FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
SYSTEM FOR CHARGING ENERGY STORAGE DEVICE
2. APPLICANT(S)
MAHINDRA & MAHINDRA LTD.
GATEWAY BUILDING, APOLLO BUNDER, MUMBAI - 400001, MAHARASHTRA, INDIAN.
The following specification particularly describes the invention and the manner in which it is to be performed.

Field of the Invention
The present invention relates to a system and method for charging energy storage device such as battery. The invention further relates to a portable charging system for tractor.
Background of the Invention
The energy storage device such as battery is recharged using a system that delivers energy into the battery in terms of controlling voltage applied across the battery to be charged, amount of current supplied to the battery and timing associated with current and voltage levels. There are various methods / modes and corresponding types of battery chargers such as trickle charger, timer based, pulse, inductive etc. The charging cycle comprises charging the battery from zero volt up to the threshold voltage and further charging the same. The time consumed for the first stage is considerably more. Conventionally trickle charging and pulse width charging mode is used in most applications. One of the challenges to be addressed during charging is to cater to the variation in the voltage of AC mains that is voltage fluctuations. The essence is to reduce time of charging without damaging cell elements of the battery and without adversely affecting battery life.
US patent 6,492,792 discloses trickle charging circuit that works with a series charging element to charge battery cells with a low, a constant current when the voltage of the cell is below a predetermined operational range. This trickle charging continues until a minimum operation voltage is reached which takes longer time.
US Patent Application 2009/0195218 discloses method for charging a battery of an electronic device using a connected a/c power adapter comprising the steps of determining a state of a transistor connecting a

regulated voltage to the battery and switching a charging current applied to the battery between a quick charge level and trickle charge level responsive to the state of transistor. This prior does not claim to charge Zero volt battery. US Patent 6,492,792 discloses the trickle charging circuit comprising of a first resistor, a second resistor and a Zener Diode.
However the systems mentioned in the prior art suffer from following drawbacks:
√ Lack of flexibility and provision to charge battery with initial high current and constant voltage; √ Considerably / substantially longer time (of the order of 30 + hours for 12-24 volt battery) for charging up to the threshold voltage; √ Lack of provision to sense and measure incoming voltage to battery terminal while charging coupled with feedback system with AC mains; √ Lack of provision of charging in steps with predetermined voltage but varying current; √ Lack of microcontroller and relay based system to control voltage and current operating in tandem with battery characteristics, current level and taking into consideration fluctuations in the AC mains voltage.
There is unfulfilled need in the market place to develop a system for charging energy storage device such as battery from zero volt up to the threshold voltage, provided with microcontroller based relay circuitry to substantially reduce time of charging, take into consideration effects of AC mains voltage fluctuations and operate based on the feedback of the current level, voltage across battery terminals and AC mains fluctuations without damaging battery elements thereby protecting battery life.

Summary of the Invention
Main object of the invention is to provide a system and method for charging energy storage device such as battery.
Another object of the invention is to provide a portable charging system adaptable on tractor.
Another object of the invention is to substantially reduce time for charging from zero volt up to the threshold voltage of the battery.
Another object of the invention is to charge battery obviating problems associated with pulse mode of charging.
Another object of the invention is to provide a microcontroller and relay based system.
Yet another object of the invention is to provide a charging system and method that takes into account AC mains fluctuations.
Yet another object of the invention is to provide a charging system that operates based on the feedback from current level, voltage across battery and AC mains voltage fluctuations.
Another object of the invention is to provide charging system to charge in steps / defined relay ratings with predetermined voltage but varying current.
Another object of the invention is to provide a charging system for tractor provided with protection in case of reverse polarity, inbuilt earthing provision, battery voltage cut-off at 11.6 volt and weather proof casing vibration resistant system.

