Product Information

Executive Summary

Our project, the Sun Start, first originated as a general need for a more efficient car jumper system. Before the existence of our product, no other car jumper system was rechargeable via solar energy. Some solar powered products existed to slowly recharge batteries, but none existed to actually jump start vehicles. Our goal was to enable a pre-existing jumper battery the ability to recharge without a wall outlet. This was achieved by incorporating a solar panel and regulator circuit as a new power source. Instead of using a common wall-outlet AC adaptor which requires a nearby outlet, our design requires nothing more than sunlight.

Normal jumper batteries lose power quickly after use, and in certain circumstances a user may not have the luxury of a nearby power outlet to aid recharging. Therefore our design gives the user the freedom to ignore location, and recharge wherever there is sunlight.

Our design process was essentially targeted at replacing the existing AC adaptor. We created a regulator circuit which took the power created by the solar panel and regulated it to match the input requirements of the battery. Once we had the regulator circuit designed, we needed to test its real life capabilities. After testing we further adjusted the variables controlling the regulator’s output until it matched the AC adaptor of the battery. We then drained the jumper battery, and recharged it with only sunlight. This concluded in a success and the product was finalized.

Design Objectives and System Overview

Our design process started with choosing a jumper battery to modify. The jumper battery we chose gave a 300 Amp output which was sufficient to start common vehicles. The battery was also one of the more economical choices, as we also aimed to reduce price as much as possi-ble. Once we obtained the battery, we analyzed it and determined its input requirements. Once the recharging input requirements were determined, we sought out to purchase a solar panel that would fit our requirements.

When choosing the solar panel, we decided to go towards the new flexible technology that has recently become available. We knew that a flexible solar panel gave our design much more du-rability and freedom. The product was intended for road use, and most likely would be stored in a trunk or back seat. It was too unreliable to have a rigid solar panel, as common use rendered a high probability of damage. Therefore a flexible panel with slightly higher power output was chosen. We chose a higher power output because we knew some situations would yield less sunlight, so we overshot to compensate this environmental factor.

Next we designed a zener diode based regulator circuit, which took the variable sunlight energy and converted it into a stable output. We also implemented a circuit involving two LED lights to indicate when charging was complete.

High-level description

Our High-Level design was implemented in the following manner. The solar panel first took in sunlight generated by the sun and turned it into a DC power source. That DC power source was then lead through a regulator circuit which reduced it to operating levels. That output was then fed into the jumper battery, which when low absorbed the power. Once the jumper battery was fully charged, the clamps could be attached to the dead car’s terminals and the jump start could be initialized.

The operating inputs of the jumper battery were 13 V by 300 mA, and after testing and design we found a regulator circuit yielding 12 V by 300 mA gave the best recharge results. The solar panel itself yielded an output of 20 V – 15 V, so we had to lower its output accordingly with the regulator circuit.