By Dan Conley

Wireless devices are everywhere in today's hospitals, but what about battery use?

Right now, many devices, especially RTLS systems, run on powerful lithium thionyl batteries, which are great, but pricey to buy and dispose of and have certain performance and risk issues vs. alkaline ones. But many RTLS systems need the power that lithium can provide.
Regarding cost, lithium batteries are are pricey – roughly 15 to 20 times more than alkaline, with only double the capacity. Viewed as cost-to-capacity, that factor is close to eightfold. This can become expensive very quickly with some devices. Costs for Real Time Location Systems (RTLS) transmitters using six lithium batteries can reach $90.00 ($15.00 per transmitter unit), making this option a very expensive choice for realizing long battery life.

On the other hand, alkalines would run only about $3.00 per transmitter unit. This means that the cost differential for a typical hospital installation could be in the hundreds of thousands of dollars over the product life span.

Performance quirks are another concern about lithium batteries. While powerful, they can suffer sudden voltage loss without warning. The makes their uptime simply less predictable than standard alkaline batteries.

“Batteries that have performance issues, such as sudden voltage exhaustion, can make maintenance planning more challenging, as replacement cycles are less predictable, and can drive costs up,” said Alan Moretti Vice President, Advanced Imaging and Radiation Oncology at of Renovo Solutions, a biomedical services firm.

This can be an especially tough problem in wireless devices, such as RTLS, where transmitters run on batteries and are installed across a facility on the ceilings.

There is also a growing concern about the safety of lithium thionyl batteries, which are more volatile than alkaline and pose a risk of explosion.

Many RTLS systems need lithium's power. but not all. RTLS maker Sonitor Technologies, for example, has has configured its ultrasound technology for the efficient use of standard alkaline batteries.

They did this by making ultrasound more battery-efficient, so it could run without the extra boost only lithium batteries can provide to systems requiring them.

The firm achieved this by focusing the ultrasound beams, saving considerable energy. This contrasts, for example, to radio waves, which emit in all directions and go straight through walls, wasting energy.

To a great extent the same radio-wave-like performance is true of infrared. This technology has an additional challenge too, in that it will be absorbed by any color in the infrared area. These physical challenges are considerably more taxing on batteries because they have to compensate for signal loss and inefficiency by pushing out more to communicate.

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