Bosch C3 Battery Charger

How do I correctly connect the C3 charger to a battery?

Connect the red (+) terminal of the charger to the (+) terminal of the battery first, then connect the black (–) terminal to the (–) terminal of the battery (or to the car body, well away from fuel pipes). Make sure both terminals are firm before connecting the power cord to the mains. Never connect the power cord to mains current before the terminals are securely attached. (Page 5)

What is the correct order for disconnecting the C3 charger from a battery?

First, switch the charger to standby by pressing the Mode selection button. Then disconnect the power cord from the mains current before disconnecting the (–) terminal (black) from the battery, followed by the (+) terminal (red). Always disconnect the power cord from the socket before disconnecting the charging cable from the battery. (Page 5)

What types of batteries is the Bosch C3 compatible with?

The Bosch C3 is suitable for charging and trickle charging 6 V and 12 V lead acid batteries, including WET batteries (with liquid electrolyte), GEL batteries, AGM (absorbent glass mat), and VRLA batteries. Battery capacity ranges from 6 V (1.2 Ah–14 Ah) or 12 V (1.2 Ah–120 Ah). It is not intended for dry or non-rechargeable batteries. (Page 3)

Which charging mode should I use for a 12 V AGM battery in cold conditions?

Mode 4 (12 V, 14.7 V / 3.8 A) is suitable for batteries with a capacity of more than 14 Ah in cold state, or for many AGM batteries. Press the mode selection button to select Mode 4, and charging will start automatically after a few seconds. After successful charging, the unit automatically switches to trickle charge mode. (Page 6)

What does it mean if the reverse polarity LED lights up on the C3?

The reverse polarity LED (9) lights up when the (+) and (–) terminals have been interchanged on connection. The charger switches to standby mode and remains there until a different setting is made. This is part of the appliance protection function designed to prevent damage. (Page 6)

What should I do if the C3 charger overheats during charging?

If the unit becomes excessively hot during charging, the output power is automatically reduced to avoid damaging the unit. You should also ensure the charger is never covered when in operation, is kept away from sources of heat, and is not exposed to temperatures in excess of 50 °C for a lengthy period. (Pages 4 & 6)