Hyundai Elantra (CN7): Charging System / Battery

Hyundai Elantra (CN7) 2021-2026 Service Manual / Engine Electrical System / Charging System / Battery

Description and operation

Description

1.	The CMF (Closed Maintenance Free) battery is, as the name implies, totally maintenance free and has no removable battery cell caps.

2.	The MF (Closed Maintenance Free) battery does not require water replenishment for the repair.

The battery is completely sealed, except for small vent holes in the cover.

•	After disconnecting then reconnecting the battery negative cable, reset some parts that require the reset procedures. (Refer to Body Electrical System – "General Information")

Specifications

▶CMF68L-DIN

Item	Specification
Model typeModel type	CMF68L-DIN
Capacity [20HR/5HR] (AH)	68 / 54
Cold Cranking Amperage (A)	760 (SAE / EN)
Reserve Capacity (Min)	110

•	Model type description

•	Cold Cranking Ampere (CCA) : Cold Cranking Amps is a rating used in the battery industry to define a battery's ability to start an engine in cold temperatures.

–	The rating is the number of amps a new, fully charged battery can deliver at -18°C (-0.4°F) for 30 seconds, while maintaining a voltage of at least 7.2 volts for a 12 volt battery.

–	The higher the CCA rating, the greater the starting power of the battery.

•	RESERVE CAPACITY (RC) : Reserve Capacity is a battery industry rating, defining a battery's ability to power a vehicle with an inoperative alternator or fan belt.

–	The rating is the number of minutes a battery at 26.7°C (80°F) can be discharged at 25 amps and maintain a voltage of 10.5 volts for a 12 volt battery.

–	The higher the reserve rating, the longer your vehicle can operate should your alternator or fan belt fail.

Troubleshooting

Repair procedures

Removal

Battery

1.	Turn the ignition switch OFF.

Disconnect the battery (-) terminal (A).

Battery (-)terminal installation :

4.0 - 6.0 N.m (0.4 - 0.6 kgf.m, 3.0 - 4.4 lb-ft)

Remove the battery (+) terminal (A).

Battery (+) terminal installation :

7.8 - 9.8 N.m (0.8 - 1.0 kgf.m, 5.8 - 7.2 lb-ft)

4.	Remove the battery mouting bracket (A).

Remove the battery insulation pad after removing the battery (B).

Battery mounting bracket installation bolt :

19.6 - 29.4 N.m (1.9 - 3.0 kgf.m, 13.7 - 30.4 Ib-ft)

Battery tray

1.	Remove the battery. (Refer to "Removal")

2.	Remove the air cleaner assembly. (Refer to Engine Mechanical System - "Air Cleaner")

3.	Remove the ECM. (Refer to Engine Control / Fuel System - "Engine Control Module (ECM)")

Remove the battery tray (A) after loosening the bolts.

Battery tray installation bolt :

19.6 - 29.4 N.m (1.9 - 3.0 kgf.m, 13.7 - 30.4 Ib-ft)

Installation

Install in the reverse order of removal.

•	When installing the battery, fix the mounting bracket on the tray correctly.

Vehicle Parasitic current inspection

1.	Turn the all electric devices OFF, and then turn the ignition switch OFF.

Close all doors except the engine hood, and then lock all doors.

(1)	Disconnect the hood switch connector.

(2)	Close the trunk lid.

(3)	Close the doors or remove the door switches.

Wait a few minutes until the vehicle’s electrical systems go to sleep mode.

•	For an accurate measurement of a vehicle parasitic current, all electriacl systems should go to sleep mode. (It takes at least one hour or at most one day.) However, an approximate vehicle parasitic current can be measured after 10-20 minutes.

Connect an ammeter in series between the battery (-) terminal and the ground cable, and then disconnect the clamp from the battery (-) terminal slowly.

•

Be careful that the lead wires of an ammeter do not come off from the battery (-) terminal and the ground cable to prevent the battery from being reset. In case the battery is reset, connect the battery cable again, and then start the engine or turn the ignition switch ON for more than 10 sec. Repeat the procedure from No. 1.

a.	Connect a jump cable between the battery (-) terminal and the ground cable.

b.	Disconnect the ground cable from the battery (-) terminal.

c.	Connect an ammeter between the battery (-) terminal and the ground cable.

d.	After disconnecting the jump cable, read the current value of the ammeter.

Read the current value of the ammeter.

•	If the parasitic current is over the limit value, search for abnormal circuit by removing a fuse one by one and checking the parasitic current.

•	Reconnect the suspected parasitic current draw circuit fuse only and search for suspected unit by removing a compoconnected with the circuit one by one until the parasitic draw drops below limit value.

Limit value (after 10 - 20 min.) : Below 50 mA

Cleaning

1.	Make sure the ignition switch and all accessories are in the OFF position.

2.	Disconnect the battery negative cables (A).

Remove the battery from the vehicle.

(Refer to Charging System - "Battery")

•	Care should be taken in the event the battery case is cracked or leaking, to protect your skin from the electrolyte.

•	Heavy rubber gloves (not the household type) should be worn when removing the battery.

4.	Inspect the battery tray for damage caused by the loss of electrolyte. If acid damage is present, it will be necessary to clean the area with a solution of clean warm water and baking soda. Scrub the area with a stiff brush and wipe off with a cloth moistened with baking soda and water.

5.	Clean the top of the battery with the same solution as described above.

6.	Inspect the battery case and cover for cracks. If cracks are present, the battery must be replaced.

7.	Clean the battery posts with a suitable battery post tool.

8.	Clean the inside surface of the terminal clamps with a suitable battery cleaning tool. Replace damaged or frayed cables and broken terminal clamps.

9.	Install the battery in the vehicle.

10.	Connect the cable terminals to the battery post, making sure tops of the terminals are flush with the tops of the posts.

11.	Tighten the terminal nuts securely.

12.

Coat all connections with light mineral grease after tightening.

•	When batteries are being charged, an explosive gas forms beneath the cover of each cell. Do not smoke near batteries being charged or which have recently been charged. Do not break live circuit at the terminals of batteries being charged.

•	A spark will occur when the circuit is broken. Keep open flames away from battery.

❮Alternator

Description and operation DescriptionThe Alternator has eight built-in diodes, each rectifying AC current to DC current.Therefore, DC current appears at alternator "B" terminal.

Battery Sensor❯

Description and operation DescriptionVehicles have many control units that use more electricity. These units control their own system based on information from diverse sensors.

Other information:

Hyundai Elantra (CN7) 2021-2026 Service Manual: Heater Core

Repair procedures Replacement1.Disconnect the negative (-) battery terminal. 2.Remove the heater and blower assembly.(Refer to Heater - "Heater Unit") 3.Remove the heater core cover (A) after loosening the mounting screws.4.Pull out the heater core (A) from the heater unit.

Hyundai Elantra (CN7) 2021-2026 Service Manual: Mode Control Actuator

Description and operation DescriptionThe mode control actuator is located at the heater unit.It adjusts the position of the mode door by operating the mode control actuator based on the signal of the A/C control unit. Pressing the mode select switch makes the mode control actuator shift in order of Vent → Bi-Level → Floor → Mix.