The battery condition monitor is a Smart Sensor that attaches to by lindahy


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									   Battery Condition Monitor

       he battery condition monitor is a Smart Sensor that attaches to an external
       12V battery to continuously log the battery charging rate and battery status.
       The purpose of a battery condition sensor is to enable constant monitoring of
the power condition of a remote Smart logging system with an external battery. This
information is stored by the Smart logger and when downloaded the data available is
the same as any other sensor’s data and can be graphed. Accessing the Smart logger
remotely via remote telemetry or telephone modem enables an early warning against
power loss or failure by allowing an operator to act before a problem occurs.

 The Battery Condition Monitor has the following functions:

  1. To measure and record the nett battery current from the solar panel to the external
battery and at 24:00, the average nett current indicating if the battery is being kept
topped up each day.

 2. The instantaneous voltage of the external battery.

 3. The instantaneous temperature of the external battery at a given point in time.

  An operator in charge of managing a remote Smart logging system can dial this
system to check the power status of the system. This will indicate if sufficient charge is
coming from the solar panel to recharge the battery and if the battery is being recharged
fully each day. The remote Smart logging system will also have a regulator on it and the
instantaneous battery voltage should then never exceed the 15 volts as controlled by the
regulator. The battery temperature is also important in that the sealed lead acid batteries
have a minimum amount of water and should not get so hot as to cause gassing. This
is because sealed lead acid batteries have no venting condition (unlike a car battery).

Excess battery temperature would lead rapidly to deterioration of the battery. Correct
control of the voltage from the regulator and the charge and discharge rate also from the
regulator will mean that the external battery remains in good condition at all times.

   ICT recommends the use of a battery condition monitor. This sensor is
   typically included as part of a FieldStation system. However, if you do not
   have one it is strongly advised that you purchase one.

Detailed Notes:

  The Battery Condition Sensor measures nett battery current, battery voltage and
battery temperature. A positive value of battery current indicates that the battery is
charging. A negative value indicates that the battery is discharging. The current is
measured in the range 5.000 Amps to -5.000 Amps. The battery voltage is measured
in the range 0 to 20.00 Volts, and the temperature of the positive terminal of the battery
is measured in the range – 20.00°C to 60.00°C. These values will be logged at a
rate determined by the
schedule selected by the
user. At midnight the daily
maximum, minimum and
average values will also be
logged. The average nett
current is a particularly
important value. This
value is normally small but
positive, indicating that
the solar panel is keeping
the battery topped up. On
heavily overcast days, this
value might be negative,
indicating a nett discharge.
A high negative value, or
persistent negative values,
needs investigation. It may
just indicate that the solar
panel needs cleaning, or it
could be more serious. The
Battery Condition Sensor
will give advanced warning
of battery problems and
will help prevent loss
of data. The number of
ampere-hours of daily charge or discharge may be calculated by multiplying the average
nett current recorded at midnight was -0.215 Amps, the discharge during that day was
24 x 0.215 = 5.16 ampere-hours. A fully charged 40 Ampere-hour battery would be
fully exhausted in less than 8 days at that rate.

                            ICT International Pty Ltd
                            PO Box 503, Armidale, NSW 2350, Australia
                            Ph: [61] 2-6772-6770 Fax: [61] 2-6772-7616

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