sonnen batteries in the UK: sonnenBatterie 10 and hybrid 9.53

sonnen, a German battery maker that has been part of Shell since 2019, sells two home batteries in the UK through certified installers: the sonnenBatterie 10, which adds storage to panels you already have, and the sonnenBatterie hybrid 9.53, which runs new panels and a battery from one box. Both use lithium iron phosphate cells and come with a 10-year guarantee. Before you compare a sonnen quote with other batteries, look at three things: the usable kWh against the power the battery can deliver, whether backup (sonnenProtect) is included, and the guarantee terms, which leave the labour for a replacement to you.

If you already own a sonnenBatterie, the sections on service and the guarantee apply to you too. If you are still deciding whether a battery is worth it at all, start with our guide to solar battery storage.

What sonnen sells in the UK

sonnen's UK website lists two batteries and two backup units. The figures below come from the datasheets linked from that site: a UK datasheet for the hybrid 9.53 (December 2025) and, for the sonnenBatterie 10, an Italian-language datasheet (June 2024), which is what the UK page links to.

sonnen says capacity can be added later with extra modules. Its UK pages aren't fully consistent on the hybrid's steps (one answer mentions 2.5 kWh modules up to 15 kWh), so go by the datasheet and the model code on your quote.

Capacity and power are different limits

A sonnenBatterie hybrid 9.53 with 13.5 kWh usable can deliver at most 3.3 kW. Emptying it at full power takes about four hours (13.5 kWh ÷ 3.3 kW = 4.1 hours), and running several large appliances at once can need more than 3.3 kW, with the rest then coming from the grid. The sonnenBatterie 10's 4.6 kW is higher, but the same applies. That doesn't make either model poor: it means you should size by your evening pattern, not only by kWh.

Example (illustrative): Ofgem's typical household uses 2,500 kWh a year, about 6.8 kWh a day (2,500 ÷ 365). A home like that uses less than 9 kWh on an average day, so the 9 kWh hybrid or the 10 kWh sonnenBatterie 10 already covers more than its evenings. The larger sizes make sense with a heat pump, an electric car or a cheap overnight rate that you can use to fill the battery for the next day.

Grid paperwork: G98 or G99

In Great Britain, on a single-phase supply, the G98 connect-and-notify route covers up to 3.68 kW of inverter output in total, counting every inverter at the property. The ENA's type-test register (Connect Direct), checked on 24 September 2026, has Compliant records for the sonnenBatterie 10 (3.4 kW under G98, 4.6 kW under G99) and for the 9.53 (3.3 kW under G98; earlier PV-side records at 3.68 kW under G98 and 4.6 kW under G99). Two newer records from January 2024, named "hybrid 9.53" and "sonnenbatterie 10s", show a status of Non-compliant, and the register gives no reason. Ask your installer which record and firmware they will cite on the G98 or G99 paperwork.

Two situations mean a G99 application, approved by the network operator before connection:

• a sonnenBatterie 10 added to existing panels, unless its output and your existing solar inverter's together stay within 3.68 kW; and
• either model registered at more than 3.68 kW.

Ask your installer which rating they will register and who applies.

Backup with sonnenProtect

Neither sonnenBatterie keeps your home running in a power cut on its own. sonnen pairs the sonnenBatterie 10 with sonnenProtect 4000 (up to 4,000 W) and the hybrid 9.53 with sonnenProtect 2500 (2,500 W, 3,000 W for 30 seconds). Both switch over automatically and supply chosen circuits, not the whole house. You can set how much charge is kept back for a power cut, and that reserve is not available for everyday savings.

Ask which circuits are on the backup side, how the reserve is set and to see the changeover tested at handover.

sonnenCommunity and tariffs

sonnen's UK site describes the sonnenCommunity and its virtual power plant, which sonnen says helps support the grid in several countries. It doesn't list a UK electricity tariff or payment for joining. sonnenFlat and similar offers on sonnen's German site are German contracts. Value a sonnen battery on your own UK tariff: the electricity it lets you avoid buying, the export you give up and any time-of-use rate you actually use.

The guarantee, read closely

sonnen publishes a GB English version of its manufacturer's guarantee (dated December 2025) on its UK site. It applies to sonnenBatterie eco 8.0 and hybrid 8.1 or later commissioned from August 2020, bought through sonnen or a sonnen-certified dealer or installer, commissioned by a certified installer and registered with its serial number at commissioning.

