Sorry, This item has been discontinued

The ONYX is the powerful 12V charger

The CTEK ONYX is the powerful 12V charger that is ideal for the charging needs of your caravan, car and boat (14-225Ah). It quickly charges your household batteries and maintains them to give a prolonged service life. The ONYX has a 3 year warranty, delivers 7A and is IP65 classified (Splash and dust proof). All CTEK battery chargers are electronic proof, non-sparking and reverse polarity and short circuit proof. IP 65. 230V. Capacity 14-225 Ah. Charging current 7A. Dimensions 191x89x48. Weight 0.8 kg.

Features & Benefits

  • Seven step, fully automatic switch mode model.
  • Charges lead-acid batteries (Wet, MF, GEL and AGM) from 14Ah to 225Ah.
  • Maintenance pulse charging increases battery life and gives superb performance.
  • Charges even drained batteries.
  • Pulse recover of slightly sulphated batteries.
  • Low back current drain, low ripple and input voltage independent (170-260V).
  • High efficiency: 85%
  • Delivered with connection lead with clamps.
  • The charger can be connected for months, ideal for seasonal vehicles.
  • Compact design with mounting holes for permanent assembly.
  • 3 year warranty.



  • Motorbike
  • Car
  • Vintage Car
  • Motorboat
  • Sailboat
  • Agricultural Machinery
  • Caravan

Technical Data

Model CTEK Onyx
Input voltage AC 170-260VAC, 50-60Hz
Output voltage Nominal: 12V
Efficiency 85%
Charging voltage 14.4V
Charging current 7A Max
Back current drain* <3mA
Ripple** Max 150mV rms, 0.3A
Ambient temperature -20C to +50C, output power is reduced automatically at higher temperatures.
Type of charger Seven step, fully automatic switch mode with pulse maintenance.
Type of batteries 12V lead-acid batteries (Wet, MF, AGM and GEL)
Battery capacity 14-225Ah
Dimensions (L x W x H) 191x89x48mm
Insulation IP 65 (splash and dust proof), outdoor use
Weight 0.8kg

*) Back current drain is what drains the battery if the charger is connected without the power cord connected.

**) Ripple denotes the amount of interference there is to the current and voltage. A high current ripple heats the battery and shortens its life. A linear charger has a current ripple of 70 - 400% which is much larger than the maximum 5% for a modern sealed battery. Voltage ripple could harm other equipment, which is connected to the battery. The MULTI XS 7000 delivers voltage and current with very low ripple. The battery gains a long service life and there is no risk of damage to other electronic devices connected to the battery.

Product Options
CTEK Onyx CTEK Onyx £0.00 Discontinued