Run-Time Estimation of a Battery-Powered Video-Streaming Payload for Balloon Flights

Wookwon Lee

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Conference: 2022 ASEE - North Central Section Conference
Location: Pittsburgh, Pennsylvania
Publication Date: March 18, 2022
Start Date: March 18, 2022
End Date: April 4, 2022
Page Count: 8
DOI: 10.18260/1-2--39257
Permanent URL: https://peer.asee.org/39257
Download Count: 357

Paper Authors

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Wookwon Lee P.E. Gannon University

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Wookwon Lee, P.E. received the B.S. degree in electronic engineering from Inha University, Korea, in 1985, and the M.S. and D.Sc. degrees in electrical engineering from the George Washington University, Washington, DC, in 1992 and 1995, respectively. He is currently a full professor in the Department of Electrical and Computer Engineering at Gannon University, Erie, PA. Prior to joining Gannon in 2007, he had been involved in various research and development projects in industry and academia for more than 15 years.

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Abstract

When operating an electronic device powered by a battery, engineering students often face the question of how to calculate the run time of the device. While there is a plethora of information on the Internet about batteries, engineering students often find it difficult to obtain a reasonably accurate estimate of the run time of a device. Such difficulty appears to be attributed to: 1) the run time estimation tends to be obtained simply from dividing the battery capacity in mAh by the current draw of a device given in mA; 2) certain electronic devices are powered via a dc-dc converter, instead of being directly connected to a battery, for a step up/down conversion or better regulation of the supply voltage to the device.

On the first attribute above, for a battery capacity of x mAh, if an electronic device draws a constant current of y mA from the battery, then, students would generally estimate the run time t of the battery by t = x/y. For instance, the run time of a device drawing a constant current of 100 mA from a 1600 mAh battery would be 16 hours; or, for a device drawing a constant current of 50 mA, the run time would be 32 hours. In reality, however, this ideal run time calculation doesn’t provide a practically accurate estimate for most, if not all, of the battery-powered devices used in student projects. Part of the reasons is that the accurate run time estimation involves various discharge characteristics of a battery and also the relation between the battery capacity and its terminal voltage is not often straightforward to determine for a device under test. All electronic devices would stop operating when the supply voltage drops below a certain threshold, and the battery’s terminal voltage also gradually drops while discharging at a certain rate depending on its discharge characteristics. So, battery-powered devices could stop operating before the battery reaches its empty state of charge, resulting in a practically inaccurate estimation of the run time if the battery’s empty-state was assumed for the estimation. On the second attribute, the use of dc-dc converters is self-explanatory for the reasons mentioned above. It should be noted, however, that dc-dc converters could effectively compensate for the drop in the terminal voltage of a battery to some extent as dc-dc converters typically have a wide range of input voltages to output a well-regulated constant voltage. Taking all of these aspects into account and estimating a practically accurate run time of an electronic device is a daunting task to most students.

This paper describes how to alternatively estimate the run time of an electronic device powered by a battery via a dc-dc converter in a way that typical engineering students can easily adopt without complete understanding of the details of battery-related parameters and characteristics. For the purposes of illustration, we utilize a set of electronic devices put together to conduct video streaming in a balloon flight during the 2017 total solar eclipse.

Citation
Format

Lee, W. (2022, March), Run-Time Estimation of a Battery-Powered Video-Streaming Payload for Balloon Flights Paper presented at 2022 ASEE - North Central Section Conference, Pittsburgh, Pennsylvania. 10.18260/1-2--39257

TY  - CPAPER
AB  - When operating an electronic device powered by a battery, engineering students often face the question of how to calculate the run time of the device. While there is a plethora of information on the Internet about batteries, engineering students often find it difficult to obtain a reasonably accurate estimate of the run time of a device. Such difficulty appears to be attributed to: 1) the run time estimation tends to be obtained simply from dividing the battery capacity in mAh by the current draw of a device given in mA; 2) certain electronic devices are powered via a dc-dc converter, instead of being directly connected to a battery, for a step up/down conversion or better regulation of the supply voltage to the device. 

On the first attribute above, for a battery capacity of x mAh, if an electronic device draws a constant current of y mA from the battery, then, students would generally estimate the run time t of the battery by t = x/y. For instance, the run time of a device drawing a constant current of 100 mA from a 1600 mAh battery would be 16 hours; or, for a device drawing a constant current of 50 mA, the run time would be 32 hours. In reality, however, this ideal run time calculation doesn’t provide a practically accurate estimate for most, if not all, of the battery-powered devices used in student projects. Part of the reasons is that the accurate run time estimation involves various discharge characteristics of a battery and also the relation between the battery capacity and its terminal voltage is not often straightforward to determine for a device under test. All electronic devices would stop operating when the supply voltage drops below a certain threshold, and the battery’s terminal voltage also gradually drops while discharging at a certain rate depending on its discharge characteristics. So, battery-powered devices could stop operating before the battery reaches its empty state of charge, resulting in a practically inaccurate estimation of the run time if the battery’s empty-state was assumed for the estimation. On the second attribute, the use of dc-dc converters is self-explanatory for the reasons mentioned above. It should be noted, however, that dc-dc converters could effectively compensate for the drop in the terminal voltage of a battery to some extent as dc-dc converters typically have a wide range of input voltages to output a well-regulated constant voltage. Taking all of these aspects into account and estimating a practically accurate run time of an electronic device is a daunting task to most students. 

This paper describes how to alternatively estimate the run time of an electronic device powered by a battery via a dc-dc converter in a way that typical engineering students can easily adopt without complete understanding of the details of battery-related parameters and characteristics. For the purposes of illustration, we utilize a set of electronic devices put together to conduct video streaming in a balloon flight during the 2017 total solar eclipse.

AU  - Wookwon Lee P.E.
CY  - Pittsburgh, Pennsylvania
DA  - 2022/03/18
PB  - ASEE Conferences
TI  - Run-Time Estimation of a Battery-Powered Video-Streaming Payload for Balloon Flights
UR  - https://peer.asee.org/39257
DO  - 10.18260/1-2--39257
ER  -