FIELD OF INVENTION
[0001] The present invention relates to a method to determine and display battery
health condition on an automobile.
• • •
BACKGROUND OF INVENTION
[0002] Vehicle battery plays an important role in vehicle by providing electrical
power to the starter system, display on instrument cluster and powering the light and sound systems. Many a times a rider of a two-wheeler vehicle may be stranded due to fault in .battery or any accident^pan.take ^place Jf. warning systems, which work on electricity, are not functioning due to battery fault. Normally batteries are checked during vehicle servicing but there is no onboard display of health status of battery that can alert the rider of any unforeseen circumstances related to battery health.
[0003] The conventional methods for measuring state of health (SOH) of the
battery are full discharge test, impedance method and cold cranking amperes method. The full discharge test involves a full load discharge applied to the battery and the amount of charge delivered is measured which is, then, compared with the charge from a full discharge test when the battery was new. A full discharge test is known for its accuracy. But the disadvantages of this approach include the length of time required to perform the full discharge and the requirement for the battery to be offline, as the battery must be recharged after the test is performed. Repeated discharging of the battery shortens its life.

[0004] The impedance method involves applying an ac current or voltage signal
across the terminals of the battery and measuring its voltage or current response. The impedance increases as the SOH deteriorates. From literature one rule of thumb with the
impedance method is that if the impedance increases by 30% from its. original impedance
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(for a new fully charged battery), the battery should be replaced. The advantage of this
method is that it can be implemented online without interfering with the battery system.
The main disadvantage of the impedance method is that the parameters are dependent on
the state of charge (SOC) and temperature and not proportional to the available capacity
of the battery. This test is indicative only. There is no direct on board device that can
estimate the health of the battery. -- ••■■ - *- -- ■ -— -
[0005] Cold cranking amperes method of measuring state of health involves a
measurement of the number of amperes that.a battery can produce at 32 degrees F ((FC) for 30 seconds and it shall not drop below 7.2 volts. This is a measurement usually reserved for SLI (automotive) type batteries. This value is related to the actual power available in the battery. This is directly related to conductance of the battery. A device in which a method is used to determine physical parameters of the battery like specific gravity (SG), cold cranking amperes (CCA) that corresponds to conductance of the battery and internal resistance (IR) of the battery are used to estimate the health of the battery.
SUMMARY OF THE INVENTION
[0006] The present invention is aimed to provide a device that estimates state of
health of the battery and lists out probable failure modes contributing to particular health.

This device uses a method which determines physical parameters of the battery like
specific gravity (flooded lead acid battery), cold cranking amperes (flooded and VRLA)
that corresponds to conductance of the battery and internal resistance (flooded and
VRLA) of the battery to estimate the health of the battery. Thus, SOH is estimated. A
display of vehicle battery status can help the rider to act appropriately at an early stage so
that the rider is not left stranded with his vehicle due to any possible battery faults. The
current invention uses the three methods of determining state of health of. a battery
namely the specific gravity method, internal resistance method and cold cranking
amperes method onboard a vehicle and provides a display on the instrument cluster
- dashboard-for~th©*userr,- ----- .-..» - •- ■ — -v ^^-. -
[0007] The specific gravity method estimates the electrolyte concentration. As the
value of specific gravity decreases, the state of health of battery deteriorates. After some cycles there is loss of water and topping of distilled water is needed which dilutes the electrolyte. Also in a long run the problem of stratification occurs which leads to capacity loss hence declining the health of the battery. Due to overcharging there is loss of electrolyte leaving the separator and other active material dry, which leads to loss of active surface for the chemical reaction. Thus, electrolyte concentration in terms of specific gravity is considered as an important measure for state of health of battery.
[0008] Cold cranking amperes: A measurement of the number of amperes that a
battery can produce at 32 degrees F (0 degrees C) for 30 seconds and not drop below 7.2 volts. This is a measurement usually reserved for SLI (automotive) type batteries. This

value is related to the actual power available in the battery. This is directly related to conductance of the battery.
[0009] Internal Resistance: It is based on the principle of ohms law. A brief load is
applied to the battery and the changes in voltage and current is measured to determine the internal resistance of the battery. The internal resistance will increase with age due to the chemical degradation of the active material. The internal resistance increases as the health of the battery decreases.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 illustrates a typical two-wheeler.
Figure 2 illustrates a typical three-wheeler.
. Figure 3 illustrates a typical instrument cluster display dashboard of a two-wheeler or the three-wheeler.
Figure 4 illustrates the block diagram for voltage measurement and display for the proposed two-wheeler.
Figure 5 illustrates the block diagram & graph for internal resistance calculation for the proposed two-wheeler.
Figure 6 illustrates the flowchart for method of display of state of health of battery for the proposed two-wheeler.
DETAILED DESCRIPTION OF THE INVENTION
[000.10] The SOH display for the proposed two wheeler can be easily obtained
once the possible faults with the vehicle battery are listed down. The common faults

