Multi-AmpBox Parallel Configuration


When one AmpBox isn’t enough, the JK‑PB2A16S lets you scale by connecting multiple units in parallel. In this configuration, all batteries must behave as a single cohesive bank, both electrically and logically, so the inverter sees the total capacity (e.g., 2 × 306Ah = 612Ah).

1. DIP Switch Addressing (The “ID” System)

Each AmpBox in a parallel stack needs a unique ID. The inverter only communicates directly with Address 1 (the Master), which then aggregates data from all other units (Slaves).

Pack Number DIP Switch Position (1 2 3 4) Logic
Pack 1 (Master) ON, OFF, OFF, OFF Address 1
Pack 2 OFF, ON, OFF, OFF Address 2
Pack 3 ON, ON, OFF, OFF Address 3
Pack 4 OFF, OFF, ON, OFF Address 4
IMPORTANT: Power off the BMS before changing DIP switches. The JK‑BMS only reads DIP positions during its initial boot sequence.
2. Data Linkage (Communication Sync)

To synchronize all AmpBoxes, you must link their BMS “brains” using the RS485 ports in a daisy chain.

  • Connect an RJ45 cable from Battery 1 (RS485‑2) to Battery 2 (RS485‑1).
  • Repeat this pattern for each additional battery.
  • The CAN port of Battery 1 (Master) is the only one connected to the inverter.
3. Power Wiring: The “Diagonal” Rule

Proper power wiring ensures current is shared evenly across all packs.

  • The Wrong Way: Connecting both inverter leads to only the first battery.
  • The Right Way:
    • Connect all positives to a common positive busbar.
    • Connect all negatives to a common negative busbar.
  • Alternative (No Busbars): Connect inverter Positive to Battery #1 and inverter Negative to the last battery. This “diagonal” method helps equalize resistance paths.
4. Matching the State of Charge (SOC)

Before tying packs together, their voltages must be closely matched to avoid large equalization currents.

  • Charge each AmpBox individually until all are within 0.2V of each other.
  • Never connect a full pack (≈55V) directly to a low pack (≈48V).
  • Large voltage differences can cause massive surge currents, tripping Short Circuit Protection or stressing MOSFETs.
5. App Verification

Once everything is wired and powered, verify that the system is behaving as a single bank.

  • Connect to the Master (Address 1) in the JK BMS App.
  • Look for a Parallel Information or Pack tab.
  • Confirm that total current and total Ah capacity reflect the sum of all packs (e.g., two 314Ah AmpBoxes should report ≈628Ah).

Summary: Successful parallel configuration comes down to Unique IDs and Equal Resistance. If DIP switches are set correctly, voltages are matched, and wiring is balanced, the JK‑BMS will automatically coordinate load sharing across all AmpBoxes.

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