Case Study
Are lithium-ion batteries really not worth the cost?
Comparing UPSs by battery life
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Lithium-ion battery has recently started being used in UPSs (uninterruptible power supplies), and it is attracting attention for a variety of benefits it offers compared to the conventional lead-acid battery.
However, we hear our customers say, "I know they have a long life, but they are expensive, right?"
So, is this really the case? In this article, we will introduce the features of lithium-ion battery and the time- and cost-saving benefits it offers.
Lithium-ion batteries have been rapidly adopted in various industries in recent years. What are the advantages of this? We will explain by comparing them with the lead-acid batteries conventionally used in UPSs.
While the expected life of lead-acid battery is generally 2 to 5 years(1), lithium-ion batteries have an expected life of about 10 years.(2) 10 years is equivalent to the expected life of the UPS itself(2), so the advantage is that the UPS can be renewed without ever having battery replacement. On the other hand, lead-acid batteries need to be replaced once or twice.
(1) At 25°C ambient temperature.
(2) For SANUPS A11K series.
Lithium-ion batteries have the advantage of being very compact and lightweight. Therefore, the UPS itself, which carries the batteries, can also be made very compact and lightweight. Compared with lead-acid battery UPSs, some models have been downsized to about half the volume(3) while others are about 40% or more than 30 kg less in weight.(3)
Reduced size is appreciated as we want to save space.
(3) Depends on the capacity and backup time. Contact us for details.
▲Comparison of volume and size (Lead-acid battery UPS vs. Lithium-ion battery UPS)
Compared to lead-acid batteries, lithium-ion battery UPS has the advantages as explained above. However, we often hear our customers say, "We prefer the lead-acid battery UPS. That should do the job."
SANYO DENKI is confident that lithium-ion batteries are more beneficial in terms of total costs and maintenance labor and we will explain three reasons hereafter.
As shown in the battery life comparison, lithium-ion batteries have a life expectancy of 10 years(1) which is equivalent to the service life of the UPS itself, while lead-acid batteries have a life expectancy of about 2 to 5 years.(1) This means that the battery will need to be replaced once or twice between the first purchase of the UPS and when it comes to the time of replacement.
The costs for this are not only the cost for the battery itself but also include the replacement work cost. There are many cases where the total cost of a lithium-ion battery UPS is lower when the cost of replacement batteries and work are considered.
(1) At 25°C ambient temperature.
Replacing UPS batteries is not only costly but also time-consuming.
The work involved in battery replacement is not limited to inquiries and battery selection. Careful consideration must be given to the peripherals involved in turning off the UPS when replacing it, and this may incur an outsourcing cost for an external contractor.(4) Lithium-ion batteries eliminate the need for battery replacement, so UPSs can be used without any worries.
Preferably, it would be less time-consuming and costly to replace the battery once before a new UPS is needed.
As shown in the comparison of UPS size and equipment weight, lithium-ion battery UPSs are compact in size and weight, reducing the labor involved when installing UPSs.
(4) Hot swapping allows battery replacement without interruptions to the load.
The difference in battery life creates not only replacement costs, but also another significant cost advantage. That is, lithium-ion batteries allow you to choose a UPS with a shorter backup time.
As a matter of fact, lead-acid batteries have a characteristic of capacity reduction due to aging deterioration. This capacity reduction refers to the time that the battery supplies power to load equipment in the event of a power failure, that is, decrease in battery backup time, over the years.
Take the case of a load equipment (800W) that requires 10 minutes of backup time for automatic shutdown.
For lead-acid battery UPSs, it is necessary to select "initial 30-minute backup time products" because the backup time will be halved or less after the battery service life of 5 years due to aging deterioration.
In addition, the battery will need to be replaced before the life of the equipment.
On the other hand, a lithium-ion battery UPS can maintain at least 80%(5) of its initial backup time even after 10 years, so if the "initial 13-minute backup time product" is selected, 10 minutes backup can be maintained even after 10 years of equipment service life.
Comparing the initial 30-minute lead acid battery UPS with the initial 13-minute lithium-ion battery UPS, some models(6) have a lower unit cost, so the lithium-ion battery UPS offers a reasonable cost advantage in terms of initial cost.
(5) Assuming a 25°C ambient temperature and 10 discharges per year on average, 80% of the initial backup time rating maintained after 10 years.
(6) Comparison between our A11K 1 kVA lead-acid battery UPS and lithium-ion battery UPS.
Considering these points, lithium-ion battery UPS, which you may have believed to be expensive, may end up costing less than lead-acid batteries in many cases.
| Product | Cost of product | Replacement battery cost | Replacement service cost | Replacement work time |
| LA battery UPS | Initial backup time rating should be over double the required time | Needed once or twice | Needed once or twice | Needed once or twice |
| Lithium-ion battery UPS | Initial backup time should only be slightly over the required time | Not necessary | Not necessary | Not necessary |
We offer a number of lithium-ion battery UPS product lines available. Here we will introduce the features and lineup of the SANUPS A11K-Li, which we recommend among them.
Automotive Part Manufacturer Company A (5000 Employees)
Company A is an automotive part manufacturer. They have installed UPSs as backups for the inspection equipment in their factory. The UPS required a 10 minutes backup time to safely store data and shut down in the event of a power outages.
Mr. Y, the factory manager, explains his concerns at the time.
"Since the factory operates 24/7, it is absolutely impossible to stop the inspection equipment. When replacing the battery of the UPS, we switch to bypass power supply and run the UPS, but if there is a power failure at that time, the inspection system will also be stopped. To prevent this risk, we wanted to ideally eliminate the battery replacement itself. I knew that lithium-ion UPS batteries have a long service life, but their expensive image prevented me to use them.
After hearing about the cost issues, a SANYO DENKI sales representative made a proposal as follows.
"Lithium-ion battery UPSs may seem costly, but they are not necessarily expensive when you consider the cost of battery replacement and the shorter backup time required for your model selection."
Mr. Y was interested in this story and asked for more details. He recounted it as follows.
"We could sort of imagine the reduction in battery replacement costs, but it was very surprising to hear about the backup time. While we needed 10 minutes backup time, we realized that a model with a initial value of 30 minutes had been selected anticipating deterioration with age. But with the lithium-ion UPS, we were told that 13 minutes(7) backup time would be sufficient. When we estimated the cost of the UPS, to our surprise, the lithium-ion UPS was less expensive," said Mr. Y.
Mr. Y began to consider adopting the UPS SANUPS A11K-Li and soon after, they officially decided to use them.
"The result was not only a reduction in the number of battery replacements, but realized cost savings UPS selection, and also reduced battery replacement costs. We thank SANYO DENKI for making a proposal that satisfied all our requirements," he said.
(7) Assuming a 25°C ambient temperature and 10 discharges per year on average, 80% of the initial backup time rating maintained after 10 years.
Reviewed by: Power Systems Business Group, Sales Headquarters, SANYO DENKI CO., LTD
Date of publication: September 13, 2022
