DN 오토모티브

Battery charging and Jump start method

We have collected our know-hows for optimal DN Automotive battery maintenance.

Charging Methods

Check the State of Charge

  • Check the indicator to see if the battery is okay, needs to be charged or requires replacement. A voltmeter is preferable for exact check.

  • If the indicator shows black color, it is necessary to be recharged. And in a general case, it is necessary to be recharged if voltage is under 12.4V.

* Battery charging requires extreme caution. If you do not have sufficient knowledge or experience, please consult a store or help center for service.
Constant Current Charging

Calculation of auxiliary charging amount

  • Charging amount

    C = C20 * D * 1.2

    • C : Charging amount (Ah)
    • C20 : 20Hr rate capacity
    • 1.2 : 120 % (coefficient)
    • D : Discharging amount(%)
  • Charging time

    T = C / A

    • T : Charging time (Hr)
    • C : Charging amount (Ah)
    • A : Charging current (A)
  • Calculation example

    MF80D26L(70Ah / 20Hr) Open circuit voltage 12.40V How to charge?

    • Charging amount : 70Ah * 0.25 * 1.2 = 21.0Ah
      (25% discharged; see TABLE 1)
    • Charging current : C20 * 0.05 = 3.5A (see TABLE 2)
    • Charging time : 21.0Ah / 3.5A = 6.0Hr
  • TABLE 1. State of Charge
    OCV [V] MARINE No.
    12.75 100%
    12.4 75%
    12.2 50%
    12.0 25%
    11.9 Discharged
  • TABLE 2. Charging Current according to state of charge by battery capacity.

    Scroll left and right to see the full contents.

    State OCV [V] ~ 40Ah
    50Ah ~
    ~ 60Ah
    ~ 70Ah
    ~ 80Ah
    ~ 90Ah
    ~ 100Ah
    100% 12.75
    75% 12.4 6Hrs
    50% 12.2 12Hrs
    25% 12.0 18Hrs
    Discharged 11.9 24Hrs
Constant Voltage Charging

To calculate a constant voltage charge

Voltage :
14.4 ~ 16.0V
Current :
Under 10A
Charging Time :
Over 12Hr (General battery)
End the charge :
The following points will tell you if a battery has been properly charged :
1) Indicator is green and current is below 1.0A during charge.
2) Open circuit voltage is stabilized at or above 12.7V.
Safety Precautions
  • 01
    Connect positive (+) charger cable to positive (+) terminal of battery.and negative (-) charger cable to negative (-) terminal
  • 02
    Always charge batteries in a well-ventilated area.
  • 03
    If violent gassing or spewing of electrolyte occurs, temporarily reduce or halt charging. (Possible battery failure)
  • 04
    If violent gassing or spewing of electrolyte occurs, temporarily reduce or halt charging. (Possible battery failure)
Jump Starting

Safety Rules

  • 01
    Before proceeding, read safety precautions in Section 1.
  • 02
    Warning - Batteries produce explosive gases.
    These instructions are designed to minimize the explosion hazard while jump-starting a car. Keep sparks, flames and cigarettes away from batteries at all times.
  • 03
    Shield eyes and face at all times. Never lean over the battery when jump starting.
  • 04
    Inspect both batteries before connecting booster cables and do not jump start a damaged battery.
  • 05
    Make sure the vehicles are not in contact with each other.
  • 06
    Turn off all electrical equipment (radio, defroster, windshield wipers, lights, etc.).
The Following Steps Should be Proceeded:
  • a
    Connect positive (+) booster cable to positive (+) terminal of discharged battery.
  • b
    Connect other end of positive (+) cable to positive (+) terminal of assisting battery.
  • c
    Connect negative (-) cable to negative (-) terminal of assisting battery.
  • d
    Make final connection of negative (-) cable to engine block of stalled vehicle,away from battery and carburetor.
  • e
    Make sure that cables are away from fan blades, belts and other moving parts of both engines.
  • f
    Start vehicle and remove cables in reverse order of connections.