Not automatically one SWI resistor
Keep battery BMS, connector, pull-up/series path, board trace and model-specific telemetry mapping open until confirmed.
IPHONE BATTERY / FUEL GAUGE / POWER-PATH FORENSICS
Read the battery.
Read the battery.
Then prove the power path.
Separate cell voltage, current shunt, gas-gauge telemetry, NTC, power-path switching, main system rail and PMU latch before replacing a battery, Tigris/Kraken, shunt or BMS assembly.
BATTERY / PMU EVIDENCE CHAIN
CELL
SHUNT
TELEMETRY
NTC
FET
VDD_MAIN
Percentage, health, charging icon and PSU current are observations. The repair comes from matching telemetry, voltage sag, load behavior and power-path evidence.
01 — BATTERY POWER & TELEMETRY HIGHWAY
Trace seven stages from cell to PMU latch
Select the architecture first because telemetry and service behavior vary by generation.
02 — SYMPTOM-TO-PROOF ENGINE
1%, shutdown, drain, battery message, fake charge and PSU behavior
Each case keeps battery, telemetry, connector, charger and board power-path branches open until confirmed.
SELECTED FAILURE
Observed evidence
Competing domains
Proof required
03 — BATTERY VS DC PSU TRIAGE
Bench supply behavior depends on battery-sense emulation
Do not interpret “0.000 A on a two-wire PSU” as a dead board until the battery telemetry and temperature-sense requirements are understood for that model.
| Power Setup | Expected Observation | What It Proves | What It Does Not Prove | Best Next Test |
|---|---|---|---|---|
| Known-good OEM battery | Normal battery telemetry and functional boot if board is healthy | Battery connector + telemetry branch can operate | Does not eliminate intermittent load sag or charger-path problems | Load test + compare VDD_MAIN / battery sag |
| Generic 2-wire PSU | Some models may not behave like a real battery | Only VBAT/GND behavior under that setup | Does not prove BATT_ID/NTC/SWI/I²C path is healthy or faulty | Use proper model-specific boot cable / battery emulator |
| Dedicated battery-emulation cable | Closer simulation of battery presence/thermistor/telemetry | Improves board current-signature testing | Still may not reproduce every authenticated BMS behavior | Compare against known-good physical battery |
| Battery fails under high load | VBAT may sag during camera/GPU/current spike | Supports high internal resistance or protection/path limitation | Does not automatically identify BMS MOSFET or shunt | Measure cell voltage at rest and under load |
04 — BATTERY / PMU REFERENCE DATABASE
Voltage + GR + resistance + state
Uploaded-source values are retained as references; exact-model schematic, boardview and known-good measurements take priority.
| Domain | Rail / Signal | Source Voltage | Source GR | Resistance | State / Protocol | What abnormal supports |
|---|
05 — LIVE BATTERY-LINE EVALUATOR
Combine electrical reading with the exact symptom
One static measurement narrows a branch; it does not prove the complete BMS or power path.
06 — SOURCE RULES CORRECTED
Do not turn one battery symptom into one component
Several direct conclusions in the uploaded V1 are intentionally downgraded to evidence branches.
Not automatically BMS MOSFET
Measure real battery sag, connector drop, shunt behavior and VDD_MAIN under load before battery-BMS conclusions.
Not automatically a capacitor
Prove the phone entered sleep and identify the leaking rail/domain before thermal localization.
Do not assume one universal pairing rule
Service/calibration behavior varies by generation, iOS version, repair history and part type. Preserve original data and use supported calibration paths where available.
Not automatically Q2100 / Tigris
Separate charger detection, VBUS path, battery acceptance, current path and charging-control state before replacing a switch or charger IC.
Does not prove telemetry or load integrity
SWI/I²C traffic, NTC behavior, intermittent connector faults and dynamic voltage droop can pass a static GR/voltage check.
07 — BATTERY / PMU CASE DOSSIER
Record telemetry, load, charger and battery-substitution evidence
Preserve exact model, battery history, panic token, rail values and known-good battery results.