IT Management

Recommendations for Prolonging the Life of Your UPS Battery

The forecasted lifespan of the valve-regulated lead-acid (VRLA) battery in an APC by Schneider Electric UPS is 3 to 5 years under recommended conditions; however, this life expectancy will fluctuate greatly depending on the following factors.  Being proactive and aware of these characteristics and conditions will ensure you maximize the life expectancy of your battery and are prepared for any imminent power failures.


Unit Placement

When installing a UPS, the user should determine where to install the unit to best provide power protection of the IT equipment in the room.  It is recommended that the UPS be installed in a temperature controlled environment similar to the intended application.  The UPS should not be placed near open windows or areas that contain high amounts of moisture; and the environment should be free of excessive dust and corrosive fumes.  Do not operate the UPS where the temperature and humidity are outside the specified limits.  The ventilation openings at the front, side or rear of the unit must not be blocked.  Further discussion on cooling strategies can be found in White Paper 68, “Cooling Strategies for IT Wiring Closets and Small Rooms”.



Most single-phase UPS batteries are classified as “maintenance free” which leads many users to feel that monitoring and maintaining UPS batteries is unnecessary, however this is not the case.  A maintenance-free battery only refers to the fact that these batteries do not require any replacement fluid, therefore understanding how to properly care for and monitor batteries is essential.


Ambient Temperature

All batteries have a rated capacity which is determined based on specified conditions.  The rated capacity of a UPS battery is based on an ambient temperature of 25°C (77°F).  Operating the UPS under these conditions will maximize the life of the UPS and result in optimal performance.  While a UPS will continue to operate in varying temperatures, it is important to note that this will likely result in diminishing the performance and lifespan of your battery.  A general rule to remember is that for every 8.3°C (15°F) above the ambient temperature of 25°C (77°F), the life of the battery will be reduced by 50 percent.  Therefore, keeping a UPS at a comfortable temperature is crucial to maximizing UPS life and capabilities.



When a power failure occurs, the UPS will automatically switch to battery power to provide the attached equipment (load) energy.  Once utility power has been restored the UPS battery will automatically recharge to prepare for the next power outage, a process known as the discharge cycle.  The chemistry of a VRLA battery, like the one used in a single phase UPS, dictates that a battery can only undergo so many discharge/recharge cycles before it reaches the end of its usable life, and must be replaced.


At installation a battery is at 100 percent of its rated capacity, however each discharge and subsequent recharge will slightly decrease the relative capacity of a battery.  The length of the discharge cycle will determine by how much a battery’s capacity is reduced.  While cycling is a necessary part of UPS operation, being aware of the cycling frequency will help to predict the life of a UPS.



Battery Chemistry


A battery is determined to require a replacement when it has reached the end of its useful life, which is defined as when it can no longer supply 80% of its rated capacity.  When the battery reaches this aforementioned point, the degradation process speeds up, and a replacement battery is needed.  It is important to note that while the useful life of a battery is defined as losing 20% or more of its rated capacity, the effects on actual UPS runtime can be much greater.

Battery Storage


Proactive UPS owners may seek to purchase a replacement battery before one is necessary in order to avoid the potential consequences of downtime.  While this is an acceptable and even recommended practice, there are a few important factors to consider when placing your UPS battery into storage.


Inevitably, an unused battery will experience a life cycle decrease.  Lead-acid batteries like the ones used in UPS units experience automatic self-discharge, therefore it is recommended that a battery in storage be charged every 3 to 4 months.  Failing to maintain your UPS battery’s charge will result in permanent loss of capacity within 18 and 30 months.


If you are unwilling or unable to charge your battery while in storage, it is recommended the battery be stored at 50°F (10°C) or less.  Doing so will slow the degradation cycle of the battery, and help to maximize its life expectancy.


UPSs and their associated batteries are designed to be durable and dependable; however maximizing the life of your device requires proper care from the user.  Most users are aware that batteries will eventually need replacement, however many overlook the importance of the battery’s maintenance.  Temperature, and cycling frequency are the two characteristics that should be most closely monitored, however the importance of periodic inspections, placement, and storage cannot be overlooked.


Batteries that last the longest, and provide the best performance are consistently the ones that are being provided the best management and care.  Providing optimal oversight to for your UPS battery should be simple; just make sure you understand the factors discussed and that your plan is simple, consistent and proactive in nature.

18 Responses to “Recommendations for Prolonging the Life of Your UPS Battery”

  1. todd chavey

    what will happen if my UPS is in an area or room that sometimes gets to 80 degrees or more with humidity. thanks.

    • Justin Solis Justin Solis

      Hi Todd,

      Higher than recommended temperatures can be harmful to both your UPS and its battery. The American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) recommends operating temperatures for IT equipment like your UPS to be between 20-25°C (68-77°F). The allowable temperature range is 15-32°C (59-90°F). Your UPS will continue to operate in the allowable temperature range, and possibly even beyond, however the further away you get from the recommended ambient temperature of 25°C (77°F), the more the lifespan of your electronics will be decreased. Specifically concerning the battery, a general rule to remember is that for approximately every 10°C (18°F) above the ambient temperature of 25°C (77°F), the life of the battery will be reduced by 50 percent. If you refer to white paper 210 ( you can see a graph of the life expectancy of the VRLA battery decreasing as the operating temperature increases. As far as the UPS itself, this rule does not necessarily coincide exactly, but the principle is the same. The more you exceed the ambient recommended temperature, the more the availability and longevity of your equipment will decrease. 80°F is not far from the ambient recommended temperature of 77°F, therefore I would not expect any lifespan decreases to be substantial, especially if the environment only increases to this temperature occasionally. For further discussion on cooling strategies, please refer to white paper 68 (


  2. Cedric

    Is it recommanded to cycle a UPS battery that is in use. I mean, is it recommended to disconnect the UPS from the main power and then have it discharge completely once every 3 months or so?
    Or if the UPS is plugged in and in use, nothing is required?

    Thank you,

  3. Justin Solis Justin Solis

    Hi Almograve,

    No, we do not recommend any sort of proactive cycling. If you feel the runtime being reported by your UPS may be off, you can run a calibration via an NMC or PCBE, however you should try to avoid doing so more than one every 6 months to a year. Every deep discharge will shorten the lifespan of your battery, so you would want to avoid that whenever possible.


  4. Syed


    I want to know what is the general batteries life for UPS, like when do i replace the batteries. UPS and Batteries are used for critical area.

    • Justin Solis Justin Solis

      Hi Syed,

      The typical lifespan of the batteries used inside most APC UPSs is 3-5 years under recommended conditions; however based on the factors noted above, this lifespan could be reduced. If you are able to provide proper storage to replacement battery, you should be able to order the appropriate model through our UPS Upgrade Selector (

      Here are some tips on providing proper storage to an unused replacement battery for your APC UPS.

      “Lead-acid batteries like the ones used in single-phase UPS units experience automatic self-discharge, therefore it is recommended that a battery in storage be charged every 6 months. Regardless of the frequency of battery recharge, cumulative storage time should not exceed one year. Failure to follow these recommendations will result in permanent loss of capacity within 18 to 30 months.

      If it is not feasible to charge a battery while in storage, it is recommended that the battery be stored at 10°C (50°F) or less. Doing so will slow the degradation cycle of the battery, and help to maximize its life expectancy.”

      For more information please refer to Whitepaper 210, Single Phase UPS Management, Maintenance, and Lifecycle. (

  5. Mike Fujan

    What happens if a battery is “too” cold. we have a UPS room that trips an alarm if the temp gets above 77 degrees, the battery temp is about 70 degrees. what is the lowest that we can get the room and not damage the batteries. I have heard that cool batteries overcharge – is this true and if so, what is the best temp range to keep our batteries? thanks

    • Justin Solis Justin Solis

      Hi Mike,

      The biggest issue affecting batteries is heat, and running a unit in a sustained warm environment can cause a shortened life span and premature battery failure. A general rule of thumb is that for every 15°F increase in temperature over 77°F, lifespan will be decreased by 50%. On the colder side of things, you will see reduced runtime, but it generally will not have an adverse effect of the actual life cycle of the batteries. You may find that the runtime estimate provided by the UPS is not as accurate as the temperature drops. Below 32°F runtime will decline very rapidly and may quickly approach zero. For optimum performance we recommend an ambient temperature of 68-77°F.

