Wiring Material

Many of today’s cars and motor cycles are equipped with a meter for monitoring the battery voltage.
 However, this meter does not provide information on the battery condition, or whether it is being charged at all. When the voltmeter reading is too low, the battery is generally in such a poor state as to necessitate switching off heavy loads to save power for use of the starter engine later. Especially on motorcycles, the battery capacity is relatively low, which justifies the need for a reliable monitoring system. A standard 30 A ammeter. offers too low resolution, and is rather awkward to fit permanently. In this charge/discharge indi- cator, the measured current is converted into a potential difference by R*, which is either two lRO 5 W resistors, a fuse, or a few turns of copper wire.

The direction of the current through R+ is detected by comparator IC1, which then indicates whether the battery is being charged or discharged by lighting the relevant LED The l00R preset enables shifting the indication threshold somewhat. Input terminal + on the indicator unit is best connected to a point behind (that is, electrically behind) the contact switch, although it is also possible to fit the circuit with a separate on/off switch. Finally, the circuit is only suitable for use in or on vehicles having a 12 V battery.