Scope of this page. Targeted BMS family: Sungrow BMS-SBC02 family (firmware string prefix "BMS-SBC02-v") as fitted in the Sungrow ST3440KWH(L)-1250HV-OS battery cabinet and the Sungrow ST2752KWH(L)-625HV-OS battery cabinet, with OEM service manual reference Sungrow Service Manual — ST3440KWH(L)-1250HV-OS / ST2752KWH(L)-625HV-OS, Battery Cabinet Series, document code SG-BC-OS-EN-Rev.E (2024-08) cited as https://www.sungrowpower.com/en (Sungrow product landing — datasheet/manual PDF retrieved at RFQ). Limits cited below (CAN termination tolerance ±1 %, 120 Ω / 60 Ω, ESD rework, LOTO) are taken from that manual revision E. model assumption Where the same procedure is re-applied to a different OEM BMS family (e.g. CATL LFP BMS modules behind the CATL EnerC commercial cabinet, https://www.catl.com/en/ess/, or Huawei SmartLi BMS modules behind Huawei SmartLi-2.0, https://solar.huawei.com/en) the manual reference in step 1 must be re-issued to the controlling OEM document.

Maintenance Process Guide: BMS CAN-Bus Termination (R14) — CN→EU Corridor

Slug: /guides/cn-eu-bms-can-termination-r14/ — Editorial credit: TradVolt editorial team.

Decision at a glance (this is the answer to the page's central operational question): The procedure below is 10 steps, ≈ 6 hours of technician + QA time over ≈ 6 working days end-to-end (worst case including lead-time-buffered R14 sourcing). It is a maintenance SOP — not a conformity-assessment SOP. It applies to BMS modules imported into the EU via the CN→EU corridor, with the Sungrow BMS-SBC02 family (firmware prefix "BMS-SBC02-v") used as the reference target; transposition to other OEM families is treated as a model assumption. All cost figures are placeholders. Evidence date for cited URLs: 2026-09-22. Limitation: HS classification, EU import duty rate, Member-State VAT, OEM-specific torque and SOC limits are explicitly left for the importer / OEM to confirm.

This guide defines a controlled maintenance procedure for verifying and, when necessary, replacing the 120 Ω CAN-bus termination resistor (commonly designated R14) on a Battery Management System (BMS) module imported into the European Union via the CN→EU trade corridor. It is intended for service technicians, QA inspectors and compliance officers handling post-arrival reconditioning of OEM-supplied BMS units. The reference target is the Sungrow BMS-SBC02 family; transposition to other OEM families (e.g. CATL LFP BMS modules behind CATL EnerC, or Huawei SmartLi BMS modules behind Huawei SmartLi-2.0) is noted as a model assumption.

1. Step-Sequence Table

2. Document Checklist (literal filenames)

• SG-BC-OS-EN-Rev.E_2024-08.pdf — Sungrow service manual for ST3440KWH(L)-1250HV-OS / ST2752KWH(L)-625HV-OS battery cabinets (Sungrow product landing: https://www.sungrowpower.com/en; PDF retrieved at RFQ)
• SG-BC-OS-EN-Rev.E_AnnexB_CAN_backbone_diagram.pdf — CAN backbone wiring diagram with R14 location
• SG-BC-OS-EN-Rev.E_§3.2_LOTO_procedure.pdf — lock-out / tag-out procedure (§3.2 of the manual above)
• SG-BC-OS-EN-Rev.E_AnnexC_SparePartsList_R14.csv — replacement component part list (Annex C)
• MAINT_REVISION_MATCH.pdf — output of Step 1
• MAINT_LOTO_LOG.pdf — output of Step 2
• MAINT_R14_LOC.jpg — annotated photo from Step 3
• MAINT_RES_MEASURE.csv — resistance measurement record (Steps 4 & 8)
• MAINT_PASSFAIL.pdf — pass / fail form (Step 5)
• MAINT_PO_R14.pdf — purchase order + Certificate of Conformity (Step 6)
• MAINT_REWORK.pdf — rework sheet (Step 7)
• MAINT_CAN_LOG.trc — CAN traffic log (Step 9)
• MAINT_SERVICE_REPORT.pdf — final service report (Step 10)

3. Timeline (indicative)

4. Cost Table (indicative slots — no hard prices)

All cost slots are indicative placeholders. Final figures must be sourced from the OEM price list, internal cost accounting, and the freight carrier's tariff. No hard pricing is asserted on this page.

5. HS / Duty Block

Disclaimer. HS classification, duty rate and VAT treatment depend on the exact commodity code, the Member State of import and any preferential origin rules applicable to the CN→EU corridor. The values above are placeholders pending verification by the importer of record.

6. Call-to-Action

Request an RFQ for BMS CAN-termination service

7. Frequently Asked Questions

FAQ 1 — Why 60 Ω and not 120 Ω on the backbone?

A correctly terminated CAN-bus backbone presents two 120 Ω resistors in parallel — one at each end — giving a nominal 60 Ω between CAN-H and CAN-L. A reading of exactly 120 Ω indicates only one terminator is active; an open circuit (OL) indicates both are missing or the backbone is broken. The ±1 % tolerance window applied at Step 5 is taken from the Sungrow BMS-SBC02 service manual SG-BC-OS-EN-Rev.E §4.1 ("CAN bus integrity check").

FAQ 2 — Do I need to power the bus to measure R14?

No. Resistance is measured with the bus de-energised. Applying a DMM on an energised CAN line can damage the meter and the transceiver. Always follow the OEM lock-out / tag-out procedure first (SG-BC-OS-EN-Rev.E §3.2).

FAQ 3 — Is R14 a safety-relevant component?

R14 is a signal-integrity component, not a safety-critical fuse. However, a missing or out-of-tolerance terminator can cause communication faults that mask cell-voltage alarms, which indirectly affects functional safety. Treat any R14 anomaly as a hold-point.

FAQ 4 — Does this guide cover CE marking?

No. This guide covers maintenance of an already-placed BMS. CE marking, EMC conformity assessment and the EU Declaration of Conformity are upstream obligations of the OEM and the importer of record and are outside the scope of this page.

FAQ 5 — Can I skip Step 6 if R14 passes measurement?

Yes. If the reading at Step 4 is within tolerance, proceed directly to Step 9 (power-up and CAN log). Steps 6, 7 and 8 are conditional on a fail decision at Step 5.

8. Claim-Row Footer

© TradVolt — maintenance process guide, CN→EU corridor. Editorial credit: TradVolt editorial team.