SolaX inverters and batteries in the UK

A SolaX X1 Hybrid G4 lists at £836.50 to £859.60 excluding VAT depending on size (the X1-IES all-in-one is £1,050), and a 5.8 kWh Triple Power battery at £1,461.60, so a 5 kW hybrid with one battery is roughly £2,400 of hardware before anyone climbs a ladder. The warranty is where the interesting reading is. Every residential SolaX inverter carries five years as standard. The ten years your quote almost certainly promises is a free upgrade that SolaX grants only once the inverter is connected to SolaX Cloud and has successfully uploaded generation data. The dongle that does the uploading is warranted for two years.

Everything below is taken from SolaX's own current UK documents, from live UK trade listings and from the Companies House register, all read on 29 September 2026. Where a figure contradicts what is circulating elsewhere, including elsewhere on SolaX's own website, the warranty document is the one quoted, because that is the one that governs a claim.

What SolaX kit costs in the UK

Between £786.80 and £1,050 excluding VAT for a single phase inverter, and £1,281 to £1,461.60 for a Triple Power battery module. These are the public list prices shown by Midsummer Wholesale, a UK solar distributor, on 29 September 2026. A logged-in installer sees lower trade prices, so read these as the ceiling rather than the number on your quote.

Add those up for the system most British households are quoted, a 5 kW hybrid with one 5.8 kWh battery, and the hardware comes to about £2,408 excluding VAT. Adding the Matebox for whole home backup takes it to roughly £3,045. Stack a second battery module and you are at about £3,870 for 11.6 kWh, which works out at around £334 per kWh of storage with the hybrid inverter, meter and cable included. For comparison, Tesla's published UK hardware price of £5,975 for a 13.5 kWh Powerwall 3 with Gateway is about £443 per kWh. SolaX is the cheaper route to storage, and it gets cheaper the more you stack.

Those are trade prices excluding VAT because that is how distributor listings are written. On a supply and install job in a home you will not add it back: solar and battery installation is zero rated until 31 March 2027 under HMRC VAT Notice 708/6, after which it goes to the 5% reduced rate rather than 20%, as set out on our 0% VAT guide. Buy the parts on their own and you pay 20%. That gap is the single most common misreading of a trade price, and it flatters the DIY route by about a fifth.

One caution on the listings themselves. Midsummer's page titles the T58 as a 5.1 kWh battery while its own description calls it 5.8 kWh, and titles the TP-HS50E as 4.6 kWh while describing it as 5.1 kWh. SolaX's warranty document gives 5.8 kWh and 5.1 kWh respectively. Check the model number rather than the headline capacity on any quote, because this kind of drift is common across UK solar listings and we have found it on Fox ESS listings too.

The ten year inverter warranty is a five year warranty with a condition

SolaX's Warranty Terms and Conditions for the UK and Ireland, version 1.7, covering products installed from 1 July 2026, gives the X1 and X3 Hybrid G4 range "5 years standard warranty" and then adds a note: if the inverter is "connected to Solax cloud and generation data been successfully uploaded to Solax server, the inverter warranty will be freely upgraded to 10 years standard warranty".

That is the whole mechanism. Nobody buys a SolaX inverter with a ten year warranty. You buy one with five, and the second five arrives on a condition that has to keep being true.

The same structure runs through the entire range, at different strengths:

• X1-IES and X3-IES all in one units: five years, upgraded to twelve with cloud data.
• X1 and X3 Hybrid G4, Fit G4, X3-Ultra, X3-HYB-G4 PRO, X1-VAST: five years, upgraded to ten.
• X1-MINI, X1-Boost, X1-SMART G2, X3-MIC, X3-Pro: five years, upgraded to ten.
• X1-Hybrid-LV, X1-Lite-LV, X3-NEO-LV, X1-Reno: five years, and the upgrade to ten requires cloud data and a SolaX battery. Pair one of these with another brand's battery and the second five years never arrives.
• X1-Hybrid and Fit G3, X3-Hybrid and Fit G2, X3-MAX, X3-MEGA G1: five years flat. No upgrade is offered at all.
• X3-MEGA G2, X3-Forth, X3-GRAND: five years, and the cloud "upgrade" adds one year of parts only. The document defines that as covering "only the cost of hardware material", excluding transport and labour.

