EP600 behavior in grid-connected mode: PV not used for self-consumption when grid is available (confirmation needed)

Product Discussion
1

Hello BLUETTI team,

I would like to ask for a confirmation or clarification regarding the operating logic of the BLUETTI EP600 in grid-connected mode, based on extensive real-world testing.

:wrench: System configuration
• BLUETTI EP600 with battery modules
• DC PV connected (strings within voltage range, PV confirmed working)
• Grid connected to inverter input
• Loads connected to backup/critical-loads output
• No feed-in contract (Feed Into Grid = OFF)
• Typical constant house load: 300–500 W

:gear: Settings used (verified multiple times)
• Charge From Grid: OFF
• Time of Use: ON (tested with multiple schedules)
• SOC Low Limit: OFF
• Balanced Mode: OFF
• Winter Mode: OFF
• Generator Mode: OFF
• SOC range tested: e.g. 50–85%

All settings were applied, saved, and the system was rebooted via System Switch OFF → ON.

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:mag: Observed behavior (reproducible)
1. When the grid is available:
• The inverter remains in Grid-connected Operation
• The battery is charged and held at ~100% SOC
• PV input shows 0 W, despite sunlight being available
• House loads (300–500 W) are supplied from the grid
• This behavior persists even with Charge From Grid = OFF
2. When the grid is physically disconnected (via breaker/isolator):
• The system switches to Off-grid Operation
• PV immediately starts supplying the loads
• Battery SOC decreases normally and/or is supported by PV
• System behaves exactly as expected for PV self-consumption
3. When the grid is restored:
• The system returns to grid-connected mode
• Battery is again charged to 100%
• PV is ignored until battery SOC drops significantly or grid is removed again

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:question: Key question to confirm

Based on the above, it appears that:

In grid-connected mode, EP600 prioritizes maintaining battery SOC (≈100%) for backup purposes and does not operate as a PV-first / self-consumption system when grid power is available, especially at low loads (300–500 W).

Please confirm:
1. Is this behavior by design?
2. Is there any firmware or setting that allows:
• PV to supply loads first
• Battery to discharge for self-consumption
• While the grid remains physically connected (but not used)?
3. Or is physical disconnection of the grid (manual or automatic via contactor) the only supported method to force PV self-consumption with EP600?

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:dart: Reason for clarification

This information is important for users who:
• Want to maximize PV self-consumption
• Use EP600 both as backup and daytime energy optimizer
• Have frequent grid outages and want predictable system behavior

At the moment, all evidence suggests that EP600 is primarily designed as an ESS / backup-oriented inverter, not a PV-first grid-tied inverter.

An official confirmation would be greatly appreciated to help users design correct and safe system architectures.

Thank you in advance.

2

Hey!
I‘m having 1:1 the same issue that you described.

Did you receive and answer or come up with a solution?

Cheers!

3

@OleksiiS
I also have one (two) EP600s, but I don’t see this behavior on mine. It might be due to how the EP600s are used differently, or I’m assuming you’re operating your EP600 outside the standard parameters.

This raises a few questions for me:

  1. How is your EP connected, exactly according to Bluetti’s wiring diagram?
  2. Do you only have this DC-PV string connected to the EP600, or are you also using AC-PV inverters (balcony power plant, etc.)?
  3. What happens if you run your base load NOT on the backup but on the grid?

I myself had a real-life test case just a few days ago when my grid went down (I blew the main fuses myself over the weekend and was therefore on emergency power for two days).
As expected, the EP itself supplied the entire house via the backup; the EP600’s DC-PV string also delivered as much power as the sun could provide at that moment, not the maximum, but not 0 either. However, my battery was no longer at 100% capacity and didn’t reach that level over the weekend either… . That may also be one reason why the DC-PV delivered at “full capacity” and wasn’t throttled.
.
In any case, my house is normally always connected to the grid and is switched from grid to backup via an automatic transfer switch-this works perfectly, except for the brief interruption during the switchover.