Video reference. "Installation Video BYD HVS＋&HVM＋" is from the BYD Battery-Box official channel. It covers the mounting and assembly sequence for the HVS+ and HVM+ models, including the bus bar connections and the DC cable run to the compatible inverter.
1. Surveying the site and confirming inverter compatibility
The BYD Battery-Box is not an all-in-one system. It is a standalone battery that requires a separate compatible inverter, which handles the DC-to-AC conversion and the communication with the battery. Before the installation can be designed, the installer confirms that the planned or existing inverter appears on BYD's compatibility list and is running a firmware version that supports the Battery-Box model being installed.
If you already have solar panels with a compatible inverter, the Battery-Box can often retrofit without replacing the inverter. If the existing inverter is not compatible, a new compatible inverter forms part of the quote. The installer also checks the proposed battery location for adequate wall strength, correct ambient temperature, and a clean cable route to the inverter.
2. Choosing the right Battery-Box model and capacity
The HVS range suits smaller households or those wanting a compact starting capacity, typically 5.1 kWh to 12.8 kWh. The HVM range suits larger households with higher solar yields or significant overnight loads, with capacity from 8.3 kWh up to 22.1 kWh. Both use lithium iron phosphate (LFP) chemistry, which is well-suited to daily cycling and has a good safety record in residential settings.
The installer looks at daily consumption patterns, overnight EV charging if relevant, solar generation data and the household's energy tariff. Batteries work best when sized to store the day's surplus solar and release it during the evening peak, rather than being oversized and sitting part-charged most of the time.
3. Mounting the base module and stacking additional modules
BYD Battery-Box modules are wall-mounted on a purpose-made bracket. The base module goes on first, checked for level and secured to the appropriate fixings for the wall type. Additional modules stack above the base, each connecting to the next via the bus bar system and a short communication cable. The installation guide specifies the tightening torque for every terminal, and the installer follows this precisely because an undertightened connection will arc and overheat over time.
Before anything is connected to the inverter, the installer verifies polarity through the full battery stack and confirms the voltage reading is within the expected range for the state of charge at delivery.
4. Connecting the battery to the inverter
High-voltage DC cables run from the Battery-Box terminals to the inverter's dedicated battery input. Cable cross-section, fuse rating and the type of DC isolator at the battery end are chosen according to the inverter manufacturer's specification and the BYD installation guide. Communication cables, usually RS485 or CAN bus depending on the inverter brand, link the battery management system to the inverter so the two can exchange state-of-charge data and protection signals.
Once all DC connections are made and verified, the inverter's commissioning interface is used to confirm it recognises the battery. A mismatch in battery model selection at the inverter can prevent the system from operating correctly, even if all the wiring is correct.
5. Running the AC supply circuit to the consumer unit
The inverter's AC output connects to the consumer unit via a dedicated circuit. Cable size is chosen for the inverter's rated AC output current and the length of the cable run, keeping volt drop within BS 7671 Regulation 525 limits. An RCBO or MCB at the consumer unit protects the circuit. The installer carries out polarity checks, earth continuity, insulation resistance and loop impedance tests before closing the board and updating the circuit schedule.
6. Fitting the CT clamp and commissioning
A current transformer (CT) clamp on the grid import conductor gives the inverter a live reading of how much power the household is importing or exporting. The inverter uses this to direct surplus solar into the battery, discharge the battery when grid import rises, or export when both battery and household needs are met. Fitting the CT in the wrong orientation inverts the reading, so the battery charges from the grid when it should be storing solar and exports when it should be storing.
The installer verifies the CT reading against a known load before completing commissioning. A test charge and discharge cycle checks the full loop. The installation is notified through the installer's Part P competent person scheme and you receive an Electrical Installation Certificate. DNO notification follows G98 for exports up to 3.68 kW per phase, notified within 28 days. Larger systems need G99 pre-approval before work starts.
When to call us
Richard installs home battery storage systems across east Kent, including BYD Battery-Box and other brands. He handles the module mounting and assembly, DC connections, AC supply circuit, CT clamp, commissioning, Part P certification and DNO notification. Get in touch for a free fixed quote.
Battery storage installation in east Kent?
Richard installs BYD Battery-Box, Sungrow, GivEnergy and other home battery systems across Sandwich, Deal, Dover, Ramsgate and Canterbury. Free fixed quotes, full certification, same-day commissioning.
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