Main Drive Power (MDP) considerations.
If the snowmobile has to drive a 62 mile (approx) course with a 12 mile extended range capability at a constant speed of 5 miles per hour, it would take the snowmobile almost 15 hours to return to base. As a guess, I'll assume the snowmobile can accomplish this task with a 28V DC motor at a constant 20A draw. If I were to use a Lithium Maganese Nickel (LiMnNi) Polymer Li-Ion Cell rated at 3.7V 40Ah weighing 2.8 lbs, I would need approximately 8 cells.
28V / 3.7V per cell = about 8 cells
New Voltage = 29.6V wich is OK
Since each cell has a capacity of 40Ah, 8 cells would give us 320 Ah total
Each cell cost about $200, our cost would be $1600 (estimated)
Total run time is now limited to 320 Ah / 20A constant draw = 16 Hours
Total weight of battery pack is 2.8 lbs per cell x 8 cells = 22.4 lbs
You can review the LiMnNi Polymer Li-Ion Cell at: