Upgrading from EcoFlow PowerOcean to SigEnergy SigenStor

EcoFlow PowerOcean and SigEnergy SigenStor — the honest version

EcoFlow's PowerOcean is a well-engineered residential storage platform: LFP batteries, a hybrid inverter and a tidy app, expandable by adding battery units. It suits a great many Scottish homes, and where one is already installed and performing, there is often no compelling reason to change.

The Sigenergy SigenStor takes a different design approach. Rather than a set of co-ordinated but separate products, it integrates the PV hybrid inverter, the battery power-conversion system, the battery pack, an optional bi-directional EV DC charger and the energy-management system into a single stackable tower. It is offered in single-phase (3.6–12 kW) and three-phase (5–~25 kW) configurations, which is the part most relevant to larger Central Belt homes.

So the question is not "which is better" in the abstract — it is "which fits your supply, your EV plans and how much you want integrated". That is exactly the call Ecoaim is set up to make impartially, because we install both.

EcoFlow PowerOcean vs Sigenergy SigenStor — comparison table

A factor-by-factor comparison. SigenStor figures are taken from the verified Sigenergy specification; EcoFlow rows describe the architecture difference rather than any quality judgement.

Specifications can change between product revisions. Ecoaim confirms the exact, current specification and warranty terms of both systems against your specific site at survey stage.

PowerOcean vs SigenStor — the numbers, reviewed 2 September 2026

The table above compares architecture. This one compares figures. EcoFlow rows are the PowerOcean specification Ecoaim works to across the 200-plus PowerOcean systems we have installed; SigenStor rows come from the verified Sigenergy specification. Note the warranty row in particular — EcoFlow wins it, and no honest comparison should bury that.

Figures as at 2 September 2026, re-confirmed against the current product revision and current pricing at quotation. Prices are indicative starting points, not quotations.

When an EcoFlow → SigEnergy upgrade actually makes sense

There are four situations where households tend to benefit from moving to the SigenStor. If none apply to you, an upgrade may not be worthwhile — and we will tell you that.

Stay on the PowerOcean, or move to the SigenStor?

Most comparisons only argue one direction. Here are both, so you can place yourself before you spend anything.

What actually happens on a PowerOcean → SigenStor changeover

Every other comparison of these two systems stops at the spec sheet. None of them tell you what the job involves — and the job is where the cost, the timeline and most of the surprises live. This is the installer's view of a changeover, written from how Ecoaim actually runs one from our Livingston EH54 base.

What carries over, and what comes off the wall

The most common misconception about this upgrade is that it means a new solar installation. It does not. In the great majority of cases the array stays exactly where it is and only the storage side changes — which is precisely why a changeover costs materially less than a first-time solar-plus-battery install. Here is the disposition list, item by item. Every line is confirmed against your actual property at survey before anything is agreed.

The DNO step every comparison skips: G98, G99 and re-notification

Changing the storage inverter changes the registered generation and storage device on your electricity connection. That means your Distribution Network Operator has to be told again — the notification made when your PowerOcean went in does not cover the system that replaces it. This is the single most commonly missed step in a battery changeover, and getting it wrong can put your export arrangement and your MCS position in an awkward place.

The threshold is 16 A / 3.68 kW per phase. At or below it, the connection is handled by a G98 notification, which can be submitted after the works are complete. Above it — which is where most SigenStor configurations sit, and certainly any three-phase one — you need a full G99 application, submitted and approved before the install. That is a programme item, not a formality.

Which network operator you deal with depends on where you live. SP Energy Networks covers most of the Central Belt — Edinburgh, Glasgow, Falkirk, Fife, the Lothians and most of Lanarkshire — and typically issues connection offers in 6–12 weeks for standard sites. SSEN covers Stirling and Clackmannanshire on a separate portal, typically 8–14 weeks. If you also need a single- to three-phase supply upgrade to make the most of a three-phase SigenStor, expect roughly 6–10 weeks lead time on top in our area. Ecoaim submits and manages the application as part of the works — you do not deal with the DNO yourself. See our DNO and G99 guide for how the process runs end to end.