• Length: 10 years from commissioning, 10,000 full cycles or 8,500 kWh of discharged energy per kWh of net capacity, whichever comes first. The energy limit works out at about 2.3 full cycles a day over 10 years (8,500 ÷ 3,652 days), so for most homes the 10 years run out first.
• Threshold: a claim arises if a battery module falls below 70% of its nominal capacity, or another component is more than 10% below its specification. sonnen's product page mentions 80% after 10,000 cycles; the guarantee's figure is 70%.
• Remedy: sonnen replaces the faulty module or component, possibly with a used part, or pays its current value, which the guarantee works out by depreciating your purchase price over 10 years, starting with 20% in the first year.
• Labour is yours: the guarantee says the labour to replace a module or component is paid by you at sonnen's rates, including travel time. At the time of the document the rate was EUR 150 an hour (gross), and it may vary by country. Ask for the UK rate before you sign.
• Online: sonnen expects the battery online (at least 16 Mbit/s download, 1 Mbit/s upload). If it isn't, you must check for updates at least every four weeks and connect it for 48 hours to install necessary ones. A fault caused by a missed necessary update isn't covered.
• Claims and transfer: claim in writing to sonnen, or through a certified partner, as soon as you notice a problem, because the time limit is counted from when you became aware of the defect. The guarantee transfers to a new owner only with sonnen's written consent, and it is governed by German law.

Your statutory rights against the seller are separate and unaffected, as the guarantee itself says.

Service for UK owners

sonnen's UK contact page sends existing customers to its international service team (international-service@sonnen.de) and asks owners who want to add a product to go back to the installer who fitted the first one. The legal entity behind the UK site is sonnen GmbH in Germany. sonnen lists the UK among its locations, but it names no UK company or UK service line.

If your sonnenBatterie is older than eco 8.0 or was commissioned before August 2020, the guarantee terms are the ones you received at purchase. Find your invoice, the serial number and the model plate before you contact anyone. sonnen's operating manuals help identify the model.

Checking a sonnen quote

There is no single installed price: the model, size, sonnenProtect, electrical work and panels all change the total. Our solar battery cost guide covers typical UK prices. A quote you can compare should list:

1. the model (sonnenBatterie 10 or hybrid 9.53), usable kWh and power in kW;
2. whether sonnenProtect is included and which circuits it covers;
3. the rating registered with the network operator, and the G98 notification or G99 application;
4. where the battery goes (indoors, within −5 °C to 45 °C) and whether that spot meets PAS 63100:2024, the BSI fire-safety specification for home batteries;
5. confirmation that the installer is sonnen-certified and will register the battery at commissioning;
6. who pays the labour if a module needs replacing under the guarantee.

MCS's product directory doesn't list batteries, and the ENA register shows only the inverter rating, so check the installer's MCS certificate as well. A battery the installer supplies and fits in your home has 0% VAT until 31 March 2027; from 1 April 2027 the rate becomes 5% unless the relief is extended.

Because sonnen's guarantee is a German contract that charges you for the labour of a swap, your protection in the UK rests heavily on the installer. Under the Consumer Rights Act 2015 you can ask the business that sold you the battery to repair or replace goods that aren't of satisfactory quality, and that claim doesn't depend on sonnen. Ask the installer to put in writing what their own workmanship guarantee covers and for how long. Consumer-code membership is no longer part of MCS certification, so check whether they belong to RECC or HIES before paying a deposit. Our guides to comparing solar quotes and choosing an installer cover the rest.

Our view: sonnen suits you if you want a well-established LFP battery with a long cycle allowance and your installer is certified, local and clear about labour costs. If you need higher power for backup or big evening loads, or want a simpler guarantee, compare it with the options in our best solar batteries guide.

sonnen FAQs

Is sonnen still sold in the UK?

Yes. sonnen's UK website lists the sonnenBatterie 10 and hybrid 9.53 and passes quote requests from the UK and Ireland to certified installers in the area.

Does sonnen's guarantee cover labour?

No. The GB guarantee says you pay the labour and travel time to replace a faulty module or component, at sonnen's rates. Parts and their transport are covered.

Does a sonnenBatterie need the internet?

sonnen expects it to be online for updates and monitoring. If it isn't, you have to check for updates every four weeks and connect it long enough to install necessary ones, or a resulting fault isn't covered.

Which sonnen suits existing solar panels?

The sonnenBatterie 10, which is AC-coupled and works alongside your existing inverter. The hybrid 9.53 is designed for new installations. Adding a battery to an existing system usually needs a G99 application, because both inverters count towards the limit.