Battery cover assembly having integrated battery condition monitoring
View Patent ↗A terminal assembly for measuring electrical current passing to and from a battery post, including an electrically conductive collar for connecting to a post of a battery, and an electrically conductive terminal for receiving a connector of a load. An electrically conductive resistor having a known resistance extends between outer surfaces of the collar and the terminal. The terminal assembly is incorporated into a battery, which also includes a volt meter connected between the outer surfaces of the collar and the terminal for measuring the voltage drop across the resistor, memory for storing the known resistance of the resistor, and a processor programmed to receive the measured voltage drop from the volt meter, retrieve the known resistance from the memory, and calculate current flow through the resistor based on the measured voltage drop and the known resistance, whereby current flow to and from the battery can be measured.
1. A terminal assembly for measuring electrical current passing to and from a battery post, comprising:
an electrically conductive collar having an inner surface for contacting a battery post;
an electrically conductive terminal for receiving a load connector;
an electrically conductive resistor having a resistance from about 50 microOhm to about 200 microOhm extending between outer surfaces of the collar and the terminal, wherein current flow from the battery post travels through the resistor from the collar to the terminal and current flow to the post travels through the resistor from the terminal to the collar;
a first lead electrically connected to the outer surface of the collar, and a second lead electrically connected to the outer surface of the terminal;
a volt meter connected between the first and the second leads for measuring the voltage drop across the resistor; and
a computer, said computer including:
memory storing the resistance of the resistor; and
a processor programmed to,
receive the measured voltage drop from the volt meter,
retrieve the resistance from the memory, and
calculate current flow through the resistor based on the measured voltage drop and the resistance.
2. A terminal assembly according to claim 1 , further comprising:
a thermometer for measuring an actual temperature of the resistor;
the memory of the computer also stores a temperature coefficient of resistivity for the resistor; and
the processor of the computer is further programmed to,
receive the actual temperature from the thermometer,
retrieve the temperature coefficient of resistivity from the memory,
calculate an actual resistance of the resistor based on the resistance, the temperature coefficient of resistivity, and the actual temperature, and
calculate actual current flow through the resistor based on the measured voltage drop and the actual resistance.
3. A terminal assembly according to claim 1 , wherein the computer further comprises a clock and the processor is programmed to calculate a total charge based on the current flow and the charge time.
4. A terminal assembly according to claim 1 , wherein the resistor is made from a material including lead.
5. A terminal assembly according to claim 1 , wherein the resistor is made from a material including manganese.
6. A battery including the terminal assembly of claim 1 , and further including:
a case;
a storage cell contained within the case for receiving and storing an electrical charge; and
an electrically conductive post connected to the storage cell and extending out of the case;
wherein the inner surface of the collar of the terminal assembly is positioned on a portion of the post extending out of the case.
7. A battery according to claim 6 , wherein the storage cell includes lead and lead-oxide plates immersed in an acid electrolyte.
8. A battery post cover for receipt on a battery having at least one battery post extending therefrom, comprising:
a terminal assembly for measuring electrical current passing to and from a battery post, said terminal assembly comprising an electrically conductive collar having an inner surface for contacting a battery post, an electrically conductive terminal for receiving a load connector, and an electrically conductive resistor having a known resistance extending between outer surfaces of the collar and the terminal, wherein current flow from the battery post travels through the resistor from the collar to the terminal and current flow to the post travels through the resistor from the terminal to the collar;
a first surface having a post port;
a second surface having a terminal port, and wherein the cover defines a substantially closed chamber; and
a circuit board received in the closed chamber;
wherein the collar of the terminal assembly is positioned in the post port of the inner cover for receiving a battery post, the terminal extends through the terminal port of the outer cover, and leads extend from the outer surface of the collar and the outer surface of the terminal into the closed chamber of the covers and connect to the circuit board.
9. A battery post cover according to claim 8 , wherein the resistor and the leads of the terminal assembly are contained within the cover.
10. A battery post cover according to claim 8 , further comprising a volt meter mounted on the circuit board and connected between the first and the second leads of the terminal assembly for measuring the voltage drop across the resistor.
11. A battery post cover according to claim 10 , further comprising a computer mounted on the circuit board and including:
memory storing the known resistance of the resistor; and
a processor programmed to,
receive the measured voltage drop from the volt meter, retrieve the known resistance from the memory, and
calculate current flow through the resistor based on the measured voltage drop and the known resistance.
12. A battery post cover according to claim 11 , further comprising:
a thermometer mounted on the circuit board for measuring an actual temperature of the resistor;
the memory also stores a temperature coefficient of resistivity for the resistor; and
the processor is further programmed to,
receive the actual temperature from the thermometer,
retrieve the temperature coefficient of resistivity from the memory,
calculate an actual resistance of the resistor based on the known resistance, the temperature coefficient of resistivity, and the actual temperature, and
calculate actual current flow through the resistor based on the measured voltage drop and the actual resistance.
13. A battery post cover according to claim 11 , wherein the computer further comprises a clock and the processor is programmed to calculate a total charge based on the current flow and the charge time.
14. A battery including the battery post cover of claim 8 , and further including:
a case having an open top sealed by the first surface of the battery post cover;
a storage cell contained within the case for receiving and storing an electrical charge; and
an electrically conductive post connected to the storage cell and extending out of the case and through the post port of the cover, and wherein the inner surface of the collar of the terminal assembly is attached to the post.
15. A battery according to claim 14 , wherein the storage cell includes lead and lead-oxide plates immersed in an acid electrolyte.