Patent US3895282A successfully refreshed from Google Patents.
US3895282A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric circuits particularly for automatic battery charging apparatus
Assignee: Electric Power Storage Ltd
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Filing: 1973-12-26
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Granted: 1975-07-15
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Expires: 1993-12-26
Abstract
Abstract Automatic battery charging apparatus is arranged to test the battery voltage at intervals of about 15 minutes, and to continue charging only if the voltage is below 2.3 volts per cell. If the voltage is higher, charging is suspended until the voltage has fallen to 2.3 volts per cell. The time needed for this fall to occur is monitored, and when on two occasions a comparison has indicated that a fall time is less than 5 percent greater than the preceding fall time, the main phase of the charge is terminated and a topping-up phase started. The apparatus is also arranged to stop charging if the battery voltage rises to 3.6 volts per cell, and a voltage doubler is arranged to raise the terminal voltage to this level if the battery is removed, so turning off the charge.
Inventors
- 👤 George William Foster
- 👤 Dennis Albert Clayton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:06
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/90; H02J7/96; Y; Y10; Y10S; Y10S320/00; Y10S320/12
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
78 words
Automatic electric battery charging apparatus comprising: means for temporarily interrupting the charging current during open-circuit intervals, the duration of each open-circuit interval depending on the fall of battery voltage during such interval, and means for terminating at least a phase of the charge of the charging circuit when the ratio of the duration of an open-circuit interval to that of a preceding open-circuit interval is below a predetermined value for more than one pair of successive open-circuit intervals.
Claim 2
Dependent Claim
78 words
Automatic electric battery charging apparatus comprising: means for temporarily interrupting the charging current during open-circuit intervals, the duration of each open-circuit interval depending on the fall of battery voltage during such interval, and means for terminating at least a phase of the charge of the charging circuit when the ratio of the duration of an open-circuit interval to that of a preceding open-circuit interval is below a predetermined value for more than one pair of successive open-circuit intervals.
Claim 3
Dependent Claim
66 words
Apparatus as claimed in claim 1 further comprising: means for supplying pulses at one frequency and at a slightly lower frequency respectively during odd and even successive open-circuit intervals, and counting means for comparing the number of pulses in the respective intervals and terminating at least a phase of the charge if the number in the even interval falls short of that in the odd interval.
Claim 4
Dependent Claim
17 words
Apparatus as claimed in claim 2 in which said counting means includes a semi-conductor binary digital counter.
Claim 5
Dependent Claim
23 words
Apparatus as claimed in claim 2 in which said counting means includes a single counter utilized for both odd and even open-circuit intervals.
Claim 6
Dependent Claim
38 words
Apparatus as claimed in claim 2 further comprising a charge time counter for determining the duration of the charging periods between the open-circuit intervals, said charge time counter being supplied with pulses from said means for supplying pulses.
Claim 7
Dependent Claim
39 words
Apparatus as claimed in claim 2 further comprising a second counter for registering the number of occasions that the ratio of the duration of an open-circuit interval to that of a preceding open-circuit interval is below a predetermined value.
Claim 8
Dependent Claim
17 words
Apparatus as claimed in claim 6 in which said second counter is a semi-conductor binary digital counter.
Claim 9
Dependent Claim
67 words
Apparatus as claimed in claim 1 in which said means for temporarily interrupting includes a signal level-responsive circuit comprising a trigger circuit having an output assuming one state when the input signal to said trigger circuit is below a lower threshold, and said output assumes another state when the input signal is above an upper threshold, and is bistable when the input signal is between the thresholds.
Claim 10
Dependent Claim
69 words
Apparatus as claimed in claim 8 in which said level-responsive circuit further comprises pulse means for applying to the input of said trigger circuit pulses of sufficient amplitude to ensure that said output assumes a predetermined state for the duration of the pulse, whereby the state of said output immediately after a pulse depends on whether the input signal is above or below a single one of the thresholds.
Claim 11
Dependent Claim
70 words
Apparatus as claimed in claim 9 in which said means for temporarily interrupting includes a controllable circuit controlled by the output of said level-responsive circuit, the duration of the pulses from said pulse means being substantially less than the operating time of said controllable circuit, so that said controllable circuit does not respond in the time taken by said trigger circuit to change state and revert to its previous state.
Claim 12
Dependent Claim
49 words
Apparatus as claimed in claim 8 in which said trigger circuit includes a differential amplifier having a resistive positive feedback path including a series diode so that feedback current can flow in only one direction and variation of said resistive feedback path affects only one of said threshold values.
Claim 13
Dependent Claim
15 words
Apparatus as claimed in claim 11 in which said differential amplifier is an operational amplifier.
Claim 14
Dependent Claim
103 words
Apparatus as claimed in claim 1 further comprising: a main rectifier having its input connected to an A.C. supply and its output connected to charger terminals to which a battery is connected to be charged; voltage responsive means for switching off the A.C. supply to said main rectifier when the voltage between the charger terminals exceeds a predetermined value; and a voltage doubler circuit connected to the input of said main rectifier and through an impedance to the battery terminals to produce across the latter an increased voltage and switch off said A.C. supply when the battery is disconnected from said charger terminals.
Claim 15
Dependent Claim
44 words
Apparatus as claimed in claim 13 in which said voltage doubler comprises a diode and a capacitor connected in series across the main rectifier input, and the junction of said diode and capacitor is connected through a resistor to one of the charger terminals.
References Cited (Backward Citations)
US3800208A
Cited
US3761795A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |