Switch mode battery charging system

A battery charger system for charging a battery and which is operable from an AC line voltage supply of a given line frequency, comprising:

• an AC line voltage input for connection to the line voltage supply;
• a switchable power supply means for being operated from the AC line voltage supply and for providing at its output a continuously variable and controllable DC battery charging voltage at variable and controllable charging currents, and wherein during a charging mode the charging voltage continuously increases up to an equalizing voltage while the charging current is decreasing from an initial maximum charging current as the equalizing voltage is approached, and when the charging current drops below a given value, the charging voltage automatically dropping, without a controlled time delay, from an equalizing voltage existing at that time down to a lower charging float voltage in a float mode for just maintaining a full charge;
• and
• said switch mode power supply means having an operating frequency substantially higher than said line frequency of said AC line voltage supply.

A battery charging system operable from an AC line voltage supply of a given line frequency, comprising:

• an AC line voltage input for connection to the line voltage supply;
• a switch mode power supply mans for being operated from the AC line voltage supply and for providing at its output a variable and controllable DC voltage at variable and controllable currents up to a maximum selected current, the current being variable simultaneously with a variance of the voltage during charging:
• said switch mode power supply means having an operating frequency substantially higher than said line frequency of said AC line voltage supply;
• and
• said switch mode power supply means including means for automatically switching from a float mode in which a battery maintenance current at a charging float voltage can be supplied substantially equal to an internal discharge current of the battery to a heavy charge and equalizing mode in which current substantially higher than the maintenance current can be provided, said automatic switching occurring when current at the output of the system exceeds a predetermined level, and wherein during said heavy charging and equalizing mode, the battery is charged up to an equalizing voltage which is higher than the charging float voltage until a predetermined minimum charging current is reached, at which time the system automatically switches to the float mode and the battery voltage drops, without a controlled time delay, from the equalizing voltage it was at when the charging current reached its minimum value down to the lower charging float voltage at which said battery maintenance current is supplied.

A battery charging system operable from AC line voltage having a given line frequency associated therewith, comprising:

• an AC line voltage input;
• a switch mode power supply means connected to operate from the AC line voltage input and for providing at its output DC battery charging voltages at DC charging currents;
• said switch mode power supply means having an operating frequency substantially higher than said line frequency at said AC line voltage;
• automatic control means connected to the switch mode power supply means for detecting whether a charging current being drawn by a battery to be charged is above or below a selected given value, and if it is above then instituting an equalizing mode for equalizing and desulfating the battery by having the system seek float voltage of the battery, and when the charging current falls below said selected given value, said automatic control means causing the battery voltage to drop, without a controlled time delay, from said surface charge voltage down to a charging float voltage;
• and
• means for adjusting said charging float voltage on the battery during the float mode so that a float current is delivered to the battery which equals an internal discharge current of the battery.

A battery charging system operable from AC line voltage having a given line frequency associated therewith, comprising:

• a AC line voltage input;
• a switch mode power supply means connected to operate from the AC line voltage input and for providing at its output a varying DC battery charging voltage which varies simultaneously with varying DC charging currents;
• said switch mode power supply means having an operating frequency substantially higher than said line frequency at said AC line voltage;
• said switch mode power supply means having a high frequency power transformer having a primary connecting at opposite ends to first and second power switching semiconductor;
• and
• automatic control means connected to the switch mode power supply means for maintaining a selected float voltage of the battery by providing a maintenance current which just balances internal battery loss currents, and for causing the power supply means to provide a desulfating voltage which is higher than the float voltage and for automatically detecting a selected minimum desulfating current level indicative of completion of desulfation and at that time automatically returning the battery, without a controlled time delay, to a charging float voltage.

A battery charger for a battery, comprising:

• a controllable power supply means for providing a variable output charging voltage at a varying charging current;
• desulfating mode sensing means connected to control the power supply means such that when a charging current is sensed which is above a predetermined minimum value, the charging voltage begins to continuously increase from an existing voltage which the battery was at up to a higher desired target surface charge desulfating voltage for desulfating the battery, and when said charging current drops below said minimum value for automatically causing the power supply means to drop down to a charging float voltage which is lower than a desulfating voltage at which the battery was being charged when it reached said minimum value of charging current, said charging float voltage being supplied at a maintenance current for just maintaining a charge on the battery;
• and
• means for adjusting the charging float voltage such that the maintenance current is equal to an internal discharge current of the battery.