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Zero power consumption from battery chargers when not in use

IP.com Disclosure Number: IPCOM000146735D
Original Publication Date: 2007-Feb-20
Included in the Prior Art Database: 2007-Feb-20
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Abstract

The battery chargers for portable electronic devices are typically connected to the mains supply even when they are not charging. This results in 93% of the energy consumed being wasted and has implications for the environment. We suggest that battery chargers should self-isolate using a relay device (or similar) and hence consume zero power when not in use. The difficulty in initially switching on the relay can be overcome by using some residual power from the cell being charged.

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Zero power consumption from battery chargers when not in use

The growth of portable electronic devices in recent years has led to an explosion in the number of batteries and battery chargers. Users typically leave battery chargers and other power supplies connected to the mains (or other power source) even when they are not in use. The power consumed by a connected power supply is small but significant. The following power and cost calculations were obtained using a popular brand of cell phone:

Power consumed when charging: 2.77 W

    
Power consumed when not charging: 0.45 W
Assuming a charge cycle of two hours, and that the phone would need charging once per week, and that the charger is left plugged in for the remaining 166 hours:

    In a year 4.14 KWh are wasted by the charger. At the current rate of 0.14 UKP (0.28 USD) per KWh, then the phone charger wastes 1.58 UKP (3.16 USD) over a typical three year lifespan. Assuming 0.43 kg CO2 per kWh, this results in
1.78 kg CO2 per cell phone per three years. These costs and emissions are not large in themselves, but given the huge growth of electronic devices, they are significant for the economy and the environment. All of this energy is wasted as it does not achieve any useful purpose. This means that 93% of the energy consumed by the cell phone charger is wasted.

    It would be better if chargers were intelligent and could know when they should be on, and consume zero power when they are not on. This would allow them to be plugged in and switched on at the mains but without any waste of e...