricity company is 'getting even with us' for going solar.

I'm wondering what the electric company has done to restructure the rates against solar.

Here under the regime of Lakeland Electric, they've singled out solar customers to be forced to eventually be on a "Residential Service Demand" rate, which is not Time of Use of course, such that the demand charges will effectively wipe out any payment to the customer for the PV electricity they've supplied. So even though my demand for peak times is zero, they are going to charge a high demand charge as if it was peak usage while I'm using during off-peak times. But they consider it "fair" because they're treating everybody equally unfair.

cupcake · April 2015

sub3marathonman wrote: »

I'm wondering what the electric company has done to restructure the rates against solar.

Here under the regime of Lakeland Electric, they've singled out solar customers to be forced to eventually be on a "Residential Service Demand" rate, which is not Time of Use of course, such that the demand charges will effectively wipe out any payment to the customer for the PV electricity they've supplied. So even though my demand for peak times is zero, they are going to charge a high demand charge as if it was peak usage while I'm using during off-peak times. But they consider it "fair" because they're treating everybody equally unfair.

Being grid tied is just as rediculous as owning a prius...

The power company can't force you to do anything.. just stop paying your bill and end all service.

Grid tied is like almost pregnant

Alaska Man · April 2015

I stand corrected, Unless you live in a Desert you will need a generator.

solar_dave · April 2015

cupcake wrote: »

Being grid tied is just as rediculous as owning a prius...

The power company can't force you to do anything.. just stop paying your bill and end all service.

Grid tied is like almost pregnant

I beg to differ greatly with this line of thought. Grid tie is much more economical with the per kWh cost much reduced.

BTW I own 2 Chevy Volts that run better than 95% of the time on electric.

cupcake · April 2015

Alaska Man wrote: »

I stand corrected, Unless you live in a Desert you will need a generator.

Yes. And it's important to note that not all deserts need to be 'hot'. As Antarctica is the largest desert on the planet. But colder more accessable deserts do exist if cold is your thing. North Carolina might as well be considered a desert as it is clear and sunny most days of the year there...

cupcake · April 2015

solar_dave wrote: »

I beg to differ greatly with this line of thought. Grid tie is much more economical with the per kWh cost much reduced.

BTW I own 2 Chevy Volts that run better than 95% of the time on electric.

Objectivley speaking grid tie makes no sense. GRID is ALWAYS cheaper. Always. Thats just a fact. Grid is so SO cheap.

Grid "tied". Just that word "tied" says it all. You are tied to the grid and you have solar as a hobby. And thats just FINE, just dont call it 'cheaper' becasue its just not.
The cheapest energy is the grid. Some say they are 'selling to the electric company'. But thier initial 'investment' is 30k-80k in D.E.B.T. -- duh..

Chevy Volt, Toyota Prius. Again, same concept, a HUGE investment (ie debt) upfront which more that makes up for the 'cheaper fuel consumption'.

I own a Honda CRX HF, 55 miles per gallon. It cost me $1,000 15 years ago (2000). Some people have those 3 banger geo metros getting the same or better mpg...

My point is, dont cut your nose to spite your face. People seem to like wasting energy to save energy. Oxymoron.

I like to call it "GRIDTIRONY"

You have all these fly-by-night solar companies hagning out in the parking lot of home-depot HUSTLING people into 70K, 4,000 gigawatt systems and getting into debt for it... all with this pipe-dream of 'getting ahead' of the power companies.... on Nevurary, 33rd.

Let's keep it real. Solar is expensive. Its not about what is cheaper or not (ie its NOT about money) its about autonomy. The neat thing about solar is that you can have power in places the grid does not reach -- like mah place for example in the desert. Thats the beauty of it, that you can live in remote areas and have the electrcity...

What sickens me, is how when solar comes up, the average person today starts yapping about $$$$ and $$$ and $$$ and 'im gonna make $$$' - COME ON! There is more to life than $$!
ENJOY NATURE!!

Rant over

god bless

-cake

BB. · April 2015

The cost of solar power is pretty easy to calculate (cost of hardware + installation + estimated repairs over 20 years)/(20 years of kWH generation via PV Watts or similar).

The cost of utility power--That is highly political and subject to lobbying and changes over time. The "original" net power agreements (such as California's) where direct subsidies from "other customers" to "GT solar customers" (and in earlier years, also a general subsidy from state and, currently federal governments).

As California hits the ~5% GT solar installed customer base (vs utility generator base)--I would expect subsidies to go away... For me, those subsides may go away in 10 years or less (basically, system is grandfathered for 20 year life by state PUC--at least for now).

What is the real value of GT solar power to the environment/utility/utility customers/state population--That is much more difficult to understand.

-Bill

Raj174 · April 2015

Hi Bob,
Take a look at this video from Outback Power about AC coupled solutions. I think you will find the information you are looking for.
http://www.youtube.com/watch?v=gOy2oZMA_gw

Rick

Going from Grid Tied to Off Grid

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