Sunsynk inverters and batteries in the UK

Sunsynk sells hybrid inverters and lithium iron phosphate (LiFePO4) batteries, supported in the UK from an office in Widnes. Its single-phase hybrids share model codes and headline specifications with Deye's, but a Sunsynk-branded unit is warranted by Sunsynk, not by Deye. The Acure C2 and Ecco datasheets give their inverters 5 years of warranty, or 10 years when installed with a Sunsynk battery. Before you accept a Sunsynk quote, get the exact model code, its entry on the ENA type-test register and the name of the company that will handle a claim.

A hybrid inverter converts the panels' DC output into AC for your home and also charges and discharges a battery; our hybrid inverter guide explains the technology.

Who stands behind Sunsynk in the UK

The UK company named on Sunsynk's website is Sunsynk UK Ltd (company number 08778087), which the site describes as part of Sunsynk Group Limited. Companies House listed it as active on 23 September 2026.

The warranty terms published on the same website name a slightly different seller, "Sunsynk Limited", at a Widnes address. For UK support, Sunsynk gives the phone number +44 151 832 4300 and the email support@sunsynk.com. Your claim normally starts with your installer, so ask them to write on the quote which company issues the warranty for your serial numbers.

Sunsynk and Deye: one hardware family, two warranties

Sunsynk's own pages don't name the factory behind its inverters. Independent UK solar guides, such as Solar Energy Concepts' "Deye vs Sunsynk", describe Deye as the manufacturer of the platform, and the datasheets show why. Sunsynk's Ecco hybrid is sold as SYNK-3.6K-SG04LP1; Deye's equivalent is SUN-3.6K-SG04LP1-EU-SM2. Their published figures match:

Similar hardware doesn't make them the same purchase. Sunsynk's warranty applies only to products that carry the original Sunsynk serial number and were bought from Sunsynk or an authorised reseller in the territory. A Deye-branded inverter falls under Deye's own warranty policy, which Deye says varies by installation country. The monitoring app and the support route follow the brand too. If a quote says "Sunsynk/Deye", ask which one will be fitted. Our Deye page covers the Deye-branded range.

Which Sunsynk hybrid is on your quote

For a UK quote, the difference that matters most between three of Sunsynk's single-phase hybrid ranges is what their datasheets say about GB grid connection:

A datasheet that doesn't list G98/G99 doesn't mean the model isn't type tested: the ENA register is the check. When we checked the register on 23 September 2026, it listed Sunsynk's SG04LP1 codes as fully type tested: the 3 kW and 3.6 kW versions under G98, the 5 kW under G99.

E.ON Next also offers Sunsynk batteries alongside its solar installations.

A hybrid can keep chosen circuits running in a power cut only when it has been wired for it: a charged battery, a backup output connected to selected circuits and the right isolation. The datasheet's "UPS" or off-grid figures describe what the inverter can do, not what your installer has wired. Our battery storage guide explains sizing and backup.

The warranty: what the 10 years needs

Sunsynk's warranty terms describe the inverter cover as 10 years in total: 5 years on all parts including labour, then 5 further years on major components, excluding labour and the LCD screen. The Acure C2 and Ecco datasheets add a condition: 10 years applies when installed with a Sunsynk battery; otherwise it is 5.

For batteries, the same terms give 5 years on the battery management system (BMS) and 10 years or 6,000 cycles on the cells. Sunsynk's battery web page says instead that all its batteries carry "a 10-year product warranty as standard". Ask your installer for the warranty document that applies to your battery model and keep a copy.

Other conditions in the terms that matter to a homeowner:

• The warranty starts on the installation date, unless you install more than six months after Sunsynk dispatched the product; then it starts six months after the manufacture date.
• The product must be installed and commissioned according to Sunsynk's manuals, and repairs are done or authorised by Sunsynk.
• Sunsynk won't reimburse anyone else who works on the product, and faulty units go to its Hong Kong or UK depot.
• Connecting a battery that isn't compatible with Sunsynk inverters is an exclusion, and so is connecting batteries made by another company that Sunsynk hasn't approved.
• A claim needs the invoice, serial number, installation date and the unit's log data.

