Battery model: Pylontech US3000C
Fault type: Water ingress, corrosion damage
Service type: Out-of-warranty specialist repair & testing
⚠️ What happened?
Following heavy snowfall, a customer’s outbuilding roof collapsed. Snow entered the building and settled directly on top of the Pylontech US3000C battery stack. As the snow melted, water ingress occurred inside the battery enclosure.
This resulted in:
- Corrosion to the CCMU mounting brackets
- Corrosion damage to the BMS
- Oxidation and damage around the balance connectors
- Internal contamination inside the battery module
🔧 Repair work carried out
After collection of the battery from the customer, the following specialist repair work was completed:
- Full strip-down and inspection of the battery
- Removal of the white balance socket
- Repair of two damaged balance pins on the top of one 5S cell brick
- Repair of damaged PCB traces on the balance board
- Replacement of the CCMU
- Replacement of one balance cable
- Cleaning and remediation of corrosion-affected areas
- Careful reassembly of the battery
🔋 Testing & validation
Once repairs were complete, the battery underwent a full validation cycle:
- Charged to 100% State of Charge
- Full discharge test performed
- Cell balance checked across all groups
- Discharged to 8% SOC
- Recharged to 88% SOC
- Left balancing at 53.2 V with ~250 mA charge current
- Passive balancing successfully reduced cell imbalance to <5 mV
This confirms correct BMS operation, healthy cells, and stable long-term balance behaviour.
🚚 Logistics
- Battery collected from the customer
- Repair completed in-house
- Battery returned using the original Pylontech packaging for safe transport
✅ Outcome
The battery was successfully repaired, electrically validated, and returned fully operational. This repair avoided a costly replacement and restored the battery to safe, usable condition.
💬 Need help with a damaged Pylontech battery?
If your battery has suffered:
- Water ingress
- Corrosion
- BMS faults
- Balance or SOC issues
We offer diagnostics, repair, and recovery services for Pylontech US2000 / US3000 / US3000C systems.
👉 Contact us before writing the battery off — many faults are repairable.