Load First, Battery First and Grid First.

The difference is where the sun's power goes first, and what the battery does. Load First sends the sun to the house, and the battery discharges when the sun isn't enough. Battery First charges the battery first and can charge from the grid when AC charging is switched on. Grid First sells the sun's surplus before the battery is charged, and the battery can sell its power. Battery First and Grid First apply in the time periods you set up.

The default mode. The house first, then the battery, then the grid.

Solar power

First to the house, then to the battery, and the rest is sold to the grid.

Charging from the grid

No.

The battery discharges to the house

Yes, when the sun isn't enough, until it reaches the lower limit you have set.

When

All the time, and when a time period with Battery First ends.

Load First is the mode most systems run in all the time. It uses as much of your own solar power as possible and buys as little as possible from the grid. It just doesn't look at the price: the battery dischargesas soon as the house needs power, even if power is cheap right now and expensive in two hours.

The battery first, then the house, then the grid.

Solar power

First to the battery, then to the house, and the rest is sold.

Charging from the grid

Yes, when AC charging is switched on. The battery is charged to a stop state of charge that you set.

The battery discharges to the house

No, not during the time period. Afterwards the inverter goes back to Load First.

When

In the time slots you have set up. Up to three a day on the SPH series.

Battery First is made for charging cheap power at night and using it when power is expensive. With a time slot set up in the inverter , it goes back to Load First when the time slot ends or the battery reaches the stop state of charge.

On the inverter's display, in the ShinePhone app or on ShineServer. Without a time period, the inverter goes back to Load First.

On an SPH, you do it like this:

1. Find the setting. On the inverter's display, in the ShinePhone app under Plant, your inverter and Control, or on ShineServer. Both the app and the display ask for a password.
2. Choose Battery First, and set a time period under Charge Period. Without a time period, the inverter goes back to Load First by itself. On the display you can only set one time period; if you want more, use ShineServer.
3. If the battery is to charge from the grid, set AC CHG to Enable. Otherwise it only charges with the solar surplus.
4. Set Stop SOC to the state of charge, which the battery should be charged up to during the period.

On MIN and MOD with a battery (TL-XH), you set the same in the ShinePhone app or on ShineServer: Battery First, a time period, AC charging and the stop state of charge.

With GridZeno you don't need to set the time periods yourself: the dongle switches mode for you according to the plan.

The house first, then the grid, then the battery.

Solar power

First to the house, then the rest is sold, and only after that's the battery charged.

Charging from the grid

No. The battery is only charged with what is left of the sun.

The battery discharges to the house

Yes, and it can sell to the grid at a power you set until it reaches a stop state of charge.

When

In the time slots you have set up.

Grid First is for selling: the solar surplus goes out to the grid instead of into the battery, and the battery can sell its power while the price is high. It only makes sense when the selling price is higher than what the power would otherwise be worth in your own house later.

The description of the three modes follows Growatt's own guide.

The names recur, but the menus and options change from series to series.

SPH, SPA, MIN TL-XH and WIT each have their own menus, and not all have the same modes. The WIT series, which our own system is, has more than the three, including one where the battery neither charges nor discharges while the house buys its power from the grid. GridZeno uses that one to hold the battery.

See which models GridZeno works with, and what each can do, on the compatibility list. Installation is described for each model under Installation.

The price changes every quarter hour and from day to day. A schedule in the inverter doesn't.

Battery First from 02:00 to 05:00 every night hits the cheap hours on some nights and not on others. Some days power is cheapest in the middle of the day, other days there's nothing at all to gain from charging from the grid, because the sun fills the battery anyway. Tomorrow's prices are only known around 13:00 the day before, so a fixed schedule can never keep up.

That's why GridZeno switches mode according to a planthat's recalculated every day from your prices, your solar forecast, your consumption and your battery.

The dongle switches mode according to the plan, and always sets the inverter back afterwards.

Charge from the grid

Battery First, with the block's target as the stop state of charge. When the target is reached, the battery stays idle for the rest of the block.

Hold the battery

The mode where the battery stays idle while the house buys cheap power, so the energy is there when power becomes expensive.

Sell from the battery

A time-limited command in the inverter that expires by itself. GridZeno doesn't use Grid First for it.

The rest of the time

The inverter's own mode, usually Load First.

When the dongle sets Battery First or the mode that holds the battery, they don't expire on their own. That's why the dongle saves the inverter's original setting before it switches the first time, and sets it back when the block ends or when the dongle starts again after a power cut. If the inverter is in a mode you or your installer chose yourselves, the dongle doesn't touch it.

The GridZeno Dongle for Growatt SPH, SPA, MIN and WIT plugs into the inverter's communication port and switches the modes by the plan.

Read how the control looks after your system.