Battery Charger for an Orthopedic Surgical Product
A division of a large company specialized in products for the orthopedic
surgery market, and they needed an electrical engineer to help them with a few
aspects of a product development project. They were developing a very high-power
silver-zinc battery system to power a surgical tool that could be configured for
various tasks, such as drilling, sawing, and chipping. The group wanted a tester
that would discharge the batteries with a constant, adjustable current. The
maximum discharge rate was 25 Amps. They also needed a timer to keep track of
the discharge time, a voltmeter, and an automatic shutoff so they would not need
to monitor the battery while it was discharging. I designed and built one unit
that met all of their requirements, and they used it in their laboratory to
characterize battery behavior. Later, the lab needed four or five more units and
I supplied them.
This project is a good example of a job well done leading to another. As my
customer progressed on the battery development and the mechanical development of
the tool, they hired me to develop a constant-current battery charger for their
final product suite. This charger included some LED indicators to indicate the
state of the charger, and a safety device that guaranteed the battery was
installed in the cradle properly before it would charge it. I designed the
electronics, developed the printed circuit board, and worked with the mechanical
designers on the product's packaging. This product passed UL certification on
the first pass.
When the product entered the manufacturing phase, I worked with my customer's
manufacturing plant to integrate the product into their system, and I
manufactured the battery charger electronics. I also developed a functional test
system for the charger, wrote a detailed test specification for the charger, and
built another discharge tester for the manufacturing plant.
