Topologies covered: Peak shaving capabilities for Solis hybrid inverters with a generator or the grid connected to the Grid Port of the Solis inverter.
Audience: Installers, system integrators, and applications engineers
Owner: Solis USA Product / Applications Engineering
Last updated: September 9, 2026
Applicable Solis Products:
- S6-EH2P(9.6-16)K-SV-YD-L-US
- S6-EH3P(30-60)K-NV-YD-H-US
- S6-EH3P(60-150)K-NV-YD-H-US
Overview
A lot of installers ask whether a Solis hybrid can hold an AC source to a fixed output while the battery quietly picks up the slack. The answer is yes. On the 9.6-16K, 30-60K, and 75K-150K hybrid platforms, the inverter can enforce a hard AC input cap on the Grid Port, trim battery charging as site load rises, and then discharge the battery to cover any load above the cap. That control works whether the source on the Grid Port is a generator or the utility. All of it is closed loop and driven by the CT/meter kit that ships with the inverter. No third party controller and no extra metering.
This article covers both cases in the same place, because they use the same underlying settings and behavior, just applied to different sources.
The first section covers a generator landed on the Grid Port, which is the configuration used to protect a generator from being overloaded on an off grid or generator supported site.
The second section covers the utility grid on the Grid Port, which is the configuration used to reduce demand charges or to hold import below a service or transformer limit on a grid connected site.
Generator Peak Shaving
When to use this configuration
Use generator peak shaving whenever a generator is landed on the Grid Port and the operator needs the total power drawn from the generator to stay under a fixed number (kW), with the battery covering anything above that limit. This is for off grid hybrid sites where the generator is sized for average load and the battery is expected to absorb load spikes and support charging headroom.
What "generator peak shaving" means in this configuration
The inverter continuously measures the AC power flowing through the Grid Port and holds it at or below a value you set. Because the generator is the source on that port, the ceiling becomes the maximum load the generator will ever see, regardless of what the site loads are doing.
In practice that means the system can:
Run the site off the generator and charge the battery from any headroom the generator has left.
Automatically pull charging back as load rises so the total draw on the generator stays under the configured cap.
Discharge the battery to supplement the generator once the load crosses the cap, so the generator itself never gets pushed past that limit.
Ramp charging back up the moment load falls again and the headroom returns.
The result is a very flat generator load profile. From the generator's point of view, the site behaves like a well behaved load that never exceeds the number you gave the inverter.
Important: Per Solis guidance, when a generator is connected to the Grid Port, the inverter must be operated in Self Use mode. Off Grid mode is intended for sites with no AC source ever, and it will not produce the behavior described here.
Note: The dedicated Smart Port (Genset input) is a different topology with its own settings such as GEN Charge Power and the ON/OFF SOC% dry contact. That configuration is covered in a separate guide. This section is specifically for a generator on the Grid Port.
Settings
Two things need to be true for the inverter to hold the generator to a cap:
Storage Mode must be set to Self Use.
Peak-Shaving must be enabled and set to the desired cap.
The peak shaving switch enables the peak shaving control. Off by default. Set to Enable to establish the cap (kW). The inverter will not allow more than this amount of power to be drawn from whatever is sitting on the Grid Port, which in this case is the generator. For example, on a 90 kW generator where the operator wants to hold demand at 70 kW, set Grid Peak-Shaving = 70000 W.
How the battery ends up charging from the generator
In Self Use mode the inverter's default logic is to serve the loads first, then charge the battery with any remaining headroom, then export if configured to do so. When the AC source is a generator and Grid Peak-Shaving is armed, that "remaining headroom" is simply the difference between the cap and the current site load. As load rises, that headroom shrinks, and the inverter automatically pulls charge power down to match. When the load crosses the cap, the battery starts discharging to supplement the generator so the number at the Grid Port stays put.
You do not need to hand tune a separate "generator charge power" for this topology. That parameter lives under Smart Port > Genset Input and applies when the generator is connected to the Smart Port, not the Grid Port. On the Grid Port, the Storage Mode logic plus the Grid Peak-Shaving cap are what shape the behavior.
Battery limits still apply. Max. Charge Current, Max. Discharge Current, Max. Charge SOC%, temperature, and BMS state will all clip the actual charge and discharge power the inverter can command. If the battery cannot accept the full headroom, the difference simply is not consumed from the generator.
Worked example, 70 kW cap on a 90 kW generator
Assume a healthy battery with room to charge and discharge, and ignore conversion losses for clarity.
Real world numbers will differ slightly because of inverter efficiency, battery C rate limits, and the state of charge at the moment the reading is taken. The behavior, though, is the one shown above.
Commissioning checklist (generator)
Land the generator on the Grid Port through a properly rated disconnect and per NEC and local code.
Install the supplied CTs (or the external meter, depending on the platform) on the AC input in the polarity and orientation specified in the installation manual.
Bring the inverter online in SolisCloud and confirm it is on current firmware.
Set Battery Type and Battery Model to match the connected battery, and confirm battery communication is healthy on the closed loop platforms.
