Vehicle battery system providing battery back-up and opportunity charging

In a power supply system for a motor vehicle including a first storage battery for supplying electrical power to a primary load of the vehicle, the improvement comprising:

• a second storage battery for supplying electrical power to a secondary load of the vehicle;
• first switching means for connecting said secondary load to said second storage battery;
• second switching means for connecting said second storage battery in parallel with said first storage battery;
• and control means including inhibit means for preventing said second switching means from connecting said second storage battery in parallel with said first storage battery when said secondary load is connected to said second storage battery, said control means including override means for overriding said inhibit means as a function of a parameter indicative of the state of charge of one of said storage batteries to enable said second switching means to connect said second storage battery in parallel with said first storage battery while said secondary load is connected to said second storage battery.

In a power supply system for a motor vehicle including a first storage battery for supplying electrical power to a primary load of the vehicle, the improvement comprising;

• a second storage battery for supplying electrical power to a secondary load of the vehicle;
• first switching means for connecting said secondary load to said second storage battery;
• second switching means for connecting said second storage battery in parallel with said first storage battery;
• and control means including inhibit means for preventing said second switching means from connecting said second storage battery in parallel with said first storage battery when said secondary load is connected to said second storage battery, said control means including first monitoring circuit means for monitoring the state of charge of said second storage battery, enabling means responsive to said first monitoring means for connecting said second storage battery in parallel with said first storage battery when the state of charge of said second storage battery is less than a preselected value, and second monitoring circuit means for monitoring the state of charge of said first storage battery, said inhibit means overriding said enabling means to prevent said second switching means from connecting said first storage battery in parallel with said second storage when the state of charge of said first storage battery is less than a preselected value.

In a power supply system for a motor vehicle including a main storage battery for supplying electrical power to a primary load of the vehicle, said primary load including at least the starter motor and the ignition circuit of the vehicle, the improvement comprising:

• an auxiliary storage battery for supplying electrical power to an electrically heated catalytic converter system of the vehicle;
• first switching means for connecting said catalytic converter system to said auxiliary storage battery;
• second switching means for connecting said auxiliary storage battery in parallel with said main battery;
• and control means including a load switch control circuit responsive to operation of an ignition switch of the vehicle to cause said first switching means to operate and connect said auxiliary storage battery to said catalytic converter system during starting of the engine of the vehicle, said control means including monitoring means for monitoring the state of charge of said main storage battery and for preventing operation of said load switch control circuit when the state of charge of said main storage battery is less than a given value, and back-up control circuit means responsive to said monitoring means for controlling said second switching means to connect said auxiliary storage battery to said primary load to enable said auxiliary storage battery to supply electrical power to said primary load of the vehicle, whereby said auxiliary storage battery serves as a back-up power source for said main storage battery.

In a power supply system for a motor vehicle including a main storage battery for supplying electrical power to a primary load of the vehicle, the improvement comprising:

• an auxiliary storage battery for supplying electrical power to a secondary load of the vehicle;
• first switching means for connecting said secondary load to said auxiliary storage battery;
• second switching means;
• and control means for controlling said second switching means to connect said auxiliary storage battery to said primary load to enable said auxiliary storage battery to supply electrical power to said primary load of the vehicle, whereby said auxiliary storage battery serves as a back-up power source for said main storage battery, and wherein said second switching means connects said auxiliary storage battery in parallel with said main storage battery whereby said main storage battery serves as a back-up power source for said auxiliary storage battery whenever the state of charge of said auxiliary battery decreases below a given level while said secondary load is connected to said auxiliary storage battery.

A power supply system for a motor vehicle for supplying electrical power to a primary load and a secondary load of the vehicle, comprising:

• a first storage battery for supplying electrical power to the primary load;
• a source of charging current connected to said first storage battery for supplying charging current to said first storage battery;
• a second storage battery;
• first switching means for connecting said secondary load to said second storage battery for supplying electrical power to the secondary load;
• second switching means for connecting said second storage battery to said source of charging current;
• and control means for controlling said first and second switching means to prevent the connection of said second storage battery to said source of charging current while said secondary load is connected to said second storage battery, said second switching means comprising at least one solid state switching device, drive circuit means for providing a drive signal for said switching device, and a relay having a pair of contacts connected in circuit with said solid state switching device, said relay being operated independently of said switching means.

A power supply system for a motor vehicle comprising:

• a main storage battery for supplying electrical power to a load,
• an auxiliary storage battery for supplying electrical power to said load,
• a source of charging current connected to said main storage battery for supplying charging current to said main storage battery,
• switching means enabled in response to a predetermined condition for connecting said auxiliary storage battery to said source of charging current to supply charging current to said auxiliary storage battery from said source of charging current, and
• control means for controlling said switching means to supply charging current to said auxiliary storage battery as a function of at least one parameter of said main storage battery, said control means including drive circuit means for producing a drive signal for said switching means for establishing the duty cycle for said switching means, and monitoring means for monitoring said one parameter of said main storage battery and controlling said drive circuit means to vary the duty cycle of said switching means, and said control means varying the duty cycle of said switching in predetermined increments during successive intervals of time with increase in the state of charge of said main battery, and wherein the change in the charging current being supplied to said auxiliary storage battery during each increment of time is correlated with a voltage transfer function:
• V=Vmax (0.9) (1x), where Vmax is the maximum charge condition for the main storage battery, and x is the duty cycle of the switching means.

A power supply system for a motor vehicle comprising:

• a main storage battery for supplying electrical power to a primary load, said primary load including at least the starter motor and the ignition circuit of the vehicle,
• an auxiliary storage battery for supplying electrical power to an electrically heated catalytic converter system,
• a source of charging current connected to said main storage battery for supplying charging current to said main storage battery,
• first switching means for connecting said auxiliary storage battery to said catalytic converter system,
• second switching means for connecting said auxiliary storage battery to said source of charging current whereby charging current is supplied to said auxiliary storage battery from said source of charging current, and
• control means for controlling said second switching means to vary the amount of charging current supplied to said auxiliary storage battery as a function of at least one parameter of said main storage battery, said control means including drive circuit means for producing a pulse modulated drive signal for said second switching means to establish the duty cycle for said second switching means, and timing means for controlling said drive circuit means for increasing the pulse width of said drive signal in successive intervals of time to thereby increase the amount of charging current supplied to said auxiliary storage battery during said successive intervals of time.