GB2050088A

GB2050088A - Cycle lighting system

Info

Publication number: GB2050088A
Application number: GB8006683A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-03-03
Filing date: 1980-02-27
Publication date: 1980-12-31

Abstract

A cycle lighting system is so arranged that when the lights are turned on by the switch SIB the interconnected switch SIA increases the output of the regulator VR at the same time by switching R2 in parallel with R1. This gives a charge current low enough to avoid battery damage when the lights are off, and a second higher range to operate the lights without battery discharge when the lights are on, both at high road speeds. <IMAGE>

Description

SPECIFICATION Cycle lighting systems This invention is concerned with cycle lighting systems, and is especially, but not exclusively, concerned with cycle lighting systems which include a rechargeable Nicad battery arranged to keep the cycle lights alight, where necessary, even though the cycle is stationary. The word "cycle" is used herein to include Mopeds and lightweight motorcycles.

Nicad cells are sturdy, light in weight, and can be hermetically sealed so that there is no risk of spillage of electrolyte. However, Nicad cells are liable to damage by charging at too high a rate, particularly when already fully charged.

One of the various objects of the present invention is to provide an improved cycle lighting system in which Nicad cells are used.

In one aspect the present invention provides a cycle lighting system for connection between a generator which gives an output which varies with the road speed, a rechargeable battery and the cycle lights, the system comprising a regulator arranged to regulate the output current fed to the battery therefrom, and a light switch, and an arrangement whereby on switching on the lights by said switch for night riding the operation of the regulator is varied to increase the output current to provide sufficient for lighting the lights adequately at high road speeds without discharge of the battery, and on switching the lights off by said switch the operation of the regulator reverts to a decreased output current which is sufficient, at high road speeds, to charge the battery but not at a rate likely to cause damage to the cells of the battery.

In another aspect the present invention provides a cycle lighting system for connection between a generator which gives an output which varies with the road speed, a rechargeable battery and the cycle lights, the system comprising a regulator, a regulator switch arranged to control the operation of the regulator, the regulator switch being so connected that when the switch is in a first condition the possible output current of the regulator is at such a rate that damage to the battery when on charge therefrom is unlikely and when in a second condition the possible output current of the regulator is increased to an amount suitable to light the lights, and a light switch so arranged that when it is in a first condition the lights are not connected across the battery and when it is in a second condition the lights are so connected, said switches being so interconnected that they can be switched from their first condition to their second condition (or vice versa) at the same time by a single control.

The above and other of the various objects of the present invention and the invention itself in its above-mentioned and other aspects will become more clear from the following description, to be read with reference to the accompanying drawings, of two cycle lighting systems illustrative of the invention; it will be realized that these two illustrative systems have been selected for description by way of example and not of limitation of the invention.

In the accompanying drawings: Figure 1 is a circuit diagram of the larger part of the first illustrative system; and Figure 2 is a similar circuit diagram of the second illustrative system.

The first illustrative system, referred to hereinafter as the system S1, is shown diagrammatically in Fig. 1. The system S1 comprises an electric generator (not shown) and a semiconductor rectifier P. The generator may conveniently consist of a Sturmey Archer Hub Dyno generator incorporated in the hub of one of the wheels of the cycle and giving an output voltage of about 20v AC when the road speed of the cycle is high and no output when the cycle is stationary. The output from the rectifier P, which is positive at the point P1 and negative at the point Q1, is fed to a smoothing electrolytic capacitor C1 and the point P1 is connected to the input terminal IN of a LM 31 7T voltage regulator VR; the point Q1 is connected to earth.The LM 317T voltage regulator is sold by National Semiconductors. The output terminal OUT of the regulator VR is connected through a control resistor R1 (4 ohms) to a terminal T1. At B is shown a battery of 5 Nicad cells connected in series, the battery B having its positive terminal connected to the terminal T1 and its negative terminal connected to earth. The battery B may consist of cells size D as sold by Ever Ready (Special Batteries) Ltd. The terminal T1 is also connected directly to the adjustment terminal ADJ of the regulator VR, a capacitor C2 (0.1of) being connected between the terminals IN and ADJ.

