Fred Feres - Academia.edu (original) (raw)
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Papers by Fred Feres
SAE International Journal of Alternative Powertrains, 2015
ABSTRACT
Journal of Power Sources, 1999
The renewed interest by the US Army in lead-acid SLI battery charging was spurred by the recent s... more The renewed interest by the US Army in lead-acid SLI battery charging was spurred by the recent shift to Army-wide use of 'maintenance free' batteries. Although the use of calcium-grid construction reduces the need for periodic water additions, using battery maintainers for extended float charging may cause an even greater problem. By charging at constant voltage, the batteries can slowly lose water if the charging is performed in the absence of suitable temperature compensation. This uncontrolled water loss is of particular significance in those batteries that do not permit access to the electrolyte. In this study, charging curves measured at constant current were obtained over a range of temperatures. The curves were modelled analytically by combining the individual effects of battery charging and gassing. The modelled results were compared with the actual measurements. The model is given as a semi-empirical equation in closed form. With this equation, the response surface is displayed graphically to visualize the effect of changes in critical variables. The results of the investigation will help determine the best charging conditions for the regular and float charging modes in order to deliver the maximum charge without excessive gassing. q 1999 Elsevier Science S.A. All rights reserved.
The US Army has recently transitioned to using "maintenance free" batteries in its ground vehicle... more The US Army has recently transitioned to using "maintenance free" batteries in its ground vehicles to increase the over-all vehicle readiness. Using leadcalcium alloy grids in place of the "reduced maintenance" design decreases water loss. This loss of water is known to be a measure of the battery self discharge. In this study, the charging of SLI batteries was examined over a range of operating temperatures as a means for characterizing the self-discharge rate as a function of battery voltage and temperature. The battery response was modeled analytically. Current activities are directed toward achieving a better description of the battery selfdischarge over extreme environmental conditions.
SAE International Journal of Alternative Powertrains, 2015
ABSTRACT
Journal of Power Sources, 1999
The renewed interest by the US Army in lead-acid SLI battery charging was spurred by the recent s... more The renewed interest by the US Army in lead-acid SLI battery charging was spurred by the recent shift to Army-wide use of 'maintenance free' batteries. Although the use of calcium-grid construction reduces the need for periodic water additions, using battery maintainers for extended float charging may cause an even greater problem. By charging at constant voltage, the batteries can slowly lose water if the charging is performed in the absence of suitable temperature compensation. This uncontrolled water loss is of particular significance in those batteries that do not permit access to the electrolyte. In this study, charging curves measured at constant current were obtained over a range of temperatures. The curves were modelled analytically by combining the individual effects of battery charging and gassing. The modelled results were compared with the actual measurements. The model is given as a semi-empirical equation in closed form. With this equation, the response surface is displayed graphically to visualize the effect of changes in critical variables. The results of the investigation will help determine the best charging conditions for the regular and float charging modes in order to deliver the maximum charge without excessive gassing. q 1999 Elsevier Science S.A. All rights reserved.
The US Army has recently transitioned to using "maintenance free" batteries in its ground vehicle... more The US Army has recently transitioned to using "maintenance free" batteries in its ground vehicles to increase the over-all vehicle readiness. Using leadcalcium alloy grids in place of the "reduced maintenance" design decreases water loss. This loss of water is known to be a measure of the battery self discharge. In this study, the charging of SLI batteries was examined over a range of operating temperatures as a means for characterizing the self-discharge rate as a function of battery voltage and temperature. The battery response was modeled analytically. Current activities are directed toward achieving a better description of the battery selfdischarge over extreme environmental conditions.