Thus in accordance, one aspect of the invention provides a system comprising a sensing transformer configured with AC mains, rectification circuit, main relay that is configured with the said sensing transformer secondary winding and the said rectification circuit; set of relays configured with microcontroller through rectification circuit; main transformer wherein primary winding of the same is connected to the
said set of relays and the secondary winding / winding tapping is configured with rectification circuit and further to the battery to be charged
wherein the system operates in steps of:
√ providing predetermined current and constant voltage to battery to initiate charging process from zero volt; √ measuring battery terminal voltage after predetermined time and feeding the same to microcontroller; √ sensing AC mainsvoltage and current using sensing transformer, taking feedback from sensing transformer and based on this selection of suitable relay rating by the said microcontroller; √ allow another set of predetermined constant voltage with the varying current and then measuring the difference of both values to analysis the state of charging the cells of battery; √ continuing the process by microcontroller with different set of predetermined current and voltage values; √ stopping the process of charging if there is no gain of voltage and current in the battery; √ if difference in values are within the set values of charging up to threshold battery voltage then charging is carried out using varying current and constant voltage; √ after attaining threshold voltage, carrying out charging with constant current and varying voltage.

In another aspect of the invention, the said system for tractor comprises a means in terms of a divider circuit of 47k and 10k resistor configured with the said microcontroller and further the said microcontroller is configured to sense battery voltage so as to cut off the circuit at the battery voltage of 11.6 V to avoid reducing it further and thus to ensure enough battery-power still available for starting of the tractor in spite of battery being used for other peripheral purposes.
In another aspect of the invention, the said system for tractor comprises a provision such as switch comprising diode / transistor to protect the system in case of reverse polarity.
In another aspect of the invention, the said system for tractor comprises a provision to shut down in the event of AC current leakage wherein the system body is insulated against current leakage.
In another aspect of the invention the said system for tractor is encased in a weather-proof casing comprising air vents for appropriate air circulation to dissipate heat, and water and dust proof provision. Further the said casing comprises movable flaps adapted to be fitted on the casing, wire connecting means and provisions. In yet another aspect of the invention the said casing comprises optional channels inside the casing to mount the said charging system conveniently inside the casing.
Description of the Invention
Features and advantages of the invention will become apparent in the following detailed description and the preferred embodiments with reference to the accompanying drawings.
Figure 1 Schematic of the charging system

Figure 2 Schematic of the casing
Figure 3 Schematic of the optional features inside the casing
Figure 1 illustrates the charging system circuitry. It comprises a source 1 to sense incoming voltage. The source is coupled to sensing transformer 2. The sensing transformer in turn is connected to main AC relay 3. The said main relay acquires signal from source for operation. The relay connects the circuit to operate at the desired voltage and current as per sensing transformer signal. A microcontroller 4 is programmed in accordance with the desired charging cycle. It is powered from 12 Volt DC source.
The output of main AC relay 3 and the microcontroller 4 is provided to rectification circuit 5. The rectification circuit comprises a set of transistors, diodes and resistors. The rectification circuit in turn is coupled with a set of relays 6. The relay with suitable rating is selected by microcontroller out of this set of relays which is suitable for input voltage based on the feedback from battery terminal voltage, sensing transformer 2 and current level. Each relay is coupled with individual set of filter circuit. The set of relays 6 is further connected to primary winding of the main transformer 7. The secondary winding is further fed to rectification circuit 8. This rectification circuit comprises a set of transistors, diodes and resistors. Further the battery to be charged is configured with the said rectification circuit 8. The system operates in steps of: √ providing predetermined current and constant voltage to battery
to initiate charging process from zero volt; √ measuring battery terminal voltage after predetermined time and feeding the same to microcontroller 4 ; √ sensing AC main voltage and current using sensing transformer 2, taking feedback from sensing transformer 2 and based on this

