Solar Panels Advice on off grid inverter wanted

[Colin33]

I've been asked to fit a Growatt spf 5000 es inverter which will have batteries (not sure what yet) and tied to the 230v domestic mains supply. Although I'm qualified to fit pv systems, I've never actually fitted any battery systems so not sure how they work in relation to connecting to the domestic supply. The inverter has an AC out terminal, but what can you connect this to? The property suffers from frequent power cuts (but loads of sunshine) so they hope to use as much as possible from the pv array and have power when the mains goes off. Does the AC out get connect to all circuits in the house or just selected circuits? Any advice much appreciated

 

[Electro-tech]

This video may be useful. Solar PV

 

[Electro-tech]

Just realised you said off gridI. Is it tied to an alternative AC power source.

 

[Colin33]

Just realised you said off gridI. Is it tied to an alternative AC power source.

Sorry, no, it's described as an off-grid inverter but in this instance it will be connected to the AC supply.

 

[James]

Sorry, no, it's described as an off-grid inverter but in this instance it will be connected to the AC supply.

Is the inverter designed to be grid tied?

 

[Colin33]

Off-grid inverter inverter for backup power and self-consumption application

• Integrated MPPT charge controller
• Equalization charging function
• Work with battery or without battery
• Maximum PV input voltage up to 450VDC
• Configurable grid or solar input priority
• Optional WIFI/ GPRS remote monitoring
• Support parallel operation for capacity expansion up to 30kW
• PV and Grid power the load jointly if PV energy unsufficient
• Flexibly schedule the Inverter charging and discharging time

 

[James]

The manual is here

https://autosolar.es/pdf/manual-spf-3500-5000.pdf

it is not a grid tied unit so when the power fails it will only be supplying the loads attached to its output
you need to watch the max load attached can’t exceed the 5kw max of the inverter.

if there is grid power available and needed to keep up with peek demand, this may not be the right unit to install.

 

[Colin33]

The manual is here

https://autosolar.es/pdf/manual-spf-3500-5000.pdf

it is not a grid tied unit so when the power fails it will only be supplying the loads attached to its output
you need to watch the max load attached can’t exceed the 5kw max of the inverter.

if there is grid power available and needed to keep up with peek demand, this may not be the right unit to install.

So if the power fails, it can only supply loads connected to its output terminals. But when power is on, will it be supplying the house with power from the pv and that which is stored in the batteries rather than drawing from the grid?

 

[James]

No, mains available or not, it will only supply what is connected to its output.

 

[James]

What you are describing is a grid tied inverter that has the ability to run in island mode when the grid fails and a contactor disconnects it from the dead grid.

 

[Colin33]

No, mains available or not, it will only supply what is connected to its output.

Thanks James. So, if that's the case then it's pretty useless for domestic use? So all the pv generated power, and what power is in the charged batteries will not be supplying the house, and can only be used by any circuits connected directly to the output. Is that right?

 

[Electro-tech]

What you are describing is a grid tied inverter that has the ability to run in island mode when the grid fails and a contactor disconnects it from the dead grid.

I think most grid-tied Inverters below 30kW have it built in now when loss of grid reference happens. Above this, you run into the accelerated loss of mains change program, where you have to provide proof to the DNO, that disconnection will happen, where the inverters monitor the rate of change of frequency & disconnect.

 

[James]

I think most grid-tied Inverters below 30kW have it built in now when loss of grid reference happens. Above this, you run into the accelerated loss of mains change program, where you have to provide proof to the DNO, that disconnection will happen, where the inverters monitor the rate of change of frequency & disconnect.

Yes, most grid tied inverters are designed to shut down on loss of grid, not all have the ability to run in island mode with an external contactor to disconnect the island from the grid.