Five years is not a scandal on its own. The Energy Saving Trust's own solar guide, last updated 1 October 2026, says "most inverters have warranties of five years as a minimum, which you can often extend by up to 15 years", and puts typical inverter replacement at around twelve years. What SolaX has done is set its floor exactly at the industry minimum and make the number everybody quotes contingent. If the property changes broadband, the dongle fails and nobody notices, or the owner opts out of sending generation data to a server in China, the inverter is on the floor figure.

This is now the sixth brand where we have found the warranty resting on a live internet connection, alongside SolarEdge, Enphase, Growatt, Fox ESS and Tesla. SolaX is the only one that frames it as a gift rather than a penalty, and the only one that puts the unconnected number at the sector's stated minimum.

The part that holds the warranty open is covered for two years

SolaX's accessories schedule gives "Pocket Wifi/Lan/4G" and the DataHub a two year warranty. Those are the devices that deliver the cloud connection that upgrades the inverter from five years to ten. A two year component is load bearing for an eight year uplift.

The good news is that the dongle ships in the box: Midsummer's listing for the X1 Hybrid G4 explicitly says "inc. WiFi dongle". The bad news is that its two year term is the shortest absolute warranty we have found on any part in this position. SolarEdge warrants its cellular communication product for five years against a twelve year inverter. Enphase warrants its IQ Gateway for five against a twenty five year microinverter. SolaX warrants its dongle for two.

Nothing in the warranty says the upgrade is revoked if the dongle dies. It says the upgrade is granted when data has been uploaded. Read strictly that is a one time event, and most installers will tell you the ten years sticks. The document does not say so in terms, which is exactly why it is worth having your installer confirm in writing what happens in year six if the connection has been dead since year three.

Your warranty may have started before you owned it

Every warranty period in the SolaX document begins from "the earlier one of the following two dates: the date on which the product was first installed; 9 months after the date of production". Not the date of purchase, and not simply the date of installation. The earlier of the two.

An inverter built in January and sitting in a distributor's warehouse until the following April is already nine months into its five years on the morning it is switched on. Clearance and end of line stock is where this bites hardest, and UK distributors run clearance sections precisely for this kind of inventory. It is worth asking for the manufacture date on the unit being fitted, particularly on a discounted quote.

Registration compounds it. Section 8 requires the customer to register the product within 90 days of commissioning, and states that if they do not, "the product warranty period will be obtained standard warranty, and counted automatically after the manufacturing date, and additional 9 months". In other words, missing the registration window removes the option of the installation date entirely and forces the manufacture-plus-nine-months clock even when it is the worse of the two.

If you are also replacing the roof, note section 10(G): moving the product after installation voids the warranty "regardless of whether it has been reinstalled subsequently or moved back to the same location", unless a qualified installer refits it at the same address and files a test report with SolaX. Anyone planning panels alongside a new roof covering should get that sequencing right the first time.

The battery cycle cap SolaX's own datasheet contradicts

The T58 datasheet advertises "Cycle life (95% DOD) >6000 Cycles" to 70% end of life. The warranty for the same battery guarantees 70% of nominal energy for 18.9 MWh of throughput, which on a 5.8 kWh pack is 3,259 cycles. Same manufacturer, same product, same 70% endpoint, and the contractual promise is 1.8 times shorter than the marketing claim.

SolaX's performance warranty covers whichever comes first, the warranty period or the energy throughput figure. Dividing each battery's throughput allowance by its nominal energy turns the table into something you can actually plan around. At one full cycle a day, which is how a UK solar battery is normally used:

Two things come out of that table. First, the twelve year batteries are not twelve year batteries in daily use. Their throughput allowances land between eight and a half and nine years, so the cap expires roughly three years before the date does. Second, TB-HR140 is the only SolaX residential battery on the list where the ten year date genuinely binds first, with an allowance equivalent to nearly eighteen years. If the warranty term is what is selling you the battery, that is the one whose headline survives contact with the arithmetic.

