title: Tracking battery state-of-charge in a continuous use off-grid electricity system

authors: Apperley, Mark

subjects: state-of-charge

abstract: The growing importance of batteries in the delivery of primary energy, for example in electric vehicles and isolated off-grid electricity systems, has added weight to the demand for simple and reliable measures of a battery's remaining stored energy at any time. Many approaches to estimating this battery state-of-charge exist, ranging from those based on a full appreciation of the chemistry and physics of the storage and delivery mechanisms used, and requiring extensive data on which to base an estimate, to the naive and simple, based only, for example, on the terminal voltage of the battery. None, however, is perfect, and able to deliver a simple percentage-full figure, as in a fuel gauge. The shortcomings are due to a range of complicating factors, including the impact of rate of charge, rate of discharge, battery aging, and temperature, to name just some of these.
This paper presents a simple yet effective method for tracking state-of-charge in an off-grid electricity system, where batteries are in continuous use, preventing static parameter measurements, and where charge/discharge cycles do not necessarily follow an orderly sequence or pattern. A reliable indication of state-of-charge is, however, highly desirable, but need be only of fuel gauge precision, say to the nearest 12-20%. The algorithm described utilises knowledge of the past, and constantly adapts parameters such as charge efficiency and total charge capacity based on this knowledge, and on the occurrence of specific identifiable events such as zero or full charge.

text: Tracking battery state-of-charge in a continuous use off-grid electricity system The growing importance of batteries in the delivery of primary energy, for example in electric vehicles and isolated off-grid electricity systems, has added weight to the demand for simple and reliable measures of a battery's remaining stored energy at any time. Many approaches to estimating this battery state-of-charge exist, ranging from those based on a full appreciation of the chemistry and physics of the storage and delivery mechanisms used, and requiring extensive data on which to base an estimate, to the naive and simple, based only, for example, on the terminal voltage of the battery. None, however, is perfect, and able to deliver a simple percentage-full figure, as in a fuel gauge. The shortcomings are due to a range of complicating factors, including the impact of rate of charge, rate of discharge, battery aging, and temperature, to name just some of these.
This paper presents a simple yet effective method for tracking state-of-charge in an off-grid electricity system, where batteries are in continuous use, preventing static parameter measurements, and where charge/discharge cycles do not necessarily follow an orderly sequence or pattern. A reliable indication of state-of-charge is, however, highly desirable, but need be only of fuel gauge precision, say to the nearest 12-20%. The algorithm described utilises knowledge of the past, and constantly adapts parameters such as charge efficiency and total charge capacity based on this knowledge, and on the occurrence of specific identifiable events such as zero or full charge.

year: 2014

title: Sustainable citizenship as a key to sustainability: Establishing a common ground on technology use in New Zealand's dairy sector

authors: Mueller, Hannah

subjects: sustainability

abstract: Sustainability is a key issue in New Zealand’s dairy industry. Arguments are often made from either a purely economic or environmental perspective. The debate is dominated by polarised viewpoints characterised by hasty rejection or assertive support of production-focused biotechnological approaches. On the one hand is the biotechnology industry and on the other environmentalists and an anxious public. In the context of this divisive discussion, progress towards sustainable development is hard to achieve. By using the concept of sustainable citizenship as a theoretical framework, it is possible to incorporate economic, environmental, political and social approaches to sustainability. This thesis employs sustainable citizenship in order to find a common ground amongst the various points of view within the dairy sector. Shared values around farming methods and biotechnology are used to find a way to facilitate sustainable development in the industry, combining current interests of various stakeholders with the long-term interest of future generations.

text: Sustainable citizenship as a key to sustainability: Establishing a common ground on technology use in New Zealand's dairy sector Sustainability is a key issue in New Zealand’s dairy industry. Arguments are often made from either a purely economic or environmental perspective. The debate is dominated by polarised viewpoints characterised by hasty rejection or assertive support of production-focused biotechnological approaches. On the one hand is the biotechnology industry and on the other environmentalists and an anxious public. In the context of this divisive discussion, progress towards sustainable development is hard to achieve. By using the concept of sustainable citizenship as a theoretical framework, it is possible to incorporate economic, environmental, political and social approaches to sustainability. This thesis employs sustainable citizenship in order to find a common ground amongst the various points of view within the dairy sector. Shared values around farming methods and biotechnology are used to find a way to facilitate sustainable development in the industry, combining current interests of various stakeholders with the long-term interest of future generations.

year: 2011

title: He Manu-Iri-i-te-Rangi - Bird of the Heavens: Tūrake Manuirirangi 1896 - 1969

authors: Manuirirangi, Hōri

abstract: Tūrake Manuirirangi was an influential tupuna of the Manuirirangi whānau. He was a devoted member of the Church of Jesus Christ of Latter-day Saints, and was instrumental in its establishment in the South Taranaki region. This chapter looks at his beliefs and leadership qualities within the Church, and within his hapū of Ngāti Tū, of Ngā Ruahine Iwi. The main focus here is to report on information collated from interviews, church records and Mormon missionary diaries.

text: He Manu-Iri-i-te-Rangi - Bird of the Heavens: Tūrake Manuirirangi 1896 - 1969 Tūrake Manuirirangi was an influential tupuna of the Manuirirangi whānau. He was a devoted member of the Church of Jesus Christ of Latter-day Saints, and was instrumental in its establishment in the South Taranaki region. This chapter looks at his beliefs and leadership qualities within the Church, and within his hapū of Ngāti Tū, of Ngā Ruahine Iwi. The main focus here is to report on information collated from interviews, church records and Mormon missionary diaries.

year: 2014