This comparison highlights how a powerful inverter pairs with a large-capacity battery, focusing on performance, longevity, and cost implications.
1. Power Capabilities
The Sunsynk 8kW inverter and the RenewSolar 50kWh battery are both designed for significant energy throughput, but their individual characteristics dictate the real-world performance of the combined system.
Sunsynk 8kW Hybrid Inverter:
- Rated AC Output Power: 8000W (8kW) continuous.
- Max AC Output Power: 8800W (8.8kW) for short durations.
- Max DC Input Power (from Solar PV): Typically around 10.4kW, allowing for significant solar array sizing.
- Battery Voltage: Operates with 48V nominal battery systems (range usually 40-60V DC).
- Max Battery Charge/Discharge Current: To deliver 8kW at 48V, the inverter would draw/supply approximately
8000W / 48V = 166.7 Amps. The inverter’s internal components are robust enough to handle this current.
RenewSolar 50kWh Battery (48V Nominal):
- Capacity: 50kWh, which for a 48V nominal system equates to approximately 1042 Ah (Amp-hours). This is derived from 48 x 314Ah cells, configured as 3 parallel strings of 16 cells in series (16S3P), yielding a total of 3 * 314Ah = 942Ah, which at 51.2V (typical full charge) is ~48.2kWh, or at 48V nominal, 45.2kWh. Let’s stick with the advertised 50kWh and the implied 1042 Ah for calculations.
- Crucial Current Limit: The RenewSolar 50kWh battery has a specified 200 Ampere (A) charge and discharge limit. This limit is set to preserve the battery’s exceptionally long life (11,000+ cycles).
- Theoretical Max Power Output (Battery Limit): Given the 200A discharge limit at 48V nominal, the battery can sustainably deliver
200A * 48V = 9600W (9.6kW).
How they Stack Up (Power):
- The Sunsynk 8kW inverter is well-matched, and in fact, slightly under the sustainable power output of the RenewSolar 50kWh battery. This is an ideal scenario for battery longevity.
- The battery’s 200A limit ensures that even when the 8kW inverter is running at its maximum continuous output (drawing ~167A from the battery), the battery is operating at a C-rate well within its longevity recommendations:
- Discharge C-rate at 8kW continuous:
166.7A / 1042Ah (approx.) = 0.16 C. This is an extremely low C-rate, which significantly extends the battery’s cycle life, potentially pushing it towards the higher end of its 11,000+ cycle rating. - Charge C-rate from a full 10.4kW solar array: The maximum charge current the Sunsynk 8kW can deliver to the battery is around 216A (10.4kW / 48V), but the battery limits this to 200A. At 200A, the charge C-rate is
200A / 1042Ah = 0.19 C. Again, a very low and healthy C-rate for charging, ensuring excellent longevity.
- Discharge C-rate at 8kW continuous:
- This pairing creates a robust system where the battery is never stressed by the inverter’s demands at its full continuous output. The battery’s large capacity also means it can comfortably handle significant daily energy demands without deep cycling, further enhancing its lifespan. For instance, storing 50kWh means that even with a high average daily consumption of 20-30kWh, the battery only undergoes a 40-60% Depth of Discharge (DoD), which is excellent for longevity.
2. Price Considerations
The pricing of these components reflects their respective roles in a solar storage system.
Sunsynk 8kW Hybrid Inverter:
- Approximate Cost (UK, Inc. VAT): £1,500 – £2,200. Prices can vary depending on the supplier and any ongoing promotions. RenewSolar price aprox £1,700
- What’s Included: As a hybrid inverter, it includes integrated dual MPPT solar charge controllers, Wi-Fi for monitoring, and the necessary hardware for intelligent energy management (e.g., CT clamp for grid monitoring). This makes it a highly integrated and relatively cost-effective “brain” for the system.
RenewSolar 50kWh Battery:
- Approximate Cost (UK, Inc. VAT): Based on RenewSolar’s published prices, the 50kWh battery is listed at £3,450 – £4,400. This makes it a very competitively priced large-capacity LiFePO4 battery in the UK market, especially considering the Grade A cells and comprehensive BMS included.
- What’s Included: The 50kWh battery comprises 48 x 314Ah cells, a robust Battery Management System (BMS) with communication capabilities (JK, PACE, or others available), and various format options (tower, rack-mount, stackable, wall-mounted). The price reflects the substantial capacity and high-quality components.
How they Stack Up (Price):
- Total System Component Cost (Inverter + Battery):
- Sunsynk 8kW: ~£1,800
- RenewSolar 50kWh: ~£3,900 (mid-range of listed price)
- Combined Estimated Price: Approximately £5,700.
- This combined price represents a highly powerful and long-lasting energy storage solution for a residential or even light commercial application. The cost is highly competitive given the 8kW continuous power output and the massive 50kWh storage capacity, which promotes extremely long battery life.
- The integrated nature of the Sunsynk inverter simplifies installation and reduces the need for additional costly components (like separate MPPTs or communication hubs), contributing to a more streamlined and budget-friendly overall system compared to a modular setup of equivalent power and capacity.
- RenewSolar’s focus on “cutting the price of the batteries and not the quality” is evident here, as a 50kWh LiFePO4 battery at this price point is highly attractive for achieving a strong ROI and extended system longevity.
Conclusion on Pairing:
The combination of a Sunsynk 8kW hybrid inverter with a RenewSolar 50kWh battery forms an exceptionally robust and efficient energy storage system. The inverter’s output capability is comfortably managed by the battery’s sustainable discharge limit, ensuring the battery operates at very low C-rates. This pairing is ideal for maximising the battery’s lifespan, potentially reaching or exceeding the 11,000+ cycle mark, and providing abundant energy for large domestic loads or even some light commercial applications. The integrated nature and competitive pricing of both components make this a very attractive option for those looking for substantial energy independence and a rapid return on investment.
