Marstek B2500-D Balcony Solar Storage with 2.24 kWh
Solar battery storage for retrofit – 2 MPPT inputs, 1,600 W PV input, 800 W output
2.24 kWh LiFePO4
1,600 W PV input (2 MPPT)
800 W output
IP65
10-year warranty
The Marstek Saturn B2500-D is a balcony solar storage unit with 2.24 kWh LiFePO4 battery that retrofits easily to an existing balcony power system. Two independent MPPT inputs accept up to 1,600 W of PV power, while the output delivers up to 800 W to your micro-inverter – perfect for 800 W balcony systems. Store excess solar power generated during the day and use it in the evening and night. With MC4 connectors, the solar storage is compatible with virtually all standard solar modules and micro-inverters, connects via plug and play in minutes, and is expandable up to 8.96 kWh.
How the solar storage works
The B2500-D sits between your solar modules and micro-inverter: the modules charge the storage via the MC4 inputs, and the storage supplies power to the inverter via its MC4 outputs. Your existing inverter continues to operate – no replacement is necessary.
Who is this suitable for?
Ideal for balcony power system owners who generate more solar power during the day than they consume and want to use the surplus themselves in the evening or night, rather than feeding it into the grid. The two MPPT inputs are particularly well-suited for east–west installations and modules with different orientations.
2 independent MPPT inputs
Up to 1,600 W PV input power (2 × 800 W), voltage range 12–59 V – optimal yield even with differently oriented modules.
800 W output, universally compatible
2 × 400 W DC output (16–40 V) via MC4 – suitable for virtually all standard micro-inverters and 800 W balcony systems.
LiFePO4 with over 6,000 cycles
Up to 15 years lifespan, 10-year manufacturer's warranty, BMS protection against overvoltage, undervoltage, overcurrent, short circuit, and over/under temperature.
Expandable to 8.96 kWh
Multiple units can be combined – the battery storage grows with your energy needs.
Automatic or manual mode
In automatic mode, feed-in adjusts in real time to your household consumption (with smart meter); in manual mode, set fixed time windows.
Marstek App with Wi-Fi and Bluetooth
Monitor solar production, charge state and consumption in real time, and adjust settings conveniently via smartphone.
Technical Specifications Marstek B2500-D
| Brand / Model |
Marstek Saturn B2500-D |
| Capacity |
2.24 kWh, expandable to 8.96 kWh |
| Battery technology |
LiFePO4, over 6,000 charge cycles to 80% capacity |
| PV input |
2 × MC4 (2 MPPT), max. 2 × 800 W (1,600 W total), 12–59 V, max. 2 × 13.5 A |
| DC output |
2 × MC4, max. 2 × 400 W (800 W total), 16–40 V, max. 15 A |
| Compatibility |
Virtually all standard solar modules and micro-inverters (MC4) |
| Protection rating / BMS |
IP65; protection against overvoltage, undervoltage, overcurrent, short circuit, over/under temperature |
| Connectivity |
Bluetooth 5.2, Wi-Fi 2.4 GHz, Marstek App |
| Operating temperature |
−10 °C to +50 °C (storage −10 °C to +55 °C) |
| Standards |
EN IEC 62109-1/-2 (safety), EN IEC 61000-6 (EMC), IEC 62619 (battery), WEEE/RoHS/REACH |
| Material |
ABS, polycarbonate, metal |
| Dimensions |
309 × 175 × 350 mm |
| Weight |
20 kg (± 0.5 kg) |
| Warranty |
10-year manufacturer's warranty |
In the box
- 1× Marstek Saturn B2500-D balcony solar storage unit
- 4× MC4 extension cables
- 1× Tool
- 1× Warranty card
Frequently Asked Questions
Can I connect the storage to my existing balcony power system?
Yes. The B2500-D is connected via MC4 between your solar modules and micro-inverter. Your existing inverter continues to be used.
Do I need a smart meter?
Not necessarily. In manual mode, you set fixed feed-in time windows in the app. For automatic, consumption-dependent feed-in, a compatible smart meter is required.
How much module power can I connect?
Up to 2 × 800 W (1,600 W total) at the two MPPT inputs. The output to the inverter supplies up to 800 W.
Can the storage unit be placed outdoors?
Yes. With IP65 protection rating, it is protected against dust and water jets and operates from −10 °C to +50 °C.
Your solar power, even after the sun has set.
2.24 kWh solar storage, 2 MPPT inputs, retrofitted in minutes.
