There are a lot of electric three wheelers (Locally called TomTom) in Bangladesh used by the Ready Made Garments factory workers to go to their workplace.  This Three Wheelers are powered by mainly lead acid  battery pack that has to be replaced every year. Since one of the Three Wheeler manufacturers wanted to introduce lithium ion battery pack in their vehicle, we had the opportunity to design, prototype and test new lithium ion battery in the existing vehicle. We have studied the existing drivetrain of the vehicle and analyzed the power and energy demand of the vehicle. Based on that, we designed this battery pack. Our design pack has performed satisfactorily and we have got the initial order to deliver 300 battery pack for that company. We are now supplying the packs the company and the new vehicles has our batter pack as the power source.