| Symptom | Likely Pinout Cause | |-----------------------------|--------------------------------------------| | Laptop powers only on AC | B+ pin corroded or broken | | Battery detected but 0% | SMBus data/clock stuck (BMS lock) | | “Plugged in, not charging” | TH pin open-circuit (no temp reading) | | Battery gets very hot | B+ sense line open → overcharging | | Random shutdown at 50% | Weak cell, but B+ voltage drop confuses EC |
The HP MU06 is a widely used Li-ion battery model found in various HP Pavilion and Compaq Presario laptop series (typically the 6-cell, 10.8V/11.1V or 14.4V/14.8V variants). Understanding its pinout is essential for technicians attempting to revive dead batteries, repair motherboard charging circuits, or repurpose the cells for other electronic projects.
To fully grasp the pinout, you must understand what lies inside the HP MU06 pack:
+-------------+ +-------------------+ +------------+
| Cell 1 (4.2V|----+ | Protection Circuit | | Connector |
| Cell 2 (4.2V| | | & Gas Gauge (BQ40Z50| | Pin 6/7 B+ |
| Cell 3 (4.2V|----+ | or similar) |----+ | Pin 1/2 GND|
+-------------+ | | | | |
| | - Overvoltage | | | Pin 3 SMBC |
+-------------| - Undervoltage | +--| Pin 4 SMBD |
| - Overcurrent | | Pin 5 TH |
| - Short-circuit | +------------+
+-------------------+
The gas gauge IC (commonly Texas Instruments BQ40Z50-R1 or BQ3060) monitors individual cell voltages via internal balancing resistors. It communicates SMBus data over Pins 3 & 4.
Critical note: The battery’s protection FETs are normally open when the battery is disconnected. Only after receiving the correct SMBus command from the laptop’s EC do the FETs close, delivering power to Pins 6 & 7. This is why a fully charged MU06 battery shows 0V on Pins 6 & 7 when unplugged from the laptop.
The HP MU06 battery uses a 5-pin connector (JST style, 1.25mm pitch). Looking at the battery connector (pins facing you, latch on top):
| Pin # | Signal | Voltage / Function | Wire Color (Typical) | | :--- | :--- | :--- | :--- | | 1 | B+ | Battery Positive (+11.4V to +12.6V) | Red or Black/Red stripe | | 2 | SMBC | System Management Bus (Clock) | White or Yellow | | 3 | SMBD | System Management Bus (Data) | Gray or Blue | | 4 | PRES | Presence Detect (Ground via 10kΩ resistor inside battery) | Orange or Brown | | 5 | B- | Battery Negative (Ground / 0V) | Black |