GB2197551A - Miniature battery re-charger - Google Patents

Abstract

The recharger enables the miniature batteries or cells commonly used in hearing aids, watches and calculators to recharged by the AC mains supply and has a housing 1, 2 similar in size and shape to a 13 amp plug. A cell to be recharged is located in the appropriate one of variously sized holes in a cell holder 6 which is then located in a cut-out 5 in the housing 1, 2 so that the cell (8), (Fig. B) is engaged between spring contacts (7) therein to be charged via a circuit comprising a series-connected capacitor (C1), (Fig. C), acting as a voltage dropper and an LED acting as both a charging initiator and as a charging current rectifier. <IMAGE>

Description

SPECIFICATION Miniature battery re-charger This invention relates to a device to enable the expensive miniature batteries or cells commonly used in watches, hearing aids and calculators to be re-charged cheaply. The device is powered by the AC mains supply, it is simple and inexpensive to manufacture, convenient to use and capable of re-charging a range of different sized miniature batteries.

According to the invention, an electrical device to enable miniature batteries to be recharged from the AC mains supply comprises of two parts. One part, the charger, is a box made of a non-conductive material, eg plastic, with lid. The box has three terminals protruding from the rear, two of which are metallic.

The box and terminals are very similar to a 13 amp plug in size and shape. The other part of the device, the battery holder, is a cross shaped piece of non-conductive material with holes made at each end of the cross to accomodate different sizes of miniature batteries.

These holes have a lip around the bottom edge so that the battery sits in the holder.

Also the ends that are inserted into the charger are tapered to ease insertion. Inside the box there is an electronic curcuit, the function of which is to reduce the AC mains voltage to a pulsing DC voltage of approximatly 1.7 volts at 0.8 milliamps to be applied across the battery to be charged via to metallic spring contacts. The circuit comprises of three resistors, one capacitor and a light emmitting diode. The diode performs two functions, one is rectify the AC voltage and the other is to indicate to the user that the battery is properly in place and charging. Due to the fact that the charger uses no transformer it is possible for the device to be simple and inexpensive to manufacture and to be of a small size.

The invention will now be described further by way of example only and with reference to the accompanying drawing in which:~ Figure A shows in perspective the battery holder and charger with cut out to enable the insertion of the battery holder.

Figure B shows a plan view of the charger with the lid off and battery holder inserted, showing internal circuitry metallic spring contacts for the battery and light emmitting diode.

Figure C shows a circuit diagram of one form of the device. Different component values to those shown could be used provided the ratio is kept similar.

Referring to Fig. A The device comprises of a box 1 with lid 2, a pair of metallic input terminals 3, and one other terminal 4. This last terminal is there to open up the 13amp socket. The cut-out and guides 5 is shown and also the battery holder 6. A sectional view of one hole is given showing the lip around the bottom edge of the hole and the tapered leading edge.

Referring to Fig. B This shows the metallic spring contacts 7 mounted in such a fashion as to make contact with the battery 8 in the battery holder 6.

Also shown is the light emmitting diode 9 which is mounted in such a fashion as to protrude through a hole in in the lid 10.

Referring to Fig. C This shows the circuit diagram of the device. It also shows terminals 3 and springs 7 with a battery inserted.

In use, the user would insert the battery to be charged into the appropriate hole of the battery holder 6 and insert the holder into the charger via cut-out 5. He would then insert the entire device into a 13amp socket, diode 9 would glow to indicate that the battery is properly in place and charging. Very good results have been obtained with this charger, though it should be noted that batteries that are totally exhausted ie dead, do not respond well. Best results are obtained with batteries that have been in use and are just starting to fail.

1. An electrical device to enable the miniature batteries or cells commonly used in hearing aids, watches and calculators to be recharged by the AC mains supply, comprising of a non conductive box with input terminals for connection to the AC mains supply and output terminals for connection to the AC mains supply and output terminals for connection to the miniature battery via circuitry to reduce the mains voltage to a level suitable for re-charging of the batteries. As the output terminals are covered for safety reasons a battery holder made of a non conductive material is used to insert the battery between the output terminals via a hole in the box.

2. A device according to claim 1 that uses a battery holder with various sized holes to accomodate a range of different sized batteries.

3. A device according to claim 1 or 2 that does not use a transformer to lower the mains voltage to a level suitable for re-charging the batteries.

