A practical guide in Spanish on how to install and set up the BSLBATT B-LFP48-300PW wall-mounted battery, 16.07 kWh. It is based on the official user manual for the BSLBATT B-LFP-PW wall-mounted series (V1.0, March 2026) and the model’s technical data sheet. This is a summary for guidance purposes only: the binding document is the manufacturer’s official manual (PDF, English), and the installation must be carried out by a qualified installer.
1. Before you start: safety
- 51.2 V unit with very high short-circuit current: always operational de-energised, with the BMS switch set to OFF and the inverter switched off. Before touching any terminals, check with a multimeter.
- Remove your watch, rings and any metal objects. Wear insulating gloves and footwear, safety goggles and use tools with insulated handles. Do not leave any tools or metal parts on top of the battery.
- For the first time the system is switched on, the manufacturer requires at least two people on the site.
- If the battery has been subjected to a heavy knock or has been dropped during installation, do not use it: contact your dealer.
- Do not open the casing. Doing so will invalidate the warranty and poses an electrical hazard.
2. Where to install it
- Inside Mandatory: The equipment is rated IP20. Dry location, humidity ≤ 60 %, free from conductive dust, away from heat sources and flammable materials.
- Operating temperature: 0 to 55 °C when charging, -20 to 55 °C when discharging. The battery will not charge below 0 °C: in cold areas, make sure the premises are heated.
- Natural cooling, no fans: leave some space around the unit to allow heat to dissipate, and do not place any objects next to the casing.
- Maximum altitude 4,000 m.
- Floor and wall with sufficient load-bearing capacity: the unit weighs 135 kg. The version with wheels (844 × 510 × 240 mm) stands on the floor and is secured to the wall via the rear bracket; the wall-mounted version (778 × 510 × 270 mm) hangs from the bracket.
3. What’s in the box and what tools you’ll need
Contents: battery with wall bracket, set of power and communication cables, and 10 M8 × 50 mm expansion plugs (wall-mounted version only). The manual is supplied in electronic format.
Tools recommended by the manufacturer: insulated gloves and footwear, safety goggles, a helmet, a screwdriver, a wire stripper, a hydraulic crimping tool, a heat gun, a multimeter, a torque wrench and a marker pen.
4. Mechanical assembly
- The battery should be moved by two people or using mechanical means; weighing 135 kg, it is not designed to be handled manually by one person.
- Position the rear bracket against the wall, level it and mark the drill holes. Use the supplied M8 × 50 wall plugs on solid walls (concrete or solid brick); for hollow-core blocks or plasterboard, you will need a specific fixing designed to support the weight.
- Secure the stand and hang or place the battery on the stand. For the version with wheels, lock the wheels once it is in position.
- Plug in the earth terminal from the battery to the installation earth before any power cables.
5. Electrical connection
5.1 Power
- The power cables are pre-fitted at the factory with crimped terminals at both ends for connection to the inverter. Ensure correct polarity: P+ and P- are screen-printed on the front panel.
- If you crimp your own cables, the conductor must be fully inserted into the terminal – never the sheath: a loose connection generates heat and may damage the inverter terminal.
- Ensure there is a gap of ≥ 30 mm between the cables and any heat-generating components. Group power cables and communication cables separately, ensuring they do not cross over one another.
- With a continuous discharge current of 200 A (up to 250 A peak), size the cable cross-section and the DC protection (fuse or DC circuit-breaker) in accordance with the REBT and the inverter’s instructions.
- If you are going to carry out wiring work when the ambient temperature is below 0 °C, bring the cables up to temperature first: the manufacturer stipulates that they must be installed at a temperature above 0 °C.
Guideline cable cross-sections and protection for 200 A
Guideline values for flexible copper cable with XLPE/EPR insulation rated at 90 °C (RV-K, H07Z-K or equivalent battery cable), in accordance with the permissible current tables in UNE-HD 60364-5-52 (ITC-BT-19 of the REBT), for surface or duct installation (method C) and an ambient temperature of 40–45 °C, typical in a plant room. The design current is the continuous discharge current of the battery (200 A); if the inverter draws less current, size the circuit according to the inverter’s maximum current, which will be the actual limit.
| Direct current |
Minimum cross-sectional area (XLPE 90 °C, 40–45 °C) |
Max. round-trip length for ≤ 1 % drop (0.5 V) |
DC fuse / switch |
| up to 100 A (5 kW inverter) |
35 mm² |
≈ 10 m |
125 A |
| up to 150 A (8 kW inverter) |
50 mm² |
≈ 5 m |
200 A |
| 200 A (battery at full power, 10 kW) |
70 mm² |
≈ 5 m |
250 A |
| 200 A with PVC 70 °C or grouped sections |
95 mm² |
≈ 7 m |
250 A |
- Why 70 mm² and not 50 mm²: 50 mm² XLPE can handle around 209 A at 30 °C on the surface, but at an ambient temperature of 45 °C this drops to around 180 A, which is below the 200 A continuous rating. With 70 mm², there is a margin of ~235 A at 45 °C.
