Hybrid Power Pack (Ultra Capacitor + Battery) for Two Wheelers Fitted with Starter Motor

Self-start two-wheelers, including motorcycles and scooters between 50 - 200 cc capacity, use standard lead-acid battery of 5, 9 and 12 Ah rating as energy source. Battery is a well-known energy source but cannot supply large amount of power in short time. The size of the battery is decided based on the starter motor requirement. Deep discharge at the time of cranking reduces the life of the battery drastically as compared to normal use. Extra factor of safety is provided for cold weather cranking performance, poor maintenance and end of life performance in view of deep discharge. Hence it is heavy and bulky. On the other hand, ultracapacitors can supply large burst of power for short time but can not store much energy (hence limited number of starts). It is seen that in Hybrid Power pack (ultracapacitor + down sized Battery) the major power requirement at the time of cranking is taken by ultracapacitor resulting in reduced load on the battery thereby making it possible to be downsized. This paper describes how a Hybrid Power pack utilizes the strengths of both, resulting in a unit which is economical, maintenance free, low in weight with good cold start capability.