need estimated cost of going from grid tie to hybrid

I got a quote from contractor , $65k for a 16.94kw pv system with 20kWh battery.

They messed up the inverter in the quote since the include inverter is rated for 7kw input while my system is 16.95kw)
Assuming they are going to SolarEdge SE10000H-US when I ask them for correction.
Panels: 44 Jinko Solar 385W Bobs
Inverter: 1 SolarEdge SE3800H-US[SI1] RGM
Battery: 2 SolarEdge Energy Bank (non-backup)

However, this is a grid tie system, not hybrid, so if grid is down, system is down, even though it has battery.
They want $15k extra to upgrade the system from grid tie to hybrid.
Does it really cost that much to upgrade from grid tie to hybrid?

From what I have been researching, the magic of going from grid tie to hybrid mostly lies in having a hybrid inverter (AC coupling), is that right?
I plan to diy my pv system, so I want to know how complicated it is to perform AC coupling

This is a DIY forum. Those costs are outrageous.

GTI can't form their own grid. This requires either replacement of the GTI with a hybrid inverter or an AC coupled inverter to form the grid. 17kW of grid-forming hybrid or AC coupled inverter isn't cheap. $15K is high.

Having batteries without grid-forming inverters is completely pointless.

Even if you went DIY with 2X EG4 18K PV units, that's $10K, but they would completely replace your GTI and perform the GT function themselves.

You found out how not to do it, now read around here and find out how to do it and save yourself an absolute fortune. Do you need plans and inspections for code or not?

cdstyle said:

However, this is a grid tie system, not hybrid, so if grid is down, system is down, even though it has battery.

Click to expand...

As The Great Eggo said there is no reason to have batteries in a grid tied system unless they are there as a backup when the grid is down. In a grid tied system, the grid is essentially your battery!

I would really question trusting any installer that tried to get you to buy batteries without being part of a grid down backup.
Also, the inverter is kind of the core of a system. So to screw that up is a pretty big deal.
You should look for a new contractor.

For pricing, a contractor has to pay for labor, overhead, and some profit; so you should expect the cost to be a good 3 times the cost of materials.

sunshine_eggo said:

This is a DIY forum. Those costs are outrageous.

GTI can't form their own grid. This requires either replacement of the GTI with a hybrid inverter or an AC coupled inverter to form the grid. 17kW of grid-forming hybrid or AC coupled inverter isn't cheap. $15K is high.

Having batteries without grid-forming inverters is completely pointless.

Even if you went DIY with 2X EG4 18K PV units, that's $10K, but they would completely replace your GTI and perform the GT function themselves.

Click to expand...

So a hybrid pv system always have 2 inverters where 1 of them would act as the grid so the other inverter thinks it is always connected to the grid?

SoggyShoes said:

As The Great Eggo said there is no reason to have batteries in a grid tied system unless they are there as a backup when the grid is down. In a grid tied system, the grid is essentially your battery!

I would really question trusting any installer that tried to get you to buy batteries without being part of a grid down backup.
Also, the inverter is kind of the core of a system. So to screw that up is a pretty big deal.
You should look for a new contractor.

For pricing, a contractor has to pay for labor, overhead, and some profit; so you should expect the cost to be a good 3 times the cost of materials.

Click to expand...

They added battery because the system is in California, where net metering value went down by 75% for new systems, and Time of use rate is ridiculously high.
But yeah, time to go down the diy route, seems super feasible based on what i found so far

cdstyle said:

So a hybrid pv system always have 2 inverters where 1 of them would act as the grid so the other inverter thinks it is always connected to the grid?

Click to expand...

No. The reason I included 2 inverters is because 1 likely isn't big enough.

If you already have a pure GTI system, either you replace it or add a grid forming inverter.

cdstyle said:

They added battery because the system is in California, where net metering value went down by 75% for new systems, and Time of use rate is ridiculously high.
But yeah, time to go down the diy route, seems super feasible based on what i found so far

Click to expand...

Okay, I take it back. If the system can use the batteries for peak shaving, it's not worthless.

I think I misread the question

sunshine_eggo said:

Okay, I take it back. If the system can use the batteries for peak shaving, it's not worthless.

Click to expand...

In California there is bad value for peak shaving since there are no demand charges.

The value comes from the fact that you can only bank at 20% now, maybe 5% in 5 years, for intra day consumption. And you get punished for this off peak too.

So you have to have a battery to self consume to offset your bills with same day production

One 18kpv can do it all.

AC coupling is only complicated when grid is down.

What's your breakeven?
Are you paying for it by selling power back to the grid or just by not having to pay for your own consumption?
Don't forget to factor in the "opportunity cost", ie the interest on the loan or what you could have earned/saved elsewhere eg by paying off a mortgage.

Go to Sol-ark's website, and search for an installer in your area. Get a quote from them.

16.9kw is a good bit of panel. 7KW seems a tad light on the inverter side, but it depends on your objective. If you are just trying to shave your bill, probably OK. They seem to be playing it that way, minimal battery supplemental power only, no intent to have a critical loads panel, feed output direct to your panel and keep it under the 120% rule. Maybe a little high price wise, not over the top for a legitimate contractor. Mounting 44 panels is non-trivial. Battery in this case is just to smooth the inverter output, you don't give the capacity. The battery is going to be the most expensive thing

I would take my time, and read thru the forums a bit more. A big SolArk or EG4 with 50A of output tied to a critical load loads panel would be much more useful. The bulk of the cost should be in the labor to mount all those panels and wire everything up. What racking system?

45North said:

What's your breakeven?
Are you paying for it by selling power back to the grid or just by not having to pay for your own consumption?
Don't forget to factor in the "opportunity cost", ie the interest on the loan or what you could have earned/saved elsewhere eg by paying off a mortgage.

Click to expand...

Usually there is still < 10 year break-even in California even without net metering. We pay $0.40 off peak and $0.60 summer peak. Winter peak in half the state is $0.40, so not terrible lol. The other half of the state, doesn't give much of a winter discount.