associated with vehicle batteries are Grid corrosion, Inter cell weld damage, Ageing, Inter cell short due to dendrite growth, Terminals corroded due to improper maintenance, Acid stratification, Very hard Sulphation, Reverse polarity, Active material shedding, Improper plate design, Hard Sulphation, Improper handling, Low Sulphation, Self-discharge, Electrolyte loss. Grid corrosion occurs primarily on the grid an'd this reaction cannot be avoided because the electrodes in a lead acid environment are always reactive.
[00011] Inter cell weld damage implies one of the cell connections is probably
cracked or came unsoldered. Aging refers to the gradual loss of a battery's rated electrical performance. After a battery is produced, it undergoes a number of irreversible chemical . reactions that cause its internal resistance to increase and its rated capacity to decrease. Inter cell short due to dendrite growth happens when the specific gravity of the acid gets too low, the lead will dissolve into it. Since the liquid (and the dissolved lead) are immobilized by the glass matte, when the battery is recharged, the lead comes out of solution forming threads of thin lead metal, known as dendrites inside the matte. In some cases, the lead dendrites short through the matte to the other plate. Terminals corroded due to improper maintenance means terminals or ports of lead acid batteries corrode due * to which connection between batteries and appliance cuts off completely or weakens. Also corrosion happens when electrolyte makes its way out to battery terminals through any leaks or joints.
[00012] Acid stratification is caused by the fact that the electrolyte in the battery is
a mixture of water and acid and, like all mixtures, one component, the acid, is heavier than water. Therefore, acid will begin to settle and concentrate at the bottom of the

battery. This higher concentration of acid at the bottom of the battery causes additional build-up of lead sulfate (Sulphation), which reduces battery storage capacity and battery life.
[00013] Very hard Sulphation occurs when lead sulfate covers surface of electrode
* • •
plates limiting the area for electro-chemical reaction. An equalizing charge removes sulphation that may have formed during low-charge conditions. This very hard sulphate fails to converts back to active material thus loosing capacity of the battery and attributing to failure of the battery. Reverse polarity is an associated fault when battery polarity can only reverse if the battery is completely dead and then charged with the negative and positive leads of the charger are reversed. This fault related to batteries is very dangerous as hydrogen gas that is given off by a dead battery may catch fire and cause personal injury. Active material shedding is a fault in which shedding of the active material from the positive plates is one of the causes of premature failure in service of lead-acid cells. The essence of this trouble is that tiny crystals and grains of lead dioxide smaller than 0.1 micron (one tenth of one thousandth of a millimeter) become dislodged from the plates. The shedding mainly takes place at the end of a charge and the beginning of a discharge.
[00014] Improper plate designs also cause fault in the batteries if the current
carried by. the various parts of the plate is not uniform because of faulty design, or careless application of the paste. This is a fault inherited during the manufacturing and not during the operating conditions. Hard Sulphation is a battery fault condition in which lead sulfate covers surface of electrode plates limiting the area.for electro-chemical

reaction. Hard lead sulfate that only decomposes during an equalization charge (controlled over-charge done in industrial battery maintenance). Improper handling: Due . to the potential energy stored in the batteries, improper handling or use of the batteries without following standard operating procedures corresponding to safe use of battery may result in bodily injury caused by electrolyte leakage, heat generation or explosion.
[00015] Low Sulphation occurs when lead sulfate covers surface of electrode
plates limiting the area for electro-chemical reaction soft lead sulfate that decomposes with a regular charge. Self-discharge is discharging of a cell which takes place while it remains open-circuited.
[00016] Electrolyte loss is a condition of battery fault in which the recharging
. process as electricity flows through the water portion of the electrolyte and water, (H20) is converted into its original elements, hydrogen and oxygen. These gasses are very flammable and that is the reason why batteries must be vented outside. This gassing causes water loss and therefore lead acid batteries need to have water added periodically. Sealed lead acid batteries contain most of these gasses allowing them to recombine into the electrolyte. If the battery is overcharged pressure from these gasses will cause relief caps to open and vent, resulting in some water loss.
[00017] Figure 1 shows a typical two-wheeled vehicle 1 with a rear wheel 2,
engine 3, air filter 4, front wheel 5, floorboard 6, utility box 7, side panel 9, front shock absorber 10, rear shock absorber 11, grab rail 12, tail lamp 13 and rider seat 14. The direction of arrow "F" shows the front direction of the vehicle and direction of arrow "R" shows the rear direction of the vehicle. The engine 3 as disclosed in Figure 1 can be

