A Study of Aircraft NiCd Battery State-of-Charge Measurement by Phase Meter.
Abstract
Experiments were performed to determine if the phase angle between alternating voltage and current could be used to predict, within a probable error of 5 percent, the state of charge of vented NiCd aircraft batteries. A 22 A-hr, 19-cell Gulton type MS24497-4 battery and several individual cells from that battery were tested in these experiments. The battery was charged for various lengths of time at 11 amperes to obtain a range of state of charge. Battery phase angle and individual cell phase angles were measured with a Hewlett-Packard HP-3575A gain-phase meter at frequencies of 350, 100, 35, 17.5, and 11 Hz; and the cells were discharged at 11 amperes to 0.1 V (1.9 V for the battery) to determine their state of charge in ampere-hours of capacity. The phase-angle, state-of-charge data were subjected to second-order polynomial curve fitting by means of least-squares analysis. The probable errors obtained from the least-squares analyses were used to judge the quality of measured correlation between phase angle and state of charge. The results for the individual cells were, on the whole, quite poor, although two of the individual cells tested achieved the stated goal of a probable error of 5 percent for the correlation between phase angle and state of charge. The 19-cell battery gave the best results with a probable error of 3.8 percent measured at 11 Hz.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 1980
- Accession Number
- ADA084935
Entities
People
- Charles C. Badcock
- Michael R. Martinelli
- Stanley W. Mayer
Organizations
- The Aerospace Corporation