Alpha ESS SMILE-G3-S5
A single-phase 5 kW hybrid inverter with stackable 10.1 kWh lithium iron phosphate battery modules, expandable to 60.5 kWh, with UPS backup and IP65.
- Best for expandable systems
- Hybrid system
- 10.1 kWh module
- 10-year battery warranty
- Made by Alpha ESS.
- Energy: 10.1 kWh per module (9.6 kWh usable, 95% depth of discharge), 1 to 6 modules in parallel up to 60.5 kWh.
- An all-in-one system: a 5 kW single-phase hybrid inverter with 10 kWp solar input, plus battery modules (the S5 is the hybrid, the B5 the AC-coupled version).
- Backup output of 5 kVA with UPS switchover; works with a grid and a diesel generator as dual supply.
- IP65 outdoor on the module, 5-year product warranty and 10-year battery performance warranty.
Not tested by us
We have not tested the Alpha ESS SMILE-G3-S5. The figures on this page come from the sources listed at the end of the page, checked on 13 November 2026, and we do not show prices. "Best for" is based on what the maker says the product is designed for, not on our own tests.
Key figures
10.1 kWh
Per battery module
5 kW
Nominal output
60.5 kWh
Maximum with 6 modules
Specifications
Last checked on 13 November 2026. The grey text under each name explains what the value means. To see it next to other products, compare it in our comparison tool.
| Specification | Value |
|---|---|
| Storage | |
| CapacityHow much energy the battery stores. Bigger means longer runtime or more of your own solar power used later. | 10.1 kWh per module (SMILE-G3-BAT-10.1P); 1 to 6 modules in parallel for 10.1 to 60.5 kWh. Alpha ESS also lists 3.8 kWh and 8.2 kWh module options (3.8 to 15.4 kWh, 8.2 to 49.2 kWh). |
| Usable capacityThe part of the stored energy you can actually use. It is lower than the nominal capacity. | 9.6 kWh per 10.1 kWh module (57.5 kWh with six) |
| Battery chemistryLFP (lithium iron phosphate) cells are known for long life and stable behaviour with heat. | Lithium iron phosphate (LFP, LiFePO4) |
| Depth of dischargeHow much of the battery can be emptied without harming it. 90% means 10% is kept in reserve. | 95% (tested at up to 0.5C and 25 ±2 °C) |
| Cycle lifeHow many full charge and discharge cycles the cells are rated for before they hold less than the stated share of their original capacity. | 10,000 cycles on the system datasheet under specific test conditions; 8,000 on the 10.1 kWh module datasheet |
| ExpansionExtra battery units that add storage to the same system. | 1 to 6 modules in parallel (10.1 kWh); parallel operation of systems is also listed |
| Power | |
| Charge and discharge powerHow fast the battery can take in and give out energy. It sets how many devices it can serve at once. | 5,000 W maximum (battery charge and discharge); 60 A maximum current. Module rated 52.5 A, maximum 60 A. |
| AC outputThe power it can deliver through its sockets or inverter, in watts. | Nominal 5,000 W, 5,000 VA at 230 V, single phase, 21.7 A at the grid port; maximum AC input 10,000 W |
| Nominal voltageThe voltage the battery is rated for. It decides which inverter or system voltage (12, 24 or 48 V) it fits. | 96 V per 10.1 kWh module (range 90 to 108 V) |
| Round-trip efficiencyThe share of the energy you put in that comes back out. The rest is lost as heat. | Not published as round-trip; maximum inverter efficiency 97.3% |
| Backup in a power cutWhether it can keep selected circuits running during a grid outage. | Yes: backup port rated 5,000 VA (21.7 A) with UPS switchover; dual power supply from grid and diesel generator is supported |
| Solar | |
| Solar inverterTurns the DC power from solar panels into AC for the home. Built in means no separate solar inverter is needed. | Built in (hybrid): maximum PV input 10,000 W (200%), 2 MPPTs with 1 string each, 100 to 550 V MPPT range, 580 V maximum, 15 A per MPPT (18.75 A short circuit) |
| Solar and off-grid | |
| Works with solar panelsWhether you can charge it from solar panels. Yes means a built-in solar input or a compatible solar setup; read the detail for the voltage and power limits. | Yes: the S5 is a hybrid inverter with its own solar input (the B5 is the AC-coupled version without solar input). |
| Off-grid useWhether the maker describes it running with no grid connection at all, for example in a cabin, van or off-grid home. Backup only means it covers power cuts but needs the grid the rest of the time. | Yes: Alpha ESS lists off-grid operation of the PV inverter, a Smart Off-Grid feature and dual supply from grid and diesel generator. |
| Connection and housing | |
