They do not have anything to do with you cars cigar lighter.They hook directly to your battery.So no problems there as mentioned above.The Sears manual saids it will discharge faster in warm weather then cold.Just be sure to charge it up every 30 days to put the charge back it may have lost.

I keep a good battery in my car.But had people asking me for a jump start.I refuse to do that and felt bad.So now I can help them with out my car being involved.

You can loose a little power with 750 amps.But 300 does not give you much to loose during discharge.Do your self a favor and spend a little more for the Sears.

Ask the security guys at your local mall they use them often when someones car will not start.Ask the used car lot guys they use them all the time.

They work okay for jump starting a car if the car is the battery is not too far gone - like the Caddy mentioned by JohnDeere, where it sits and the voltage gets a little too low to start it. In super cold weather it would help a lot if the battery pack was warm when you used it - for instance if it was in a warm house or another heated vehicle immediately before you took it out to use it. A big problem with jump starting is that often the connection between the booster battery and the battery in the dead vehicle is poor, and with 12 volts you need a good connection to get enough amps through to do the job. So sometimes you need another vehicle with the engine running, and then leave it hooked up long enough to charge the dead battery some, because you cannot get enough amps through the connection you have to actually turn the starter on the vehicle with the dead battery.