BMW 61218381749 Battery, Manuf.: Douglas (Warranty Only)

To measure the battery voltage accurately, the top charge must be removed. Achieving this involves switching on the higher lights for a period of ten seconds and then turning them off to allow the vehicle stay for about two minutes. Battery check begins by taking off the battery cover and unplugging both the negative and positive battery cables. The indicator eye at the top of the battery should be visually examined; it has to be black meaning that it should be charged if yellow or replaced in case of defects. Open circuit voltage is measured using a digital voltmeter, which should give about 12.6 volts for a fully charged battery. Charge your battery first if it is less than this value before you proceed with other steps. A load tester is next used to carry out a load test on your battery. Connect this device to your terminals, apply its load within fifteen seconds without letting your cells' voltage drop below 9.6 volts. When it is weak or defective, an indication will appear in a load tester's display window. During replacement of one's battery, check with dealer parts department or auto parts store that sells batteries so as to get accurate choice of battery required in such cases. Remove relevant trim panels and also loosen up the positive plus negative cables connected to my battery Remove relevant trim panels and also loosen up the positive plus negative cables connected to my batter Ensure that there is no corrosion beneath your cells after lifting them out carefully as they are heavy Avoid being careful when lifting out my cell due to its weight; look at underneath if corroded clean It should first connect new batteries and lastly attach negatives.

Before testing, load battery with 15 amperes for one minute with battery load-tester or switch headlights ON for about one minute without engine running. Connect digital voltmeter across battery terminals. Open-circuit voltage levels are given in Table c. If open-circuit voltage is OK but battery still lacks power for starting, perform a load voltage test. If open-circuit voltage is below 12.4 volts, recharge battery and retest. Battery charging notes are in this repair group.

The Ah rating of BMW batteries is an indication of the average current that can be discharged over time before the voltage drops below a specified level. The CCA rating specifies how much starting current the battery can provide at -18°C (0°F). Battery testing gives information about a battery's condition and charge. Therefore, before testing a battery make sure that its terminals are clean and tight.

To access the battery, one has to open the rear hood and look for the spare tire and air suspension compressor, below which the battery is housed. To get to the battery, the owner has to refer to the repair group and both fit and remove it. Batteries are described in term of ah which is the number of hours that a particular current drain can be maintained to a point of exhaustion or in terms of CCA which refers to the number of amps that are available to crank the engine in a cold environment. Overall, when choosing a replacement battery, it will be best to choose one that will have the same or a higher rating as the original battery. There is also a hold-down plate which is essential in the protection of the battery in that; the vibrations and road shock can harm the battery.

Ensure that the charging voltage does not exceed 16.5 volts.

Next, remove the fasteners on the air suspension compressor supports and tilt the compressor and supports back to access the battery.

Do not pry under it or attach any other ground wires to the negative cable end.

Connect the positive cable first, then the negative cable.

Check the external condition of the battery for any damage or loose connections.

For the most accurate results, ensure the battery is fully charged.

To calibrate the compass in the interior mirror, press a push button until the letter C appears in the compass display. Then, drive the vehicle in a circle at a specific speed. The calibration is complete when the direction display appears.

Close the switch and connect a digital multimeter in series across the switch, setting the meter to milliamp (mA) scale.

Prior to disconnecting the battery, you should read the battery disconnection cautions given in 001 Warnings and Cautions.

The charging voltage at the battery should not exceed 16.5 volts.

The wet-cell lead-acid battery is rated by ampere/hours (Ah) and cold cranking amps (CCA).

It is important to avoid charging the battery with a conventional charger.

The Ah rating indicates the average amount of current the battery can deliver over time without dropping below a specified voltage.

A yellow color denotes a defective battery that needs replacement.

Prior to testing, ensure that the cables are tight and free of corrosion.

The original equipment battery in E53 models is maintenance-free, with the original electrolyte typically lasting the entire service life under moderate climate conditions.