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Nickel Cadmium
NiCad
Lithium Primary 3.6V
Li-SOCl
2
Lithium Iron Disulphide
Li-FeS
2
Lithium Ion and Lithium
Polymer
LiON, LiPo
In-line Battery Modules
Capacitor Module T24-PSSA
This is used for batteries which have an internal resistance of greater than 150mOhms overcoming voltage drops
during high current phases of the low power mode cycle.
This problem becomes apparent when attempting to communicate with a T24-SA using the T24 Toolkit or power
cycling when the battery is near the end of its life. In normal operation (Low power mode) with a handheld T24-
HS where the T24-SA is connected to an uninterrupted battery this module is generally not required.
Using lower impedance strain gauges (or multiple parallel strain gauges) exacerbates this problem.
Consult Sales for details. Alternatively fit an electrolytic capacitor across battery of 2000uF or greater. This
capacitor should be of low ESR (< 70mOhms).
Lithium Ion /Polymer Module T24-PSSB
Provides a means of charging the Lithium Ion or Polymer battery from a nominal 5V DC supply and also providing a
low quiescent current 3.3V regulator to supply the T24-SA. This overcomes the max voltage limitation of the T24-
SA and the higher cell voltage and charging requirements of the Lithium Ion cell.
Acquisition Module Battery Life – Strain Gauge Input
Rough Guide
As a rough guide battery life of a T24-SA connected to a 1K load cell with a 5 millisecond sample time is as
follows:
Years = Usable Battery Capacity
(10 / TX per second)
Example of 2 X AA GP 15A with a usable capacity of 1.9Ah. The loadcell is 1K and the transmission rate is 3Hz
with a 5 millisecond sample time.
Years =
1.9
(10 / 0.33)
Years = 0.063 = 23.1 days
Mantracourt Electronics Limited T24 Technical Manual
Most cells are 1.2V so two in series gives 2.4 Volts. Three in series can be used to
give 3.6 Volts. These do not have the usable capacity of an alkaline battery.
These are generally only useful if they are to be charged on a regular basis. If
charging these cells in circuit precautions must be taken to ensure that the
maximum voltage on the T24-SA is not exceeded.
Example:
Recommend T24-PSSA module to maximise usable capacity.
Lithium cells can be used but note that the maximum voltage is 3.6 Volts.
Select a cell with low internal resistance.
Example: Saft LS17500 (A), Saft LSH20 (D)
Recommend T24-PSSA module as these cells usually have a high internal
resistance.
These can be found at 1.5 Volts and can therefore be a direct replacement for
Alkaline cells. The low internal resistance and high capacity make these
batteries an ideal choice.
Example: Energizer L91
These generally start at 3.7V and exceed the maximum allowable voltage. These
are usable if a regulator and charging circuit can be installed between the T24-
SA and the battery. Care must be taken here that the regulator does not draw
too much current when idle so that the low power modes are not compromised.
Recommend T24-PSSB module.
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