Inside a DELL D610 battery :: connector, pinout and signal timing

12 May 2009
Posted by Laptop Junction

To learn a little bit more about the DELL D5xx and D6xx battery range, here you find a few bits and pieces about it's internals. It's a first attempt with still many question unanswered. Anyone who likes to comment or make a suggestion, drop a note at the contact section.

DELL AC Adapter not recognisedDELL ID chip diedDELL design failureInside a DELL battery



In a hurry? Go directly to the DELL D5xx D6xx Battery findings.

One of the questions to be answered by this attempt; Is the voltage to charge the battery available - unconditionally - once the laptop battery is plugged in? If so, there's a chance to charge the battery unconditionally. Even with an AC adapter with a dead ID chip.

Reason for this attempt are widespread problems with the charging circuitry in a range of DELL laptops, covered here:

AC Adapter ID chip failure - DELL charging circuitry and the Maxim DS2501 memory chip
AC Adapter plug soldering - Soldering inside a DELL DC plug

So let's have a look if there's a possibility to charge a DELL battery in a DELL Laptop when the ID chip in the AC Adapter is dead.

DELL D500 / D600 battery measurement ingredients

Ingredients for this attempt to figure out DELL battery operations are:

  • Operational D610 laptop
  • Dead (empty) DELL D500 / D600 battery (case removed)
  • DELL AC Adapter with a dead DS2501 identification chip
  • DELL AC Adapter with working DS2501 identification chip

First the battery connector of the DELL battery was de-soldered. Next the connector was connected to the battery charger PCB using a 1 meter wire to be able to measure signals during operations.

For those who want to know how to crack the battery casing, read more about that here.

DELL D500 D600 battery test setup for pinout and signal timing

Cable to measure DELL Battery signals

Unfortunately, 2 cells of the battery were completely dead holding only a few millivolts. (In the picture the left 2) The rest of the 4 batteries all had about 1 volt left.

The batteries are configured in 3 sets of 2 cells in parallel. With a full charge this makes about 11 volts in total.

The transparent connection block is used to measure signals using a Fluke ScopeMeter.

Next the battery connector was connected to the DELL Latitude D610 laptop in power off state. Then the DELL AC adapter was connected.

The charger circuitry works with the laptop in the power-off state. In this configuration the signal levels were measured at the wires between connector and battery PCB.

DELL D500 / D600 battery pinout

Now during measurements the following DELL Battery pinout was discovered - leaving 2 unknown pins of the 9 available.

DELL D500 D600 battery pinout and voltage levels

Signals at Pin 3 and 6 could not be determined in this test setup. Voltage levels were close to zero during measurement attempts. See the table below for the completed DELL battery pinout based on the D610 schematics.

In September 2009 the final DELL battery pinout could be completed with access to the battery connector schematic:

D5xx, D6xx DELL Latitude Laptop battery pinout
Pin Battery Pinout Pinout description
1 BATT1+ Permanently connected to BATT2+
2 BATT2+ Permanently connected to BATT1+
3 SMB_CLK 2- wire System Management Bus signal (SMbus)
4 SMB_DAT 2- wire System Management Bus signal (SMbus)
5 BATT_PRESS# Battery Output - signal goes to D610 Motherboard
6 SYSPRES# Not used connected permanently to BATT1- and BATT2-
7 BATT_VOLT Battery Output - signal goes to D610 Motherboard
8 BATT1- Permanently connected to BATT2-
9 BATT2- Permanently connected to BATT1-

Previously PIN 5 was assumed to be a GND connection. Which apparently was wrong. Why this pin didn't carry any voltage remains unknown. (The battery used in this case was already dead)

Pin 2 and 3 are designated as a 2 wire SMBUS defined by Intel® Corporation in 1995.

TIP 1 : Looking for a DELL battery contra-connector? Have a look at these Standalone laptop battery chargers.

TIP 2 : Measure remaining laptop battery capacity with a simple laptop battery test.

TIP 3 : New laptop battery diagnostics : battery not charging

The signals measured during this attempt:

DELL D500 D600 battery pinout and signal timing

5 seconds after the AC adapter is connected, the laptop switches 9 volts on V+. This all happens while the Laptop is in Power Off State.

Why the supplied voltage is just 9 volts and not 11 volts or higher is unknown. During 60 seconds +9 volts stays, the green charge LED on the laptop switches on - but flashes then turning into the red flashing light indicating the battery is failing. The DATA line has constant communication going during the 60 seconds.

DELL D500 / D600 battery measurement conclusion

Once the ID chip of the AC adapter is dead, battery charging voltage does not appear at the V+ pin of the laptop battery. This is controlled by the DELL Latitude D610 laptop even when it's in power off state.

So what controls this battery charging functionality? Most likely it's embedded POST software or charging is controlled from within the battery.

Anyone with more info is invited to comment through the contact section.