GB2060181A

GB2060181A - Battery testing device

Info

Publication number: GB2060181A
Application number: GB7934156A
Authority: GB
Original assignee: FISHER KARPARK IND Ltd
Current assignee: FISHER KARPARK IND Ltd
Priority date: 1979-10-02
Filing date: 1979-10-02
Publication date: 1981-04-29
Also published as: GB2060181B

Abstract

A battery testing device particularly for use with a 6-volt lantern battery of the type used in traffic warning lamps has a red light emitting diode 14 and a green light emitting diode 15. When the terminals 12 and 13 are connected to the battery, lighting of both the red and green diodes indicates that the battery has a useful life under load in a traffic warning lamp of over eight hours. If only the red diode is lit, the useful life is less than eight hours. <IMAGE>

Description

SPECIFICATION Battery testing devices The invention relates to battery testing devices.

The invention provides a battery testing device comprising a pair of contacts for connection to the terminals of a battery to be tested, a load connected between the contacts to represent the load normally driven by the battery, and signalling circuitry incorporating a plurality of light emitting diodes, different states of the battery causing different combinations of diodes to emit light.

The signalling circuitry may be such that when the battery has a useful life under load of less than a predetermined period fewer diodes emit light than when the battery has a useful life under load of more than the predetermined period.

The signalling circuitry may be such that one diode emits light when the battery has a useful life under load of less than eight hours, and two or more diodes emit light when the battery has a useful life under load of more than eight hours.

The diodes may be respectively arranged in parallel branches of the signalling circuitry, the branches being progressively loaded such that while a relatively low battery will cause the diode of a first branch to conduct, the diodes of successive branches each require a better state of battery charge than the preceding one to cause the associated diode to conduct.

Different diodes may be arranged to emit different colours of light to assist a user of the device to recognise different combinations associated with different states of the battery.

The signalling circuitry may include means to protect the light emitting diodes if the contacts of the battery testing device are connected to the battery terminals the wrong way round.

The invention includes a battery testing device as defined above in combination with a battery to be tested.

By way of example, a specific embodiment of battery testing device according to the invention will now be described, with reference to the accompanying drawings, in which: - Figure 1 is a perspective view of a battery testing device according to the invention, about to be applied to a 6-volt lantern battery; and Figure 2 is a circuit diagram of the device shown in Figure 1.

The device forming the subject of this embodiment is specifically designed for use in testing the state of charge of 6-volt lantern batteries such as that shown at 10 in Figure 1. In addition to their use in torches and lanterns, such batteries are used in traffic warning lamps which are used in large quantities to warn vehicle drivers of roadworks or other hazards on roads and motorways. Since large quantities of the lamps are used, and they may have to be left on for long periods, there is a very large consumption of batteries. If workmen using the lamps are uncertain of the state of charge of the batteries and cannot be sure that the batteries will last for a required period, they generally err on the safe side and throw the batteries away.This can lead to considerable wastage and there are great savings to be made if a simple means of indicating the state of the batteries can be provided.

The battery testing device which forms the subject of this embodiment provides such a means, and as shown in Figure 1 it comprises a simple housing 11 from which a pair of contact pins 12 and 13 projects. On the top of the housing 11 there is visible a red light emitting diode 14 and a green light emitting diode 1 5.

Figure 2 shows how the diodes 14 and 1 5 are connected between the contact pins 12 and 13.

A load is connected between the contact pins in the form of two resistors R1 and R2 arranged in series. R1 has a value of 4.7 ohms and R2 has a value of 10 ohms.

Connected between the junction of resistors R1 and R2, and the contact pin 12, are two parallel branch networks 1 6 and 1 7. Branch 1 6 comprises the diode 14 in series with a resistor R3 having a value of 220 ohms. Branch 17 consists of light emitting diode 1 5 in series with an ordinary diode D1 and a resistor R4 which has a value of 100 ohms.

The loading of the branches is such that if the battery is in a poor state of charge, such that it has a useful life under load of less than eight hours, insufficient potential is developed across the green diode 1 5 to cause it to conduct. Unless the battery is almost totally dead however sufficient potential is developed across the red diode 14 to cause it to conduct and so it emits light.

Should the battery have a more healthy state of charge, such that it will provide more than eight hours useful life under full load, then diode 15 will also conduct and so both red and green light will be emitted.

Thus in use all a user has to do is place the pins 12 and 13 against the terminals 1 8 and 19 of the battery. If neither diode emits light, the contact pins have probably been placed in position the wrong way round and the user should reverse the position of the device to reverse the polarity. If the diodes still do not emit light, then the battery is totally dead. If only the red diode emits light, the user knows that the battery has a useful life of less than eight hours. If both diodes emit light, then the user knows that the battery has a useful life of more than eight hours.

The invention is not restricted to the details of the foregoing embodiment. For instance the device may be adapted to test batteries other than the 6-volt lantern battery described. Furthermore, the signalling circuitry may be provided with one or more further branches each containing a further light emitting diode, so that battery charge information can be obtained which is more accurate than merely having an indication of whether the useful life is less than or more than eight hours.

Where the device is to be used with batteries powerful enough to damage the light emitting diodes if the contact pins are placed in position the wrong way round and current attempts to flow in the wrong direction, the circuit may include a protective device, e.g. a diode arranged in the positive supply line.

Claims

1. A battery testing device comprising a pair of contacts for connection to the terminals of a battery to be tested, a load connected between the contacts to represent the load normally driven by the battery, and signalling circuitry incorporating a plurality of light emitting diodes, different states of the battery causing different combinations of diodes to emit light.

2. A battery testing device as claimed in Claim 1, in which the signalling circuitry is such that when the battery has a useful life under load of less than a predetermined period fewer diodes emit light than when the battery has a useful life under load of more than the predetermined period.

3. A battery testing device as claimed in Claim 2, in which the signalling circuitry is such that one diode emits light when the battery has a useful life under load of less than eight hours, and two or more diodes emit light when the battery has a useful life under load of more than eight hours.

4. A battery testing device as claimed in any one of the preceding claims, in which the diodes are arranged in parallel branches of the signalling circuitry, the branches being progressively loaded such that whilst a relatively low battery will cause a diode of a first branch to conduct, the diodes of successive branches each require a better state of battery charge than the preceding one to cause the associated diode to conduct.

5. A battery testing device as claimed in any one of the preceding claims, in which different diodes are arranged to emit different colours of light to assist a user of the device to recognise different combinations associated with different states of the battery.

6. A battery testing device as claimed in any one of the preceding claims, in which the signalling circuitry includes means to protect the light emitting diodes if the contacts of the battery testing device are connected to the battery terminals the wrong way round.

7. A battery testing device constructed and arranged substantially as herein described with reference to the accompanying drawings.

8. A battery testing device as claimed in any one of the preceding claims, in combination with a battery to be tested.

9. A battery testing device as claimed in Claim 8, in which the battery is a 6-volt lantern battery.