SAJ Solar Battery 48V 5.1kWh (B1-5.1-48) – compact 48V home battery

The SAJ Solar Battery 48V 5.1kWh, type B1-5.1-48, is a low-voltage 48V home battery for residential PV installations. With a total capacity of 5.12 kWh and about 4.6 kWh of usable energy, this is an ideal module for storing your own solar power and using it later. The battery has an integrated BMS, uses safe _LiFePO4 cells and, thanks to its IP65 enclosure, is suitable for installation in the home or in a sheltered technical room.

Note: This battery is designed to work together with SAJ AS1 retrofit battery inverters and SAJ H1 hybrid inverters. The B1-5.1-48 is therefore a battery module, not an all-in-one system with integrated inverter. :contentReference[oaicite:1]{index=1}

When to choose the SAJ B1-5.1-48 48V battery?

• You have an SAJ AS1 AC retrofit kit and are looking for an (additional) 48V battery module.
• You have an SAJ H1 hybrid inverter and want a nice matching low-voltage battery pack.
• You want to start small first and expand later: several B1 modules can be placed in parallel per AS1/H1.
• You prefer a 48V system (low voltage) instead of a high-voltage rack.

The B1-5.1-48 is modular. Depending on the inverter configuration, you can use several modules in parallel to incrementally increase the storage capacity. :contentReference[oaicite:2]{index=2}

Key features SAJ Solar Battery 48V 5.1kWh

• Nominal energy content: 5.12 kWh total, approx. 4.6 kWh usable (≤ 90% DoD).
• Rated voltage: 51.2V (48V system, 16S _LiFePO4).
• Battery chemistry: lithium iron phosphate (_LiFePO4) – high safety and long service life.
• Service life: ≥ 6000 cycles under normal conditions.
• Maximum charge/discharge current: 60 A.
• Integrated BMS: monitors voltage, temperature, current and protects against over- and undervoltage.
• IP65 enclosure: dust-proof and protected against water jets; preferably placed indoors or under cover.
• Dimensions (h × w × d): 410 × 650 × 186 mm.
• Weight: approx. 48 kg.
• Warranty: up to 10 years manufacturer’s warranty, subject to conditions and registrations from SAJ. :contentReference[oaicite:3]{index=3}

Technical specifications

• Type: SAJ B1-5.1-48 (Solar Battery 48V 5.1kWh)
• Manufacturer: SAJ
• Manufacturer code (known to us): 1020050300AND020100
• Total capacity: 5120 Wh
• Usable capacity: 4600 Wh
• Rated voltage: 51.2 V
• Voltage range: 42 – 58.4 V
• Max. DoD: ≤ 90%
• Max. charge/discharge current: 60 A
• Operating temperature: 0 – 50 °C
• Relative humidity: 0 – 95 % (non-condensing)
• Cooling: natural convection
• Protection rating: IP65
• Standards: UN38.3, IEC 62619
• Dimensions (h × w × d): 410 × 650 × 186 mm
• Weight: 48 kg

Compatibility & expandability

• Suitable as a battery module for SAJ AS1 retrofit battery inverters.
• Suitable for SAJ H1 hybrid inverters (48V battery input).
• You can place several B1 modules in parallel per system (refer to your AS1/H1 manual for the maximum and exact configuration).
• As the modules operate in parallel, the storage grows linearly with them; ideal for later expansion as your consumption changes.

Installation tips for do-it-yourselfers and installers

• 1. Choose a suitable location
  Preferably mount the battery indoors or under a roof, protected from direct sunlight and rain. Ensure adequate ventilation around the cabinet (at least 50 cm clear at the top and sides) so that natural convection can do its job. :contentReference[oaicite:4]{index=4}
• 2. Solid wall & suspension
  The B1 weighs about 48 kg. Use a solid wall (concrete, sand-lime brick, solid brick) and the supplied wall bracket + fixing materials. Drill with the right size, use solid plugs/anchors and hang the battery level.
• 3. Always work without power
  Turn off the DC switch and the battery and BMS switch before working on the cabling. Always have AC connections and coupling to the inverter done or checked by a qualified installer.
• 4. Use original cable sets
  When connecting in parallel, use the original SAJ battery and communication cables. Pay close attention to polarity (BAT+ / BAT-) and follow the connection diagram in the SAJ manual.
• 5. Planning parallel expansion
  In the initial design, take account of possible expansion (several B1 modules next to each other). Leave sufficient space on the wall for additional batteries and observe the spacing recommendations from the manual.
• 6. Commissioning via AS1/H1 manual
  After mounting and wiring, commission the system according to the steps in the AS1 or H1 inverter manual. In the inverter monitoring, check that the correct battery capacity and number of modules are recognised.

Buy SAJ Solar Battery 48V 5.1kWh

With the SAJ Solar Battery 48V 5.1kWh (B1-5.1-48), you choose a safe, compact and modularly expandable home battery that fits perfectly with SAJ AS1 and H1 solutions. Ideal if you want to upgrade your existing PV system with storage or build a new 48V battery set around SAJ hardware.

Unsure if this battery fits your inverter or how many modules you need? Send us a picture of your meter box, SAJ inverter and nameplate, and together we will calculate which configuration best suits your consumption and future plans.