Deye makes the OEM platform behind Sunsynk hybrid inverters, so the hardware family is closely related. That does not make the two badges one purchase. The badge still decides warranty, firmware support and the paperwork route, and it decides who answers the phone when something misbehaves.
In the UK I would default to the Sunsynk. I would only buy a Deye-badge unit when it is meaningfully cheaper and the seller documents the exact model, current grid listing, firmware and who handles faults. In South Africa both badges are normal retail, so the decision is local price, stock and warranty, not “import versus brand”. For which menus and controls actually differ, see my Sunsynk vs Deye capabilities comparison.
Where each badge is sold, and what actually changes
The platform family is global. The buying risk is local. Sunsynk’s own site runs installer programmes and offices that put the UK and South Africa front and centre. Deye sells more widely under its own badge and through partners. Use this as a map, not a promise that every country has the same stock or warranty path.
| Where you are | What usually changes | What I would weight most |
|---|---|---|
| United Kingdom | Support channel, firmware path, G98/G99 type-test listing for the exact model, DNO paperwork. | Who answers the phone, and whether the exact unit is listed for the connection you need. |
| South Africa | App and installer ecosystem, local warranty process, price and stock. Both Deye and Sunsynk appear as normal retail hybrids. | Local price, who holds warranty, and the installer or seller you can actually reach. |
| Elsewhere | Other badges on related platforms (for example Sol-Ark in the US). Sunsynk distribution can be thinner outside its strong markets. | The brand that has local support and a documented unit, not a UK or SA rulebook. |
Are Deye and Sunsynk really the same inverter?
They can be very close, but “same factory” is not a complete buying decision. Deye is the manufacturer behind OEM and private-label inverter platforms, including Sunsynk. That explains the resemblance between some units. It does not prove that every Deye and Sunsynk model has the same firmware, approval status, warranty or support route.
I would compare the full model number, not the badge alone. On this page that means a common UK Sunsynk 5kW ECCO, model SYNK-5K-SG04LP1, against a related Deye 5kW, model SUN-5K-SG03LP1-EU. They are closely related single-phase, 5kW hybrid inverters for 48V low-voltage batteries. This is a cross-generation retail pair for buying risk. It is not a claim that every SG03 and SG04 board is the same revision. For menu-level differences on a closer generation pair, use the capabilities comparison and its model notes. Deye describes its OEM and partner route.
What is different between the Sunsynk 5kW ECCO and Deye SUN-5K-SG03LP1-EU?
The useful comparison is not Deye versus Sunsynk as whole brands. It is this exact pair of 5kW units and the route by which you buy them. The two models share headline characteristics, but the available evidence does not establish that the exact SG03 and SG04 units use the same electrical platform. Check sales channel, certification, firmware and after-sales details unit by unit.
| Buying point | Sunsynk 5kW ECCO SYNK-5K-SG04LP1 | Deye SUN-5K-SG03LP1-EU |
|---|---|---|
| Type and rated output | Single-phase 5kW hybrid inverter. | Single-phase 5kW hybrid inverter. |
| Battery system | 48V low-voltage battery support, 40V to 60V. | 48V low-voltage battery support, 40V to 60V. |
| Published electrical detail | 5kW rated output, 5.5kW maximum AC output and 120A battery limit. | Do not assume matching figures without checking the exact Deye datasheet. |
| UK hardware price and sales route | £855 excluding VAT was shown in UK retail stock on 13 July 2026. | UK price and UK sales channel were not verified in the research. |
| Grid documentation | Confirm the exact unit’s current G98/G99 listing before connection. | The official manual lists G99, but confirm the exact supplied suffix and current listing. |
| Support and warranty | UK retail stock was shown at the time of writing. Confirm the supplying retailer’s current warranty process, firmware support and fault-support contact before buying. | Confirm who provides firmware help, warranty handling and fault support before paying. |
The Sunsynk figures above come from its 5kW ECCO datasheet and the UK retailer listing that showed the £855 excluding-VAT price. The Deye manual covers the SUN-3.6-6K-SG03LP1-EU range and lists G99.
Why do firmware and the G98/G99 listing matter more than the badge?
A UK grid connection is based on the equipment being connected, not on a broad claim that two brands use the same factory. The DNO process needs the correct equipment evidence. A manual that covers a product family is useful, but it is not a substitute for checking the exact suffix, certificate and firmware supplied to you.
This is where a bargain can become expensive, and it is the real difference between the two badges in the UK. Closely related hardware does not mean identical support: the question that matters is who answers the phone when the firmware misbehaves. Before ordering, ask the seller for the exact model suffix, the current G98 or G99 listing that covers it, and the firmware version it will ship with, then keep those answers with your installation paperwork. You can search the live device register through the ENA Connect Direct type-test tools. My wider guide to choosing an inverter explains why the inverter is a system decision rather than just a power rating.
