Powering instrumentation: Batteries, wireless

Applications that demand self-contained power supplies are growing with the wider deployment of remote and wireless devices. Many alternative sources of energy are emerging, and batteries still represent a reliable and inexpensive method. Battery types have characteristics suited for specific applications.


The variety of applications that demand self-contained power supplies is growing with the wider deployment of remote and wireless devices. While many alternative sources of energy are emerging, batteries still represent a reliable and inexpensive method.

Like many products, there is a variety of battery types with characteristics that make them suited for specific types of applications. Understanding how to apply various offerings can make your job easier. While there are many interesting rechargeable battery technologies, for purposes of this brief discussion, we will zero in on disposable designs.

Industrial applications generally focus on longevity first. Few companies have large enough maintenance staffs to change batteries regularly, so a lifetime that is both long and predictable is very desirable. With this in mind, battery manufacturers have achieved high levels of consistency in their products, so performance is quantified and dependable. With some research, you should be able to find data that will help you evaluate performance and make a wise choice.

There are many types of batteries that exhibit specific discharge characteristics that should be matched with your devices consumption characteristics to optimize power flow.

For example, some devices drain power constantly at the same rate. The manufacturer should be able to give you current consumption vs. lifetime data, which makes predicting battery life very simple (see graph). On the other hand, some devices, such as wireless instruments, consume short pulses of relatively high draw with long periods of inactivity in between. You can average this to an extent, but the battery may not see it as perfectly linear. Consult with your prospective supplier and make sure the battery is suited to the peak load. You can mitigate this effect by adding a capacitor that will draw current at a consistent low level from the battery and then discharge to power the transmission pulse.

High-performance batteries cost more than those at your local drug store, but should be compared against maintenance costs to change. “For long-life industrial applications where temperature and long maintenance intervals are important, the cost of the solution is not really that important,” says Lou Adams, application engineer for Tadiran Battery Co. “On the other hand, if the battery is easily changed and the temperature rarely gets very hot or cold, a low-cost alkaline solution quite easily fills the bill.”

Remember that predictable life depends on predictable power consumption. If a device changes its power usage due to new operational parameters, settings, or other reconfiguration, battery life will change proportionally. Understanding how batteries work often begins with understanding the devices they power.

This graph shows load vs. life curves for two types of "D"cells.suitable for a high discharge device such as a flashlight, although they can operate for five, ten, or more years when power is drawn at a low rate.  The green curves apply to a common alkaline battery. Note that output voltage begins to decline immediately and continues until exhaustion. It is capable of putting out more current, but for a shorter period of time.

Author Information

Peter Welander is process industries editor for Control Engineering. Reach him at PWelander@cfemedia.com .

No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Big Data and IIoT value; Monitoring Big Data; Robotics safety standards and programming; Learning about PID
Motor specification guidelines; Understanding multivariable control; Improving a safety instrumented system; 2017 Engineers' Choice Award Winners
Selecting the best controller from several viewpoints; System integrator advice for the IIoT; TSN and real-time Ethernet; Questions to ask when selecting a VFD; Action items for an aging PLC/DCS
This digital report will explore several aspects of how IIoT will transform manufacturing in the coming years.
Motion control advances and solutions can help with machine control, automated control on assembly lines, integration of robotics and automation, and machine safety.
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Future of oil and gas projects; Reservoir models; The importance of SCADA to oil and gas
Big Data and bigger solutions; Tablet technologies; SCADA developments
SCADA at the junction, Managing risk through maintenance, Moving at the speed of data
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
Fire & Life Safety Engineer; Technip USA Inc.
click me