The retention floor is 70% of nominal energy, measured with the pack starting at 25 to 30 degrees and charging at 0.5 C. That puts SolaX level with Enphase, below Tesla, which guarantees 80% at ten years for UK installs, and above Growatt at 60%. For how much of a battery you can actually use on any brand, and whether you need one at all, start with our solar battery storage guide.

Two clauses shape how you should run the battery. SolaX states that where a battery is charged from the grid, "the total energy taken from grid won't be completely the same as the total energy discharged from the battery system. Hence, the warranty claim under such conditions will not be accepted." Anyone planning to fill the battery on a cheap overnight rate should read that carefully before assuming a capacity claim will succeed. And section 1 excludes from cover "all external and ancillary parts and units (eg. Monitoring/Comm devices, batteries, hardware/software controllers etc) installed with inverters by third-parties", so pairing a SolaX hybrid with a third party battery leaves the battery side outside SolaX's warranty entirely.

3.68 kW is where SolaX drew the line

The X1 Hybrid G4 is sold as a 3.0, 3.7, 5.0, 6.0 or 7.5 kW inverter, and the 3.7 model's rated output is 3,680 W, which at 230 V is exactly 16 A. That is not a coincidence. 16 A per phase is the threshold in the Energy Networks Association's EREC G98, the line below which your installer can connect the system and tell the distribution network operator afterwards. Midsummer's own product picker drops the marketing rounding and lists it as 3.68 kW.

Everything above it needs a G99 application submitted to the distribution network operator and approved before the system is connected, which can add weeks. The 5.0 kW model draws about 21.7 A, the 6.0 about 26.1 A and the 7.5 about 32.6 A. Our G98 and G99 guide covers what each route involves and how long approval takes. This is Great Britain's framework; in Northern Ireland the registration goes to NIE Networks.

Watch out for a second 16 A on the same datasheet that means something completely different. Every X1 Hybrid G4 model lists "max. input current per MPPT 16 A / 16 A", which is a DC limit on the panel side and has nothing to do with the grid connection rule. Two identical numbers, two unrelated constraints. The generic version of this distinction lives on our solar inverters guide.

What you actually get in a power cut

SolaX's emergency power supply output matches the inverter's rating right across the X1 Hybrid G4 range, so a 5 kW hybrid gives 5,000 VA of backup and a 7.5 kW gives 7,500 VA. That sounds unremarkable until you put it next to a rival. Growatt's SPH 4000, 4600, 5000 and 6000 all publish the same 4,000 VA standalone backup rating, so buying the bigger Growatt hybrid buys you no extra backup at all. SolaX's scales. Peak output runs to 150% for ten seconds, which is what gets a fridge compressor or a pump through its start up surge, and switchover is under 10 ms.

Two things to watch. Whole home backup needs the Matebox at £637 excluding VAT, not just the inverter. And SolaX requires that off grid installations are "inspected annually by a qualified electrician and recorded in form of documentation", warning that failure to do so "may invalidate any warranty claims". That obligation applies to full off grid setups rather than to a normal grid connected home with backup, but if your installer is proposing something unusual, ask which side of that line it sits.

One more thing owners notice and worry about. SolaX's own guidance says a Triple Power battery sitting at its 10% minimum overnight will keep drifting down as the system consumes power, and at 5% it will pull a charge from the grid to recover. SolaX calls this normal behaviour that "won't affect the battery life". If your battery charges itself from the mains on a dark February morning, that is the design working, not a fault.

Northern Ireland is covered, and the small print is in Shanghai

SolaX's warranty applies to products "installed in the destination defined within the United Kingdom and Ireland", which includes Northern Ireland. That is worth saying because it is not the norm. Enphase's current UK warranty names a covered territory of "Scotland, England, and Wales" and leaves Northern Ireland out. SolaX covers all four nations.

