Method for detecting low battery state without precise calibration
First Claim
Patent Images
1. A portable electronic system, comprising:
- at least one microprocessor;
at least one battery power connection, and a ground terminal;
a voltage-sensing interface, connected so that said microprocessor can detect the voltage drop across said battery connection; and
a current-sensing interface, connected so that said microprocessor can detect the current flow through said battery connection;
said microprocessor being configured to repeatedly compare the voltage and current at said battery connection, at an instant when the current through said connection is small, with the voltage and current at said battery connection at another substantially contemporaneous instant when the current through said connection is larger; and
to indicate imminent battery failure when the source impedance seen at said battery connection is accordingly detected to have risen in a pattern corresponding to the internal impedance of a battery which is imminently failing.
4 Assignments
0 Petitions
Accused Products
Abstract
A portable electronic system, which can accurately predict impending battery failure, without using expensive comparators, by using voltage and current measurements to determine the source impedance of a battery. Preferably two banks of batteries are used, with a load-switching relay; the voltage and current of both banks is monitored, so that voltage drop under load can be monitored. Alternatively, the voltage variation of a single battery bank can simply be correlated to the current drawn by a changing load.
-
Citations
17 Claims
-
1. A portable electronic system, comprising:
-
at least one microprocessor; at least one battery power connection, and a ground terminal; a voltage-sensing interface, connected so that said microprocessor can detect the voltage drop across said battery connection; and a current-sensing interface, connected so that said microprocessor can detect the current flow through said battery connection; said microprocessor being configured to repeatedly compare the voltage and current at said battery connection, at an instant when the current through said connection is small, with the voltage and current at said battery connection at another substantially contemporaneous instant when the current through said connection is larger; and
to indicate imminent battery failure when the source impedance seen at said battery connection is accordingly detected to have risen in a pattern corresponding to the internal impedance of a battery which is imminently failing. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A portable electronic system, comprising:
-
at least one microprocessor; first and second battery power connections; a voltage-sensing interface, connected so that said microprocessor can detect the voltage drop across said first battery connection, and also, independently thereof, can detect the voltage drop across said second battery connection; and a current-sensing interface, connected so that said microprocessor can detect the current flow through said first battery connection, and also, independently thereof, can detect the current flow through said second battery connection; said microprocessor being configured to repeatedly compare the voltage and current at said first battery connection, at an instant when the current through said first battery connection is small, with the voltage and current at said first battery connection at another substantially contemporaneous instant when the current through said first battery connection is larger, and to repeatedly compare the voltage and current at said second battery connection, at an instant when the current through said second battery connection is small, with the voltage and current at said second battery connection at another substantially contemporaneous instant when the current through said second battery connection is larger; and to indicate imminent battery failure when the source impedance seen at said battery connection is accordingly detected to have risen in a pattern corresponding to the internal impedance of a battery which is imminently failing. - View Dependent Claims (7, 8, 9, 10)
-
-
11. A method for automatic battery management, in a portable electronic system, comprising the operations of:
-
repeatedly measuring the voltage and current of a battery bank, under changing load conditions; making a calculation, in a microprocessor, which is substantially equivalent to estimating the internal impedance of the battery bank; and indicating imminent battery failure when the internal impedance of the battery bank is accordingly estimated to have risen in a pattern corresponding to a battery which is approaching failure. - View Dependent Claims (12, 13, 14)
-
-
15. A method for automatic battery management, in a portable electronic system, comprising the operations of:
-
repeatedly measuring the battery voltage and load current of a battery bank, under changing load conditions; making a calculation, in a microprocessor, of how the battery voltage responds when the load current changes; and indicating imminent battery failure when an observed change in load current causes a change in battery voltage which is sufficiently large, in relation to the observed change in load current, to approximate the voltage-change-to-current-change ratio of a battery which is approaching failure. - View Dependent Claims (16, 17)
-
Specification