Battery manufacturers such as U.S. Battery know that flooded lead-acid battery technology is still the most cost effective for golf cars and other global industries utilizing battery operated vehicles and equipment. Aside from the company’s recognition as a top customer service provider to small and large corporations, U.S. Battery also dedicates itself to examining new ways to improve the performance of deep-cycle, flooded lead-acid battery technology. In 2016, for example, U.S. Battery redesigned its most popular golf car battery line and created flooded lead-acid batteries that are more efficient and provide a better value for individual consumers as well as for use in a variety of global industries. The result was the launch of the company’s Endurance Plus batteries that are available in six, eight and 12-volt models.
Although the company’s products were already well known for providing maximum performance and life, its latest advancements pushed the capabilities of flooded lead-acid batteries further. These include the highest initial capacity, fastest cycle-up time to full-rated capacity, improved recharge-ability, and the highest total energy delivered of any battery in its class.
While these improvements are definitely noteworthy and have been embraced by a majority of industries who utilize and depend on fleets of battery powered vehicles, the marketing and cost comparisons with lithium-ion batteries have taken the front stage over any news on advancements in flooded lead-acid battery technology, and its greater environmental sustainability over lithium-ion batteries.
The battery industry and battery experts are quick to point out, however, that although lithium-ion has its place in many industries and technologies, it doesn’t translate to the same expected results in other applications. Golf car owners and fleets need to have all of the information before attempting to utilize lithium-ion as a less-expensive alternative, as not all of the actual costs of switching to lithium batteries are fully disclosed.
An example of this was a recent article in the Summer 2017 edition of Battery and Energy Storage Technology Magazine, where technical editor Dr. Mike McDonagh points out the half-truths put out by the lithium industry. “Energy densities of current lithium-ion battery chemistries are given at around three to five times the gravimetric and volumetric energy density of lead-acid at the cell level, which in part, explains why the older technology has been all but ignored,” said McDonagh. “Factor in the connectors, spacing in a battery pack, the control and safety equipment, battery management system, fire control, and cooling equipment which are required for the safe operation of larger lithium-ion batteries, and the net result is that an installed working lithium-ion battery will have a working capacity less than one-half its nameplate value.”
According to Fred Wehmeyer, Senior VP of Engineering for U.S. Battery Manufacturing, when you add up the actual costs of each type of system, there’s a discrepancy. In a recently published comparison between a 48-volt Lithium-ion battery pack and a 48-volt Flooded Lead-Acid battery pack for a typical golf car, Wehmeyer says the total cost comparison was not accurate because not all the necessary components to operate a lithium system were provided. “The comparison was between a 240 Ah – 48-volt (11,520 Watt-hr) lead acid battery and a 60 Ah – 48-volt (2880 Watt-hr) lithium ion battery. The result of the comparison was that the lithium-ion battery had a weight savings of 422 lbs with an expected life of five to 10 times that of the lead-acid battery,” said Wehmeyer. “Even though the comparison included a battery management system (BMS), it did not appear to include thermal management, fire control and a new charger necessary for safe operation.” Even without these safety features, the cost of the lithium-ion pack was $0.42 – 0.52 per watt-hr vs $0.07 –0.10 per watt-hr for the lead-acid pack.
“The lithium battery has only 25 percent of the energy of the lead acid battery and still costs 50 percent more (if the data are accurate),” says Wehmeyer. “Since the energy of the battery pack translates directly to driving range, the lithium battery would have 25 percent of the driving range of the lead acid battery. Driving range directly affects depth of discharge (DOD). If driving the same distance, the DOD of the lead acid battery would be only 20 percent (25% x 80%). This would increase the cycle life from 650 cycles at 80 percent DOD, to 3300 cycles at 20 percent DOD. This compares well with the lithium battery at 2,000 cycles. The information given on the 5,000 cycle upper limit for lithium is for single lithium cells cycled in the lab under optimum conditions.”
Comparisons like these can be misleading especially given that many of them are also done in a laboratory environment, not in real-world settings. “The performance data given in comparison between lithium-ion and flooded lead-acid batteries is often done with a single cell,” said McDonagh in his article. “This type of comparison, however, does not include any additional components needed for proper operation. The data very conveniently ignores the additional architecture required for safe operation in most installations and it is safety that manufacturers claim is their greatest concern.”
According to Wehmeyer, it’s important for anyone making a comparison to add in all of the costs. “A single LiFePO4 cell has a nominal voltage of 3.2-volts, thus requiring eight cells in series for a 24-volt batt ery pack – double that for a 48-volt system,” said Wehmeyer. “Th e average retail price of one 100 Ahr (amp-hour) cell is $155, putting the pack cost around $2480 for an average golf car. A compatible BMS and charger cost $290 and $1075 respectively. Altogether, a conversion would cost $3845 and will provide a reported 2000 cycles at a lower energy content of 5120 watt -hours vs 10,500 watt -hours for a comparable flooded lead-acid battery pack costing about $800. Th e lead-acid battery would provide twice the runtime for 1/5 the cost.
Despite the actual operational costs involved, there’s also an issue of environmental factors. Concern over the environmental impact of batteries must also be addressed in any comparison between lithium-ion and flooded lead-acid technology. According to the Battery Council International, the governing body of the battery industry, the recycling rate of flooded lead-acid batteries in the United States is greater than 99 percent. “When you take into account environmental cost and safety, on top of the performance issues, the lithium-ion case over lead-acid doesn’t stack up to anything as manufacturers would have you believe,” said McDonagh in his article. “You need to look very carefully at their numbers. Lead-acid is a safe sound and, sadly, overlooked technology that’s 150 years young and completely recyclable.” More information on the performance, easier maintenance and ways to lower annual operating costs using flooded lead-acid batteries can be found on the U.S. Battery Manufacturing website, www.usbattery.com.