4. A device according to claims 1 to 3 that uses a light emitting diode to rectify the charging current and indicate to the user that the battery is properly in place and recharging.

5. A device according to claims 1 to 4 wherin the charger is broadly similar in size and shape to a standard 13 amp plug.

6. An electrical device substantialy as described with reference to the drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Miniature battery re-charger This invention relates to a device to enable the expensive miniature batteries or cells commonly used in watches, hearing aids and calculators to be re-charged cheaply. The device is powered by the AC mains supply, it is simple and inexpensive to manufacture, convenient to use and capable of re-charging a range of different sized miniature batteries. According to the invention, an electrical device to enable miniature batteries to be recharged from the AC mains supply comprises of two parts. One part, the charger, is a box made of a non-conductive material, eg plastic, with lid. The box has three terminals protruding from the rear, two of which are metallic. The box and terminals are very similar to a 13 amp plug in size and shape. The other part of the device, the battery holder, is a cross shaped piece of non-conductive material with holes made at each end of the cross to accomodate different sizes of miniature batteries. These holes have a lip around the bottom edge so that the battery sits in the holder. Also the ends that are inserted into the charger are tapered to ease insertion. Inside the box there is an electronic curcuit, the function of which is to reduce the AC mains voltage to a pulsing DC voltage of approximatly 1.7 volts at 0.8 milliamps to be applied across the battery to be charged via to metallic spring contacts. The circuit comprises of three resistors, one capacitor and a light emmitting diode. The diode performs two functions, one is rectify the AC voltage and the other is to indicate to the user that the battery is properly in place and charging. Due to the fact that the charger uses no transformer it is possible for the device to be simple and inexpensive to manufacture and to be of a small size. The invention will now be described further by way of example only and with reference to the accompanying drawing in which:~ Figure A shows in perspective the battery holder and charger with cut out to enable the insertion of the battery holder. Figure B shows a plan view of the charger with the lid off and battery holder inserted, showing internal circuitry metallic spring contacts for the battery and light emmitting diode. Figure C shows a circuit diagram of one form of the device. Different component values to those shown could be used provided the ratio is kept similar. Referring to Fig. A The device comprises of a box 1 with lid 2, a pair of metallic input terminals 3, and one other terminal 4. This last terminal is there to open up the 13amp socket. The cut-out and guides 5 is shown and also the battery holder 6. A sectional view of one hole is given showing the lip around the bottom edge of the hole and the tapered leading edge. Referring to Fig. B This shows the metallic spring contacts 7 mounted in such a fashion as to make contact with the battery 8 in the battery holder 6. Also shown is the light emmitting diode 9 which is mounted in such a fashion as to protrude through a hole in in the lid 10. Referring to Fig. C This shows the circuit diagram of the device. It also shows terminals 3 and springs 7 with a battery inserted. In use, the user would insert the battery to be charged into the appropriate hole of the battery holder 6 and insert the holder into the charger via cut-out 5. He would then insert the entire device into a 13amp socket, diode 9 would glow to indicate that the battery is properly in place and charging. Very good results have been obtained with this charger, though it should be noted that batteries that are totally exhausted ie dead, do not respond well. Best results are obtained with batteries that have been in use and are just starting to fail. CLAIMS

1. An electrical device to enable the miniature batteries or cells commonly used in hearing aids, watches and calculators to be recharged by the AC mains supply, comprising of a non conductive box with input terminals for connection to the AC mains supply and output terminals for connection to the AC mains supply and output terminals for connection to the miniature battery via circuitry to reduce the mains voltage to a level suitable for re-charging of the batteries. As the output terminals are covered for safety reasons a battery holder made of a non conductive material is used to insert the battery between the output terminals via a hole in the box.

2. A device according to claim 1 that uses a battery holder with various sized holes to accomodate a range of different sized batteries.

3. A device according to claim 1 or 2 that does not use a transformer to lower the mains voltage to a level suitable for re-charging the batteries.

4. A device according to claims 1 to 3 that uses a light emitting diode to rectify the charging current and indicate to the user that the battery is properly in place and recharging.

5. A device according to claims 1 to 4 wherin the charger is broadly similar in size and shape to a standard 13 amp plug.

6. An electrical device substantialy as described with reference to the drawings.