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Browse Prior Art Database

BATTERY BANK SWITCHING

IP.com Disclosure Number: IPCOM000005832D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2001-Nov-09
Document File: 1 page(s) / 48K

Publishing Venue

Motorola

Related People

Jim T Wiggenhorn: AUTHOR

Abstract

In some uses of battery operated equipment there is a need to have extended operating time from a single rechargeable battery source. This may require the use of multiple battery packs within the same enclosure. It would be desirable to parallel the batteries but due to the problem in exactly matching the cells and safety this is not done.

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MOlYlROLA Technical Developments Volume 10 March 1990

BATTERY BANK SWITCHING

by Jim T Wiggenhorn

   In some uses of battery operated equipment there is a need to have extended operating time from a single rechargeable battery source. This may require the use of multiple battery packs within the same enclosure. It would be desirable to parallel the batteries but due to the problem in exactly matching the cells and safety this is not done.

This proposed method would "bank switch" strings of battery cells. This could be done with an electrical circuit as described below.

   Two or more banks of batteries would be used in conjunction with pass transistors, comparators and voltage reference diodes. There would be two separate paths from each bank of batteries and only one bank of batteries at a time would be discharged.

   When battery banks A & B are fully charged and are at the same voltage level, the circuit will first route current from bank B until the voltage level of B is below the zener voltage Di. The first comparator (Cl) would determine if the voltage level of bank B was higher or lower than the reference zener (Dl). If it is higher it would turn 01 ON allowing a current path from bank B. If lower it would turn OFF Ql and signal comparator (C2) to turn ON Q2 allowing current to flow from bank A. When the comparator C2 turns ON Q2 it also triggers zener diode D2 and holds Ql OFF. This results in hysterisis keeping Ql from turning ON and OFF while the circuit switches...