Comparative Study of Lead Acid and Lithium Ion Battery Used in Safa Tempo in Kathmandu Valley

Abstract

Safa tempo (clean vehicle) was introduced in Kathmandu valley in 1993 A.D to reduce air pollution of Kathmandu valley. Safa tempos are powered by lead acid and lithium ion batteries. There are 37 charging stations and 17 routes and about 700 safa tempos running every day. The quality of the conventional lead batteries used as the driving force for Safa tempos in Nepal are found degraded in course of time and their price increased. Because of this situation, answer to the profitability of the safa tempo in operation is needed. In 2017 lithium ion battery was introduced in Nepali market but it has high price, so tempo owners are confused as to choose which type of battery. The objective of this study is to compare and analyze the performance, income generation, energy consumed by both batteries. For this study, safa tempo powered by Trojan T-125 (240Ah, 72V (6V*12 no’s in series connection)) and Sinopoly LiFePO4 (300Ah, 76.8V (100Ah*3 no’s in parallel connection)) are chosen for the same route about 9 km length and one and same charging station is used. One set lithium ion battery can make 9 loops (81 km) per day while 2 sets of lead acid batteries can make 8 loops (72 km) per day. Energy consumed by safa tempo per loop with lithium ion battery is 2.21 kWh of energy per loop and with lead acid battery is 3.99 kWh of energy. The price of 1set lead acid batteries is 33% of 1set lithium ion battery. It is found that the average gross income generated per day by lithium ion (1set) battery is about 10% more than that of lead acid (2sets) batteries on a single charge. But in comparison with life span of both batteries, lithium ion battery generates 300% more income in comparison to lead acid battery. As per financial analysis, IRR (internal rate of return) for lithium ion and lead acid battery is found to be 42% and 16% respectively.