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Field Test of Large Battery Charging Technologies


Both the commercial and industrial sectors rely on electrically charged fork lifts to do work. Due to the size of the industrial batteries associated with the fork lifts, the electric draw for charging can be substantial from both a demand (kW) and an energy (kWh) standpoint. The majority of battery chargers in operation are of two types: Ferro resonant (FR) or silicon controlled rectifier (SCR). However, new high frequency (HF) battery chargers can potentially provide improved power conversion during the charging procedure and speed up the process to fully charge batteries.

A CARD grant titled “Field Test of Large Battery Charging Technologies” was awarded to Franklin Energy Services to evaluate the installation of 12 HF chargers against either FR or SCR charging technologies. Electricity use of all chargers will be monitored, including assessment of power conversion efficiency, maintenance power, no battery power, and power factor. Existing chargers will be categorized by age and condition, and operational parameters will be documented based on feedback from participants. While the project is primarily looking to measure energy usage from the various charger types—to determine whether the HF chargers save energy—it will also consider whether the HF technology affects charging operations, which could impact energy or demand at each installation.

The ultimate goal of the field test is to determine whether industrial HF battery chargers are a viable energy saving measure that can be included in utility-based Conservation Improvement Programs (CIPs). The potential could be substantial because there is a large number of fork lift battery chargers connected to the electrical grid day-in and day-out in Minnesota. For instance, in the manufacturing sector alone, the US Census 2011 County Business Patterns reports that Minnesota has 7,297 businesses classified by NAICS code as manufacturing, and the typical manufacturer has at least one electrically charged fork lift.

Results from this study are expected to be available by the end of April 2015. Mark Garofano is the Division of Energy Resources’ project manager for this CARD project.