Comparing Alkaline and Lithium Polymer Battery Performance in a BalloonSat Flight

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Comparing Alkaline and Lithium Polymer Battery Performance in a BalloonSat Flight. Team Voltanators: Harley Ihrig Jim Kim Bonnie Levitt Gerardo Pulido Community College of Aurora COSGC Symposium April 20, 2013. - PowerPoint PPT Presentation

Transcript of Comparing Alkaline and Lithium Polymer Battery Performance in a BalloonSat Flight

Slide 1

Team Voltanators:Harley IhrigJim KimBonnie LevittGerardo Pulido

Community College of AuroraCOSGC Symposium

April 20, 2013Comparing Alkaline and Lithium Polymer Battery Performance in a BalloonSat Flight

1This mission is designed to determine whether lithium-polymer batteries can perform at least as well as the alkaline batteries for the duration of the BalloonSat flight.

Lithium-polymer batteries will reduce the mass needed to power the BalloonSat as well as saving money due to their ability to recharge.

Reducing the base mass of the payload will allow future students more mass for their experiments.

Simple Performance Comparison TestMission Overview

Visual Representationof First Prototype

(created with SketchUp8)

1. The lithium polymer batteries attain and maintain at least as much heat as the alkaline batteries.

2. The lithium polymer batteries remain above the cutoff voltage at least as long as the alkaline batteries.

3. During the flight, the lithium polymer batteries must meet conditions 1 and 2.

The Three Conditions of Success

Structural Design Features

Velcro closing mechanism.Bumpers for shock absorption.

Foam compartments to secure batteries, camera, and flight tube.Braided Wires for 9 volt connectors

Foamcore Channels for Secure Mounting of Digital Temperature Sensors.Braided WiresHeat shrink tubing to secure wires and to prevent shorts.Heaters with foamcore backing, secured with twist ties.

Coiled wiresHeartbeat LED for verification of data writing to microSD card.Recessed switch to prevent accidental shut down.Zip ties to stabilize switches.Circuit Diagram

Bench TestData

Cold Test DataTwo Lipos/Three Alkaline comparison200 ms sampling rate Alk/Lipo voltage with behavior characteristics.Temperature Data superimposed on voltage data?

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Cold Test DataTwo Lipos/Three Alkaline comparison200 ms sampling rate Alk/Lipo voltage with behavior characteristics.Temperature Data superimposed on voltage data?

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Flight DataCutoff voltage of LiposTemps, 619, 644, 661Pressure (optional)

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Cutoff voltage of LiposTempsPressure (optional)

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Accelerometer Data

Cost and Mass AnalysisComparison of Alkaline and Lipo Cost and Mass:

Mass savings per battery: 28%, or 13 grams. Mass savings per 850 gram payload (assuming 4 batteries/payload): 7%, or 56 grams. Cost savings for the life of a lipo battery (assuming 300 charge cycles): 95%, or $1501.65. Cost of 1 lipo battery = Cost of 15 alkaline batteries. Lipos pay for themselves after 15 charge cycles.Dollars$1.32$13.9532.7 grams45.7 grams$1584.00$80.85Lipos have a larger upfront cost, but they pay for themselves after 15 charge cycles.18

Box Redesign

Box Redesign: Keep it compact (no wasted air space); use foam insulation.

Foamcore can withstand higher temperatures than foam.

Aluminum tape is conductive. Dont short your electronics!

Allow for plenty of time to test the experiment.

Lessons LearnedTwo lipos will perform as well as three alkalines to power the heating circuit.

Conclusions

Two lipos will perform as well as three alkalines to power the heating circuit.

Lipo batteries contain protection circuitry to prevent an overdischarge.

For the specific heating circuit used in our BalloonSat, lipos performed better than the alkalines due to their higher nominal voltage, smoother voltage discharge curve, higher energy density, lower mass, and long-term cost savings.

Conclusions