D250T is a 24V DC-DC battery charger for dual battery systems with starter battery and service battery. D250T is designed to be used as onboard charger for charging and maintaining the service battery from alternator when motor is running, this will give you enough of power in the service battery when arriving to the destination.

Part no. 40-373


24V | Charges the battery while you drive

D250T is a fully automatic, 4 step DC-DC charger that supplies up to 10A of power to charge any 24V lead-acid service battery. The charger is also a battery isolator that separate the service battery and starter battery to protect the starter battery from being drained when motor is not running. With the D250T you can be confident that the service battery always will receive the optimal charging voltage, with reduced charge time and ensuring the charging will be 100% complete. You will get a stable and efficient charging of the battery that is not dependent in alternator capacity or resistance in cables. D250T will reduce environmental impact and lower the maintenance costs through extended battery life and a reduced idle time.


  • Truck, Heavy Vehicles, Boats, Recreational vehicles, Busses, Transport trucks and all other systems with a 24V battery

Technical data

25.8–32 V, 10-15 A
28.8 V, 10 A
Battery capacity
28–200 Ah
Charging category
DC charging
Back current drain*
Corresponding to less than 1 Ah/month
Battery voltage
24 V
Battery chemistry
Lead acid
Ambient operating temperature
-20 ˚C to +50 ˚C (- 4 °F to +122 °F)
Less than 4 %
Battery types
24 V:; WET; MF; Ca/Ca; AGM; EFB; GEL
Degree of protection
Gross weight (unit in box)
0.9 kg
Dimensions (L x W x H)
192 x 110 x 65 mm
Net weight (unit with cables)
0.7 kg
2 years
*) Back current drain is the current that drains the battery if the charger is not connected to the mains. CTEK chargers have a very low back current.
**) The quality of the charging voltage and charging current is very important. A high current ripple heats up the battery which has an aging effect on the positive electrode. High voltage ripple could harm other equipment that is connected to the battery. CTEK battery chargers produce very clean voltage and current with low ripple.
CTEK issues a limited warranty to the original purchaser of the product. Depending on the product, the limited warranty period will vary. The limited warranty is not transferable. The warranty applies to manufacturing faults and material defects. The warranty is void if the product has been handled carelessly or repaired by anyone other than CTEK or its authorized representatives. CTEK makes no warranty other than this limited warranty and is not liable for any other costs other than those mentioned above, i.e. no consequential damages. Moreover, CTEK is not obligated to any other warranty other than this warranty.