Battery with charge indicator (magic eye), checking

Fig 1: Locating Magic Eye

Courtesy of VOLKSWAGEN UNITED STATES, INC.

The charge indicator - arrow - provides information on the electrolyte level and charge level of the battery to be tested.

Three different colored indications are possible:

color indicator	Battery status
Green	Battery adequately charged.
Black	Not charged or inadequately charged.
Colorless or yellow	Critical electrolyte level reached; topping up with distilled water essential.

NOTE:

If a battery is more than 5 years old and the indicator is colorless, replace battery.

Test sequence

NOTE:

When recharging the battery, and during driving, air bubbles may form under the "magic eye". They distort the color displayed by the magic eye.
If batteries are fitted with sealing plugs for production reasons, these are covered with plastic foil.
Prior to visual inspection, use screwdriver handle to tap gently and carefully on "magic eye" to disperse any bubbles.
Observe color of charge indicator → Battery with charge indicator (magic eye), checking .