You’re looking at a fascinating comparison, pitting a highly integrated, well-known brand against a more modular, high-capacity, and competitively priced solution from RenewSolar. The Tesla Powerwall (specifically the latest Powerwall 3) represents the epitome of a “plug-and-play” home energy storage system, deeply integrated into Tesla’s ecosystem, while the Sunsynk 8kW + RenewSolar 50kWh system offers a powerful and flexible alternative, potentially with superior value for money and longevity for high-demand users.
Let’s break down how they compare in terms of power, price, and other key aspects.
System Comparison: Sunsynk 8kW + RenewSolar 50kWh vs. Tesla Powerwall 3
This comparison highlights the fundamental differences in approach between a bundled, integrated energy storage system and a more component-based, high-capacity solution.
1. Power and Capacity Comparison
| Feature/System | Sunsynk 8kW + RenewSolar 50kWh | Tesla Powerwall 3 |
|---|---|---|
| Inverter Type | Sunsynk 8kW Hybrid Inverter (separate) | Integrated Solar Inverter (within Powerwall 3 unit) |
| Battery Chemistry | LiFePO4 (RenewSolar battery) | NMC (Nickel Manganese Cobalt) (Tesla’s chemistry) |
| AC Output Power (Continuous) | 8kW (from Sunsynk) | 11.5kW (AC) per unit |
| Peak Power Output | Up to 8.8kW (Sunsynk) | 11.5kW (AC) continuous, 185A motor start capability |
| Solar PV Input (Max DC) | Up to ~10.4kW (Sunsynk) | Up to 20kW DC per unit (via 6 MPPT inputs) |
| Battery Capacity (Usable) | 50 kWh (RenewSolar) | 13.5 kWh per unit |
| Scalability (Battery) | Very flexible, can add more RenewSolar batteries or different types. Sunsynk 8kW can parallel up to 16 units.(128 kw total) | Up to 4 Powerwall 3 units (54 kWh total) |
| Battery Voltage | 48V Nominal (RenewSolar battery) | High Voltage DC (Integrated system, not typically stated for external compatibility) |
| Charge/Discharge Limit (Battery) | 200 Amps (RenewSolar 50kWh battery) at 48V = 9.6kW | 11.5kW continuous (internal battery limits managed by Tesla) |
| Ideal Power Match | The Sunsynk 8kW (drawing ~167A) is well below the RenewSolar 50kWh battery’s 200A limit, ensuring very low C-rate operation (approx. 0.16C discharge). This is excellent for longevity. | Powerwall 3’s integrated inverter matches its internal battery. Operates at a higher C-rate relative to its own capacity (11.5kW from 13.5kWh is ~0.85C). |
| Depth of Discharge (DoD) | Typically 80-90% for best life, though 100% is technically possible with LFP. | 100% DoD (Tesla states usable capacity is as advertised) |
| Operating Temp Range | Sunsynk: -25°C to 60°C. RenewSolar Battery: 0°C to 45°C (for longevity, capacity drops at lower temps). | -20°C to 50°C (integrated thermal management) |
Analysis of Power & Capacity:
- Capacity: The RenewSolar 50kWh battery offers significantly more raw storage capacity than a single Tesla Powerwall 3 (50 kWh vs. 13.5 kWh). To match the RenewSolar capacity, you’d need four Powerwall 3 units (4 x 13.5 kWh = 54 kWh).
- Power Output: A single Tesla Powerwall 3 has a higher continuous AC output (11.5kW) than the Sunsynk 8kW inverter. However, the Sunsynk 8kW is a robust inverter that can deliver substantial power, and it perfectly matches the RenewSolar battery’s safe 9.6kW continuous output (from its 200A limit). If higher peak power is needed for very specific loads, multiple Sunsynk inverters can be paralleled.
- Longevity through C-rate: The Sunsynk + RenewSolar combination shines here. Because the 50kWh RenewSolar battery is so large, and its internal limit is 200A (9.6kW), the 8kW Sunsynk inverter will operate the battery at a very low C-rate (around 0.16C). This significantly extends the battery’s cycle life, potentially pushing it to the upper end of its 11,000+ specified cycles. The Powerwall 3, while engineered for 100% DoD, operates at a much higher C-rate relative to its capacity (around 0.85C), which inherently contributes to a faster degradation rate over time compared to a deeply oversized battery system.
2. Price Comparison (UK, as of June 2025)
This is where the direct comparison becomes stark.
| Feature/System | Sunsynk 8kW + RenewSolar 50kWh (Estimated Total) | Tesla Powerwall 3 (Estimated per unit, installed) |
|---|---|---|
| Inverter Cost (Est.) | £1,500 – £2,200 (Sunsynk 8kW) | Integrated into Powerwall 3 unit |
| Battery Cost (Est.) | £3,450 – £4,400 (RenewSolar 50kWh) | Integrated into Powerwall 3 unit |
| Installation & Hardware | Standard installation costs + cabling/fuses (Sunsynk includes CT) | Included in Powerwall 3 installation price (integrated gateway) |
| Estimated System Price | £4,950 – £6,600 | £8,095 – £8,500+ per unit (installed) |
| Price per kWh | £90 – £132 per kWh (for 50kWh) | £599 – £630 per kWh (for 13.5kWh) |
RenewSolar matching:
2x8kw inverters and 2x 15kwh batteries comes in around £6,600 This give you twice the storage and a little more power than the power wall and still comes in considerably lower cost that the tesla offering while having significant perks and safety. Save 82%!
Price Difference Calculation:
Absolute Difference: £33,190 – £5,775 = £27,415
Cost Difference:
Tesla System Cost: £33,190
RenewSolar System Cost: £5,775
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