GivEnergy EPS Not Working During a Power Cut
You have a GivEnergy battery but the house went dark during a grid outage. EPS (Emergency Power Supply) is disabled by default on all GivEnergy inverters and requires both a software setting and a dedicated wired circuit. This guide covers every reason EPS may have failed — and how to set it up correctly. For the general technical background, see how backup power works.
Jump to cause
EPS setup on GivEnergy varies between Gen 1, Gen 2, Gen 3, and All-in-One models. Whether your system has a wired EPS circuit, what the SoC minimum should be set to, and which portal settings apply — we can review and configure this remotely.
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What GivEnergy EPS actually does — and what it doesn't
EPS (Emergency Power Supply) is GivEnergy's battery backup function. Understanding exactly how it works is essential before diagnosing why it failed.
Powers a dedicated backup circuit
When the grid fails, GivEnergy's EPS mode switches the dedicated EPS output terminals from grid power to battery power within approximately 20ms. Only circuits wired to those specific terminals receive backup power.
Does not back up the whole house
The main consumer unit and all sockets and lights not wired to the EPS circuit remain off during a grid outage. EPS is for essential circuits only — typically a few key sockets, boiler, or lights selected at installation.
Both wiring and settings
EPS requires: (1) a dedicated EPS output circuit physically wired by the installer to the inverter's backup terminals, AND (2) EPS mode enabled in the GivEnergy portal. Missing either one means no backup power.
EPS mode is not enabled in the portal
EPS is disabled by default on every GivEnergy inverter. It must be explicitly enabled in the GivEnergy portal. This is the most common reason backup power doesn't work — the physical wiring is correct but the inverter has never been told to use it.
How to check if EPS is enabled
Go to givenergy.cloud → My Inverter → System Mode Settings.
EPS settings are typically found in the System Mode Settings or Advanced Settings section depending on your portal version. Look for a toggle or option labelled EPS, Emergency Power Supply, or Backup. If it is set to Off or Disabled, this is your problem.
GivEnergy firmware updates can reset settings including EPS mode back to defaults. If EPS was working and then stopped after an update, check whether the setting has reverted to disabled.
No dedicated EPS output circuit was installed
Even if EPS mode is enabled in the portal, backup power only reaches circuits that are physically wired to the inverter's EPS output terminals. Many UK GivEnergy installations do not include this wiring — it is an optional additional cost that many installers don't include as standard.
How to tell if you have an EPS circuit
Adding an EPS circuit — what's involved
Adding an EPS circuit is an electrical installation job. A qualified electrician or GivEnergy-experienced engineer runs a dedicated circuit from the inverter's EPS output terminals to a sub-board or specific sockets and circuits that you want backed up.
You need to decide which loads to back up — common choices are a key socket, the boiler, fridge, and critical lighting. The total load must not exceed the inverter's EPS output rating (typically 3kW on Gen 2, 6kW on Gen 3 and AIO).
This is a notifiable electrical installation and should be done by a Part P registered electrician or a qualified solar engineer.
Battery was below the minimum SoC reserve at the time of the outage
GivEnergy EPS will not activate if the battery state of charge is at or below the EPS reserve threshold. If the outage happened at night after a long discharge period, or the battery has been undercharging due to a separate fault, EPS may have had nothing to draw from.
Check battery SoC at time of outage
In the GivEnergy portal, navigate to the battery SoC graph and look at what the SoC reading was at the time the outage occurred. If the battery was at or near the reserve minimum (or at 0%), EPS had insufficient charge to operate.
The EPS reserve setting is typically in Battery Options under the minimum SoC or reserve percentage. Check what this is set to — if the battery was above this at the time of the outage but EPS still didn't work, the SoC is not the cause.
Configuring the EPS reserve correctly
The EPS reserve (minimum SoC) determines how much battery charge is held back specifically for backup power. Setting it too low means EPS may be unavailable when you need it. Setting it too high means less battery capacity for daily use.
EPS tripped immediately — load exceeded inverter backup rating
EPS activated but then cut out within seconds. The total power draw on the EPS circuit exceeded the inverter's backup power rating, triggering the overload protection. This produces the fault code STORAGE_ERROR_BACKUP_OVERLOAD_FAULT.
GivEnergy EPS power ratings
Ratings vary by inverter model. Always verify against your specific model's datasheet before sizing an EPS circuit.
