CTEK D250SE Dual DC-DC Charger



£206.65 ex VAT

  In Stock


The D250SE is a fully automatic, 5 step charger that supplies up to 20A of power to any 12V lead-acid or lithium service battery from 40–300Ah. It has selectable charge algorithms for flooded, AGM and lithium batteries and can use power from both the alternator and a solar panel or a wind turbine. The D250SE can maintain a stable output up to 20A to vehicles fitted with smart, ECU controlled alternators and also has a temperature sensor for optimised charging, regardless of weather conditions.

The D250SE is designed for use with solar panels rated at up to 300W but won't be damaged if a larger panel is connected – as long as the voltage from the panel is no more than 23V. Connecting a larger panel is actually a good way of compensating for poor perfomance on cloudy days!

The D250SE also features a battery maintenance function which sends 3-second pulses to the starter battery every 15 seconds. The current will vary according to the amount of power coming from the solar panel and the voltage at the starter battery.

Ideal for use in campervans, especially if they have smart alternators, the D250SE can be used on its own or with a CTEK Smartpass. The Smartpass 120S is also lithium compatible.

For full information, see the manual.

More Information


Manufacturer's product code:40-315
Suitable for use with smart alternators?:Yes
Input Voltage - Volts:11.5 / 23
Output voltage - Volts:Max 14.4V (14.7V in AGM mode)
Max. charging current - Amps:20
BACK CURRENT DRAIN:Less than 1Ah/month
Battery Temperature Sensor:YES
Charging Ports:1
Input from alternator - V:11.5v TO 23v
Input from solar panel - V:11.5V to 23V
Conventional alternator cut-in:>13.1V, for 5 sec. (engine running, alternator charging)
Conventional alternator cut-out:<12.8V, for 10 sec. (engine running, alternator not charging) or service battery voltage > starter battery voltage
Smart alternator cut-in V:>11.8V, for 5 sec. (engine running, alternator charging)
Smart alternator cut-out V:<11.4V, for 10 sec. (engine running, alternator not charging) or service battery voltage > starter battery voltage
Suitable for battery types:All 12V lead-acid batteries including: Wet, A.G.M, gel, calcium and maintenance free + LiFePO4 lithium batteries
Max. power input from solar panel - Watts:300
Solar regulator type:MPPT
Cooling method:Convection cooled
Operating temperature range - ?C:minus 20 degrees C to plus 50 degrees C Automatic reduction of power at high ambient temperature.
Power reduction:30 degrees C 16A, 50 degrees C 13A
Enclosure class:IP65 (splash and dust proof)
Notes:This charger can only be used with solar panels that have a peak voltage of 23V. Please ensure that your panel is compatible before purchasing.
Protections:Temperature compensated charging, Reverse Polarity protection
Certification:Fully certified for use in vehicles
Dimensions (L x W x H) - mm: 192 x 110 x 65mm
Item in Kg:1.047
Warranty - years:2

What's in the box

  • 1 x Unit with wired temperature sensor

Customer Questions

Asked by Andrew

Does the CTEK D250SE take any current from the vehicle's starter battery when the engine is off?

Answered by Andrew Harris at RoadPro on January 18th, 2021

No. The consumption from the D250SE when it's in standby mode (green light flickering) is only about 3mA and this current comes from the leisure battery.

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