GB2115242A

GB2115242A - Battery charging

Info

Publication number: GB2115242A
Application number: GB08234295A
Authority: GB
Inventors: Wolfgang Hoht
Original assignee: Auergesellschaft GmbH
Current assignee: Auergesellschaft GmbH
Priority date: 1982-02-17
Filing date: 1982-12-01
Publication date: 1983-09-01
Also published as: FR2521792A1; DE3206081A1

Abstract

Batteries of different rated capacities can be charged using a standardised constant current charging supply 1 by associating with each battery 3 a programming circuit, comprising a resistor 10, which automatically adopts the charging supply 1 so that the battery receives an appropriate normal or fast charging current. After a predetermined period a time switch 12, energised from the supply 1, removes a short across a resistor 11 whereafter the battery is trickle charged. In an alternative embodiment (Fig. 2), the resistor 11 is omitted and after a predetermined period of normal charging a timer (14) energises a pulse generator (15) which via an opto-coupler (13) periodically opens and closes the charging current path between the supply 1 and battery 3 to effectively trickle charge the battery. <IMAGE>

Description

SPECIFICATION Battery-charging system The invention relates to systems for charging batteries of different rated capacities from a standardised constant current charging device of the kind which comprise a mains transformer and a rectifier with a regulator.

For charging batteries of different rated capacities by the compensating or trickle charging method, it is known to switch overthe battery charging unit by hand to the capacity required for the corrresponding kind of battery which is to be charged, and to switch back to the trickle charging current for trickle charging operation by means of the battery voltage, such a system is disclosed in United States Patent Specification No. 3,278,823. However, erroneous values may be set upon switching the charging unit over to the capacity required forthe corresponding kind of battery, so that the battery is either inadequately charged or overcharged.Switching back to the trickle charging current by means of battery voltage is equally unreliable, because is individual battery cells arefaulty,the voltagewhich corresponds to a fully charged battery is not reached and the reverse switching action does not occur at all.

It is therefore an object of the invention to provide a system for chargeable batteries of different rated capacities, which on the one hand provides total adaptation of the corresponding kind of battery to a standardised constant current charging unit, and on the other hand assures reverse switching to the trickle charge current as a presettimefortricklecharging operation.

In accordance with the invention, this problem is resolved in a system of the kind hereinabove set forth in that the batteries which are to be charged have pre-connected to them a programming element integrated with the batteries, which in the condition of connection to the charging unit automatically adaptsthecharging unittothecharging current required forthe batteries, and the programming element has associated therewith an operation control system which receives its operating voltage from the charging unitand operates a compensating or trickle charge circuit.

In particular,the advantages secured by means of the invention consist in that the charging current of a standardised charging unit is adapted automatically to the kind of battery in question by association of the programming element with the chargeable battery, and that reverse switching to the trickle charging current occurs independently of the battery voltage.

A plurality of batteries of different rated capacities may be charged by means of a single charging unit.

In orderthatthe invention may be more clearly understood, two embodiments thereof will now be described in conjunction with the accompanying drawings, in which: Figures 1 and 2 show circuit layouts of the two embodiments respectively.

Referring nowto the drawings, as will be apparent from Figure 1 ,the system comprises two units, viz. a constant current charging unit 1 and a programming section 2 with the battery 3 connected thereto for charging.

The constant current charging section 1 comprises a mains transformer 4, a rectifier5, a smoothing capacitor6 and an integrated stabiliserwired as an I,,,,, regulator 7, with a post-connected resistor 8 which sets the regulator 7 to the lowest charging current which isto be expected.

The mains transformer 4 and the rectifier 5 as well as the regulator7 should be arranged so that the constant current charging device 1 can supply the maximum charging current which isto be expected and the appropriate charging voltageforthe batteries which are to be charged in different manner. The charging device 1 may be coupled to the programming section 2, via athree-wire plug and socket output circuit 9.

The programming section 2 having a chargable battery 3 post-connected to it, substantially comprises a resistor 10, a resistor 11 post-connected to the former, and an operation control system 12 controlling the trickle charging current, which as an essential element includes a time switch which is connected in parallel in the charging current circuit between the two resistors 10 and 11.

The resistor 10 is rated in accordance with the kind of battery in question, so thatthe normal charging current or else an increased charging current for a fast charging operation may flow in accordance with the rated capacity in question of the battery, in the condition of connection to the charging device. The resistor 1 1 is rated forthetricklecharging operation in accordance with the trickle charging current required in each case.

The resistor 10 is connected in parallel with the resistor 8 upon connecting the programming section 2 to the constant current charging section 1. The constant current charging section 1 is then programmed automatically to the charging current required for the battery, and the time switch 12 overbridgesthe resistor11 and short-circuitsthesame. The switch 12 is supplied with operating voltage required by the charging section 1,the pre-programmed charging period running from establishing the connection of the programming section 2 to the charging section 1.

Afterthe period specified for normal or rapid charging action has elapsed, the switch 12 switches to the trickle charging mode of operation . The short-circuiting or overbridging of the resistor 11 is then cancelled, the resistors 10 and 11 then programming the charging section 1 connected to the charging current required fortrickle charging. A withdrawal of current from the charged battery for the time switch 12 is prevented by means of a diode 13. The programming operation is performed via the third wire.

Another advantageous embodiment of the invention is depicted in Figure 2, the operation control system controlling the trickle charging current being associated with the charging unit 1 in this case. The operation control system essentially comprises an opto-coupler 13, atime switch 14 and a pulse generator 15.

The operation is the following: Upon inserting the programming section 2 into the charging section 1 via the plug and socket connection 9, the opto-coupler 13 switches the time switch 14 to zero via the reset terminal, and triggers the same for the "constant charge" loading mode. After the period preset in the time switch 14 has elapsed, e.g. 14 hours for normal charging, the "constant charge" loading mode is terminated by the fact that the time switch 14 de-energises the opto-coupler 13. The pulse gener ator is triggered via another output terminal of the time switch, which then takes over the "trickle charge" loading mode at the cadence of its preprogrammed timing ratio, in accordance with which the pulse generator 15 switches the opto-coupler 13 on and off attiming intervals.

No resistors are switched in the programming section 2, in this embodiment.

Claims

1. A system for charging batteries of different rated capacities from a standardised constant current charging unitwhich comprises a mains transformer and a rectifier with a regulator, wherein the battery of batteries which are to be charged have preconnected to them a programming element integrated with the batteries, which in the condition of connection to the charging unit automatically adapts the charging unit to the charging current required forthe batteries, and the programming element has associated with it an operation control system which receives its operating voltagefrom the charging unit and operated a compensating ortrickle charge circuit.

2. Asystem for charging batteries according to claim 1,wherein the programming elementcomprises two resistors connected to the batteries, which in the condition in which the programming element is connected to the charging unit has a resistor ofthe charging unit connected in parallel with them and which adjust the charging unit to the charging current required for the batteries.

3. Asystemforcharging batteries according to claim 1 or 2, wherein a time switch which receives its operating voltage from the charging unit is connected in parallel with the charging current circuit between the two resistors of the programming element.

4. A system for charging batteries according to claim 1, wherein the operation control system controlling the compensating charge current is coordinated with the charging device.

5. A system for charging batteries according to claim 1 or 4, wherein the operation control system comprises an opto-coupler, a time switch and a pulse generator, which are connected in parallel with the constant current charging circuit.

6. Asystemforcharging batteries substantially as hereinbefore described with reference to Figure 1 ofthe accompanying drawings.

7. A system for charging batteries substantially as hereinbefore described with referenceto Figure 2 of the accompanying drawings.