EcoFlow DELTA Pro 3 Error ERR 115: High-Voltage Solar BMS Communication Fault
Error code ERR 115 signifies a communication timeout or data packet corruption between the internal High-Voltage Solar Input Controller (MPPT DC-DC subsystem) and the master Battery Management System (BMS). When the high-voltage bus (up to 150V DC / 15A) engages, the system isolates the charging circuitry via internal relay disengagement to protect the LiFePO4 battery pack from unregulated power flow.
Hardware Diagnostic Matrix
Spec Ref #1ad33222Required Diagnostic Tools & Instrumentation
Multimeter Probing Targets & Circuit Tolerances
Bench Calibrated ±5%| Test Point / Circuit | Target Nominal Spec | Expected State | Fault Condition |
|---|---|---|---|
| Main Logic DC Bus | 3.3V / 5.0V DC (±0.1V) | Stable DC Potential | <2.9V (Brownout / Sag) |
| Thermistor / NTC Sensor | 10kΩ - 100kΩ @ 25°C | Smooth Thermal Curve | 0Ω (Short) or ∞ (Open) |
| Safety Ground / PE Continuity | < 0.5Ω Resistance | Solid Earth Bond | > 1.0Ω (Floating Chassis) |
Common Symptoms & Fault Manifestations
- LCD display and EcoFlow app show active code ERR 115 with a blinking solar icon
- Solar charging immediately ceases or fails to initiate upon plugging into the High-Voltage Solar port
- Audible relay clicking observed during input handshake followed by immediate thermal or protection disconnect
Root Causes & System Failure Modes
CAN/UART bus communication timeout between the high-voltage MPPT sub-board and the central BMS processor
Open-circuit solar array voltage exceeding rated input tolerance (>150V DC) triggering emergency bus shutdown
Corrupted or out-of-sync sub-controller firmware on the MPPT communications module
Loose internal ribbon cable harness or pin fretting on the internal DC-DC/BMS interconnect bridge
High-Voltage & Mechanical Safety Isolation
Prior to opening access panels, disconnecting terminals, or probing wiring, perform complete lock-out / tag-out (LOTO). Disconnect all AC mains, DC string isolators, and lithium battery banks. Allow internal smoothing capacitors at least 3 to 5 minutes to dissipate stored residual energy below safe threshold (<30VDC).
Step-by-Step Diagnostic & Resolution Procedure
Safe Array Isolation & Power Cut
Immediately disconnect the solar array from the high-voltage solar input port using an MC4 disconnect tool. Power down the DELTA Pro 3 by holding the master power button for 3 seconds until the display shuts off completely.
Photovoltaic Array Voc & Polarity Verification
Using a CAT III digital multimeter, measure the Open Circuit Voltage (Voc) and verify polarity across the positive and negative MC4 leads under peak sunlight. Ensure total array Voc does not exceed 150V DC under cold-weather temperature coefficients, and verify no ground leakage faults exist to array mounting rails.
BMS & MPPT Synchronous Logic Reset
Disconnect all AC, DC, and expansion battery connections. Press and hold the primary power button for 15 seconds to discharge internal capacitors and reset the BMS/MPPT communication bus registers. Power on the unit with zero loads attached.
Firmware Resynchronization & Solar Commissioning
Open the EcoFlow App, navigate to Settings > Firmware, and ensure both the Master BMS and Sub-controller firmware versions match and are fully updated. Re-insert the solar input cable while keeping loads disconnected; verify steady state MPPT handshake and positive wattage ramp-up without recurrence of ERR 115.
Hardware Reset & Fault Clear Sequence
Controller ProcedurePrevention & Routine Maintenance Guidelines
- Calculate string open-circuit voltage (Voc) accounting for lowest recorded ambient temperatures to prevent exceeding the 150V ceiling
- Keep device firmware updated via the EcoFlow app to ensure optimal MPPT and BMS bus timing parameters
Frequently Asked Diagnostic Questions
What does error code ERR 115 indicate on EcoFlow DELTA Pro 3?
Error code ERR 115 signifies a communication timeout or data packet corruption between the internal High-Voltage Solar Input Controller (MPPT DC-DC subsystem) and the master Battery Management System (BMS). When the high-voltage bus (up to 150V DC / 15A) engages, the system isolates the charging circuitry via internal relay disengagement to protect the LiFePO4 battery pack from unregulated power flow. In engineering telemetry, it indicates high-voltage solar bms communication fault requiring circuit verification.
What are the primary triggers causing error ERR 115?
Diagnostic bench telemetry isolates the following common root causes: CAN/UART bus communication timeout between the high-voltage MPPT sub-board and the central BMS processor; Open-circuit solar array voltage exceeding rated input tolerance (>150V DC) triggering emergency bus shutdown; Corrupted or out-of-sync sub-controller firmware on the MPPT communications module; Loose internal ribbon cable harness or pin fretting on the internal DC-DC/BMS interconnect bridge.
How do I reset and clear EcoFlow error ERR 115?
Disconnect all inputs (solar, AC) and accessory battery cables. Press and hold the main power button continuously for 15-20 seconds until the display flashes off and internal relays release. Release the button, wait 60 seconds, and short-press the power button to reboot the system. If the error status repeats immediately after clearing, discontinue clearing and test circuit continuity.
Can I safely resolve error ERR 115 without specialized shop tooling?
This fault is graded as Intermediate difficulty with High severity. Standard diagnostics require an insulated digital multimeter and appropriate hand tools. Always observe high-voltage isolation procedures.