EPS setup on GivEnergy varies between Gen 1, Gen 2 and Gen 3 hybrids (the All-in-One backs up through a Giv-Gateway instead). 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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I have a GivEnergy system consisting of two batteries, two inverters and a controlling EMS (Energy Management System) which has not worked since Nov 2025. After six months I discovered Solar Tech Support, reached out to them and Ron phoned me back – how often do you get that service? Could not be more helpful – worked directly with me over the phone, outside what I would call normal working hours. Lucid explanations and we were able to discuss the issues and history using camera and email history. As this was a very rare setup, Ron was able to access an EMS expert in the field to confirm the solution. One sunny day in, I am now only paying for standing charge and a few pence for spikes in grid consumption while battery catches up with house demand.
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EPS (Emergency Power Supply) is GivEnergy's battery backup function. Understanding exactly how it works is essential before diagnosing why it failed.
When the grid fails, GivEnergy's EPS mode switches the dedicated EPS output terminals from grid power to battery power. On a hybrid or AC-coupled inverter that changeover takes about a second in our experience, so it is a quick restart rather than an uninterrupted handover. A Giv-Gateway on an All-in-One is quicker: we see about 20 ms. Only circuits wired to those specific terminals receive backup power.
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.
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 is disabled by default on every GivEnergy hybrid inverter and on the AC 3.0. 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.
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.
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.
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: 2.6kW on a Gen 1 hybrid, 3.6kW on a Gen 2 or Gen 3 3.6/5.0kW hybrid, 8 to 10kW on a Gen 3 8.0/10.0kW hybrid and 3kW on the AC 3.0. The Gen 1 All-in-One (6kW and 3.6kW models) has no EPS terminals: it backs up the whole house through a Giv-Gateway (6kW continuous), or not at all.
This is a notifiable electrical installation and should be done by a Part P registered electrician or a qualified solar engineer.
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.
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.
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 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.
The Gen 1 figure is the most it can supply from the battery alone. Ratings vary by inverter model. Always verify against your specific model's datasheet before sizing an EPS circuit.
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.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.
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.
Do not simulate a power cut yourself. A competent person tests EPS by isolating the supply upstream of the inverter, with instruments on. They check that the backed-up circuits stay powered, then that the system reconnects to the grid on its own.
Some appliances are sensitive to the changeover gap when EPS activates. On hybrid and AC-coupled EPS terminals the handover takes about a second in our experience, so computers, NAS devices and some boiler controls will restart during the 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.
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.
See battery not charging →Battery fault codes including EPS overload and protection events.
See red light / battery alarm →Firmware updates that reset EPS mode or other system settings.
See firmware issues →Browse all GivEnergy fault guides — battery, portal, BMS comms, firmware and more.
See all GivEnergy problems →This is a brand-specific version of our general no backup during power cut guide, which covers all brands.
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.
I’ve worked on hundreds of GivEnergy systems and know the kit inside out. If yours is playing up, my promise is simple — no fix, no fee: just £125 if we fix it, free if we don’t.
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