The Livoltek iPower HES1-3K6S2 is a single-phase hybrid all-in-one Energy Storage System (ESS) combining a 3.68 kW transformerless hybrid inverter with an expandable stack of lithium iron phosphate (LFP) battery modules — available from 5.12 kWh to 25.6 kWh (one to five 5.12 kWh BLF-SR packs). Inverter and battery share a slim 680 mm wide, 198 mm deep column footprint and can be configured for wall or floor mounting. The 200% PV oversizing ratio and 70 V start-up voltage extend daily generation into low-irradiance morning and evening periods that most hybrid inverters cannot harvest. 97.6% peak efficiency and fanless natural-convection cooling minimise running losses, while the backup circuit transfers protected circuits in under 10 milliseconds during a grid outage. At ≤35 dB — quieter than a library — the unit suits any room. A 2-week lead time applies to all bundles; please specify battery capacity and mounting preference when ordering.

AC Output

3.68 kW

Max PV Input

7.2 kW

Battery Storage

5.12–25.6 kWh

Peak Efficiency

97.6%

Backup Switch

<10 ms

Noise Level

≤35 dB

⚠ Lead Time, Availability & Configuration Notes

2-week lead time: All bundles are built to order. Allow approximately two weeks from order confirmation to delivery on a pallet.

Wall or floor mounting: Both are supported. Specify your preference at order. Floor-mounted units require a firm, level surface; a built-in spirit level and adjustable feet assist commissioning.

4- and 5-pack configurations (BLF-SR20 / BLF-SR25): Four or more battery modules split into two parallel stacks and require a dedicated Combiner Box + Junction Box (supplied with the bundle). Confirm adequate wall or floor space for the dual-stack footprint before ordering.

Parallel inverter operation (2× units): Connecting two HES1-3K6S2 units to deliver 7.36 kW combined output and up to 70 kWh storage is currently in development and will be released as a firmware update. Not available at time of writing.

⚠ Installer & Grid-Connection Requirements

This system must be installed by a qualified electrician in compliance with BS 7671 (IET Wiring Regulations). The HES1-3K6S2 rated output current at 230 V is 16.0 A — on the boundary between G98 (≤16 A/phase) and G99 (>16 A/phase). Confirm the notification route with your Distribution Network Operator (DNO) before commissioning; some DNOs require G99 at exactly 16 A.

To qualify for the Smart Export Guarantee (SEG) tariff, installation must be carried out by an MCS-accredited installer and the system confirmed as meeting MCS requirements. Anti-islanding protection is built in; all grid-connection, DNO notification, and metering approvals remain the installing contractor's responsibility.

ℹ LFP Battery Chemistry — Stable, Long-Cycle Storage

The BLF-SR modules use lithium iron phosphate (LFP) cells — the most thermally stable lithium chemistry. Each pack carries an independent Battery Management System (BMS) and a built-in active fire prevention module. Rated at 6,000 cycles at 90% depth of discharge (0.5C, 25°C, 70% end-of-life capacity), this equates to roughly 16+ years of daily cycling. Built-in low-temperature auto-heating activates below 15°C, enabling normal charging in cold garages and utility spaces. IP65-rated packs are suitable for wall or floor installation indoors or in sheltered external areas.

Key Features & Engineering Advantages

200% PV Oversizing & 70 V Low Start-Up Voltage

Where most hybrid inverters cap the PV array at 100–150% of rated AC output, the HES1-3K6S2 accepts up to 7.2 kW of DC input (200% of the 3.68 kW AC rating). A 70 V MPPT start-up threshold — versus the 150 V typical of competing products — means the system begins generating from low early-morning and late-evening irradiance that would otherwise be wasted. On overcast days, high-power panel arrays can boost yield by 30–50% over conventional 1:1 sizing. Compatible with all mainstream cell formats: 156 mm, 182 mm, 210 mm, and 210R.

<10 ms Backup Transfer — Invisible Grid Outage Response

The backup relay switches from grid to battery in under 10 milliseconds — below the detection threshold of most consumer electronics, so routers, NAS drives, computers, and medical equipment continue uninterrupted. In off-grid mode the inverter delivers a continuous 3.68 kW, with a 7.36 kW ten-second surge to absorb motor inrush from heat pump compressors, washing machine drums, and pumps. A generator input (up to 9.2 kW AC) can supplement battery and PV during extended outages.

Modular LFP Stack — 5.12 kWh to 25.6 kWh, Expandable

Each BLF-SR battery module adds 5.12 kWh of storage in a 680 × 198 mm slim-column section. Modules connect via a plug-and-play bus — no inter-module cabling — eliminating wiring errors and reducing installation time. Battery capacity can be increased post-installation without replacing the inverter, protecting the initial capital outlay. Each pack carries an independent BMS and the 6,000-cycle LFP cell life makes this a long-term asset. Packs can be individually serviced without taking the whole stack offline.

