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Universal Adapting Battery Charger 2007
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The objective of this topic is to develop an efficient battery charger power supply
capable of adapting to a range of applications. The requirement is a small plug-in power
supply capable of automatically charging a wide range of battery configurations. This would
reduce the needs for battery-charging devices in a typical home or office from several to
as few as one.
Status
The project is in its testing phase.
Technical Specifications
Minimum requirements:
- Devices must operate without degradation or derating for input supplies ranging from 48 Hz to 440 Hz and 95 V to 270 V RMS.
- Devices must adapt and successfully charge any of the following battery combinations
without external settings, switches, or other user intervention. (The listed combinations
represent nominal voltages of 2 V to 18 V.)
- Lead-acid cells, single or series combinations up to nine cells.
- Nickel-cadmium cells, series combinations of two to fifteen cells.
- Nickel-metal-hydride cells, series combination of two to fifteen cells.
- Lithium-ion cells, single or series combinations up to five cells.
- Charging currents up to 1 A must be possible at all voltages.
- Batteries are to be charged in situ: it is assumed that the individual product to be
recharged by this device has a barrel-type dc jack that provides access to the battery
terminals. Teams should plan on a configuration that permits multiple jack adapters for
maximum flexibility.
- The charger must address the specific needs of each battery configuration, including
but not limited to: no overcharge of lithium cells, appropriate end-of-charge action for
each chemistry, safe charging methods to minimize thermal runaway possibilities.
- External indication of “charging” and “charge complete” conditions.
- Polarity-insensitive design. Batteries can be charged without trouble regardless
of their connection polarity to the charger.
- Protection against open-circuit and short-circuit conditions.
- Device draws no more than 0.25 W when no battery is connected.
- After battery charge is complete, devices draws no more than 0.25 W plus twice any
power required for maintaining battery “float charge” if needed for a given chemistry.
- Power drawn during charging not to exceed 0.5 W plus twice the power delivered to the
battery terminals.
- Manufacturing cost in high-volume production (>1 M units/year) not to exceed US$10,
including the cost of at least one output adapter.
Optional
- Operation from a vehicle dc outlet (12-15 V typical)
- Device draws no more than 0.1 W when no battery is connected.
- Charging currents up to 2 A are supported.
- Operation supports nominal battery voltages from 2 V to 24 V (up to 12 lead-acid cells,
20 nickel cells, 6 lithium cells)
- Ability to support rechargeable alkaline cell combinations of two to four or more cells
in series.
- Size less than 15 cm x 6 cm x 3 cm, not including cords. Mass less than 0.4 kg.
- Display indicates battery configuration and state of charge.
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