What Is a Battery Testing Flex?
This is not a replacement battery cable—it’s a diagnostic tool used in repair workflows. It mimics the battery’s presence by providing the necessary SMBus signal and power-enable lines to the logic board, allowing the MacBook to:
- Power on without a battery installed
- Test logic board functionality independently
- Diagnose whether a no-power issue is caused by the battery or logic board
Compatible With
- MacBook Pro 15″ (2018–2019)
- Model: A1990
- Model Identifiers: MacBookPro15,2
- Chip: Intel Core i7/i9
⚠️ Not compatible with A1707 (2016–2017), A2159 (16″), or any M1/M2 models.
Key Features
- Simulates battery presence via correct SMBus resistance and ID signals
- Includes power-enable circuitry matching Apple’s safety protocol
- Pre-terminated with OEM-style connector for A1990 logic board
- Allows safe bench testing of logic boards during repair
Common Use Cases
- Diagnosing “no power, no fan spin, no display” issues
- Verifying if a logic board powers on without risking a shorted battery
- Testing after liquid damage or DC-in board replacement
- Avoiding unnecessary battery replacements during diagnostics
⚠️ Important Notes
- Not for permanent installation—intended for temporary diagnostic use only
- Does not charge or store power—requires connected USB-C power adapter to operate
- Must be used with a known-good power adapter (87W recommended)
- Not a consumer part—designed for professional repair shops and technicians