Intelligent Energy Management — CT Metering, ECO Mode & Heat Pump Control

The built-in Current Transformer (CT) clamp monitors grid import/export in real time, enabling zero feed-in and peak-shaving control without an external meter — a significant installation cost saving. ECO mode continuously optimises self-consumption against export income. A dedicated heat pump control output diverts surplus PV to an ASHP rather than the grid. A 6-period, 24/7 charge/discharge schedule enables time-of-use tariff optimisation, managed via the iOS/Android app (Wi-Fi or Bluetooth) or web dashboard.

Inverter Technical Specifications — HES1-3K6S2

PV Input Parameters
Model	HES1-3K6S2
Max. PV Input Power	7.2 kW (200% of rated AC output)
Max. PV Input Voltage	500 V
Nominal PV Input Voltage	370 V
MPPT Voltage Range	60–500 V
Start-Up Voltage	70 V
Number of MPPTs / Strings per MPPT	2 / 1
Max. PV Current per MPPT	18 A / 18 A
Max. Short-Circuit Current per MPPT	22 A / 22 A
AC Output — Grid-Tied
Nominal AC Output Power	3.68 kW
Max. Apparent Output Power	4 kVA
Max. AC Grid Input Power	13.8 kW
Nominal AC Voltage	220 / 230 / 240 V (L/N/PE)
AC Frequency	50 / 60 Hz (operating range: 45–55 / 55–65 Hz)
Rated Output Current	16.7 A @ 220 V / 16.0 A @ 230 V
Max. Output Current	18.4 A @ 220 V / 17.6 A @ 230 V
Max. AC Input Current	60 A
Total Harmonic Distortion (THDi)	<3%
Power Factor	~1.0 (0.8 lagging to 0.8 leading)
AC Input — Generator
Max. AC Generator Input Power	9.2 kW
Nominal Voltage (Generator)	220 / 230 / 240 V (L/N/PE)
Backup / Off-Grid Output
Nominal Backup Power	3.68 kW
Backup Peak Power (10 seconds)	7.36 kW (2× rated output)
Backup Output Voltage	220 / 230 / 240 V (L/N/PE)
Grid → Backup Transfer Time	<10 ms
THDv (Rated Power)	<3%
Battery Interface
Compatible Battery Chemistry	Lithium Iron Phosphate (LFP) — BLF-SR series
Battery Voltage Range	40–60 V
Max. Charge / Discharge Current	125 A
Efficiency
Max. Efficiency	97.6%
Euro Efficiency	96.8%
Min. Efficiency @ 30% Rated Power	93.0%
General Data
Topology	Transformerless
Inverter Dimensions (W × H × D)	680 × 405 × 200 mm
Inverter Weight	28 kg
Noise (Typical)	≤35 dB(A)
Cooling Method	Natural convection (fanless)
Ingress Protection — Inverter	IP66
Mounting Method	Wall-mounted or floor-mounted
Operating Temperature Range	−25°C to +60°C (derating above +45°C; no derating at 45°C)
Ambient Humidity	0–100% (non-condensing)
Max. Operating Altitude	2,000 m
Display / Monitoring	LED status display · iOS/Android App · Web dashboard
Communications	Wi-Fi, Bluetooth
Surge Protection Level	Type II (DC), Type II (AC)
Overvoltage Category	OVC II (DC), OVC III (AC)
AFCI	Optional
Built-In Protections	PV reverse polarity · Battery reverse polarity · Anti-islanding · AC overcurrent · AC overvoltage
Warranty	5 or 10 Years (site-dependent — refer to Livoltek Warranty Policy)

Battery Stack Configurations — BLF-SR Series (1 to 5 Packs)