started either by the electrical starter mechanism or by the help of the kick starting mechanism.
[00018] Figure 2 shows a three-wheeler 25 with a driver's seat 23, instrument
cluster or dashboard 20', front wheel 21, rear wheel 22, chassis 24, pillion passenger seat 28 and cabin rear space 27. The condition of battery in this three wheeler is proposed to be displayed on instrument display 20'.
[00019] Figure 3 shows the location of display for the state of health of vehicle
battery on the two-wheeled vehicle 1. Figure 2 shows an instrument cluster dashboard display 20 & 20', odometer 31, display region 32, display regions left 33L, display regions right 33R. Based upon the requirement any of the display regions alone or in any combination with the other display regions can be utilized for displaying the state of health of the vehicle battery.
[00020] As shown in Figure 4, initially a voltmeter is connected to a battery 4 to
obtain OCV (Open Circuit Voltage) of the battery for calculating SOH and is displayed in the display 6. Then micro controller selects the load current I_load required to pass . through the battery to obtain AV2 through voltage measurement and micro controller for calculating internal resistance of the battery. This internal resistance is used to calculate CCA value using the formula given in flowchart. In addition, the OCV value is used to calculate the (specific gravity) SG and hence formula mentioned is used to calculate SG. Finally the micro controller uses the calculated values of SG, CCA and IR to calculate SOH. Then the signal is processed in microcontroller to display SOH of the battery and possible failure modes of the battery.

[00021] Figure 5 shows block diagram and a typical graph related to calculation of
internal resistance of a typical battery. The method used for internal resistance calculation uses two-pulse load test. This test is performed in order to get internal resistance value
that is used in expression to calculate SOH. There are three modes in two-pulse load test.
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In mode 1 the battery is placed at rest at least for two minutes. Then in mode 2 and mode
3, two current pulses are given to the battery with interval of ten seconds and the change
in voltage is captured from the second pulse (AV2). Each pulse will be applied for a time
span of ten seconds.
[00022] Figure 6 shows the method for display of state of health of battery (SOH)
for various possible battery faults which are listed previously in the description. The calculations for SOH Battery are done as shown in the flowchart, a, b, c and d are constants that pertain to particular type of battery used for analysis.
[00023] These constants are obtained by curve fitting tool for the experimental data obtained for various parameters like SOH, CCA, IR and SG. The constants a and P are obtained by applying curve fitting mechanism between CCA and IR that are obtained from experiments. Similarly, the constants m and n are obtained by linear regression of experimental data of OCV and SG. According to the expression, the microcontroller using the formula calculates the SOH and the failure modes corresponding to the SOH are

selected by the microcontroller and displayed in the text form. The SOH and failure. modes display is placed on the speedometer for the convenient usage of the customer.
[00024] The system and method of vehicle battery health, status as being
determined and displayed in the current invention is applicable for any automobile. The display being in form of texts, numerals, audio announcement or symbolic representation.

We claim:
1. A method for monitoring the condition of a battery (40) for an automobile, the
method comprising:
measuring internal resistance (51) of the said battery (40);
. measuring cold cranking ampere (CGA) of the said battery (40);
measuring specific gravity (SG) of the said battery (40);
wherein the real time values of said internal resistance; cold cranking ampere and specific gravity of the said battery are mapped to correspond to at least one quantified value corresponding to at least one health condition of the said battery (40), and the corresponding health condition - •- ~ • • obtained-from quantified value being displayed on the display regions* (32, — —«-*—: 33L, 33R) of an instrument cluster dashboard display (20, 20').
2. A system for monitoring the condition of a battery (40) for an automobile, the
system comprising:
a means for measuring internal resistance (51) of the said battery (40);
a means for measuring cold cranking ampere of the said battery (40);
a means for measuring specific gravity of the said battery (40);
a means for mapping and quantifying plurality of health conditions of the said battery (40) by using real time parametric values of internal resistance (51), cold cranking ampere (CCA) and specific gravity (SG) of the said battery (40); and a means for displaying the health condition of the said battery on display regions (32, 33L, 33R) of an instrument cluster dashboard display means (20, 20').
3. The method of claim 1 and system of Claim 2 wherein real time measurement and
display of the battery (40) health condition is performed.

4. The method of claim 1 and system of Claim 2 wherein the display of the health condition of the battery is provided on the instrument cluster or the dashboard display (20, 20').
5. The method of claim 1 and system of Claim 2 wherein the condition of the battery (40) is quantified in real time to provide real time display for the health condition of the said battery (40).