Tools - Fully Automatic Battery Charger: Overview

90bmw07 Group 04 Tools and Equipment
Bulletin Number 04 24 89 (1964) Page 1 of 4
Woodcliff Lake, NJ April 1990 Service Engineering



This Service Information bulletin supersedes S.I. 04 24 89 (1964) dated November 1989. It incorporates information not included in the Owner's Manual (see page 2).

Please remove and discard S.I. 04 24 89 (1964) dated November 1989 from your S.I. binder.

SUBJECT: BMW Fully Automatic Battery Charger

BMW engineers have recognized the need for a premium-quality battery charger for use by BMW Automotive Dealers. Common chargers (normally used to charge automotive batteries) are of simple and unregulated construction. They don't duplicate the same performance with every charge, and they don't compensate for variations in AC voltage. If a rise or drop in AC voltage occurs, the output of an ordinary automotive battery charger to the battery will rise or fall accordingly. When the rate of charge to the battery is inconsistent, it's virtually impossible to obtain full charge without risking damaging overcharge.

Full charge is necessary to keep the battery active and healthy. However, an overcharge will do immediate and irreversible damage, so it is very important that you use a battery charger that can sense battery condition accurately every time the battery is charged.

Solution: Lester Electrical, a leading manufacturer of commercial and industrial battery chargers for many types of electrically powered vehicles, has developed a fully automatic electronic timing device that determines when batteries are fully charged and shuts off the charger. They have been selling fully automatic, patented chargers under the Lestronic label for a number of years.