  6. Mohan Radhakrishnan

    The dealer told me that he has to use more distilled water after about 8 months. Is that correct ? They mentioned this procedure is required every 3 months. Where do I get a comprehensive maintenance guide to verify these claims ?

  7. Robert

    My questions are similar to Mike’s.

    If we are willing to sacrifice some battery run time in a UPS application to extend battery life, will maintaining the battery at a lower temperature extend the battery life? If every 15F increase in temp reduces lifespan by 50% then what is the corresponding increase in lifespan for every 15F (or every 1F) below 77F?

    Also, will the battery float charge voltage need to be reduced if the battery is maintained at a lower temperature. If so, by how much per degree F?

    Thanks for your help.

    • Justin Solis Justin Solis

      Hi Robert,

      The optimum temperature for a lead acid battery is 77°F . It is important to remember that the temperature inside your UPS will be several degrees warmer than the ambient temperature in the install location. We generally find the optimum ambient temperature to be 68°F. As you mentioned, every 77°F increase in temp reduces lifespan by 50%, unfortunately lowering temperatures does not have the same impact on battery life. As you get colder however, you will start to see a decline in runtime from the battery, which becomes a significant issue below 50°F. Below 50°F you should also rightfully start to scale back on charging rates. Back-UPS and Smart-UPS models do not have user adjustable charge rates. These models are best left to data center and (home) office type environments. Chances are, if you are comfortable with the temperature, your UPS will be too.


  8. Jason

    Great Article.
    My question is how the cycles happen? If out of power, then back in 1 minute, will that be a cycle?
    Also if out of power, is it better to shut computer down immediately or wait the UPS to automatically turn off?

  9. Justin Solis Justin Solis

    Hi Jason,

    The length of the discharge cycle will determine by how much a battery’s capacity is reduced. Therefore, as an example, if the power is out for 5 minutes, but the UPS had 20 minutes of available runtime at full capacity, this will equate to approximately 0.25 discharges. If the battery is completely depleted, that will equate to an entire (100%) discharge.

    From the chart above, you can see if if the average discharge depth is 100% (the battery is completely depleted), you can expect the battery to last for 200 – 300 cycles. However, if the average discharge is only 30% (70% of the battery power remains when the power comes back) you can expect it to last for approximately 1100 to 1200 cycles.

    In regards to your second question, that is really up to you, the user. The less the battery is depleted during a cycle, the longer it will last. However, even at complete discharges you can expect the battery to last for up to 300 cycles. So it really depends on you using your best judgement to weigh continuing working and slightly shortening the batteries life vs. safely shutting down as soon as possible and maximizing the remaining life of the battery.


  10. Brace headon

    I got a replacement last week for bx1100 that only lasted short of 2 years. under warrenty thankfully. the new unit I got is BX1400UI a higher capacity which can be connected via USB, pretty neat. normal use my setup consumes 170w and under load it goes a little over 300w. the APC service guy told me I should run a full discharge once every 1 or 2 month if I didn’t get any power cut, is that correct ? I hope this one lasts me for 3 years. it will probably get discharged 3 to 5 times a year. unless something happened. would it last me for 3 years?

  11. Justin Solis Justin Solis

    Hi Brace,

    Apologies for the miscommunication with the APC service representative you spoke to, but we do not recommend a periodic full discharge and recharge of VRLA batteries like the one in the BX1200UI you referenced. Unfortunately, we cannot say with certainty that the battery in your APC UPS will last 3+ years, because there are a lot of variables that must be taken into account. As the blog above references, the lifespan of your battery is dependent upon: unit placement, maintenance, ambient temperature, the number of discharge cycles, and the battery’s chemistry. Variances in any of these factors will affect the life of the battery; however, if you take the above recommendations you should be able to make sure you get the most out of the battery, and maximize its lifespan.



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