Sunsynk's warranty registration form asks UK installers for the MCS certificate number, so registration normally happens after your installer has issued that certificate. Because labour is excluded after year five, ask the installer what they charge to swap a unit and whether their own workmanship guarantee covers it. If the installer belongs to the RECC consumer code, that guarantee must last at least two years and be backed by insurance. Check membership on the RECC website; MCS certification alone no longer guarantees it.

G98, G99 and the ENA register

In Great Britain, the size of your inverter decides the grid paperwork. EREC G98 covers generation up to 16 A per phase, which is 3.68 kW on a single-phase supply: the installer connects and then notifies the network operator (DNO) within 28 days. Anything larger follows EREC G99, which needs the DNO's approval before connection. The limit applies to all inverters at one connection point, so a Sunsynk hybrid added to an existing solar inverter counts together with it.

G98 also expects each inverter model to be fully type tested and registered on the Energy Networks Association (ENA) type-test register. A 3.6 kW Sunsynk is rated at 3,600 W, just under the 3.68 kW G98 limit, but its datasheet lists a higher maximum output (3,960 W, or 3,960 VA on the Acure C2), and no Sunsynk document we read says the output is capped. Only the ENA register entry for its exact model code shows that it has been type tested, and limited, for a G98 connection; on 23 September 2026 the register listed the 3 kW and 3.6 kW SG04LP1 versions under G98. The Acure C2 datasheet names G98/G99; the Ecco and Lynks datasheets don't. Ask your installer for the register entry before you sign, or search the model code yourself in ENA Connect Direct, which now holds the register. Our guide to comparing solar quotes shows where this belongs on a quote.

Should you shortlist Sunsynk?

Sunsynk deserves a place on your shortlist if you want a hybrid inverter with a matching battery range, a UK support office and a supplier channel (E.ON Next) as well as independent installers. It is a strong fit when you plan to use Sunsynk batteries, because that is what unlocks the 10-year inverter cover. Our guide to the best solar batteries compares battery options.

It fits less well if you want to pair the inverter with another brand's battery: you lose the 10-year inverter term, and an incompatible or unapproved battery is excluded altogether. Weigh the labour exclusion in years six to ten too. And don't let a cheaper Deye-branded unit be swapped in without a written warranty from Deye for your address.

If you're comparing Sunsynk because a GivEnergy system has failed, read our GivEnergy owner guide first: your installer may owe you a repair or replacement.

Before you accept a Sunsynk quote

• The full model code (for example SunC2-5.0LV01), not just "Sunsynk 5 kW".
• The ENA type-test register entry for that exact code, and whether the system is G98 or G99.
• The battery model, and confirmation that the 10-year inverter term applies with it.
• The company named on the warranty, and who pays labour after year five.
• Which circuits, if any, are wired for backup in a power cut.
• The MCS certificate, the installer's workmanship guarantee and any consumer code membership.

Frequently asked questions

Is Sunsynk the same as Deye?

The hardware is closely related: the single-phase Ecco uses the same SG04LP1 model family as Deye, with matching datasheet figures. The warranty is not shared. Sunsynk covers Sunsynk-serialled products bought through its channel; Deye covers Deye-branded units under its own country-dependent policy.

Who do I contact if my Sunsynk inverter fails?

Start with your installer, who has the commissioning records and deals with Sunsynk. Sunsynk's UK support line is +44 151 832 4300 and the email is support@sunsynk.com. Have your invoice, serial number, installation date and the inverter's log data ready.

Can I use a non-Sunsynk battery with a Sunsynk inverter?

The inverters take 40–60 V lead-acid or lithium batteries; lithium batteries must communicate with the inverter through their BMS. The inverter warranty drops to 5 years without a Sunsynk battery, and the terms exclude batteries that aren't compatible with Sunsynk inverters or that come from another maker without Sunsynk's approval. Get the combination confirmed in writing.