PW2 vs 16kw SolarEdge system question

[omega]

Hello everyone,

I have a 16kW SolarEdge Solar system (Sunpower panels), and 1 Tesla PW2. The Tesla authorized installer finally finished the work, however yesterday we had a power outage and noticed the PW was not charged by the solarsystem, after checking I noticed the inverters didn't even have input power. Initially I thought the PW was disabling this somehow, but after seeing not input power at the inverter, I'm thinking the inverters were not even wired as a backup load?
We called the installer and they told us because we have only 1 PW which can handle 5kW, it cannot provide power to the 16kW solar system...Is this all accurate?

Thank you in advance!
DK

 

[Evans]

Yes, that is correct. During an outage the excess solar energy can't go to grid and so the excess will need to go to the battery. However if you are producing more than the battery can handle (5kW continuous) the system will shutdown the inverter.

 

[omega]

Yes, that is correct. During an outage the excess solar energy can't go to grid and so the excess will need to go to the battery. However if you are producing more than the battery can handle (5kW continuous) the system will shutdown the inverter.

Thanks. Is it a sw feature of the PW, or the inverter circuit was not even wired to be a backup load in the PW? Asking because during the outage was not very sunny and the total production was more like 3kw and still none went in the PW...At all times regardless of the KW output the inverter lights were off (no input power?),,,

 

[Vines]

Thanks. Is it a sw feature of the PW, or the inverter circuit was not even wired to be a backup load in the PW? Asking because during the outage was not very sunny and the total production was more like 3kw and still none went in the PW...At all times regardless of the KW output the inverter lights were off (no input power?),,,

It sounds like your inverter is not on the backup circuit at all. With my SE7600 inverter there is a light on the bottom that will illuminate whenever grid voltage is present.

It sounds like they sold you a system that is "one and done" where whatever battery charge you have is what you have when you go off grid and it will not ever recharge off solar when off grid.

Basically the ratio is about 7.6 kW of power from a PV system per powerwall is the design limit. your system sounds like it needs more like 2-3 batteries to be able to have a solar system of this size on the backup circuit.

Most solar systems that are on the backup circuit will curtail production as the battery reaches full when the grid is down. If your inverter never wakes up during a grid outage then it is setup as I suspect.

If you have multiple inverters it is reasonable that one of the inverters could be relocated onto the backup circuit and the other could remain off the backup circuit.

 

[omega]

It sounds like your inverter is not on the backup circuit at all. With my SE7600 inverter there is a light on the bottom that will illuminate whenever grid voltage is present.

It sounds like they sold you a system that is "one and done" where whatever battery charge you have is what you have when you go off grid and it will not ever recharge off solar when off grid.

Basically the ratio is about 7.6 kW of power from a PV system per powerwall is the design limit. your system sounds like it needs more like 2-3 batteries to be able to have a solar system of this size on the backup circuit.

Most solar systems that are on the backup circuit will curtail production as the battery reaches full when the grid is down. If your inverter never wakes up during a grid outage then it is setup as I suspect.

If you have multiple inverters it is reasonable that one of the inverters could be relocated onto the backup circuit and the other could remain off the backup circuit.

Many thanks, you are spot on. I just asked them to wire my 6kw inverter through a backup circuit inside the PW, with that I'm also within the 5kw PW limit. In my setup I have 2 solaredge inverters: one 10kw, and one 6kw. Thanks for the idea! Do you think there is something they could argue with this solution?
Sure adding another 2-3 PW will be better but here in Spain they are more expensive, and not worth IMHP with so much sun....

 

[Vines]

Many thanks, you are spot on. I just asked them to wire my 6kw inverter through a backup circuit inside the PW, with that I'm also within the 5kw PW limit. In my setup I have 2 solaredge inverters: one 10kw, and one 6kw. Thanks for the idea! Do you think there is something they could argue with this solution?
Sure adding another 2-3 PW will be better but here in Spain they are more expensive, and not worth IMHP with so much sun....

I can't really say if they could argue, it depends on what you signed and agreed to.

If you have 2 inverters and one of them could be on the backup circuit, I can't think of a way they could justify this as being the only solution unless the wiring from that inverter isn't easy to split off the generation system due do distance or physical limitations.