Hard Facts About Data Center Reliability
One hard fact about data center Uninterruptible Power Supplies (UPS) is that the very system that is supposed to prevent an outage – the UPS – is too often the cause of it.
In its Annual Outage Analysis 2021, Uptime Institute referenced its 2020 global survey that shows on-site power failure is still the biggest cause of significant outages, accounting for 37% of the total.
Of those power-related outages, the number one root cause at 53% was failure of the UPS.
This is an increasingly serious issue, as the Uptime Institute research also suggests that the cost of outages is rising, with over half of the those studied saying their outages cost them more than $100,000. “Each year, there are certainly many cases that cost several million dollars, or tens of millions,” the Uptime Institute reports.
“The number one root cause of on-site power failures within data centers is failure of the UPS. – Uptime Institute, 2021”
So when considering data center reliability and its impact on the business bottom line, it’s important to take a hard look at the UPS, and the batteries that power it.
What Happens When Battery Strings Fail
While lead-acid batteries have been the workhorse technology for decades, data center operators have new choices, particularly lithium-ion and nickel-zinc, with distinctly different reliability characteristics.
One distinct reliability advantage is the ability to sustain battery discharge despite failure of an individual battery cell. In a UPS system, individual batteries are connected in a serial string (often paralleled) to support the required system voltage, power output and run time. When a lead-acid and lithium-ion cell fails, it creates a high impedance or an open circuit that halts battery string operation. The UPS system has then lost some or all of its back-up capacity and the data center is at unnecessary risk.
Unlike lead-acid and lithium-ion, NiZn cells remain conductive when they are weak or depleted, which allows for continuous string operation and uninterrupted uptime. This capability delivers a distinct increase in battery string reliability.
Moreover, this critical difference in string operation changes what would be an emergency situation due to a lead-acid or lithium-ion battery cell failure into a simple replacement of a NiZn battery at the next planned maintenance cycle with no operational impact along the way. Maintenance costs are managed, along with the risk of outage.
“NiZn cells remain conductive even when they are weak or depleted, a capability that delivers a distinct increase in battery string reliability.”
Reliability and Long Life Reduce OpEx Costs
There are other characteristics of NiZn batteries that make UPS systems more reliable. First, NiZn is an alkaline chemistry that does not sulfate over time, a contributing factor to an operational life as long as three lead-acid battery replacement cycles. Longer product life and fewer replacements naturally leads to a more reliable UPS system.
Moreover, ZincFive NiZn batteries operate over a wider operating temperature range, so they can endure accidental high heat excursions, such as a cooling system failure, without compromising the performance or voiding the warranty. Unlike lead-acid batteries, they do not require trickle charging to maintain capacity performance, which simplifies system design and increases energy efficiency.
In sum, less maintenance, fewer replacements, simpler design and higher efficiency all serve to reduce the operating expenditure (OpEx) costs.
Greater reliability and lower OpEx? That’s not hard to appreciate.
See the whole story about why NiZn batteries are a better choice for battery backup in your data center UPS by downloading the tech brief The Ideal Battery for Backup.