Why don't you just think about replacing your lead-acid batteries with lithium(-ion) ones when they are unable to hold a charge anymore? Lithium batteries are becoming the standard for renewable energy storage. No matter which dimension to consider, such as DOD (Depth of Discharge), Cycle count, Charge/Discharge Rate, Voltage Sag, Size, Weight, and safety and so many other aspects, you can absolutely replace lead acid batteries with lithium（-ion) instead of restoring lead acid batteries that are clearly past their prime.

Jetspower as a factory direct brand, is a lithium battery solution provider specializing in the field of overseas industrial vehicles, with production plants based in Xuzhou, Jiangsu Province, Luoyang, Henan Province and Bengbu, Anhui Province. We have spent more than 10 years serving more than 1254 domestic mining and industrial vehicle enterprises with the brand name of FREY, and now we are using Jetspower brand to practice our professional, reliable and high-end service concept for global customers. In the past over 5 years, based on China
University of Mining and Technology, Chinese Academy of Science and its various Battery Research Institutes, Jetspower has been served hundreds of clients in many fields such as industrial vehicles, mining, energy storage, robots and etc..

Lithium-ion has a higher upfront cost, but can have a dramatic effect on the bottom line over time. Our analysis of customer usage shows that lithium batteries save nearly 50% of the total cost per forklift compared to lead-acid batteries.