Philips M3000A, Service Manual

Page: 146 / 293

Battery Handling, Maintenance and Good Practices
130 Maintaining the Instrument
Conditioning a Battery
What is Battery Conditioning?
Battery conditioning recalibrates the battery to ensure that it has accurate information on the
actual battery capacity.
Why is Battery Conditioning Necessary?
The capacity of a battery decreases gradually over the lifetime of a battery. Each time a
battery is charged its capacity decreases slightly. Therefore, the operating time of a monitor
running off the battery also decreases with each charge cycle.
Battery conditioning ensures that the value stored in the battery for its full capacity takes
account of this decrease, so that the remaining battery charge can be calculated accurately,
and the low battery warning given at the right time.
When Should Battery Conditioning be Performed?
Battery conditioning should be performed:
• Every 50 charge/discharge cycles, or every three months, which ever comes first.
• When indicated by the Battery Status.
What Causes the Conditioning Message on the Monitor?
In addition to the value for the full capacity, the battery also stores a value for the Max Error.
The Max Error tracks the maximum possible deviation of the estimated charge of a battery
from the actual charge.
If a battery is charged or discharged partially, or if it is charged while the monitor is being
used, the accuracy of the “reference points” for the fully discharged and fully charged states
decreases, causing an increase in the value for the Max Error (see diagram, below).
When the Max Error is greater than 20%, a message is displayed prompting the user to
condition the battery, as described in “Conditioning a Battery Using the Monitor” on
page 131.
WARNING Never use a monitor that is monitoring a patient to perform battery conditioning.
You can reset the value for the Max Error before the battery needs conditioning, by
discharging the battery completely and then recharging it in a monitor that is plugged in but
turned off. A conditioning message may also appear if the battery has been stored in a
monitor that has not been in use for several weeks. Refer to “Conditioning a Battery” on
page 130.