If your quote names the Trina Vertex S+, find the model code on it before you sign. The 2026 EU datasheet for the TSM-NEG9R.28 advertises "up to 25 years product warranty and 30 years power warranty", while Trina's current Global Limited Warranty, revision AC dated June 2026, lists that same model in its 15-Year Limited Product Warranty section. The panel is sold in six power bins from 450W to 475W, with module efficiency from 22.5% to 23.8%. The 30-year power warranty is in both documents. The product warranty term is the one to get in writing.
Checked in October 2026 against Trina's 2026 EU datasheet for the NEG9R.28, Trina's Global Limited Warranty PS-M-0135 revision AC (June 2026), and MCS certificate BABT 8804 R7 from TUV SUD BABT.
Ask each installer for the panel model code and the warranty document that goes with it. Then get a second and third price for the same system size in kWp.
Get a Quote →The warranty gap on the datasheet
Trina's 2026 EU datasheet for the NEG9R.28 lists a 25 year Product Workmanship Warranty and a 30 year Power Warranty under a heading reading "Extended Vertex S+ Warranty", then adds the line "Please refer to product warranty for details".
In revision AC of Trina's Global Limited Warranty, dated June 2026, the TSM-NEG9R.28 sits under section 1 h) (ii), N-type i-TOPCon Mono-facial Dual Glass Products. The warranty for that group is in section 3 c): a 15-Year Limited Product Warranty, covering defects in materials or making that stop the panel generating. Fifteen years on the panel itself, not twenty-five.
Section 13 of the same document says that, apart from statutory rights or a change made in writing and signed by an officer of Trina Solar, this is the only express warranty Trina gives, and nobody else is authorised to restrict, expand or otherwise modify it. So if your contract promises 25 years on the panel, ask the installer for the written warranty that delivers it, with your model code on it. A longer UK term may exist. It is not in the global document, and a brochure is not a warranty.
Two more points from that document. It covers panels delivered on or after 1 June 2026 and runs until Trina issues a new revision, so panels delivered before that date fall under an older version. It also applies in every country except Germany and Turkey, which have their own. The UK runs on this global text.
The 30-year power warranty is the solid half
For the N-type i-TOPCon dual glass products under h) (i) and h) (ii), which include the NEG9R.28, Trina warrants power output for 30 years: no more than 1.0% drop in the first year, no more than 0.4% average a year from year two to year 30, and no less than 87.4% of nameplate power at the end of year 30. The datasheet's warranty graph shows the same 0.4% maximum annual degradation and the same 87.4% at year 30, so this half of the warranty is consistent across both documents.
Output is measured at Standard Test Conditions, either by Trina or by an outside test lab both sides accept. The figure it is measured against, P0, is the lower limit of the nominal power written in your contract or on the nameplate. That is why the minimum power in the contract matters more than the bin number.
When the warranty starts, and it is not install day
Under revision AC, the Warranty Start Date is the date of initial delivery to the customer by Trinasolar or its authorised manufacturer, or six natural months after the module's factory-out date as queried from the serial number, whichever is earlier.
If the panels have been sitting in a distributor's warehouse, the clock can start before they reach your roof, because the factory-out date plus six months can land earlier than delivery. Ask your installer for the serial numbers and the factory-out date. Keep the purchase invoice too, because Trina's claims procedure asks for it.
What the NEG9R.28 is
The TSM-NEG9R.28 comes in six bins at Standard Test Conditions: 450W, 455W, 460W, 465W, 470W and 475W. Module efficiency runs from 22.5% at the 450W bin to 23.8% at the 475W bin. The panel measures 1,762mm by 1,134mm by 30mm and weighs 21.0 kg.
The cells are N-type i-TOPCon monocrystalline. The front is 1.6mm heat-strengthened glass with an anti-reflective coating, the rear is 1.6mm heat-strengthened glass, and the frame is 30mm black anodised aluminium alloy. The junction box is rated IP68. Test loads are 5,400 Pa snow and 4,000 Pa wind, and maximum system voltage is 1500V DC to IEC. For how efficiency figures compare across cell types, our guide to solar panel efficiency in the UK covers the differences.
Dual glass does not mean bifacial. Trina lists the NEG9R.28 under Mono-facial Dual Glass Products, and the 30-year power warranty in section 3 e) (i) covers the front side of those panels, without the junction box. Bifacial panels sit under section 1 g) (i) and (ii) with weaker numbers: 1.5% in the first year, up to 0.5% a year after that, and 84.0% at year 30. For the same checks on a different brand, see our Jinko Tiger Neo page.
The panel is certified to IEC 61215, IEC 61730, IEC 61701 and IEC 62716.
The range and its MCS certificates
MCS certificate BABT 8804 R7, issued by TUV SUD BABT, ran from 23 January 2025 and expired on 31 July 2026. It covers MCS 005 Solar Photovoltaic Modules at Issue 3.1 and MCS 010 Factory Production Control Requirements at Issue 2.0. It lists each dual glass model with its own certificate reference and the power range certified.
| Model code | MCS certificate | Power range certified |
|---|---|---|
| TSM-NEG9R.28 | BABT8804-123 | 395 to 450 W |
| TSM-NEG9RC.27 | BABT8804-124 | 395 to 450 W |
| TSM-NEG18R.28 | BABT8804-125 | 470 to 505 W |
| TSM-NEG9R.25 | BABT8804-129 | 375 to 460 W |
Two things stand out there. R7 lists the NEG9R.28 at 395 to 450 W, while the 2026 datasheet sells bins up to 475 W. And R7 expired on 31 July 2026. Trina's EU product page for the TSM-NEG18R.28 gives it a maximum power output of 525W, above the 470 to 505 W on the certificate. The annex names four factories: Suqian and Yancheng in Jiangsu, Yiwu in Zhejiang, and Changzhou in Jiangsu. MCS says a Smart Export Guarantee tariff needs a system installed by an MCS certified installer using certified products, and a supplier may ask to see your MCS certificate, so ask for the current certificate number for the exact panel you are being sold and check it on the MCS product directory.