What to do about an overload
STORAGE_ERROR_BACKUP_OVERLOAD_FAULTCheck the portal event log for this code — if present, the load on the EPS circuit exceeded the inverter's backup power rating.Suitable and unsuitable EPS loads
Total load on the EPS circuit must not exceed the inverter backup rating. Account for startup surges — motor-driven loads like fridges draw 2–3× their running wattage for 1–2 seconds on startup.
Enabling and configuring GivEnergy EPS correctly
Before enabling EPS in the portal, confirm that a dedicated EPS output circuit was physically wired at installation. Enabling EPS without the correct wiring has no effect — it will not provide backup power and may cause unexpected behaviour.
EPS setup checklist
Verify with your installer documentation or by visually checking the consumer unit for a dedicated EPS/backup circuit. If not installed, contact a qualified engineer to add one before proceeding.
Go to givenergy.cloud → My Inverter → System Mode Settings. Find the EPS or backup power setting and enable it. Press Submit to apply. The exact label and location varies between portal versions — it may be under Battery Options or Advanced Settings on some models.
Under Battery Options, set the minimum SoC reserve to the level that gives you your desired backup duration. A 20–30% reserve is a reasonable starting point for most households. This is the charge held back exclusively for EPS use.
To test EPS without a real power cut, you can turn off the main AC isolator below the inverter while the battery is charged and EPS is enabled. The EPS circuit should remain powered from the battery. Only do this if you understand what you are doing — turning off the AC isolator isolates the inverter from the grid. Restore it promptly. Do not turn off the consumer unit main switch as this may disconnect EPS loads.
Appliance compatibility with EPS
Some appliances are sensitive to the ~20ms switching time when EPS activates. Computers, NAS devices, and some boiler controls may restart during the brief switchover even when EPS is working correctly. This is not an EPS fault — it's a limitation of the technology. A UPS (uninterruptible power supply) on sensitive equipment can bridge this gap.
EPS and the inverter status light
During EPS operation, the inverter status light behaviour changes — the inverter is no longer connected to the grid and operates in island mode. This is normal. If the battery depletes fully during EPS and the grid is still down, all power will be cut. The inverter will restart automatically when grid power returns.
Battery not charging overnight — low SoC means less EPS reserve too.
Battery fault codes including EPS overload and protection events.
Firmware updates that reset EPS mode or other system settings.
Browse all GivEnergy fault guides — battery, portal, CAN, firmware and more.
GivEnergy EPS questions
No. GivEnergy EPS only powers circuits physically wired to the inverter's dedicated EPS output terminals. Your main consumer unit and all sockets and lights not on the EPS circuit will remain off. EPS is designed for essential loads only — a few key circuits selected at installation time. If you want whole-house backup, that requires a different system architecture.
Duration depends on the battery capacity, the SoC at the start of the outage, the EPS reserve setting, and the load on the backup circuit. As a rough guide: a 5kWh battery at 80% charge running a 200W load would last approximately 20 hours. Running a 1kW load (fridge + a few lights + boiler) would last around 4 hours from that starting point. Reduce load to extend duration.
Yes, in most cases. A GivEnergy-experienced electrician can add the EPS output circuit retrospectively. The inverter already has the backup terminals — it's a matter of wiring the correct circuits to them and enabling EPS in the portal. This is a notifiable electrical installation and must be done by a qualified Part P registered electrician.
Two possible causes: the boiler isn't wired to the EPS circuit (it's on a standard circuit that goes off during an outage), or the boiler control system is sensitive to the ~20ms EPS switching delay and resets. Some boiler controls need to complete a power-on sequence and won't do so correctly after a brief interruption. A small UPS on the boiler can bridge this gap if the ~20ms delay is the issue.
Yes. EPS draws from the battery regardless of whether solar panels are generating. During a night-time power cut, EPS will run entirely from stored battery charge. If the grid outage extends into daylight and your system has panels, solar will also charge the battery and extend EPS duration — but only if the panels can generate (clear skies, inverter running in island mode).
EPS not working? We'll find out why and configure it correctly.
Tell us whether you had EPS wiring at installation, what the battery was showing at the time of the outage, and what the portal settings look like. We'll identify the cause and configure EPS correctly for your system.
This is a brand-specific version of our general no backup during power cut guide, which covers all brands.