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Historically, lead acid batteries have been the most commonly utilized backup power source for uninterruptible power supplies. While newer technologies are quickly gaining traction in the mission critical industry, lead acid still remains a relatively popular choice for many use cases.
If you’re considering lead acid to power your UPS, there are three battery types to consider:
VRLA (valve-regulated lead acid)
VLA (vented lead acid)
also referred to as wet cell or flooded cell
Pure Lead VRLA
Finding the right battery for your UPS requires consideration of:
Required runtime
Expected life
of the battery/ replacement interval
Cost
Operating conditions
such as temperature
The types of lead acid batteries all have different characteristics, so each choice much be carefully considered. Learn more about the different types below or explore upgrading to lithium ion.
VRLA batteries have been the most prevalent type of battery utilized for UPS applications due to the benefits they offer over the more traditional VLA battery type; they are a “sealed” battery in that the only venting to the atmosphere is a one-way safety pressure relief valve. Because of the “sealed” nature of the design, the batteries (1) do not lose electrolyte; (2) are leak proof; and (3) can be installed in any position.
All of these benefits mean that VRLA batteries require less maintenance than VLA type batteries. While the maintenance is minimal, it is recommended to perform regularly scheduled maintenance checks and monitor the batteries to verify their condition and help mitigate the risk of thermal runaway.
Out of the different types of lead acid batteries, VRLA tend to be the most cost-effective solution for the initial upfront investment. They have good performance and work well for most runtime requirements outside of long (hour plus) situations, but do sacrifice lifespan compared to the other lead acid types.
While VRLA batteries have a design life of 10 years, they realistically need to be replaced every 4-5 years to ensure peak performance.
Battery life can be adversely affected when constantly subjected to a higher ambient temperature than recommended by the manufacturer. Discharge cycles for the batteries also factor into life expectancy, with the rate, length, and frequency of the discharge all playing a role. Lastly, charging attributes influence VRLA battery life; they should be maintained at a float voltage equal to or below the battery manufacturer’s recommendation. Exceeding this preferred value will lead to an overcharge situation and reduce battery life.
Mitsubishi Electric works with several trusted vendors to provide VRLA UPS lead acid batteries. Whether you are replacing an existing battery or choosing an option for a new UPS installation, Mitsubishi Electric can help you make your decision. Browse the runtime graphs below to find the right capacity and performance for your needs.
Check out the various safety data sheets for VRLA batteries from our trusted vendors.
For additional questions, a quote, or to inquire about upgrading to Lithium Ion
Known properly as a VLA (Vented Lead Acid) battery, wet cell batteries differ from VRLA batteries in that they utilize a vent to allow gas to escape to the atmosphere. They are typically encased in large clear enclosures so end users can inspect the levels of liquid electrolyte and condition of the actual lead plates.
Compared to VRLA, VLA batteries provide a considerably longer life (up to 20 years) and do not require the frequent replacements, while also being more resistant to overcharging than a VRLA battery. VLAs also typically have longer runtimes than other options and are commonly used in the telecommunications and utility industries.
For these reasons, wet cell batteries may command a higher up-front cost than VRLAs, but if long runtimes and life are needed, the total cost of ownership can work out in their favor.
Even though VLA batteries have a longer lifespan, they do require more maintenance over its lifespan compared to VRLA batteries.
Because they are vented to the atmosphere, it is essential to monitor electrolytic fluid on a continual basis, adding water periodically to ensure that proper fluid levels are maintained. VLA battery installations are physically larger than VRLAs and always rack mounted (as opposed to being installed in a cabinet) to provide easy maintenance access and avoid damage from any spills. As the liquid electrolyte present in VLA batteries is corrosive, spill containment systems and hydrogen monitoring are required.
Mitsubishi Electric works with a number of trusted vendors, so if you are considering wet cell batteries for their extended runtime and longevity, you can contact us to review your application and needs.
Check out the safety data sheets for VLA batteries from our trusted vendors.
Pure lead batteries have become a popular alternative to regular VRLA and VLA batteries and, in some cases, where there is concerns about lithium ion batteries from authority have jurisdiction (AHJ).
Pure lead batteries are a type of VRLA battery but have some differences compared to the traditional VRLA people are often familiar with. Though each manufacturer has differences in what they refer to as pure lead batteries, the two most common traits are:
Pure lead batteries deliver several desirable characteristics, such as a prolonged lifespan (12-year design life), longer warranties, longer shelf life without needing charged, and can be designed for a higher tolerance of increased temperatures.
Another defining feature is, in cases where an under five-minute runtime is all that is needed, a pure lead battery solution can accomplish this whereas regular VRLA batteries cannot be applied or are not warrantied.
These more appealing features do, however, come with an upfront cost that is slightly than VRLA but less than VLA.
You will need to assess your cost/benefit priorities before making a decision. As pure lead batteries need to be replaced less often than their VRLA counterparts, the higher upfront cost could be worthwhile – especially if you only require the short 5 minute or less runtime.
Mitsubishi Electric works with industry-leading vendors to provide pure lead battery options compatible with our UPS systems. Browse the runtime graphs below to find the right capacity and performance for your needs.
Check out the safety data sheets for pure lead batteries from our trusted vendors.
Explore our runtime vs. load graphs for VRLA batteries.