Sofar ESI vs Deye: Which hybrid inverter for your solar storage?

Two opposing philosophies for domestic solar storage

Installing solar panels with storage batteries has become the norm for avoiding electricity price increases and achieving energy independence. But when it comes to choosing the core of your installation, two major philosophies clash on the market: the closed and reassuring ecosystem versus the open and ultra-customisable system.

On the one hand, we offer the "All-in-One" solution with Sofar ESI hybrid inverters and their ESI (BTS) batteries. On the other hand, there are Deye inverters, true Swiss Army knives of energy, combined with reputable third-party batteries such as Delong, Pylontech or Leapton.

"The choice between Sofar ESI and Deye is not just a question of price: it is a strategic decision between the simplicity of an integrated ecosystem and the freedom of a modular architecture."

Sofar ESI + BTS Battery: The peace of mind of "Zero Blah Blah"

The Sofar ESI range (which combines the hybrid inverter with BTS stackable battery modules) is the very definition of an integrated system. It is the perfect solution for those who want a highly aesthetic and hassle-free system.

The major advantages of the Sofar ESI ecosystem

One manufacturer, no fuss in case of problems

This is the major strength of this solution. The inverter and battery are designed by the same brand. In the event of a communication problem or a need for technical assistance, there is no buck-passing between the inverter manufacturer and the battery manufacturer. Everything is managed centrally by Sofar and our after-sales service.

This approach completely eliminates BMS (Battery Management System) compatibility issues and guarantees perfect integration from the very first start-up. Firmware updates are synchronised between the inverter and batteries, ensuring total system consistency.

A clean and sleek design

The system is designed to blend harmoniously into the home. BTS 5K batteries stack easily like a tower with their management unit (BDU) at the top. There is no complex visible cabling; installation is plug and play and visually impeccable.

Each BTS 5K module (5.12 kWh) connects with a simple plug-in connection, with no visible external wiring. The system accepts up to 6 modules stacked vertically, offering a maximum capacity of 30.72 kWh with a minimal footprint.

Easy management and pre-programmed modes

The inverter manages flows completely autonomously thanks to pre-programmed modes. The application is intuitive, it's "Set and Forget". The main modes available include:

• Self-consumption mode: maximises the use of solar energy produced
• Off-peak mode: charges the batteries duringoff-peak hours
• Backup mode: prioritises energy reserves for power cuts
• Economy mode: optimises battery life
• Full sale mode: feeds all production into the grid

Estimated budget for the Sofar ESI solution on Wattuneed

A position justified by the absolute peace of mind offered by a proprietary system with a unified warranty.

Deye + Delong / Pylontech / Leapton batteries: The king of flexibility

If Sofar is the equivalent of the "Apple ecosystem" of solar energy, Deye is the powerful, custom-built PC. Deye hybrid inverters (48V low voltage) are the most open, intelligent and comprehensive on the Belgian and French photovoltaic market.

The major advantages of Deye's architecture

Scalable as you wish: freedom of choice of batteries

With Deye, you are not locked into one brand. The inverter is compatible with almost all 48V batteries on the market thanks to its universal communication protocol (CAN 2.0, RS485). You can:

• Start with an excellent Delong Top Energy 5.12 kWh battery (Grade A BYD cells)
• Expand your fleet over the years with additional modules
• Opt directly for the impressive 15.36 kWh Delong block for maximum autonomy
• Mix different brands (Pylontech US5000 + Leapton EL-A05) according to your budget

"The multi-brand compatibility of Deye inverters offers a major economic advantage: you can choose the best offer available without compromising on technical performance."

Deye Copilot: the AI revolution in solar storage

This is the revolutionary argument of the moment! Deye integrates the first AI-driven EMS (Energy Management System). The system analyses:

• Weather forecasts: anticipates solar production for the next 48 hours
• Your consumption habits: learns your daily life cycles
• Dynamic electricity rates: identifies off-peak and peak hours
• The condition of your batteries: optimises charging cycles to extend their lifespan

The result: the system decides on its own to charge the battery at night when electricity is free (two-tier pricing), to discharge during peak hours and slash your bill. AI can generate additional savings of 15 to 30% compared to a conventional self-consumption mode.

Multi-flow architecture and magic GEN port

The Deye inverter has a multi-talented "GEN" port, which sets it apart from the competition:

This versatility makes the Deye inverter a true "energy control tower" capable of simultaneously managing solar production, battery storage, domestic consumption, grid injection and controllable loads.

