Checking the Battery Pack

Checking the Battery Pack

Battery charging will not start until the Fuel-Gauge shows that less than 90% of the total power remains; with this condition the battery pack will charge to 100% of its capacity. This protects the battery pack from being over-charged or having a shortened life.


  1.  Models 355x and 360x battery pack does not  contain a microprocessor. In the following,  ignore any reference to the storage switch.
  2.  Before you perform the following procedure,  check the following:

  3.  Power-off the computer.
  4.  Remove the battery pack and measure the voltage between battery  terminals

    NOTE: The following figure hows the battery for the Model 370C,  750x, 755C, and 755Cs.  The battery for Models 355x and 360x, do not have the  storage switch, but the battery terminals are the same.


    Terminal Voltage (V dc) / Signal
    1 + 8.0 to + 16.0
    2 Send
    3 Thermal
    4 Ground (-)
    5 R1
    6 Select
    7 R2


    NOTE: Signal lines, not used in these steps,  are used for communication between the system and the battery.  The storage switch is used to control the power to the  internal microprocessor of the battery.  The storage switch should be  set to off (0) only when the battery is going to be kept in storage  for more than two months.

  5.  If the voltage is less than + 8.0 Vdc, the battery pack has  been discharged or is defective.  Recharge the battery.  If the recharging does not work,  go to Step 5 to check the charging circuit.

     If the voltage is still less than + 8.0 Vdc after the recharging,  replace the battery.

  6.  If the voltage is more than + 8.0 Vdc,  measure the resistance between  battery terminals 3 and 4.  The resistance must be 4 to 30 kilohms.

    If the resistance is not correct, replace the battery pack.

    If the resistance is correct, replace the DC/DC card.

  7.  To check the charging circuit, do the following.  Plug in the AC Adapter with the battery pack removed, then  power-on the computer.
  8.  Measure the charging voltage between DC/DC terminals  1 (+) and 4 (-).
  9.  If the voltage is less then + 9.0 Vdc, replace the DC/DC card.  If the voltage is more than + 9.0 Vdc, the charging circuit is  working correctly, replace the battery pack.

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