Growatt SPF 3000TL LVM-ES No Solar Power

[beavo451]

I'm building my first off grid system to play around with. I have the 48V Growatt all-in-one inverter listed in the title. It is supposed to be able to run off solar only with no batteries attached. I will add a battery in the future (I have one on backorder).

I have 8, 12V 100w panels connected in series. The voltage at the inverter is ~144 Voc. I also have utility power connected.

I tested each individual panel with a small solar generator and they all work.

The manual states that there are four modes. The description for SUB mode is if solar energy is insufficient, "solar and utility will power loads at the same time." No matter which of the four modes I select, it is in constant "AC Bypass" and will only draw power from the grid.

I did test disconnecting grid power and it will run off of solar only. Voltage drops to ~135 volts under load. But when I reconnect gird power, it goes back into AC bypass.


Does this sound like normal behavior? Does the SUB and other modes only work if there is a battery connected?

 

[Hanker777]

Beavor451: This unit will operate without a battery connected.
If you check your display and walk through different display screens you should see
voltage from PV , another screen showing Amps from PV and another with Watts from PV.
The display shows the inverter in bypass as well as power from PV ( see page 22 of user manual , Line Mode )
In short, your output Watts should equal your AC in Watts + any Watts from PV.
So, what your seeing may be the PV is adding some Amps / Watts to the inverter to supply the demand of the output.
One thing , your PV voltage being at 144 is just a little lower than the MPPT charge controllers stated "start-up-Voltage" 150V +/- 10V and PV Array MPPT Voltage Range 120 - 250 V. (See Page 42 User Manual)
It may take a min or two for the MPPT controller to "Find Its Happy Tracking Spot" before supplying amps to the inverter.
You may try to create a small output load, lets say 200 Watts, and on a good sunny day with your inverter set to SUB mode, check your display and see what your PV voltage is, Amps , and watts. It should show ( after a few min ) 200 watts from PV and 0 from Utility.
Anyhow. I have one just like yours and It has been working for 3 weeks without a battery.

Hank

 

[beavo451]

Interesting. I will try adding another 12v panel tomorrow.

Today, I tested by putting a roughly 250 watt load on it. With it connected to grid power, it stayed in AC Bypass. 0 amps from PV and 2 amps from grid. I then disconnected grid power and then PV went to 2 amps. When I turned grid power back on, it goes back to AC Bypass, 2 amps from grid, and 0 amps from PV.

 

[severin20]

Beavor451: This unit will operate without a battery connected.
If you check your display and walk through different display screens you should see
voltage from PV , another screen showing Amps from PV and another with Watts from PV.
The display shows the inverter in bypass as well as power from PV ( see page 22 of user manual , Line Mode )
In short, your output Watts should equal your AC in Watts + any Watts from PV.
So, what your seeing may be the PV is adding some Amps / Watts to the inverter to supply the demand of the output.
One thing , your PV voltage being at 144 is just a little lower than the MPPT charge controllers stated "start-up-Voltage" 150V +/- 10V and PV Array MPPT Voltage Range 120 - 250 V. (See Page 42 User Manual)
It may take a min or two for the MPPT controller to "Find Its Happy Tracking Spot" before supplying amps to the inverter.
You may try to create a small output load, lets say 200 Watts, and on a good sunny day with your inverter set to SUB mode, check your display and see what your PV voltage is, Amps , and watts. It should show ( after a few min ) 200 watts from PV and 0 from Utility.
Anyhow. I have one just like yours and It has been working for 3 weeks without a battery.

Hank

Not to hijack the thread but do you run more than one of these inverters? I'm thinking about putting 2 in parallel to have enough draw to power AC, electric water heater, electric stove, etc all at the same time.

 

[Hanker777]

Severin20: NO WAY, would two of these 3000 Watt inverters ( two for 6Kw ) would power Electric Water Heater, AC and a Electric Stove unless they were ALL the SMALL 120 Volt ones used in an RV. Regular home type Water heater ( 240V ) , AC and electric range (240 Volt )ALL on at same time
would not be possible. Maybe 6 of these in parallel, then your going to need 15 thousand dollars worth of batteries and PV.

 

[beavo451]

Not to hijack the thread but do you run more than one of these inverters? I'm thinking about putting 2 in parallel to have enough draw to power AC, electric water heater, electric stove, etc all at the same time.

Electric water heaters draw around 4500 watts.
Electric stoves draw up to 2500 watts per burner. Up to 4000 watts for an electric oven.
My tiny mini-split AC draws 450 watts.

You could run one of each appliance at a time with 6000 watts worth of inverter. You wouldn’t have much power left over.

 

[beavo451]

Update:

After leaving it overnight, it started working as expected this morning at dawn.

 

[Cidpineda]

Beavor451: This unit will operate without a battery connected.
If you check your display and walk through different display screens you should see
voltage from PV , another screen showing Amps from PV and another with Watts from PV.
The display shows the inverter in bypass as well as power from PV ( see page 22 of user manual , Line Mode )
In short, your output Watts should equal your AC in Watts + any Watts from PV.
So, what your seeing may be the PV is adding some Amps / Watts to the inverter to supply the demand of the output.
One thing , your PV voltage being at 144 is just a little lower than the MPPT charge controllers stated "start-up-Voltage" 150V +/- 10V and PV Array MPPT Voltage Range 120 - 250 V. (See Page 42 User Manual)
It may take a min or two for the MPPT controller to "Find Its Happy Tracking Spot" before supplying amps to the inverter.
You may try to create a small output load, lets say 200 Watts, and on a good sunny day with your inverter set to SUB mode, check your display and see what your PV voltage is, Amps , and watts. It should show ( after a few min ) 200 watts from PV and 0 from Utility.
Anyhow. I have one just like yours and It has been working for 3 weeks without a battery.

Hank

so it does work ? on supplying energy with solar and grid at thesame time ?