selection of suitable relay rating from the said relay set 6 by the said microcontroller 4; √ allow another set of predetermines constant voltage but the varying current and then measuring the difference of both values to analysis the state of charging the cells of battery; √ continuing the process by microcontroller 4 with different set of predetermined current and voltage values. √ stopping the process of charging if there is no gain of voltage and current in the battery; √ if difference in values are with in the set values of charging up to threshold battery voltage then charging is carried out using varying current and constant voltage; √ after attaining threshold voltage, carrying out charging with constant current and varying voftage.
Figure 2 depicts the system for the tractor. The charging system is
encased in the casing 21. One or plurality of air vent provisions 22 on
one of the surfaces. The casing further comprises dust and
waterproof air vent 23 comprising water absorbing material cover. Optional provision 24 is provided in terms of slots for battery connection. Figure 3 depicts internal details of the casing 21 provided with optional features. Sliding arrangement 30 is provided to mount the said charging system in the casing. The flaps 31 are provided on the side of the casing. In one of the embodiments the said casing comprises optional channels inside the casing to mount the said charging system inside the casing.
The said system for tractor further comprises a means (not shown in the Figures) such as comparator for cut off at the battery 11.6 voltage to enable tractor start by providing starting current for the tractor in spite of battery being used for other peripheral purposes. In another variant a divider circuit of 47k and 10k resistor for the reduction of

voltage so as to reduce voltage to 3.7 Volts at the said microcontroller wherein in the event of reduction of battery voltage below 11.6 Volt, the said microcontroller senses the voltage less than 3.67 V to shut off circuit so that sufficient energy is left in the said battery to enable starting the tractor in spite of battery being used for other peripheral purposes. The said system for tractor further comprises a provision such as switch comprising diode / transistor to protect the system in case of reverse polarity. The said system for tractor further comprises a provision to shut down in the event of AC current leakage wherein the system body is insulated against current leakage. In one of the embodiments the system comprises jumper wires having crocodile connector to enabie connection with battery.
It is evident from the present invention that the synergistic combination of the microcontroller with relay set that enables selectively utilizing relay rating based on the feedback from current level, voltage across battery terminals and AC mains fluctuations provides battery charging system that substantially reduces charging time for charging up to threshold voltage takes in to consideration AC mains voltage fluctuations without damaging battery elements thereby protecting battery life.

We Claim
1. A system for charging energy storage device of tractor comprising sensing transformer configured with AC mains, main AC relay, rectification circuit, set of relays configured with microcontroller through rectification circuit; main transformer, DC source for the microcontroller, filter circuit wherein the sensing transformer is connected to main AC relay that acquires signal from the said AC mains and connects the circuit to operate at the desired voltage and current as per sensing transformer signal;
wherein the rectification circuit comprises a set of transistors,
diodes and resistors wherein the output of main AC relay and the microcontroller is provided to the said rectification circuit; the microcontroller is programmed in accordance with the desired charging cycle, the rectification circuit in turn is configured with the set of relays wherein each relay is configured with individual set of the filter circuit;
the set of relays is further connected to primary winding of the main transformer, secondary winding of the main transformer is further fed to the rectification circuit wherein energy storage device to be charged is configured with the said rectification circuit.
2. A system for charging energy storage device as claimed in claim 1 wherein the energy storage device is a battery.
3. A system for charging energy storage device as ciaimed in claims 1, 2 operates in steps of:

√ providing predetermined current and constant voltage to battery to initiate charging process from zero volt; √ measuring battery terminal voltage after predetermined time and feeding the same to microcontroller; √ sensing AC main voltage and current using the sensing transformer, taking feedback from the sensing transformer and based on this selection of suitable relay rating by the said microcontroller; √ allow another set of predetermined constant voltage but varying current and then measuring the difference of both values to analysis the state of charging the cells of battery; √ continuing the process by the microcontroller with different set of predetermined current and voltage values; √ stopping the process of charging if there is no gain of voltage and current in the battery; √ if difference in values are within the set values of charging up to threshold battery voltage then charging is carried out using varying current and constant voltage; √ after attaining threshold voltage, carrying out charging with constant current and varying voltage.
4. A system for charging energy storage device as claimed in claims 1-3 comprising a divider circuit of 47k and 10k resistor for the reduction of voltage so as to reduce voltage to 3.7 Volts at the said microcontroller wherein in the event of reduction of battery voltage below 11.6 Volt, the said microcontroller senses the voltage less than 3.67 V to shut off circuit so that sufficient energy is left in the said battery to enable starting of the tractor in spite of battery being used for other peripheral purposes.
5. A system for charging energy storage device as claimed in claims 1-4 wherein the system is encased in a weather-proof casing

