The alternator produces current to replenish power to the battery. This power output is controlled by a regulator which increases and decreases the current flow from the alternator on demand. Although your vehicle electrics may run at 12 V power, alternators will produce higher voltages to the battery as required.

Alternators are available from Motorparts.ie as new or reconditioned units. As part of the motor industry's efforts towards the environment, the old core of alternators and starters are returned whereby all internal moving and wearing parts are replaced within the old casing. In effect a reconditioned unit has proved as reliable as a new one and are much more competitively priced.

It is important to know the amp rating of the Alternator on your Opel Astra before selecting one. It is written on a plate attached to Alternators. It is the Alternator that feeds electricity to your battery and as different models consume more power, the current power supply to the battery is important. If your alternator fails the battery will not power your Opel Astra electrics for long on its own.