Login to web portal:
https://server.growatt.com/
After login, scroll down to: My Photovoltaic Devices > Settings
Write password at the bottom of page: growatt20260522 (growatt followed by date) then click Advanced Settings.
Any setting you need to change, you must select it from "Read drop down" and click "Read" first, after that scroll up to this setting and change it then click "Yes"
AC output source:
This choice ("Program 01" on your Growatt screen) dictates how your inverter balances solar, battery, and grid power to run your household appliances.
Picking the right one depends on two factors: whether you want to completely eliminate your electricity bill or if you prioritize keeping your batteries full in case of a sudden blackout.
1.
SUB Priority (Solar ➔ Utility ➔ Battery)
Best For: Saving money on electricity bills without wearing out your Lithium batteries.
How it works: Solar panels power your house first. If the sun goes behind a cloud or your appliances pull more power than the panels can produce, the "Utility Grid" instantly steps in to seamlessly supply the remaining balance.
The Battery Role: The battery is kept strictly on standby. It is "only used as an emergency backup" if the utility grid goes down entirely.
Why choose it: It offers the smoothest power delivery, zero cycling wear on your batteries during normal days, and ensures your batteries are always at 100% capacity when a real blackout strikes.
2.
SBU Priority (Solar ➔ Battery ➔ Utility)
**Best For: Maximizing your solar investment and going as "off-grid" as possible.
How it works: Solar powers your house first during the day. As soon as the sun goes down, the inverter instantly transitions your house onto "Battery power". Your home will run entirely off the batteries all night long.
The Utility Role: The Grid is treated as a last resort. The inverter will only reconnect to the utility grid if your battery drains down to your threshold (Program 12, which we set to 25%–30%).
Why choose it: This option slashes your electric bill to the absolute minimum because you intentionally drain your stored solar energy every single night instead of paying for grid power.
3.
Solar First (Solar ➔ Battery ➔ Utility—with a twist)
How it works: This behaves very similarly to SBU mode, but it places a heavy emphasis on solar availability before letting the battery take over certain behaviors. In most standard Growatt configurations, "SBU" is preferred over "Solar First" for daily residential cycling because SBU handles night transitions much more cleanly based on battery state-of-charge.
4.
Utility First (Utility ➔ Solar ➔ Battery)
Best For: Bad weather periods, stormy seasons, or pure emergency backup setups.
How it works: The utility grid powers your home 24/7. Solar power is used exclusively to charge your batteries up to full.
The Battery Role: It sits perfectly full, waiting for a grid failure.
Why choose it: If you are expecting consecutive days of heavy rain or storms and cannot risk your system turning off, switching to Utility First keeps your home completely stable and your batteries topped off.
Summary: Which one should you pick right now?
* Choose **SUB** if you want your batteries preserved exclusively for blackouts and want the grid to handle any heavy appliances solar can't cover.
* Choose **SBU** if you want to aggressively use your Lithium batteries every single night to avoid paying for grid electricity.
AC input model
(options: Appliance, UPS, Generator):
1.
Generator Mode (Highly Recommended if using a Generator)
Best For: Running your system off a fuel-powered generator (Diesel, Gas, or Eco-Throttle units).
How it works: Fuel-based generators naturally cause "dirty power"—meaning their voltage bounces up and down and their frequency (Hz) wavers whenever heavy items like a water pump or refrigerator kick on.
Why choose it: Standard inverters will constantly reject generator power because they think the fluctuating power is a fault. Selecting "Generator Mode" tells the inverter's brain: "Expect erratic voltages and unstable frequencies. Do not panic, do not throw an error, just accept the power and use it to run the house and charge the batteries."
2.
Appliance Mode (APL)
Best For: Everyday use with standard household items and typical grid electricity.
How it works: This is the standard "wide gate" setting for utility grid power. It allows the incoming voltage from the street to drop low or climb high without disconnecting. It takes about 20 milliseconds to switch to battery if the power dies completely.
Why choose it: It keeps the system incredibly stable if your local grid suffers from frequent voltage sags or brownouts. Your major appliances (fridges, washing machines, lights) won't even notice the 20ms switch time.
3.
UPS Mode
Best For: Dedicated backup for desktop computers, servers, or sensitive IT gear.
How it works: This is the "strict gate" setting. If the incoming power fluctuates even a tiny bit, the inverter instantly drops the grid and switches to battery in under 10 milliseconds.
Why choose it: You only want this if your incoming grid power is flawlessly stable and you are running electronics that will instantly crash or reboot if the power transfers too slowly.
Which one should you select?
Select Generator if you have a backup generator hooked up to the AC input of your inverter.
Select Appliance if you are hooked up to normal utility grid power. It provides the best day-to-day stability without the inverter constantly clicking back and forth during minor voltage drops.
"Battery to mains working point" and "Mains to battery operating point":
Mains to Battery Working Point (which is labeled as "Program 13" in your Growatt menu) is the exact voltage or battery capacity percentage where the inverter decides it is safe to (stop using grid power and switch back to running your home entirely on batteries).
To fully understand it, it helps to look at it as the twin sister to Program 12 (
Battery to mains working point). They work together like a see-saw to manage your power transitions when you are running in "SOL" (Solar First) or "SBU" (Solar-Battery-Utility) modes.
The See-Saw Dynamic: How it actually works:
Imagine a typical day/night cycle on your system:
1. The Battery Drops (Program 12): At night, your home drains the battery. When the battery drops down to your "Program 12" setting (e.g., 48V), the inverter panics. It switches your home over to the grid (Mains) so your family doesn't get left in the dark, and it starts charging the battery.
2. The Battery Recharges (Program 13): The next morning, the sun comes up and your solar panels (or the grid) start charging the battery back up. The battery voltage climbs past 49V, 50V, 52V... but the inverter 'stays' on grid power to prevent toggling back and forth rapidly.
3. The Switch Back Happens: The exact moment the battery hits your "Mains to Battery Working Point" (Program 13) setting (e.g., 54V), the inverter says: "Okay, the battery is sufficiently full and healthy again. I am disconnecting from the grid and switching the house back to battery/solar power."
What should you set it to?
How you set this depends entirely on whether your battery type is set to "USE" (User-defined voltage numbers) or "LI" (Lithium with a direct communication data cable).
If using custom Voltages (Program 05 set to USE or US2)
For a standard 48V system, you want this number high enough that the battery has a substantial charge before taking on the house load again.
**Recommended for Lithium (LiFePO4):54.0V or 54.4V
**Recommended for AGM / Gel Lead-Acid: 54.0V
If using Lithium % (Program 05 set to LI)
If your inverter is talking directly to your battery's computer (BMS), Program 13 changes from a voltage number to a "State of Charge (SOC) Percentage".
(
Recommended Setting: Battery to mains working point: 30%, Mains to battery operating point: 35%
Why? This ensures that the sun is up and the battery started to charge before the inverter transfers your load back onto it, preventing the battery from immediately draining right back down to the cutoff point on a cloudy day.
Battery Undervoltage Cut-off Point:
The "Battery Undervoltage Cut-off Point" (which is Program 21 on your Growatt screen) is the absolute final line of defense for your battery bank.
If the utility grid goes down at night or during a storm, your inverter is forced to stay on battery power. As your home runs appliances, the battery voltage will steadily drop.
Once it hits the Program 21 Cut-off Point, the inverter will emit a continuous alarm tone, display an F04 (Battery Low) Error, and instantly shut down all AC power to your house to save the battery's life.
The inverter will remain dead until the next morning when your solar panels receive enough sunlight to wake the system back up and push the voltage back above safety limits.