Background: If the starter battery of an automobile is discharged accidentally (for example, by leaving the lights on overnight), it can be recharged enough to start the car in only a few minutes. Product Resources, Inc. was engaged by a consumer product marketing company to design and manufacture a portable power source which will re-energize a discharged battery via the automobile cigar lighter socket, thereby eliminating the need for a stranded motorist to find a good Samaritan and a set of jumper cables.

Project: The product operates by transferring the energy from an internal rechargeable battery into the car battery. The voltage of the internal battery must be no more than 12 volts to enable it to be recharged by the automobile alternator, but this must be boosted to 14 volts to quickly charge the car battery. At the same time, the charging current must be limited to prevent, among other things, blowing the fuse that protects the cigar lighter socket. Of course, being a consumer product, it must have a low cost of manufacture and be incapable of causing injury even if grossly abused. Patents covering existing competitive products required Product Resources to invent a new technique to generate 14 volts from a nominal 12 volt battery. A U.S. patent has been granted.

The product was completely designed by Product Resources' engineers and a production cell set up to produce fully functionally tested units at the rate of 200 per day. The first production run achieved a quality rating of 98.3% immediately upon startup.

Technologies: high frequency switching boost converter, lead acid battery charge and discharge, application of PTC thermistors, wide temperature range operation, sheetmetal and injection molded plastic enclosure design, low cost assembly and test techniques

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