Estimated budget for the Deye solution on Wattuneed

Being able to choose your battery brand offers an undeniable financial advantage. Here are the most popular configurations:

An extremely competitive entry cost for a true energy control tower with integrated AI.

Comparison table: Sofar ESI vs Deye

To help you make the best decision, here is a detailed comparison of the two solutions based on eight essential criteria:

The verdict: Which one is right for your project?

"In both cases, you are investing in state-of-the-art equipment certified for the Belgian and French markets. The difference comes down to your priorities: peace of mind vs. maximum flexibility."

Battery options compatible with Deye: detailed comparison

One of the great advantages of Deye's architecture is the freedom to choose your batteries. Here is a comparison of the three most popular brands at Wattuneed:

Real-life use cases: which solution for which profile?

Profile 1: Family of 4 in a single-family home (Belgium)

Context: Annual consumption of 4,500 kWh, planned 6 kWp installation, looking for simplicity.

Recommended solution: Sofar ESI 5 kVA + 2x BTS 5K (10.24 kWh)

Why? The family prioritises peace of mind and aesthetics. The stackable design of the BTS batteries fits perfectly in the garage. The 5 pre-programmed modes allow for automatic management without intervention.

Total budget: ~ €3,900 (inverter + 2 batteries)

Profile 2: Entrepreneur with dual hourly rates (France)

Context: Annual consumption of 7,000 kWh, off-peak/peak rates, existing 9 kWp installation with micro-inverters.

Recommended solution: Deye 6 kW + Delong Top Energy 15.36 kWh + Deye Copilot

Why? Deye Copilot AI automatically charges the batteries during off-peak hours and discharges them during peak hours. The GEN port in AC Coupling mode recovers the output from the existing micro-inverters. Estimated annual savings: 40-50% on the electricity bill.

Total budget: ~ £3,600 (inverter + XL battery + Copilot subscription)

Profile 3: Professional installer looking for versatility

Context: Diverse customer portfolio, need to offer solutions tailored to every budget.

Recommended solution: Complete Deye range

Why? Multi-brand compatibility allows adaptation to each customer's budget. The 12 advanced functions cover all use cases (AC Coupling, Smart Load, backup generator). Comprehensive technical training available on Wattuneed support.

AC Coupling: adding storage to an existing installation

Do you already have solar panels with a string inverter or micro-inverters? Deye and Sofar ESI hybrid inverters both supportAC Coupling, a technology that allows you to add batteries to an existing installation without replacing everything.

How does AC Coupling work?

AC Coupling connects your hybrid inverter in parallel to your domestic AC grid. Your existing installation continues to operate normally, while the hybrid inverter:

1. Monitors the output of your existing installation
2. Captures surplus energy that would normally be fed into the grid
3. Charges the batteries with this surplus
4. Discharges the batteries to power your home when solar production is insufficient

Deye advantage: The dedicated GEN port greatly simplifies AC coupling connection and offers maximum compatibility with Enphase, APsystems, Hoymiles and other micro-inverters.

Installation and commissioning: what you need to know

Sofar ESI + BTS: installation in 5 steps

1. Wall mounting: Install the wall bracket for the ESI inverter (weight: 15-18 kg)
2. Battery stacking: Stack the BTS 5K modules with their BDU at the top (max. 6 modules)
3. BMS connection: Connect the communication cable between the BDU and the inverter (automatic connection)
4. DC/AC connection: Wire the solar panels (DC) and the domestic grid (AC)
5. Commissioning: Switch on the system and select the operating mode (Solarman application)

Estimated installation time: 3-4 hours for a qualified installer.

Deye + Third-party batteries: 6-step installation

1. Wall mounting: Install the wall bracket for the Deye inverter (weight: 12-16 kg)
2. Battery installation: Secure the batteries to the wall or floor depending on the model (Delong, Pylontech, Leapton)
3. BMS connection: Connect the CAN 2.0 or RS485 communication cable
4. BMS configuration: Configure the communication protocol in the inverter menus
5. DC/AC connection: Wire the solar panels (DC) and the domestic grid (AC)
6. Commissioning: Test communication, check operating modes (SEMS Portal application)

Estimated installation time: 4-5 hours for a qualified installer (BMS configuration included).

Technical support and warranties: an essential point

Manufacturer warranties

Wattuneed support: our commitment

Whatever your choice, Wattuneed supports you with:

• Dedicated technical support: support.wattuneed.com
• Knowledge base: installation guides, connection diagrams, tutorial videos
• Telephone hotline: +32 87 45 00 34 (Monday-Friday, 9 a.m.-5 p.m.)
• Email support: info@wattuneed.com (response within 24 hours)
• Technical blog: regularly updated articles by experts

Frequently asked questions (FAQ)

Can I start with a small battery and expand later?