| Grid connectionThe supply type it is built for. Check it matches your home's supply. | Single phase, 230 V, 50/60 Hz; grid codes listed include VDE 4105, EN 50549, CEI 0-21, RD 1699, AS 4777.2 and NRS 097 |
| Dimensions (W × D × H)Check the space before you buy, including room around it for airflow and cables. | Inverter 610 × 212 × 366 mm; 10.1 kWh module 610 × 212 × 793 mm |
| WeightMatters for lifting, wall mounting and moving it. | Inverter 19.5 kg; 10.1 kWh module 90 kg |
| Protection ratingIP ratings show protection from dust and water. IP55 and IP65 are rated for outdoor-style exposure; check the installation guidance. | System IP65 (outdoor) or IP21 (indoor); 10.1 kWh module IP65 |
| Operating temperatureThe range it is rated to work in. Cold and heat can reduce performance. | -10 to 50 °C for the battery (charge and discharge current may derate with temperature and charge level) |
| Battery heatingA built-in heater that lets the battery charge in cold weather. | Not stated by Alpha ESS |
| ConnectivityHow you monitor and control it, usually through an app. | Ethernet and Wi-Fi; battery communication over CAN |
| CertificationsSafety and grid standards the maker says the product meets. | Inverter: IEC 62109, IEC 62040, EN 61000-6-1/-2/-3/-4. Battery: IEC 62619, IEC 63056 and UN 38.3 |
| Warranty | |
| WarrantyThe period the maker covers. Read the terms: conditions and capacity guarantees differ. | 5-year product warranty and 10-year battery performance warranty (system datasheet); the 10.1 kWh module datasheet lists a 10-year battery warranty |
Compatible with
What Alpha ESS says this product works with. Anything not listed here is not confirmed.
- Modules
- 3.8 kWh (1 to 4 in series), 8.2 kWh and 10.1 kWh modules (1 to 6 in parallel); Alpha ESS lists the 3.8 kWh module as available only in Europe.
- Generator
- Dual power supply from the grid and a diesel generator.
- Grid services
- Alpha ESS lists support for multiple VPP applications (virtual power plants).
Rules where you live
An installed battery system normally needs a qualified electrician, and in many countries you must also tell your grid operator, especially if it can export. This is not a plug-in battery. Rules, incentives and tax treatment differ by country: see our country guides for what applies where you live.
Strengths and things to check
Strengths
- Hybrid inverter and modular battery in one system
- Expandable from 10.1 to 60.5 kWh
- 5 kVA UPS backup with generator support
- 10-year battery performance warranty
Worth checking before you buy
- The 10.1 kWh module weighs 90 kg and the inverter 19.5 kg
- Cycle life differs between datasheets (10,000 versus 8,000)
- Battery heating and round-trip efficiency are not published
- The system datasheet is dated 2023
Change log
We record changes to this page here, so you can see when figures such as the warranty were last updated.
- 13 November 2026
- Page published. Figures are from the Alpha ESS SMILE-G3-S3.6/S5/B5 datasheet (V08.01062023), the SMILE-G3-BAT-10.1P datasheet and the Alpha ESS product page. Warranty at publication: 5 years product and 10 years battery performance.
Where this information comes from
We have not tested this system. Every figure above comes from Alpha ESS's SMILE-G3-S3.6/S5/B5 datasheet (V08.01062023), the SMILE-G3-BAT-10.1P module datasheet and the Alpha ESS product page, last checked on 13 November 2026. The figures describe the S5 with 10.1 kWh modules. A value that Alpha ESS does not publish is shown as Not stated.
We do not show prices, because they depend on the installer's quote.
- Manufacturer Alpha ESS SMILE-G3-S3.6/S5/B5 datasheet (V08.01062023)
- Manufacturer Alpha ESS SMILE-G3-BAT-10.1P datasheet
- Manufacturer Alpha ESS SMILE-G3-S5/B5 product page
Spotted an error?
Tell us through the contact form on our About Us page.
Common questions about Alpha ESS SMILE-G3-S5
How much can the SMILE-G3-S5 store?
With the 10.1 kWh module Alpha ESS lists 10.1 kWh per module and up to six modules in parallel, 60.5 kWh in total (57.5 kWh usable).
What is the difference between the S5 and the B5?
Alpha ESS lists the S5 as a hybrid inverter with solar input (10,000 W maximum) and the B5 as an AC-coupled inverter without solar input; both are 5 kW.
What warranty does it have?
Alpha ESS lists a 5-year product warranty and a 10-year battery performance warranty on the system datasheet.
Related guides
Is a modular hybrid system right for your home?
Our calculator uses your own usage and tariff to estimate what a home battery could save, with conservative assumptions.