Do the same check for Sunsynk. A UK-supported brand makes the conversation easier, but it does not remove the need to match the actual inverter to your connection paperwork. The model number on the listing, the unit and the certificate should all agree.
What the November 2024 Deye lockout showed about badge and territory
There is a second risk beyond paperwork. In mid-November 2024, multiple installers and owners reported that some Deye-branded hybrid inverters in markets with exclusive regional partners were remotely locked out. Contemporary reporting of the on-screen message said the unit was not allowed for use in Pakistan, the USA or the UK, and told owners to contact Inverex, Sol-Ark or Sunsynk respectively, then return the unit to their supplier. Solarboi’s contemporaneous write-up collected that wording and the early corroboration; Sol-Ark publicly said it was not servicing Deye-badge units and framed the problem as unauthorised Deye-branded sales into its territory.
I treat that episode carefully. It does not prove that every Deye unit everywhere will be switched off tomorrow. It does prove something the badge story usually only implies: territory and channel are load-bearing, and cloud-connected units can be used to enforce them. For a UK buyer, a cheap Deye-badge box with a monitoring stick is not only a G98 question. It is also a channel-legitimacy question. If the factory’s own lock screen names Sunsynk as the UK contact path, that is the clearest public illustration I have seen that the badges are commercial territories, not stickers on identical risk.
What do I get by paying for Sunsynk?
With Sunsynk, the important extra is not a magical difference in the inverter hardware. It is the established support and warranty route around it in the markets where Sunsynk is strong. For someone building or maintaining a DIY system in the UK, a recognisable channel and a large community can make a fault, firmware question or compatibility query less uncertain.
Do not confuse that with a good cloud product. Owners of both Sunsynk and Deye units often treat the stock WiFi dongle and manufacturer app as the weak part of the system. The monitoring stack I would actually run is local: Solar Assistant on a Raspberry Pi (or similar) talking to the inverter, so logs and automations stay under your control when the vendor cloud is slow, offline or used for remote updates. Paying for the Sunsynk badge buys channel and support. Serious day-to-day monitoring is still a third-party decision for either badge.
The 5kW ECCO was listed at £855 excluding VAT in UK retail stock on 13 July 2026. That is a hardware price, not an installed-system price. VAT, delivery, labour, DNO work, backup equipment and an installer’s willingness to fit customer-supplied hardware are separate costs. My experience with the smaller Sunsynk 3.6kW ECCO is why I would treat the support route as part of the component, not an afterthought. Once you own the box, the useful depth is practical: CT clamp placement and extension, and the Solar Assistant rules and automation guide for living with a Sunsynk day to day.
When is the Deye the sensible choice?
A Deye can be the sensible choice when it is genuinely cheaper for the same job and the seller can document exactly what you are buying. In the UK, the potential saving only counts after you know the sales route, current firmware, G98/G99 evidence, warranty claimant and support contact. After the November 2024 territorial lockouts, I would also want a straight answer on whether the unit is sold through a channel the manufacturer will still recognise, and whether it depends on a cloud stick for normal operation. At that point, you are comparing a real offer rather than an assumed clone.
In South Africa, a Deye-badge unit is often just another mainstream hybrid on the shelf, not a grey import. There the sensible case is local stock, a clear warranty holder and a price that beats the Sunsynk next to it for the same installer job. I would still want the answers in writing before paying. “Deye made it” is not enough if a firmware issue appears later and the retailer, distributor and manufacturer each point elsewhere.
In the UK, check the model against the UK inverter directory, then ask who will handle a fault and what evidence they need from you.
Which would I choose?
In the UK, I would choose the Sunsynk 5kW ECCO when I value a clear warranty and support channel, a known retail route and the practical help of the DIY community. The £855 excluding-VAT reference gives a starting point, but I would still check the delivered and installed total rather than comparing sticker prices. I would choose the Deye only when the exact SUN-5K-SG03LP1-EU (or the exact unit offered) is meaningfully cheaper and the seller confirms firmware, current UK certification and responsibility for support and warranty.
In South Africa, I would not default to Sunsynk just because the brands share a factory story. I would compare the exact models in front of me, the local warranty process and the installer or seller I can reach. Closely related hardware does not automatically mean the same buying risk.
If the question is menus and schedules rather than badge and warranty, go to the capabilities comparison. If you are also comparing other hybrid brands for a UK DIY system, see my Solis versus Sunsynk hybrid inverter comparison.