Sofar ESI: Yes, you can start with 1 BTS 5K module and add up to 5 additional modules (total 30.72 kWh). The addition is done by simple stacking without complex reconfiguration.

Deye: Yes, and with even greater flexibility. You can start with a Delong 5.12 kWh battery and add other modules (up to 16 batteries in parallel depending on the model). You can even mix brands (e.g. Delong + Pylontech) if they use the same communication protocol.

What is the actual lifespan of the batteries?

The LiFePO4 (Lithium Iron Phosphate) batteries used in both solutions are guaranteed for 6,000 cycles at 90% depth of discharge (DOD). In real use with daily discharge:

• 1 cycle per day = 6 ,000 days = 16.4 years
• 0.7 cycles per day (actual average) = 23+ years

After 6,000 cycles, the residual capacity is generally 80%; the battery continues to function but with reduced capacity.

Is Deye Copilot really useful in Belgium/France?

Yes, especially if you have:

• A dual hourly rate (off-peak/peak hours): AI automatically optimises charging/discharging
• Capacity tariffs (under development in Belgium): Copilot avoids costly consumption peaks
• A large installation (>10 kWp): optimisation generates substantial savings

Annual savings observed with Deye Copilot: 15-30% more than with a conventional self-consumption mode.

Can I install these systems myself?

Not recommended. Although technically feasible for an experienced DIY enthusiast, installing a hybrid inverter with batteries requires:

• Knowledge of electricity (handling DC/AC currents, differential protection)
• Compliance with electrical standards (RGIE in Belgium, NF C 15-100 in France)
• A declaration of conformity signed by an approved professional
• BMS configuration (inverter-battery communication protocols)

Furthermore, non-compliant installation may void manufacturer warranties and create safety risks.

Do the batteries work in the event of a power cut?

Yes, both solutions offer a backup function:

Sofar ESI: Backup mode with automatic transfer in < 10 ms. Loads connected to the backup output continue to be powered.

Deye: UPS (Uninterruptible Power Supply) mode with transfer in < 4 ms. Priority outputs can be configured (refrigerator, internet box, etc.).

Important: To benefit from the backup, you must:

• Install a switch box separating critical loads
• Configure backup mode in the inverter
• Respect the maximum output power (3-6 kW depending on model)

What battery capacity do I need?

Rule of thumb: Battery capacity = Night-time consumption × 1.2

Concrete examples:

• House 3,500 kWh/year (night-time consumption ~4 kWh) → 5 kWh battery
• House 5,000 kWh/year (night-time consumption ~6 kWh) → 7.5-10 kWh battery
• House 7,000 kWh/year (night-time consumption ~9 kWh) → 10-15 kWh battery

The coefficient 1.2 compensates for conversion losses (inverter efficiency ~95-97%).

Can I use these inverters for an off-grid site?

Sofar ESI: No, ESI inverters are designed for grid-tied mode with backup. They cannot operate autonomously without a connection to the electricity grid.

Deye: Yes, Deye inverters support full off-grid mode. By connecting a generator to the GEN port, you create a fully autonomous system that is ideal for:

• Isolated cottages
• Tiny houses
• Industrial sites without connection
• Mountain refuges

The generator starts automatically when the batteries reach a critical threshold (e.g. 20% SOC).

Conclusion: investing in energy independence

The choice between Sofar ESI and Deye is not a question of "better" or "worse", but of installation philosophy:

• Sofar ESI = Peace of mind, simplicity, aesthetics, single point of contact
• Deye = Flexibility, scalability, AI intelligence, value for money

Both solutions will allow you to:

• ✅ Reduce your electricity bill by 50 to 80%
• ✅ Increase your self-consumption rate to up to 90%
• ✅ Protect yourself against power cuts (backup function)
• ✅ Increase the value of your property (energy performance certificate, green value)
• ✅ Contribute to the energy transition

"Solar energy with storage is no longer a luxury, it is a profitable investment over 10-15 years with a guaranteed positive ROI. In 2025, not installing it will be like leaving money on the table."

Note: The prices shown are indicative and based on the current Wattuneed catalogue. They may vary slightly depending on current promotions. Please visit our website for up-to-date prices.

Wattuneed SPRL
Rue Henripré 12, 4821 Andrimont, Belgium
Tel: +32 87 45 00 34 – info@wattuneed.com
www.wattuneed.com | Technical support