FAQs

CTEK D250S

Is this the right charger for you?

  • DC to DC charger ideal for secondary battery charging from alternator, solar panel or other 12 vt. Source.
  • 20 amp.
  • Charging range: 40 - 300 Amp Hour charging and maintenance.
    Ideal for long term battery maintenance.
    For use in temperature range -4°F to 120°F.
  • Desulfates batteries.
  • Compatible with all lead acid, AGM, and GEL batteries. (CTEK Lithium US is required for lithium batteries.)

GLOSSARY
Consumer output= anything connected directly or indirectly to the battery that draws current/energy to operate, example: fridge, microwave, oven, etc.
Service battery= Auxiliary battery, house battery, consumer battery
Starter battery = standard battery for starting and operating the vehicle.
Ground = Connection to frame or common ground.
Shunt= Switch, relay
A.C. Power= 110 volt input, wall or shore power.
D.C. Power = 12 volt input, alternator, solar panel, or other source.

  1. Why is the POWER- led lamp not lit?
    Make sure the system is properly connected and the ground terminal firmly tightened.
    Check that the voltage on the service battery is higher than 9 vt. (the POWER- led lamp lights up when +9 vt.)
  2. Why is the POWER- led lamp flashing rapidly?
    The charger has gone into power save mode due to low voltage from the starter battery.
  3. Why is the POWER- led lamp glowing faintly?
    The charger has gone into power save mode due to low voltage from the starter battery.
  4. Why does the D250S DUAL not start charging?
    In order to start charging, the supply voltage from the D250S DUAL needs to be above 13.1V at the service battery input, or above 11.5V from the solar input on the D250S DUAL.
    In addition, the voltage on the service battery has to be above 5V for the charge process to begin.
    Measure the voltage of the batteries, and verify that they are within the levels specified above.
  5. Why does the D250S DUAL not stop charging the service battery even though the alternator or charger on the starter battery has been turned off?
    When the engine is turned off, D250S DUAL will continue charging as long as the voltage of the starter battery is above 12.8V. Due to this, the end of charging will be briefly delayed.
    NOTE: It will NOT drain the starter battery. If there is power to the D250S DUAL from the solar panel, it will charge/maintain the service battery.
  6. What do the LED lamps mean?

  1. Why is the error lamp flashing?
    Possible Cause: The charger has detected a problem. Note what/which led lamps are also flashing and what problem has occurred. See table below: