Field

The present invention relates generally to apparatus for jump-starting a vehicle having a depleted or faulty (open circuit) starter battery.

Background

The following discussion of the background to the invention is intended to facilitate an understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge in Australia or any other country as at the priority date of any one of the claims of this specification.

The automobile industry is replete with devices used for jump starting a vehicle when the battery of the vehicle has insufficient charge to accomplish this task. The simplest means by which to jump start a vehicle with a dead battery is to connect a pair of jump starter cables or jump leads between a fully charged battery of another vehicle to the engine circuit of the vehicle with the dead battery. However, this solution is only possible in situations where other vehicles are in the vicinity.

To address this problem, portable booster devices comprising an internal battery were devised. These portable booster devices can be connected to the vehicle's engine starter via a pair of jump leads and battery terminal clamps to jump start the vehicle.

Problems such existing portable booster devices arise when either the jumper terminals or clamps of the cables are inadvertently brought into contact with each other while the other ends were connected to a charged battery, and when the positive and negative terminals are connected to the opposite polarity terminals in the vehicle to be jumped, thereby causing a short circuit resulting in sparking and potential damage to batteries and/or bodily injury.

Moreover, in existing portable booster devices it is possible for the battery to be charged to a gassing state by faulty vehicle alternator.

It would therefore be desirable to provide an apparatus for jump starting a vehicle having a battery, which will overcome or substantially ameliorate at least some of the deficiencies of the prior art, or to at least provide an alternative.

Summary

A first aspect of the present invention provides an apparatus for jump starting a vehicle having a battery, the battery having positive and negative battery terminals, including: a rechargeable internal power supply; battery clamps respectively having positive and negative polarities; one or more contactors connected between the internal power supply and the battery clamps; a vehicle battery sensor connected to the battery clamps, and configured to detect both the presence and polarity of a vehicle battery connected to the battery clamps; and a microcontroller configured to receive an output signal from the vehicle battery sensor, and to provide an output signal to selectively close the one or more contactors, wherein the vehicle battery sensor is configured to: a) sense a voltage range between the battery clamps including voltages indicative of, an absence of the vehicle battery connected to the battery clamps; and the polarity of the vehicle battery connected to the battery clamps; and b) convert the sensed voltage range into a corresponding voltage range able to be read by the microcontroller.

The vehicle battery sensor may be further configured, at step (a), to sense a short circuit between the battery clamps.

The vehicle battery sensor may be configured to sense a short circuit between the battery clamps by: sensing a voltage range between the battery clamps including voltages indicative of a potential short circuit; applying a voltage pulse to the battery clamps; and if the sensed voltage between the clamps is close to zero, activating a short circuit protection circuit to protect against short circuiting.

The vehicle battery sensor may be configured to separately sense voltages indicative of a positive polarity and a negative polarity connection of the vehicle battery connected to the battery clamps.

In one or more embodiments, the microcontroller is further configured to selectively close the one or more contactors to connect the internal power supply to the battery clamps in response to a signal from the vehicle battery sensor indicating to the microcontroller that a vehicle battery is connected to the battery clamps with a proper polarity.

The microcontroller may be further configured to selectively close the one or more contactors automatically.

The vehicle battery sensor may act to convert a first range of clamp voltages including both positive and negative voltages to a second range of voltages able to be read by the microcontroller. In one or more embodiments, the conversion is linear.

In practice, the first range of voltages may be from +40V to -30V, and the second range of voltages is from 0V to +3.0V.

A second aspect of the present invention provides a method for sensing an operative state of an apparatus for jump starting a vehicle having a battery, the battery having positive and negative battery terminals, including a rechargeable internal power supply; battery clamps respectively having positive and negative polarities; one or more contactors connected between the internal power supply and the battery clamps; a vehicle battery sensor connected to the battery clamps, and configured to detect both the presence and polarity of a vehicle battery connected to the battery clamps; and a microcontroller configured to receive an output signal from the vehicle battery sensor, and to provide an output signal to selectively close the one or more contactors, the method including the steps of: at the vehicle battery sensor, a) sensing a voltage range between the battery clamps including voltages indicative of: an absence of the vehicle battery connected to the battery clamps; and the polarity of the vehicle battery connected to the battery clamps; and b) converting the sensed voltage range into a corresponding voltage range able to be read by the microcontroller.

The method may further include, at the vehicle battery sensor, at step (a), sensing a short circuit between the battery clamps.

The method may further include, at the vehicle battery sensor, separately sensing voltages indicative of a positive polarity and a negative polarity connection of the vehicle battery connected to the battery clamps.

A third aspect of the present invention provides a method of operating of an apparatus for jump starting a vehicle having a battery, the battery having positive and negative battery terminals, including a rechargeable internal power supply; battery clamps respectively having positive and negative polarities; one or more contactors connected between the internal power supply and the battery clamps; a vehicle battery sensor connected to the battery clamps, and configured to detect both the presence and polarity of a vehicle battery connected to the battery clamps; and a microcontroller configured to receive an output signal from the vehicle battery sensor, and to provide an output signal to selectively close the one or more contactors, the method including the steps of: at the vehicle battery sensor: sensing a voltage range between the battery clamps including voltages indicative of; an absence of the vehicle battery connected to the battery clamps; and the polarity of the vehicle battery connected to the battery clamps; and converting the sensed voltage range into a corresponding voltage range, sensing a short circuit between the battery clamps by, sensing a voltage range between the battery clamps including voltages indicative of a potential short circuit, applying a voltage pulse to the battery clamps, and if the sensed voltage between the clamps is close to zero, activating a short circuit protection circuit to protect against short circuiting.

The method may further include: at the microcontroller, selectively closing the one or more contactors to connect the internal power supply to the battery clamps in response to a signal from the vehicle battery sensor indicating to the microcontroller that a vehicle battery is connected to the battery clamps with a proper polarity.

The method may further include: at the microcontroller, selectively closing the one or more contactors automatically.

Brief Description of the Drawings

The invention will now be described in further detail by reference to the accompanying drawings. It is to be understood that the particularity of the drawings does not supersede the generality of the preceding description of the invention.

Figure 1 is a perspective view of one embodiment of an apparatus for jump-starting a vehicle according to the invention;

Figure 2 is a functional block diagram of electronic and electrical components forming part of the apparatus for jump-starting a vehicle shown in Figure 1 ;

Figure 3 is a circuit diagram of a first embodiment of vehicle battery sensor forming part of the electronic and electrical components shown in Figure 2, the vehicle battery sensor being configured to detect both the presence/absence of a vehicle battery and positive or negative polarity connection between the battery terminal clamps and positive and negative battery terminals of the vehicle battery;

Figures 4 is a state diagram chart showing operation of the electronic and electrical components shown in Figure 2 to detect active the battery jump- starting apparatus and detect the application of clamps to the battery terminals;

Figure 5 is a flow chart depicting operations taken by the vehicle battery sensor of Figure 3 and a Master Control Unit forming part of the electronic and electrical components shown in Figure 2 to detect both the presence/absence of a vehicle battery and positive or negative polarity connection between the battery terminal clamps and positive and negative battery terminals of the vehicle battery;

Figure 6 is a state diagram chart showing operation of the electronic and electrical components shown in Figure 2, when including the first embodiment of vehicle battery sensor shown in Figure 3, to automatically engage the battery jump-starting apparatus, and under what conditions automatic engagement occurs;

Figure 7 shows a circuit diagram of a second embodiment of vehicle battery sensor forming part of the electronic and electrical components shown in Figure 2;

Figure 8 is a state diagram chart showing operation of the electronic and electrical components shown in Figure 2, when including the second embodiment of vehicle battery sensor shown in Figure 7, according to a first mode of operation; and

Figure 9 is a state diagram chart showing operation of the electronic and electrical components shown in Figure 2, when including the second embodiment of vehicle battery sensor shown in Figure 7, according to a second mode of operation.

Detailed Description

The present invention is predicated on the finding of an apparatus for use in jump starting a vehicle, in which the apparatus comprises a rechargeable power supply consisting of a plurality of rechargeable lithium-based cells. Each of the cells can accept a high charge current, which means that the rechargeable power supply can be fully recharged by an alternator of the vehicle in a matter of mere minutes.

Referring firstly to Figure 1 , there is shown generally a perspective view of a portable apparatus 10 for use in jump starting a vehicle (not shown) according to a preferred embodiment of the present invention.

The apparatus 10 includes a housing 12, a handle 14, positive and negative jumper leads 16 and 18, battery terminal clamps 20 and 22, electrically connected respectively to the ends of jumper leads 16 and 18. The housing 12 includes a display panel 24 and user-operable buttons 26 to 34 to facilitate user control of the apparatus 10.

It should be appreciated that Figure 1 merely depicts one possible embodiment of an apparatus for jump-starting a vehicle according to the invention, and that many variations are possible.

For example, the display panel 24 could be replaced or supplemented with audible user alerts, and the user-operable buttons 26 to 34 could be replaced by a single multi-function button, dial or other user operable device. Alternatively, the apparatus could be controlled by a mobile phone app connected via Bluetooth or similar connection, and all control and alert/display functions could take place on the mobile phone.

Similarly, whilst the positive and negative jumper leads 16 and 18 are shown as being fixed in Figure 1 , they could easily be removable leads in other embodiments.

Figure 2 is a functional block diagram of electronic and electrical components forming part of the apparatus 10. The apparatus 10 includes a rechargeable power supplies 50 and 52 having positive and negative terminals, cell voltage sensing and balancing circuits 54 and 56, a DC-DC regulator 58, a charging circuit 60, short circuit detection circuit 62, contactors S1 to S4, battery terminal clamps 64 and 66, a master control unit (MCU) 68, keypad and backlight 70 - including buttons 26 to 34 - and the display 24, as well as a vehicle battery sensor 72. The battery terminal clamps 64 and 66 can be connected to positive and negative terminals of a vehicle starter battery 74, which is connected in parallel with an alternator 76. The MCU 68 receives various inputs and produces data as well as control outputs, as depicted in Figure 2 and described herein. The MCU 68 is programmable, and in one embodiment comprises a 32-bit microcontroller with 128K x 8 bits of flash memory. Microcontrollers are well known, and other configurations will be able to be envisaged.

The rechargeable power supplies 50 and 52 comprises one or more lithium-based rechargeable cells connected in series. The size of cells is largely determined by cranking current required to jump start a vehicle.

In the preferred form, rechargeable power supplies 50 and 52 comprises four lithium-iron phosphate (LiFePC ) cells connected in series.

LiCo02 cells can provide higher current than LiFePCM for the same size of battery, however LiFePCM is safer. If 4 cells are connected in series it matches the 12V vehicle alternator voltage. As a result, it can be recharged by alternator.

LiFePCM cells also offer longer lifetimes and have a constant discharge voltage that stays close to the nominal output voltage (3.2V) associated with the cell during discharge until the cell is exhausted. This allows lithium-iron phosphate cells to deliver virtually full power until they are discharged.

A variety of lithium-iron phosphate cell are commercially available including but not limited to LiFePCM, LiFeMgPCM and LiFeYPCM based cells.

The rechargeable power supplies 50 and 52 are respectively connected to cell voltage sensing and balancing circuits 54 and 56. The cell voltage sensing and balancing circuits sense and balance the cell voltages across the lithium-based rechargeable cells (not shown) forming each rechargeable power supply.

Once the cell voltage for each of the rechargeable cells has been determined, the difference in cell voltage between rechargeable cells is then compared to identify the cell with the minimum voltage (Vmin) and the cell with the maximum voltage (Vmax) The (Vmin) and (Vmax) values are then used to balance the overall cell voltage across the four cells. By virtue of this arrangement, it is possible to selectively discharge a cell if the cell voltage of that cell is greater or less than a predetermined voltage threshold.

A more detailed disclosure the voltage sensing and balancing circuits is provided in International Patent Application No. WO 2018/064713, in the name of the present Applicant, the entire contents of which is hereby incorporated into the present Application.

The contactors S1 to S4 configured to selectively connect either of the rechargeable power supplies 50 and 52, or both rechargeable power supplies 50 and 52 in series, to the battery terminal clamps 64 and 66. In the example depicted in Figure 2, contactors S1 , S2 and S4 are closed by the MCU 68 when +12V are intended to be supplied to the vehicle starter battery 74 / alternator 76, whereas contactors S2 and S3 are closed by the MCU 68 when +24V is intended to be supplied to the vehicle starter battery 74 / alternator 76.

When the MCU 68 detects that the charging voltage is present between the battery terminal clamps 64 and 66, it causes contactor S5 to connect rechargeable power supplies 50 and 52 in parallel. After that, it turns on an internal MOSFET to allow the input current to charge the rechargeable power supplies 50 and 52. The MCU 68 monitors the cell voltage and terminal voltage of rechargeable power supplies 50 and 52. The charging process is terminated, in this exemplary embodiment, if the cell voltage reaches 3.6V and terminal voltage reaches 14.4V.

To check whether or not the battery terminal clamps 64 and 66 are short circuited, the MCU 68 activates a low current voltage source and applies the voltage source or voltage pulse across the clamps. Then, the MCU 68 monitors the clamp voltage. If the clamp voltage is measured being close to zero, the MCU 68 activates the short circuit protection circuit 62 to protect against short circuiting. The diode D2 allows the MCU 68 to be woken up by clamp voltage. The diode D1 allows the MCU 68 to turn on the DC-DC regulator 58 once it “wakes up”.

Figure 3 shows several electronic elements forming a first embodiment of the vehicle battery sensor 72. The vehicle battery sensor 72 includes a differential amplifier 90 including two inputs 92 and 94, an output 96 and reference voltage input 98. The vehicle battery sensor 72 further includes potential dividers 100 and 102 respectively connected between the battery terminal clamps 64 and 66 and the inputs 92 and 94, a voltage reference circuit 104 connected to the reference voltage input 98, and a voltage smoothing circuit 106 connected between the output 96 and an input of the MCU 68 to reduce the output 96 to an acceptable range able to be read by the MCU 68. The potential dividers 100 and 102 act to scale down clamp voltages at the battery terminal clamps 64 and 66, in this example, by a factor of 10. The voltage reference circuit 104 acts to apply an offset voltage, in this example of +3V, to the voltage at the output 96 of the differential amplifier 90.

The vehicle battery sensor 72 acts to linearly convert a range of clamp voltages including both positive and negative voltages, in the case from +40V to -30V, to a range of voltages able to be read by the microcontroller 68. In this example, the range of voltages is of a single polarity, and is a range of positive voltages from 0V to +3.0V. By reading and analysing the output of the voltage smoothing circuit 106, the MCU 68 is able to obtain the clamping voltage and its polarity.

The MCU 68 uses the clamp voltage to determine whether:

1. An operator needs to be alerted to confirm the voltage selection,

2. A 12V electrical system is connected,

3. A 24V electrical system is connected, or

4. The clamps are reversely connected.

When a 12V or 24V electrical system is detected, the MCU 68 activates the corresponding contactors S1 to S4 automatically to provide 12V or 24V jumpstart voltage.

Accordingly, the vehicle battery sensor 72 acts to sense a voltage range between the battery clamps including voltages indicative of an absence (e.g. 0V) of a vehicle battery between the battery clamps, a positive polarity connection of the vehicle battery (e.g. +12V) between the battery clamps and the positive and negative battery terminals and a negative polarity connection of the vehicle battery (e.g. -12V) between the battery clamps and the positive and negative battery terminals, and then convert the sensed voltage range into corresponding voltage range (e.g. +4.2V, +3V and +1.8V) at the output 96. In practice, the voltage at the output 96 can vary from 0 to 7V. The voltage smoothing circuit 106, which includes a potential divider and filter capacitor, is connected between the output 96 and an input of the MCU 68 to scale the voltage at the output 96 down to a range (0V to +3.0V) able to be read by the MCU 68.

The relationship between clamp voltages and vehicle battery sensor output voltages to the MCU 68 for these three conditions, in relation to the embodiment of the vehicle battery sensor 72 shown in Figure 3, is set out in Table 1 below.

Table 1

In such an arrangement, short circuit resulting in sparking and potential damage to batteries and/or bodily injury resulting from the positive and negative terminals being connected to the opposite polarity terminals in the vehicle to be jumped are avoided.

Advantageously, in such an arrangement a power switch can be either manually or automatically turned on to connect the internal power supply to the battery clamps in response to a signal from the vehicle battery sensor indicating to the microcontroller that a vehicle battery is connected to the battery clamps with a proper polarity.

Figure 4 depicts a series of possible states of the apparatus 10 during jumper starter wake-up and clamp detection, and conditions which will cause the MCU 68 to change the state of the apparatus 10.

In inactive state 120, the apparatus 10 is off and will remain so if the detected clamp voltage remains between -3V and +3V. The MCU 68 causes the apparatus 10 to manually wake up, or enter an activated state 122, upon activation of one or more of the user operable buttons 26 to 34. Once a user has then connected battery terminal clamps 64 and 66 to the starter battery 74, the apparatus 10 then enters an operable state 124.

The operable state 124 can also be entered automatically from the inactive state 120 if clamp engagement is detected by the MCU 68, which in this case occurs if a clamp voltage greater than +3V and less than -3V is detected by the MCU 68. Figure 5 shows a series of operations performed by the MCU 68 and the vehicle battery sensor 72 to determine if a vehicle battery is connected to the battery clamps with a proper polarity. At step 130, the vehicle battery sensor 72 senses a range of clamp voltages including both positive and negative voltages, and notably including voltages between the battery clamps indicative of an absence of connection, positive polarity connection and negative polarity connection between the battery clamps and the positive and negative battery terminals.

At step 132, the vehicle battery sensor 72 converts the sensed range of voltages into a range of voltages able to be read by the microcontroller 68.

At step 134, the MCU 68 determines at step 136 if the voltage level at the output of the vehicle battery sensor 72 indicates that the battery 74 is connected, but with reverse polarity. At step 138, the MCU 68 determines at step 140 if the voltage level at the output of the vehicle battery sensor 72 indicates that no battery is connected to the apparatus 10. At step 142, the MCU 68 determines at step 144 if the voltage level at the output of the vehicle battery sensor 72 indicates that the battery 74 is connected, and with correct polarity.

Figure 6 depicts a series of possible states of the apparatus 10 during automatic engagement, and conditions which will cause the MCU 68 to change the state of the apparatus 10. From an idle state 150, the apparatus 10 enters an operable state 152 (corresponding to operable state 124) when the MCU 68 detects a clamp voltage greater than +3V or less than -3V.

In this operable state 152, the MCU 68 disengages the contactors and detects if there is any failure of contactors which leads to permanent connection between rechargeable power supplies (50 and 52) and battery terminal clamps (64 and 66). If failure is detected, the apparatus 10 enters an error state 154.

The MCU 68 also checks the temperature of rechargeable power supplies (50 and 52), ambient temperature and contactors’ temperatures. The apparatus 10 enters the error state 154 if the temperatures are outside the pre defined operational range.

The MCU 68 also checks the voltage of rechargeable power supplies (50 and 52). The apparatus 10 enters the error state 154 if the voltage is below 12.95V. The MCU 68 further monitors the clamp voltage via the vehicle battery sensor 72.

The apparatus 10 enters the error state 154 if reverse polarity is detected (e.g. the output of vehicle battery sensor 72 is below 1 28V or calibrated value).

The apparatus 10 enters an 12V Contactors Activated state 156 if the clamp voltage is detected by the MCU 68 between 1 and 14.6V. The apparatus 10 alternatively enters 24V Contactors Activated state 158 if the clamp voltage is detected by the MCU 68 between 19 and 30V.

The error state 154 is entered, and an operator alert is correspondingly generated on the display 24 or by other audible or visible means, if the error conditions of low battery voltage level, excessive clamp voltage, internal battery and ambient temperatures, internal battery permanently short-circuited to battery terminal clamps 64 and 66, clamp reverse connection, contactor overtemperature, or short circuit of battery terminal clamps 64 and 66, are detected by the MCU 68.

Over voltage protection is provided by the MCU 68 together with the cell balancing circuits 54 and 56. The MCU 68 monitors the cell and battery pack voltage through the cell balancing circuits 54 and 56. If the battery pack voltage is detected to be greater than 15.6V, a warning signal or other operator alert is displayed on the screen 24.

If the MCU 68 detects a clamp voltage of between 1V and 14.6V, then a state 156 is entered in which selective operation of contactors S1 to S4 is made to connect one or both of the rechargeable power supplies 50 and 52 in parallel, to provide 12V charging of the battery 74. However, if the MCU 68 detects a clamp voltage of between 19V and 30V, then a state 158 is entered in which selective operation of contactors S1 to S4 is made to connect both of the rechargeable power supplies 50 and 52 in series, to provide 24V charging of the battery 74.

Figure 7 shows several electronic elements forming a second embodiment of the vehicle battery sensor, referenced 200 in this figure. The vehicle battery sensor 200 includes a differential amplifier 202 which is identical to the differential amplifier 90 in Figure 3. The differential amplifier 202 includes two inputs 204 and 206, an output 208 and reference voltage terminal 210. Input circuitry 212 connecting the battery terminal clamps 214 and 216 to the vehicle battery sensor 200 is functionally identical to the potential dividers 100 and 102 shown in Figure 3. However, in this embodiment, output circuitry 218 connected to the output 208 and reference voltage terminal 210 acts as a voltage clamp which limits the output voltage from output terminal 208 to a range able to be read by the MCU 68.

The voltage clamp is formed by offset voltage reference circuit 222, resistor 228 and diodes 230 and 232, and limits the signal from output 208 to 3.3V. The offset voltage reference circuit 222 acts to apply an offset voltage, in this example of +2.5 V, to the voltage at the output 208 of the differential amplifier 202.

The vehicle battery sensor 200 covers clamp voltages from -5V to +30V, and is configured to provide a linear relationship between voltages at output 208 and input 204 from -5 to +2V. The vehicle battery sensor 200 also provides a linear relationship from +1 V and +30V between the clamp voltage and an OUT+ terminal between series connected resistors 234 and 236 interconnecting the clamp terminals 214 and 216.

The relationship between clamp voltages and vehicle battery sensor output voltages to the MCU 68 for these three conditions, in relation to the embodiment of the vehicle battery sensor 200 shown in Figure 7, is set out in Table 2 below.

Table 2 The vehicle battery sensor 72 shown in Figure 3 covers full range of clamp voltages (-40V to 30V), and the voltage at output 106 and the clamp voltage maintains a linear relationship in this range. However, in order to use an MCU which has high resolution Analog to Digital Converter (ADC) whilst minimising production costs, in the vehicle battery sensor 200 shown in Figure 7 the voltage at the output 208 of the linear amplifier 202 maintains a linear relationship with the clamp voltage only at reduced range from -5 to 2V. The clamp voltage outside this range is measured at OUT+.

Advantages provided by such an arrangement include reduction of ADC required resolution, better visibility at low clamp voltages and providing detection of short circuits before connecting the internal battery to the clamp.

The vehicle battery sensor 200 notably enables the microcontroller 68 to provide primary short-circuit, reverse polarity and clamp connection detection. In this embodiment, the output voltage of the vehicle battery sensor 200 has about 0.1V difference between short-circuit, open clamp connection and reverse polarity conditions, as follows:

• When the battery terminal clamps 64 and 66 are open, due to the leakage current from the vehicle battery sensor 202 resistors 220 and 224 forming part of the input circuitry 212 create a net input voltage and the voltage at output of the vehicle battery sensor 200 equals to around 2.6V (which may need to be calibrated).

• When the battery terminal clamps 64 and 66 are shorted, resistors 224 and 226 forming part of the input circuitry 212 are in parallel. The combined resistance of these two resistors 224 and 226 is selected to be close to that of resistor 220. As a result, the leakage current effect is effectively cancelled out and no net input voltage is created. The voltage at the output of vehicle battery sensor 200 becomes 2.5 V (need to be calibrated).

• When the battery terminal clamps 64 and 66 are reversely connected with 0.2 V source 222, the voltage at the output of the vehicle battery sensor 200 becomes around 2.4V.

During production, the output voltage of the vehicle battery sensor 200 is may be calibrated under short circuit and open clamp conditions. The calibrated voltages are stored in a memory of the MCU 68. When the portable apparatus 10 is turned on or battery terminal clamps 64 and 66 are connected to a starter battery 74 - as indicated by a voltage of more than +1.5V or less than -1.5V - the internal MCU 68 firstly wakes up and checks the voltage at the vehicle battery sensor 200 output according to the state diagram shown in Figure 8.

As can been seen in that state diagram, at a Welcome state 300, the MCU 68 checks the vehicle battery sensor 200 output voltage. Prior to wake up, that is where voltage of more than +1.5V or less than -1.5V is not detected between the battery terminal clamps 64 and 66, the MCU 38 remains in an idle state 301.

If the vehicle battery sensor 200 output voltage is greater or equal to 2.7V, the MCU 68 will check the voltage at the secondary clamp voltage sensing point at state 302. According to value of the secondary clamp voltage, the MCU 68 will go to a 12V relay activation state 304, a 24V relay activation state 306 or to a manual override state 308.

If the vehicle battery sensor 200 output voltage is between 0.15V and 2.4V, the MCU 68 will go to reverse connection warning state 310.

If the vehicle battery sensor 200 output voltage is greater than/equal to 2.4V and less than 2.7V, the MCU 68 will apply 12V pulse to the clamps at state 312. If the vehicle battery sensor 200 output voltage increases at least 50mV above the calibrated open circuit voltage, the MCU 68 will go to the manual override state 308. However, if the vehicle battery sensor 200 output voltage increases less than 50mV above open circuit voltage, the MCU 68 will return to Welcome state 300.

If the vehicle battery sensor 200 output is equal to the calibrated short- circuit voltage after 12V pulse is applied, the MCU 68 will go to a short-circuit warning state 314.

At the Welcome state 300, if 12V or 24V button is pressed, the MCU 68 will go to the manual override state 308.

Furthermore, the vehicle battery sensor 200 also provides reverse polarity detection. When the clamps are reversely connected with 0.2 V source, the voltage at the vehicle battery sensor 200 output becomes around 2.4V.

When the portable apparatus 10 is turned on or battery terminal clamps 64 and 66 are connected to a starter battery 74 (which has more than 1 5V), at a Welcome state 400, the internal MCU 68 firstly wakes up and checks the voltage at the vehicle battery sensor 200 output according to the state diagram shown in Figure 9. Prior to wake up, that is where voltage of more than +1 5V or less than -1 5V is not detected between the battery terminal clamps 64 and 66, the MCU 38 remains in an idle state 401.

If the vehicle battery sensor 200 output voltage is greater or equal to 2.7V, the MCU 68 will check the secondary clamp voltage sensing point at state 402. According to the value of the secondary clamp voltage, the MCU 68 will go to a 12V relay activation state, a 24V relay activation state 406 or to a manual override state 408.

If the vehicle battery sensor 200 output voltage is between 0.15V and 2.4V, the MCU 68 will go to a reverse connection warning state 410.

If the vehicle battery sensor 200 output voltage is outside the above voltage ranges, the MCU 68 will stay in Welcome state 400 until a 12V or 24V button is pressed.

On a Welcome screen during the Welcome state 400, if a 12V button is pressed, the MCU 68 will go to a 12V override screen at the override state 408. If 12V button is pressed again in this state, the MCU 68 will go to the 12V relay activation state 404, connect the internal battery to the battery terminal clamps 64 and 66 and monitor the clamp output voltage. If the clamp output voltage is less than 4.5V, the MCU 68 will go to a short-circuit warning state 412.

On Welcome screen during the Welcome state 400, if a 24V button is pressed, the MCU 68 will go to a 24V override screen at the override state 408. If 24V button is pressed again, the MCU 68 will go to 24V relay activation state 406, connect the internal battery to the battery terminal clamps 64 and 66 and monitor the clamp output voltage. If the clamp output voltage is less than 8V, the MCU 68 will go to the short-circuit warning state 412.

While the invention has been described in conjunction with a limited number of embodiments, it will be appreciated by those skilled in the art that many alternative, modifications and variations considering the foregoing description are possible. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variations as may fall within the spirit and scope of the invention as disclosed. Where the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components, or group thereof.