VRLA batteries have long been a preferred UPS energy source given their reliability, low initial purchase cost, and management ease. However, with the decreased price of lithium-ion batteries over the past few years, they’re quickly becoming a viable critical power option for data centers and critical environments of all sizes. But despite their rise in popularity, we’re still frequently asked about their benefits and the differences between lithium-ion and VRLA.
Here are a few things to consider when contemplating which battery to use.
Lithium-ion Battery Lifetime
To know how much you’re truly investing in a battery, you must weigh the lifetime. How soon you’ll need to replace the battery determines the end value and overall benefits. We measure lifetime in two different metrics: the service life and calendar life.
The service life is the estimated time a battery will last before it reaches 80% of its energy capacity, meaning the end of life for the battery. Service life is determined by the assumption that the battery is operating under everyday “real world” conditions; therefore, it can vary. The calendar life of the battery is the estimated time that the manufacturer has determined the battery will last if it were to remain trickle charged for its entire life, kept in perfect conditions, with no power outages.
The service life of a VRLA battery is typically 3-6 years. While more expensive at the time of purchase, the Li-ion battery can boast a service life of more than ten years.
Lithium-ion also provides a greater cycle life (the number of charge/discharge cycles ranges from extends into the thousands, versus approximately 500 for VRLA batteries). Additionally, lithium-ion UPSs can provide more runtime in the same footprint without the need for external battery modules (EBMs).
Size & Weight
Lithium-ion batteries not only have a smaller footprint due to their high energy density, but they are also much smaller in size. Compared to the VRLA batteries, the Li-ion batteries are 70% smaller and 60% lighter.
Several manufacturers now also offer lithium-ion battery solutions for small office/rackmount UPS. These are dramatically lighter than UPSs with VRLA batteries and the battery typically lasts the entire life of the UPS.
Lithium-ion UPS System Maintenance
The most common benefit our customers cite for making the switch to lithium-ion is their longer service life. IT professionals can easily deploy lithium-ion UPSs without the maintenance and refresh challenges typically associated with traditional lead acid batteries. The extended battery life enables users to align their UPS refresh cycles with the rest of IT stack, saving the time and money that would be spent on labor and battery replacement. This “set it and forget it” value proposition is especially appealing to edge environments or anywhere operations are critical yet IT resources are constrained.
Costs Associated with Lithium-ion Batteries
While the cost of lithium-ion battery systems for UPSs have plummeted 50-75% over the last four years, the initial setup and commissioning costs associated with lithium-ion are still more expensive than VRLA. However, the longer lithium-ion battery life of the UPS – 2x longer than VRLA – can eliminate the cost of procuring replacement batteries as well as the labor cost for in-person battery replacement. So, while it is true that the capital expenditure is higher for lithium-ion, the lower OPEX costs can offset the up-front investment for many of our customers.
Bottom line, Which Is Better?
While the initial cost of lithium-ion batteries is more than VRLA, and they cannot be put in series or parallel with other types of batteries, their many long-term benefits make them the smart choice.
- They require fewer replacements (if any) over the life of the UPS, eliminating the risk of downtime with battery replacement.
- Lithium-ion boasts up to ten times more discharge cycles and about four times less self-discharge.
- Lithium-ion batteries are three times lighter than their VRLA counterparts yet have the same amount of energy potential.
- Their charging capabilities are four times faster than VRLA.
- Longer standard warranty.
Want to make the switch from traditional valve-regulated lead acid batteries to lithium-ion? CEG can help. We can assess your specific power needs, as well as provide you with lithium-ion batteries, lithium-ion UPS systems, and retrofit systems which can include new cabinets and batteries. From enterprise to edge, we can address the critical power needs of infrastructures of all sizes. CONTACT US today to make the switch.