comprising air vents for air circulation to dissipate heat, water and dust proof provision, movable flaps adapted to be fitted on the casing, wire connecting means, optional channels inside the casing to conveniently mount the said charging system.
6. A system for charging energy storage device as claimed in claims 1-5 wherein the said system comprises provision such as switch comprising diode / transistor to protect the system in the event of reverse polarity avoiding fuse blow and shutting down of the system.
7. A system for charging energy storage device as claimed in claims 1-6 wherein the system comprises provision to shut down in the event of AC current leakage wherein the system body is insulated against current leakage to the system casing.
8. A system for charging energy storage device as claimed in claims 1-7 wherein the said system comprises jumper wires having crocodile connector to enable connection with battery.
9. A system for charging energy storage device as claimed in claims 1-8 comprising sensing transformer configured with AC mains, main AC relay, rectification circuit, set of relays configured with microcontroller through rectification circuit; main transformer, DC source for the microcontroller, filter circuit wherein the sensing transformer is connected to main AC relay that acquires signal from the said AC mains and connects the circuit to operate at the desired voltage and current as per sensing transformer signal; wherein the rectification circuit comprises a set of transistors, diodes and resistors wherein the output of main AC relay and the

microcontroller is provided to the said rectification circuit; the
microcontroller is programmed in accordance with the desired
charging cycle,
the rectification circuit in turn is configured with the set of relays
wherein each relay is configured with individual set of the filter
circuit;
the set of relays is further connected to primary winding of the
main transformer, secondary winding of the main transformer is
further fed to the rectification circuit
wherein energy storage device to be charged is configured with
the said rectification circuit
wherein system operates in steps of
√ providing predetermined current and constant voltage to battery to initiate charging process from zero volt; √ measuring battery terminal voltage after predetermined time and feeding the same to microcontroller; √ sensing AC main voltage and current using sensing transformer, taking feedback from sensing transformer and based on this selection of suitable relay rating by the said microcontroller; √ allow another set of predetermines constant voltage but the varying current and then measuring the difference of both values to analysis the state of charging the cells of battery; √ continuing the process by microcontroller with different set of predetermined current and voltage values; √ stopping the process of charging if there is no gain of voltage and current in the battery; √ if difference In values are within the set values of charging up to threshold battery voltage then charging is carried out using varying current and constant voltage; √ after attaining threshold voltage, carrying out charging with constant current and varying voltage.

10. A system for charging energy storage device comprising sensing transformer configured with AC mains, main AC relay,
rectification circuit, set of relays configured with microcontroller through rectification circuit; main transformer, DC source for the microcontroller, filter circuit wherein the sensing transformer is connected to main AC relay that acquires signal from the said AC mains and connects the circuit to operate at the desired voltage and current as per sensing transformer signal;
wherein the rectification circuit comprises a set of transistors, diodes and resistors wherein the output of main AC relay and the microcontroller is provided to the said rectification circuit; the microcontroller is programmed in accordance with the desired charging cycle,
the rectification circuit in turn is configured with the set of relays wherein each relay is configured with individual set of the filter circuit;
the set of relays is further connected to primary winding of the main transformer, secondary winding of the main transformer is further fed to the rectification circuit wherein energy storage device to be charged is configured with the said rectification circuit.
11. A system for charging energy storage device as claimed in claim 10 operates in steps of: √ providing predetermined current and constant voltage to battery to initiate charging process from zero volt; √ measuring battery terminal voltage after predetermined time and feeding the same to microcontroller; √ sensing AC main voltage and current using sensing transformer, taking feedback from sensing transformer and

based on this selection of suitable relay rating by the said microcontroller; √ allow another set of predetermines constant voltage but the varying current and then measuring the difference of both values to analysis the state of charging the cells of battery; √ continuing the process by microcontroller with different set of predetermined current and voltage values; √ stopping the process of charging if there is no gain of voltage and current in the battery; √ if difference in values are within the set values of charging up to threshold battery voltage then charging is carried out using varying current and constant voltage; √ after attaining threshold voltage, carrying out charging with constant current and varying voltage.