Warranty: the part of the upgrade that costs you money

This deserves its own section because it is the strongest argument against the upgrade, and you will not find it in a manufacturer comparison. The EcoFlow PowerOcean carries a 15-year warranty — the longest of any battery Ecoaim fits, longer than the SigenStor's roughly 10 years. That cover attaches to the EcoFlow equipment. Take the equipment off the wall and the remaining years go with it.

So if your PowerOcean is three years old and healthy, an upgrade is not just the price of a SigenStor — it is the price of a SigenStor plus a dozen years of unused warranty you paid for and are writing off. That is a real number and it belongs in the decision. Whether the balance of the cover can pass to a private buyer if you resell the unit is governed by EcoFlow's own warranty terms, and you should confirm that with EcoFlow before assuming resale recovers it.

The upgrade cases where this objection disappears are the obvious ones: equipment already out of warranty, equipment that has failed, or a household whose requirement has genuinely outgrown what a single-phase 5 kW system can deliver. Those are the cases we take on.

What it costs — and the VAT position

We do not publish a changeover price, because a genuine one does not exist: it turns on stack size, single- or three-phase, whether an EV DC charger module is included, the state of the existing DC side and how much removal work is involved. What we can publish are the reference points. SigenStor battery modules start from around £2,500 per 5 kWh ex-install, and the integrated EV DC charger module from around £3,500. For a sense of scale in the other direction, a first-time PowerOcean install starts from £6,800 fully installed at 5 kWh.

Installation of qualifying energy-saving materials carries 0% VAT until 31 March 2027, after which the reduced rate is scheduled to return. That deadline is the one genuine piece of timing pressure in this decision, and it applies to a new install and a changeover alike. Figures are as at 2 September 2026 and confirmed at quotation.

Set against that, the changeover saving is the array: panels, mounting and usually the DC cabling stay, so you are not paying for a solar installation twice.

Export payments and tariffs after the change

Your export rate is set by your electricity supplier, not by the battery, so an upgrade does not by itself change what you are paid. What it does change is the paperwork. A new MCS certificate is issued for the new configuration, and your Smart Export Guarantee account has to be updated to match it — if that step is skipped, export payments can stall. Ecoaim issues the MCS certificate and tells you exactly what to send your supplier.

As a reference point for modelling, Octopus Outgoing has paid 12p per kWh exported since 1 March 2026. One important caveat if you are planning around tariffs: Octopus paused Flux to new customers in March 2026, and as of 16 September 2026 its Flux page is taking sign-ups again — check it is open for your postcode before you plan around it. The Sigenergy EMS optimises against whichever time-of-use import and export arrangement you are actually on, which is set up during commissioning rather than left on factory defaults.

Why Ecoaim is the right installer for the upgrade — the honest broker

Most installers stock one brand and steer every customer towards it. Ecoaim installs EcoFlow and SigEnergy, which changes the conversation: the recommendation follows your roof, supply and goals, not our stockroom.

• We install both EcoFlow and SigEnergy, so the recommendation is based on your roof, supply and goals — not on whichever brand we happen to stock.
• If your existing EcoFlow PowerOcean is doing the job, we will say so. An upgrade only makes sense where three-phase, integrated EV DC charging, larger stacks or the AI EMS genuinely add value.
• Where an upgrade is worthwhile, we design the changeover end to end — supply review, system design, install and commissioning from our Livingston EH54 base.
• Systems are supplied direct by sigenergy uk platinum distributor, and Ecoaim is ecoaim is a sigenergy-certified installer.

Mobile show-stand sales tour with the Platinum Distributor being arranged — so if you would like to see the SigenStor in person before deciding, ask and we will let you know when the roadshow reaches your area.

The SigenStor in brief

Frequently asked questions — EcoFlow to SigEnergy