Making a claim from the UK
Start with the installer who sold you the system. Section 9 of the Consumer Rights Act 2015 treats every contract to supply goods as including a term that the quality is satisfactory, and section 19 gives you rights against the trader when goods fall short of it, including the short-term right to reject and the right to repair or replacement. The panel warranty sits on top of that. MCS 001-1 clause 4.4.2(f) also says a contract should clearly and accurately state the make, model number, power rating and storage capacity of the equipment, along with the estimated delivery or installation dates, so the model code should be in your paperwork already.
Trina's own route is a claim through its customer service portal at customerservice.trinasolar.com. The claim has to carry the purchase invoice with the purchase date, the product details, a description of the problem, the serial numbers of every affected panel in editable form, and photographs and data. The European service centre named in revision AC is Trina Solar (Schweiz) AG, Birkenweg 4, 8304 Wallisellen, Switzerland.
If a claim succeeds, Trina picks the fix at its sole discretion from five options: repair the panels, refund the value of the missing power, refund the salvage value, send extra panels to make up the shortfall, or replace them with new or remanufactured ones. Inside the warranty period Trina pays the direct repair costs and the transport of whatever it sends. Removal, handling, repacking, installation and reinstallation stay with the buyer.
Two exclusions are worth knowing before you sign. Glass breakage is covered only when nothing outside the panel caused it, so the glass or the module itself has to be at fault. And looks are not covered: scratches, stains, wear, rust, mould, deformation and discolouration do not count as a defect.
Who Trina Solar are
Trina Solar was founded in 1997 and lists Changzhou, China as its global headquarters.
Over a 15 or 30 year term, the claim you can enforce under section 19 of the Consumer Rights Act 2015 is against the trader who supplied the goods. For the inverter side of a quote, our Growatt inverter and battery page asks the same questions. For prices and payback, start with the UK solar panel cost guide.
Request quotes from MCS-certified installers. Ask each one for the exact panel model code, the system size in kWp, the estimated annual generation in kWh, and the warranty document that applies to that model.
Get a Solar Quote →Frequently asked questions
Both numbers are published. The 2026 EU datasheet for the NEG9R.28 advertises up to 25 years product warranty under an "Extended Vertex S+ Warranty" heading and tells you to refer to the product warranty for details. Trina's Global Limited Warranty revision AC, dated June 2026, lists the NEG9R.28 under section 1 h) (ii) and gives those products a 15-Year Limited Product Warranty. Section 13 of that document says it is the only express warranty Trina gives. Ask your installer for the written warranty that applies to your model code.
For the NEG9R.28, Trina warrants no more than 1.0% power decline in the first year, no more than 0.4% average annual decline from year two to year 30, and no less than 87.4% of nameplate power at the end of year 30. Output is measured at Standard Test Conditions by Trina or by a third-party testing institute recognised by both sides, against the lower limit of the nominal power in your contract.
Under revision AC it is the date of initial delivery to the customer by Trinasolar or its authorised manufacturer, or six natural months after the module's factory-out date as queried from the serial number, whichever is earlier. It is not your installation date, so panels held in stock can arrive with time already used.
They were. MCS certificate BABT 8804 R7, issued by TUV SUD BABT, ran from 23 January 2025 and expired on 31 July 2026. It covers MCS 005 Solar Photovoltaic Modules at Issue 3.1 and MCS 010 Factory Production Control Requirements at Issue 2.0, and lists the NEG9R.28 as BABT8804-123 at 395 to 450 W. Because that certificate has expired, and because it stops at 450 W while the 2026 datasheet sells up to 475 W, ask for the current certificate number for your exact panel and check it on the MCS product directory.
Start with the installer who sold you the system: under section 9 of the Consumer Rights Act 2015, goods supplied under a contract with a trader must be of satisfactory quality. Trina's own route is its customer service portal at customerservice.trinasolar.com, and the claim must include the purchase invoice with the purchase date, product details, a description of the claim, serial numbers of every affected panel in editable form, and photographs and data. The European service centre is Trina Solar (Schweiz) AG in Wallisellen, Switzerland. Removal and reinstallation costs stay with the buyer.
No. Trina lists the NEG9R.28 under N-type i-TOPCon Mono-facial Dual Glass Products, with 1.6mm heat-strengthened glass front and rear. The 30-year power warranty in section 3 e) (i) covers the front side of those panels, without the junction box. Bifacial panels sit under section 1 g) (i) and (ii) with their own figures: 1.5% in the first year, up to 0.5% a year after that, and 84.0% at year 30.
The NEG9R.28 is sold in six bins from 450W to 475W, and the figure that binds is the lower limit of the nominal power stated in your contract or on the nameplate, because that is the P0 the power warranty is measured against. Ask for the minimum power per panel and the total system size in kWp in writing, and compare quotes on those two numbers.