Battery, Charging

Battery, Charging

Special tools and equipment
- Battery charger

Batteries should be charged using a V.A.G battery charging unit e. g. V.A.G 1471, V.A.G 1648 or V.A.G 1974.

WARNING:
- The battery plugs must be fully tightened when charging, measuring voltage or performing load tests.
- Rooms in which batteries are charged must not be entered with a open flame or while smoking. As the battery forms gas which is readily flammable during the charging process.

NOTE:
- The battery temperature must be at least 10 degrees C.
- Batteries should only be fast charged (e. g. boost starting) in exceptional circumstances; as fast charging causes damage.
- If fast charging is performed on heavily discharged batteries, they fail to absorb any charging current or register as being fully charged prematurely due to so-called surface charging. They appear to be OK.

Sequence of operations
- Switch off battery charger.
- Switch off ignition.

See Caution before beginning repairs on the electrical system







- Push cover over battery to the right -arrow 1- and remove by lifting off -arrow 2-.







- Disconnect Ground strap -1- on battery negative terminal and detach positive cable -2- on battery positive terminal.







- Connect positive lead of battery charger to positive terminal of battery.
- Connect negative lead of battery charger to negative terminal of battery.
- Set charging current on battery charger in accordance with battery capacity. It must be about 10 % of battery capacity. Therefore approx. 6 A on a 60 Ah battery.
- Switch on battery charger.
Installation is the reverse order of removal while observing the following:

See Caution for connecting Telematics battery

- Connect battery. Required steps.

Notes on heavily discharged batteries:
Batteries which have not been used for long periods of time, e.g. vehicles that have been stored, are subject to self-discharge.

A battery is heavily discharged, if the no-load voltage has dropped below 11.6 V. Measuring no-load voltage

With heavily discharged batteries, the electrolyte (mixture of sulfuric acid and water) is more or less all water, with a greatly reduced sulfuric acid content.

At minus zero temperatures the battery can freeze and casing can crack.

Heavily discharged batteries become sulfated, i.e. all the plate surfaces of such batteries become hard. The electrolyte is not clear, but has a slight whitish color.

If a heavily discharged battery is re-charged immediately after heavy discharge, the sulfation can be reversed.

If this is not done, the plates become even harder and their ability to absorb charge is impaired, thus resulting in a loss of power reserves.

Procedure for charging heavily discharged batteries, which have become sulfated
Heavily discharged batteries, which have become sulfated, must be charged as follows using a low charging current:
- Set charging current to approx. 5 % of battery capacity, i. e. for a 60 Ah battery charging current is approx. 3 A (ampere).

Charging voltage (Umax) must not exceed a maximum of 14.4 V (volts).

Heavily discharged batteries must never be rapid charged.