The system S1 includes a regulator switch S1A and a light switch S1 B; these switches are both single pole single throw switches.

The switches S1A and S1B are mechanically connected together so that they can be opened (or closed) at the same time by manipulation of a single control knob. When the switches S1A,S1B are open, as shown in Fig.

1, the terminal OUT of the regulator VR is connected to the terminal T1 solely by the resistor R1. In this condition the regulator VR provides an output current, which charges the battery B, not exceeding 300 mA even at the highest likely cycle speed; the actual value of the maximum output current is dependent on the value selected for the resistor R1, being approximately inversely proportional to Rl's value. At slow speeds of the cycle the output current of the regulator VR falls away to about 200 mA, while if the cycle is stationary the output is zero.

By closing the switch S1 B the lights L1 are switched on across the battery B and also a resistor R2 (4 ohms) is placed in parallel with the resistor R1. In this condition the regulator VR provides an output current not exceeding 600 mA at high cycle speeds, and this is enough to give full brilliance to the lights L1 with, perhaps, a little charging of the battery B. At medium speeds the output from the regulator VR is about 400 mA and this together with a further 200 mA provided by the battery B remains sufficient for the lights L1.

At low speeds the regulator VR provides about 200 mA and the battery B provides 400 mA, while when the cycle is stationary the battery B provides the whole 600 mA.

With the system S1, in daylight hours, the battery B is being charged whenever the cycle is in use, the switches S1A,S1B being open.

Due to the operation of the regulator VR the rate of charge is restricted, whatever the speed of the cycle, to a rate not likely to cause damage to the cells of the battery B whether the battery B is already fully charged or not. When the lights L1 are needed the switches S1A,S1B are closed and the battery B and regulator VR combine to keep the current through the lights L1 at least approximately constant regardless of the cycle speed, thereby increasing the probable life of the lamps and adding to the safety of the rider.

Turning now to the second illustrative system, referred to hereinafter as the system S2, this is shown diagrammatically in Fig. 2. The system S2 comprises an electric generator, semiconductor rectifier and smoothing capacitor like those of system S1. The output from the rectifier is positive at the point P2 and negative at the point 02. The point P2 is connected to the emitter of a regulator series pass transistor TR 1 (an AD162) the collector of which is connected to a terminal T2. The terminal T2 is connected to the positive terminal of a battery B2 of 5 Nicad cells connected in series, the negative terminal of the battery B2 being connected to earth, as is also the point Q2. The battery B2 may consist of cells size AA as sold by Ever Ready (Special Batteries) Ltd.

The system S2 includes a regulator switch S2A and a light switch S2B; these switches are both single pole single throw switches.

The switches S2A,S2B are mechanically connected together so that they can be opened (or closed) at the same time by a single control knob. When the switches S2A,S2B are open, as shown if Fig. 2, the emitter of a transistor TR4 (a BFY 51) is connected to ground solely through a resistor R2A. The upper end of the resistor R2A is connected to the base of a transistor TR2 (a BC 108), the emitter of which is connected to ground and the collector of which is connected to the point P2 by a resistor R4 (22K). The collector of the transistor TR2 is also connected to the base of a transistor TR3 (a BC 108) which is arranged to form a Darlington pair with the transistor TR4, the collectors of the transistors TR3,TR4 being connected together and also to the lower end of a resistor R5 (6.8 ohms).

The upper end of the resistor R5 is connected to the base of the regulator transistor TR 1. A resistor R3 (33K) connects the base of the transistor TR2 to the point P2.

The value of the resistor R2A is selected (or adjusted) so that when the switches S2A,S2B are open, as shown in Fig. 2, the output current of the regulator transistor TR 1, to the terminal T2, is controlled so as not to exceed 45 mA even at the highest likely cycle speed.

This current will charge the battery B2, but is not at a rate likely to cause damage to the cells of the battery B2. At lower and lower speeds the charging rate will become less and less. Riding the cycle by day will thus safely charge the battery B2.