The counterweight is section 15(B). The warranty "shall be governed by and construed in accordance with the laws of P.R. China", with disputes settled by arbitration at the Shanghai International Arbitration Centre, in English, loser pays costs. The warrantor named on the document is SolaX Power Network Technology (Zhejiang) Co., Ltd in Hangzhou.

In practice it matters less than it reads. A manufacturer's voluntary warranty sits on top of your statutory rights rather than replacing them. Under the Consumer Rights Act 2015 your claim for goods that are not of satisfactory quality is against the trader who sold them to you, which on a solar installation is your installer, not a company in Zhejiang. Use the warranty as the backstop and the installer as the first call. SolaX's own claims procedure says the same thing, directing claimants to "the local distributor where the product was purchased, or the installer who installed the inverter" before escalating.

There is a genuinely reassuring detail here that most brands do not offer. Section 7 states that "the transportation costs of replacement units, including shipments, duties, import & export fees, are covered by this warranty in the United Kingdom and Ireland". Parts and freight are on SolaX. Labour is not: section 10(M) excludes "travel and subsistence expenses as well as on-site installation, modification and normal maintenance costs". A warranty swap in year seven means a free part delivered free, and an electrician's day rate out of your pocket.

The warranty is also transferable. Section 13 lets a customer pass it to "successors and assigns" for the remaining term, with no fee and no form mentioned. That is better than Growatt, whose battery warranty is not transferable at all, and better than Enphase, which charges. Combined with the no-moving rule it transfers with the house rather than with the kit, which is the right way round for anything that affects what solar does to a sale.

The one SolaX buying route to avoid

eBay currently ranks in the top ten UK Google results for both "solax" and "solax battery", and buying SolaX hardware that way is the fastest method of ending up with no warranty at all. Three separate clauses close that door.

Section 1 applies the warranty only where products are "purchased from an authorized reseller, and installed and activated by an installer who is certified by SolaX or its distributors". Section 10(O) excludes anything bought from "nonofficial channels". Section 14 invalidates units sold for one country and installed in another without written approval from SolaX first, which catches a great deal of what turns up on auction sites from continental sellers.

SolaX also runs a serial number blacklist. Its warranty page explains that registration will fail for units from a batch stolen on 18 July 2022 in transit from the Netherlands to the Czech Republic, and that for those "we will not provide any effective warranty protection, as well as service or technical support". If you are buying anything second hand or unusually cheap, ask the seller for the serial number and check it before money changes hands.

Where SolaX fits, honestly

SolaX is the value hybrid in the UK market: cheaper per kWh of storage than Tesla, better specified on backup than Growatt, and backed by paperwork that is more conditional than the sales pitch suggests. None of that makes it a bad choice. A 5 kW hybrid with 5.8 kWh of storage at roughly £2,400 of hardware is competitive, the EPS output genuinely scales with the inverter, and the UK entity behind it has been filing accounts since 2018.

That last point is worth stating because the two previous brands we checked did not have it. SOLAX POWER UK LIMITED, company number 11596551, is active at Riversdale House in Atherstone, Warwickshire, incorporated on 1 October 2018, with accounts filed to 31 December 2025 and a confirmation statement dated 10 September 2026. Its registered activity is wholesale of electronic equipment, which is exactly what it does: it supplies distributors and installers rather than selling direct to the public. By contrast, Growatt's two named UK companies were both dissolved in 2019, and Enphase's UK company was dissolved in 2018 with a branch only reopened in August 2025. Continuity of a UK presence is not nothing when you need a part in year six.

What to do about it is straightforward. Ask the installer to confirm in writing which SolaX model they are fitting, its manufacture date, that they will register it inside 90 days, and what the warranty term is if the internet connection stops. If the quote says ten years, ask them to write ten years. A quote that will not put its own warranty claim in writing is telling you something.

SolaX hardware is one line on a solar quote, and the line that decides your payback is the total. Our UK solar panel cost guide covers what a full system runs to, and the choosing panels guide covers the modules that sit above the inverter. The Energy Saving Trust puts a typical 4.5 kWp UK system at around £7,600 and payback at about 9 years in London, 10 to 11 in Manchester and 11 to 12 in Stirling, with export payments included.

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