Parameter	BLF-SR05 1 Pack	BLF-SR10 2 Packs	BLF-SR15 3 Packs	BLF-SR20 4 Packs ⚠	BLF-SR25 5 Packs ⚠
Total Rated Energy	5.12 kWh	10.24 kWh	15.36 kWh	20.48 kWh	25.60 kWh
Rated Capacity	100 Ah	200 Ah	300 Ah	400 Ah	500 Ah
Max. Discharge Power	5.8 kW	7.68 kW	7.68 kW	7.68 kW	7.68 kW
Max. Charge / Discharge Current	85 A / 100 A	150 A / 150 A	150 A / 150 A	150 A / 150 A	150 A / 150 A
Cell Type	LFP (Lithium Iron Phosphate)	LFP (Lithium Iron Phosphate)	LFP (Lithium Iron Phosphate)	LFP (Lithium Iron Phosphate)	LFP (Lithium Iron Phosphate)
Nominal Voltage	51.2 V	51.2 V	51.2 V	51.2 V	51.2 V
Operating Voltage Range	43.2–57.6 V	43.2–57.6 V	43.2–57.6 V	43.2–57.6 V	43.2–57.6 V
Depth of Discharge	90%	90%	90%	90%	90%
Rated Cycle Life	6,000 cycles²	6,000 cycles²	6,000 cycles²	6,000 cycles²	6,000 cycles²
Charge Temperature	0°C to +60°C (self-heating below 15°C)	0°C to +60°C (self-heating below 15°C)	0°C to +60°C (self-heating below 15°C)	0°C to +60°C (self-heating below 15°C)	0°C to +60°C (self-heating below 15°C)
Discharge Temperature	−10°C to +60°C	−10°C to +60°C	−10°C to +60°C	−10°C to +60°C	−10°C to +60°C
Ingress Protection — Battery	IP65	IP65	IP65	IP65	IP65
Communication	RS485 / CAN	RS485 / CAN	RS485 / CAN	RS485 / CAN	RS485 / CAN
Cooling	Natural (passive)	Natural (passive)	Natural (passive)	Natural (passive)	Natural (passive)
Installation Options	Wall-mounted or floor-mounted	Wall-mounted or floor-mounted	Wall-mounted or floor-mounted	Wall-mounted or floor-mounted	Wall-mounted or floor-mounted
Dimensions (W × D × H)	680×198 ×552 mm	680×198 ×983 mm	680×198 ×1,415 mm	Dual stack¹: 680×198×1,183 + 680×198×1,092 mm	Dual stack¹: 680×198×1,615 + 680×198×1,092 mm
Weight (battery stack only)	58.5 kg	109 kg	159.5 kg	227.4 kg	277.9 kg

¹ Four- and five-pack configurations split into two parallel stacks and require a Combiner Box and Junction Box (included). ² Test conditions: 0.5C charge/discharge, 25°C, 90% DoD, 70% end-of-life capacity.

Frequently Asked Questions

What does this bundle include — inverter, batteries, or both?

This listing covers the complete HES1-3K6S2 bundle: the 3.68 kW hybrid inverter unit plus your chosen number of BLF-SR LFP battery pack modules (1–5 packs / 5.12–25.6 kWh). Inverter and battery ship together as a pre-matched set. Four- and five-pack orders include the required Combiner Box and Junction Box. A current transformer (CT) clamp for grid monitoring is included. DC and AC cabling, consumer unit work, and DNO notification are the installing contractor's responsibility.

Can I add more battery capacity after the initial installation?

Yes — the modular BLF-SR column is designed for future expansion. Packs from the same version range can be added without replacing the inverter. If packs come from a different manufacturing lot, charge all existing packs to 100% SoC before fitting the new modules. Expanding from three to four or more packs also requires adding a Combiner Box and Junction Box. Contact us before purchasing expansion packs to confirm lot compatibility.

Does this system qualify for the Smart Export Guarantee (SEG)?

SEG export payments require that the installation is completed by an MCS-accredited installer and that the system meets MCS requirements. Please confirm MCS eligibility with your installer before purchase. Grid connection also requires DNO notification under G98 or G99 — see the installer requirements panel above for the model-specific output current and applicable route.

What does the 2-week lead time mean, and how will my order arrive?

All bundle configurations are built to order rather than held as finished stock. After order confirmation, please allow approximately two calendar weeks for manufacture and delivery. The system ships on a pallet given the combined inverter and battery weight. Contact us if you have a time-critical installation date and we will advise on current availability.

Can two systems be connected in parallel for more power or storage?

Parallel operation is currently in development and not yet available at time of writing. When released via firmware, two HES1-3K6S2 units can be connected in parallel to deliver 7.36 kW combined AC output and up to 70 kWh of total storage. Please verify the latest firmware release status with us before relying on this feature in a system design.

How does the system behave during a grid power cut?

When the grid fails, the HES1-3K6S2 transfers the protected backup load circuit in under 10 milliseconds — transparent to most appliances and sensitive electronics. The inverter sustains 3.68 kW of continuous backup output, with a 7.36 kW ten-second surge for motor inrush loads (heat pump compressors, washing machine drums, borehole pumps). If battery reserves are depleted, the system accepts up to 9.2 kW of generator AC input to sustain loads and recharge simultaneously. The system returns automatically to grid-tied mode when supply is restored.