By closing the switches S2A,S2B a resistor R2B is placed in parallel with the resistor R2A and also the lights L2 are switched on across the battery B2. The cycle is then ready for riding at night. The value of the resistor R2B is selected (or adjusted) so that when the switches S2A,S2B are closed the regulator transistor TR1 gives an output not exceeding 450 mA at high cycle speeds, and this is enough to give full brilliance to the lights L2.

As the cycle speed is decreased, as with the system So, the transistor TR1 provides less current and the battery B2 provides more, the battery and regulator transistor combining to keep the current through the lights L2 at least approximately constant regardless of the cycle speed. The actual values set for the resistors R2A,R2B will depend, largely, on the gain of the transistor TR4.

The systems S1 and S2 thus operate in a very similar fashion, keeping the battery on charge (but never at a dangerously high rate) in daylight hours, and ensuring that when the switches are closed for night riding the current through the lights is kept at least approximately constant. Having the switches SiA/SiB (and S2A/S2B) connected together so that they will be opened (or closed) at the same time by a single control ensures that, for example, the switch S1 B is not closed and the switch S1A left open, resulting, possibly, in early discharge of the battery B, and that the switch S1A is not closed with the switch S1 B left open, resulting, possibly, in charging the battery B at an unduly high rate.

It may also be added that in the system S1 there is a certain loss of power in the resistors R1,R2, and this loss is avoided in the system S2.

If it is found that the ratio of night riding to daytime riding is so high that the battery B gets insufficient daytime charging to make up for nighttime discharging, when the cycle is not in use the system S1 may be discon nected from the generator and connected to a mains transformer giving about 1 8v A.C. to provide additional charging time.

Claims

1. A cycle lighting system for connection between a generator which gives an output which varies with the road speed, a rechargeable battery and the cycle lights, the system comprising a regulator arranged to regulate the output current fed to the battery therefrom, and a light switch, and an arrangement whereby on switching on the lights by said switch for night riding the operation of the regulator is varied to increase the output current to provide sufficient for lighting the lights adequately at high road speeds without discharge of the battery, and on switching the lights off by said switch the operation of the regulator reverts to a decreased output current which is sufficient, at high road speeds, to charge the battery but not at a rate likely to cause damage to the cells of the battery.

2. A cycle lighting system for connection between a generator which gives an output which varies with the road speed, a rechargeable battery and the cycle lights, the system comprising a regulator, a regulator switch arranged to control the operation of the regulator, the regulator switch being so connected that when the switch is in a first condition the possible output current of the regulator is at such a rate that damage to the battery when on charge therefrom is unlikely and when in a second condition the possible output current of the regulator is increased to an amount suitable to light the lights, and a light switch so arranged that when it is in a first condition the lights are not connected across the battery and when it is in a second condition the lights are so connected, said switches being so interconnected that they can be switched from their first condition to their second condition (or Vice versa) at the same time by a single control.

3. A system according to claim 2 wherein the regulator is an l.C. regulator such that its output current is dependent on the resistance value of a control arrangement connected between an output terminal of the regulator and the battery, and wherein the resistance value of the control arrangement is decreased when the regulator switch is set from its first condition into its second condition thereby to increase the output current of the regulator as the lights are connected across the battery by the accompanying change in the condition of the light switch.

4. A system according to claim 2 wherein the regulator is a series pass regulator transistor so arranged that its output current is dependent on the resistance value of a control arrangement connected to its base, and wherein the resistance value of the control arrangement is decreased when the regulator switch is set from its first condition into its second condition thereby to increase the output current of the transistor as the lights are connected across the battery by the accompanying change in the condition of the light switch.

5. A system according to claim 3 which comprises a battery of Nicad cells and is arranged and adapted to operate substantially as hereinbefore described with reference to Fig. 1.

6. A system according to claim 4 which comprises a battery of Nicad cells and is arranged and adapted to operate substantially as hereinbefore described with reference to Fig. 2.

7. A cycle fitted with a lighting system according to any preceding claim.