DN Automotive

Directions for Battery Maintenance

We have collected our know-hows for optimal
DTR 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)
(A = C20 * 0.05)
Ex) 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]	Approximate State of Charge
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.

State	OCV [V]	~ 40Ah 2.0A
100%	12.75
75%	12.4	6Hrs
50%	12.2	12Hrs
25%	12.0	18Hrs
Discharged	11.9	24Hrs

Constant Voltage Charging

ⓓ End the charge
     The following points will tell you if a battery has been properly charged :
       – Indicator is green and current is below 1.0A during charge.
       – Open circuit voltage is stabilized at or above 12.7V.

Notice

ⓐ Connect positive (+) charger cable to positive (+) terminal of battery.and negative (-) charger cable to negative (-) terminal
ⓑ Always charge batteries in a well-ventilated area.