Abstract: A method of obtaining information relating to the charge capacity of one or more cells utilizing information from the initial discharge period of the cell or cells. The method involves measuring a variable cell parameter for at least a part of an initial period of discharge during which the cell voltage initially decreases to a through voltage and then increases to a plateau voltage (the Coup De Fouet period), and relating the variable cell parameter to reference information to obtain the absolute or relative charge capacity of the cell or cells. An estimation model for predicting the absolute or relative capacity of a battery includes input for a variable battery parameter and one or more battery operating conditions and/or battery condition, reference information, compensation means determining a correction factor for the variable battery parameter, and calculation means relating corrected variable battery parameter to absolute or relative battery capacity.

Abstract: A switched mode power supply which uses a shieldless transformer (11) in the dc to dc converter. Common mode switching noise is reduced by connecting two capacitors (17, 18) in series between the transformer primary (12) and secondary (13) circuits and connecting an inductor (19) between the junction of the two capacitors (17, 18) and chassis earth. The values of the capacitors (17, 18) and inductor (19) are selected such that the capacitors (17, 18) present a low impedance to noise signals and the inductor (19) presents a high impedance to noise signals.

Abstract: A method of testing one or more cells and parameterising the results in order to obtain a characteristic curve/function from which cell discharge reserve time can be predicted from cell voltage. The test involves obtaining a plurality of data points representing the voltage of a cell as a function of charge remaining, and parameterising the data points to obtain a function representing cell voltage and charge remaining. The function allows charge remaining to be calculated from cell voltage. The invention also provides for a device for measuring capacity and predicting discharge reserve time of a cell, the device including a voltage and current measuring means adapted to measure the voltage and load current of a cell. The device also includes a timing means so that a number of voltage and current data points can be obtained with respect of time.