- Voltage drop: Keep the battery cables as short as possible and ensure the positive and negative cables are the same length. At 200 A, a 3 m round trip in 70 mm² results in a voltage drop of 0.3 V (0.6 %); in 50 mm², 0.42 V (0.8 %). A drop of more than 1 % causes differing voltage readings between the BMS and the inverter, leading to premature shutdowns due to low voltage.
- Protection: a 250 A DC fuse (MEGA, NH gPV or Class T type, rated voltage ≥ 80 V DC) or a 250 A, 80 V DC DC circuit breaker, as close as possible to the battery terminal. The 250 A peak for 1 s specified by the battery will not blow a 250 A fuse (long-time curve).
- Terminals: A tinned copper tubular terminal of the same cross-section as the cable and the same diameter as the terminal (usually M8), crimped using a hydraulic crimping tool and protected with heat-shrink tubing. Recommended tightening torque for M8 is 10–12 N·m unless otherwise specified by the manufacturer; check the inverter manual for the torque specifications of its terminals.
- Parallel: Each battery is connected by its own 70 mm² cable to a busbar rated for the sum of the currents (2 units: 400 A), with an individual 250 A fuse per battery. From the busbar to the inverter, the cross-sectional area is determined by the inverter’s maximum current, not the combined current of the batteries.
These values do not replace the installer’s calculations in accordance with the REBT or the inverter manufacturer’s instructions.
5.2 Communication with the investor
The front panel has ports CAN, RS485, RS232 and two ports RS485-1/2 for the battery parallel connection, as well as a dry contact (DRY), a DIP switch for selecting the direction, a reset button and the BMS switch.
- CAN (500 kbps): the standard port for inverters. RJ45 pinout: pin 4 CAN-H, pin 5 CAN-L, pin 2 GND. This is the port used by Victron, Studer, Deye, Solis, Goodwe, SolaX and SMA.
- RS485 (9,600 bps): an alternative for investors who require it (Deye, Lux Power, SUNSYNK, Phocos). RJ45 pinout: pin 1 RS485-B, pin 2 RS485-A, pin 3 GND (and pin 8 B, pin 7 A, pin 6 GND).
- RS232 (9,600 bps): only for connecting the manufacturer’s monitoring software from a PC; it does not connect to the inverter.
- Use a standard Ethernet cable with an RJ45 connector. BSLBATT offers a cable specifically designed for the Victron (blue, 3 m) and a universal cable (black, 3 m) as optional extras. Note: CAN and RS485 share the RJ45 connector but not the pinout; use the correct cable for your inverter.
- From the battery screen, you can change the protocol to adapt it to the inverter brand: see the list of compatible investors.
6. Connecting several batteries in parallel
- Up to 32 units can be connected in parallel (514 kWh). The manufacturer recommends not exceeding 30 units in a single group.
- Power: positive to positive and negative to negative, using cables of equal length and cross-sectional area (the manual gives 25 mm² as an example for 100 Ah modules; for this 314 Ah battery, calculate the cross-sectional area based on the actual current in each branch and the common busbar).
- Communication: Connect the RS485-1/2 ports of one battery to the next using a standard RJ45 cable.
- Directions: Battery No. 1 is the teacher and it is the only one that connects to the inverter via CAN or RS485. The manual sets out the 6-position DIP switch table (master = 1 0 0 0 0 0, slave 2 = 0 1 0 0 0 0, and so on up to 63), although it states that the BMS assigns addresses automatically in recent versions. If a unit fails to communicate, check that the DIP switch settings and the RS485 terminator are correct.
7. Commissioning
- Once everything has been wired up and tested, switch on the battery management system (BMS) switch (starting with the master unit first in parallel systems).
- Press MENU on the screen: under “Analog Info” you can see voltage, current, temperature and SOC; under “BMS Status”, alarms and protection features. Buttons: SW1 MENU, SW2 ENTER, SW3 DOWN, SW4 ESC. The screen switches off after one minute of inactivity; pressing any key reactivates it.
- Select the inverter protocol from the display if it does not match the factory setting.
- Switch on the inverter and check that it recognises the battery (on the Victron, the Cerbo GX should display the battery in the device list and on the status panel).
- Check that charging and discharging are taking place within the correct limits and that no alarms are triggered.
8. The most common alarms and what to do
- High or low temperature (charge, discharge or MOSFET): Check the room temperature; switch off the battery and restart it once it is back within the range.
- Cell or total over/under-voltage, low SOC: Leave the battery to rest for 30 minutes and then restart the charging process.
- Overcurrent during charging or discharging: If it does not recover within 5 minutes, restart the system.
- RS485 parallel fault: Check the RS485-1/2 cables, DIP switch settings and terminator.
- If any of these issues persist, please contact technical support, providing the serial number, firmware version, date of installation and a description of the fault.
9. Maintenance
Every 6 months: check that the fastenings and terminals are tight, inspect the condition of the casing and cables, clean around the battery to ensure heat dissipation is not compromised, and check that there is no water or insects present. If the battery is to be left unused for a long time, charge it to at least 50 % SOC every 6 months; self-discharge is ≤ 3 % per month.
Documentation
Product details: BSLBATT B-LFP48-300PW · 16.07 kWh. Find out more about the brand at BSLBATT.
