The true cost of poor battery selection

The risks of choosing the wrong battery for a device are significant. It can mean unplanned downtime for devices, safety risks, regulatory exposure, reputational damage, and an escalation of the total cost.

The wrong selection can come down to any number of things. For some it is a simple act of cost-cutting and looking to acquire cells at the lowest possible cost – which can mean compromising on quality, reliability and performance. In many cases, though, it can be traced back to the design process and not having sufficient time and research put into choosing the right battery solution.

Here we explore some of the risks of getting battery selection wrong and share a few tips on how to avoid these common pitfalls.

Understanding the risks

Going offline and data gaps

In IoT systems, failed batteries can mean offline devices and, as a result, large periods of time when vital data is not being collected and relayed to the server. This can affect everything from meter billing accuracy to city wide environmental or infrastructure monitoring.

For devices deployed in critical infrastructure, such as healthcare settings, smart security systems or ATEX zones, avoiding downtime is even more important. Here, a non-operational sensor due to premature battery failure can be the difference between sensing a hazard and not.

Safety Hazards and Regulatory Exposure

Poor-quality cells that are not properly matched to their deployment can overheat, short circuit, or even combust. This not only causes the device to go offline (or even be damaged), but it has potentially dangerous effects on surrounding infrastructure should a fire break out.

When applications go wrong, the reputational damage and the financial cost of recalling and replacing multiple devices is massive. Though the root cause of the Sensus smart meter fires in the US and Canada remains unclear to this day – there are reports that it was due to faulty product design or power surges – the impact will still be felt.

Quality cells, safety certifications, and built-in BMS features such as overcharge protection, thermal cut-off and capacity tracking, can mitigate risks of fires or recalls. In many industrial IoT applications, certification is mandated.

Reputation and trust

Speaking of reputational damage, this can be severe. Developers of devices who have multiple customers will know that confidence in the quality of the product is key. Devices that develop a reputation for unexpected failure or poor performance can be difficult to market and can seriously hinder commercial growth.

Total Cost of Ownership

Replacing batteries more frequently than expected increases both material and labor costs.

Devices deployed in smart cities, such as underground meters, or those deployed in remote environments are particularly expensive to service. Unexpected battery failure forces physical interventions and negates any savings from cheap batteries.

Sustainability

Constantly having to replace failed batteries increases waste and sets back a company’s sustainability goals. Not only is this damaging to the environment, but regulations (such as that effective in the EU since mid-2024) now mandate stricter energy efficiency and waste standards, meaning poor battery performance may trigger compliance costs or penalties.

Avoiding the common mistakes

Jean-François Savin, one of our Application Engineers, joined Saft in 1987. It would be fair to say he’s seen his share of horror stories from customers who’ve come to Saft having had bad experiences with batteries.

“I’ve seen quite a few different cases where the wrong battery was chosen because the cell selection was an afterthought,” he says. “You need to think about the battery at the outset of the project and really ‘look behind the wall’ of information and understand the various factors that come into play.”

“The most common question I get from customers who have come to us is, ‘Why did my battery not last as long as I expected?’. Sometimes they’ve underestimated the needs of their device, or maybe not accounted for a loss of capacity due to discharge. Even if discharge is small, over a ten-year lifespan that can really impact performance over time. And whenever you have to alter the product design and change your power source you run into complications of cost, and sometimes not even having the required space in the device to hold the battery.”

The best advice, he says, is to invest plenty of time in the design process and take advantage of online tools and datasheets to better refine your search. Saft’s IoT Smart Selector is one such tool that helps guide developers through device parameters towards possible battery solutions.

“I think that can be a good starting place. But even some datasheets can be misleading. We’re confident in the accuracy of our datasheets, but there are definitely cases I’ve seen where customers have been ‘sold a dream’ by what was promised on a datasheet. Sometimes the quoted figures are closer to a battery’s potential performance than its actual performance.”

“So, it’s always worth complementing independent research with conversations with battery experts. There might multiple possible solutions – maybe you would be better off adding a capacitor to a cell to achieve the required current and voltage, for example – and an expert can really help guide you through the process and the full range of options. More often than not it will save you time and money by getting the right battery solution from the outset.”