Under Storage Mode Setting, select Self Use.
Under the peak shaving settings:
Set Grid Peak-Shaving Switch to Enable.
Set Grid Peak-Shaving to the desired cap in watts (for example 70000 for a 70 kW cap).
Confirm battery parameters. Max. Charge Current, Max. Discharge Current, Max. Charge SOC%, and the reserve settings should reflect the customer's operating goals for this site.
Validate on site. Step the site load through several values below and above the cap and confirm the reading at the Grid Port stays at or below the configured limit in each case. It helps to log a few minutes of data in SolisCloud during the test.
Notes and limitations (generator)
The cap is a steady state control. Very fast transients still traverse the generator before the inverter can react, so size the generator with margin above the cap.
Charging response is bounded by the battery's allowed charge current, state of charge, and temperature. The BMS on closed loop batteries has final say over the charge curve.
Discharge support above the cap is bounded by battery state of charge and by the inverter's own discharge rating. As the battery approaches its lower limits (for example Over Discharge SOC%), the inverter will stop drawing from it, and any load above the cap will then push the generator past the cap until load drops.
Battery Reserve Switch and Batt Reserved apply to on grid, normal operation. Those settings decide how much stored energy is held back for a true outage, so keep them in mind if the customer expects the battery to be available for outage backup as well as for peak shaving on the generator.
Allow Export and Max Export Power relate to utility export and do not need to be enabled for the generator peak shaving behavior itself. If the site has no utility at all, these settings will not affect operation on the generator.
Grid Peak Shaving
When to use this configuration
Use grid peak shaving whenever the utility is landed on the Grid Port and the operator needs to cap the amount of power imported from the utility. Common reasons include reducing peak demand charges on a commercial service, staying under a service or transformer rating, honoring a utility interconnection limit on import, or shaping the site's import profile through the day. The inverter uses the same underlying control as the generator case, only now the "source" is the utility rather than a genset.
What "grid peak shaving" means in this configuration
The inverter measures the AC power flowing in from the utility through the Grid Port and holds imported power at or below a value you set. Anything the site wants beyond that number is supplied by PV first and by the battery second.
In practice:
When site load is under the cap, the inverter imports what is needed and keeps the battery idle, preserving stored energy for when it is actually needed.
When site load is at the cap, the inverter holds import at the cap and covers any additional demand from PV and battery.
When site load exceeds the cap, the battery discharges to make up the difference, so utility import stays at the configured limit.
When PV is available, PV serves load first per the Self Use priority. Grid peak shaving only kicks in on the import side when load exceeds what PV and battery can cover in real time.
Because the battery is intentionally kept idle below the cap, its stored energy is available for the moments that would otherwise trip a new demand peak. That is where the value of grid peak shaving comes from on demand charge tariffs.
Settings
Two things need to be true for the inverter to cap utility import:
Storage Mode must be set to Self Use.
Grid Peak-Shaving must be enabled and set to the desired import cap.
The peak shaving switch enables the peak shaving control. Off by default. Set to Enable to establish the cap (kW). The inverter will not allow more than this amount of power to be drawn from whatever is sitting on the Grid Port, which in this case is the generator. For example, to keep utility import at or below 100 kW on a service that would otherwise pull higher during evening ramp, set Grid Peak-Shaving = 100000 W.
Worked example, 100 kW import cap
Assume PV is producing 40 kW and the battery has capacity to discharge.
Real world numbers will vary with PV output, battery SOC and rating, and load type, but the cap on utility import behaves as shown.
Commissioning checklist (grid)
Land the utility on the Grid Port per the interconnection agreement and local code.
Install the supplied CTs (or the external meter, depending on the platform) on the AC input in the polarity and orientation specified in the installation manual.
Bring the inverter online in SolisCloud and confirm it is on current firmware.
Set Battery Type and Battery Model to match the connected battery.
Under Storage Mode Setting, select Self Use.
Set Allow Export and Max Export Power to match the interconnection agreement.
Under the peak shaving settings:
Set Grid Peak-Shaving Switch to Enable.
Set Grid Peak-Shaving to the desired import cap in watts.
Validate on site. Step site load above the cap and confirm the utility side reading holds at or below the configured limit while the battery covers the difference.
Notes and limitations (grid)
Peak shaving on import is bounded by battery state of charge. Once the battery reaches its lower limit (for example Over Discharge SOC%), it will stop discharging and utility import will rise to serve load again.
Consider the interaction with Battery Reserve Switch and Batt Reserved. Those settings hold energy back for outage backup and reduce the pool available for shaving import peaks. Set them to reflect how the customer wants to trade off backup runtime against demand charge reduction.
Grid peak shaving is a steady state control. Fast transients still traverse the utility briefly before the inverter reacts.
The Grid Peak-Shaving cap governs import only. Export is governed independently by Allow Export, Max Export Power, and Export Power Calibration.
Was this article helpful?
That’s Great!
Thank you for your feedback
Sorry! We couldn't be helpful
Thank you for your feedback
Feedback sent
We appreciate your effort and will try to fix the article