Hello guys. I was wondering what you think about the instant battery jump starter that plugs right into the cigar. lighter area? Do they really work? I've seen those a lot and they claim they will jump start your car w/o having a second car hooked up to yours. Thank you for your replies.

This is my first time hearing of this.

Will it cross and give the whole system a shock?

The trick of using the jumper thru the cigar lighters is to charge the dead battery first. Once the dead battery is charged to certain point via the cigar lighter; the dead battery now providing some current plus the current coming from a good battery, you should be able to start the car unless the dead battery is very dead and/or bad battery terminals. The jumper cable should have a current limiter so that burning the wire or fuse in both cars is not an issue. The problems I found are the poor contacts inside the cigar lighters and the time to charge the dead battery. It is much easier using a regular jumper cable with caution.

David