10. Charging Cables or an Auto Jump Starter will start your car.

The cigarette lighter charging cable's advertising states "charges weak batteries in minutes." There is little doubt that charging cable products will certainly recharge your car battery if you have enough time and your battery is in good condition. Cigarette lighters are normally fused at 10 amps, so to be safe they probably limit current flow to 7.5 amps. Given the size of the cord, the amount might be even less.

They work by applying higher voltage from the good battery to "recharge" the bad one. Now let's assume it is a hot day and that you need just of 3% of the battery's capacity to start the engine from a 40 amp hour battery. This means you will need at least 7.5 amps for 10 minutes to flow from the good battery to the bad one. Now let's also assume that it is below freezing and you have left your lights on. You will need at least 50% capacity or 20 amp hours to start the vehicle. This will take over two hours to partially charge the dead battery.

An auto jump starter uses special high current batteries to provide up to 900 peak amps to start your engine. It can provide 200-300 amps for up to 8-10 seconds. After this, the unit has to be recharged for 24 to 48 hours. Standard AA alkaline batteries are used to trickle charge the special batteries. This type of emergency starter should start all but diesel engines up to six or eight times, depending on the condition of the engine and the temperature.

11. A larger capacity battery will damage my car.

A starter motor will only draw a fixed amount of current from the battery, based on the resistance of its load. A larger current capacity battery supplies only what is required. It will not damage your vehicle. Using batteries with higher or lower voltage or physically too tall could potentially damage your vehicle.

12. Lead-acid batteries have memories.

Lead-acid batteries do not have the "memory effect" found with first generation Ni-Cad batteries; however, continuous under charging will lower the capacity of the battery. Deep discharges below 12.0 volts can also damage starting and deep cycle batteries or will shorten their lives.

13. Bad batteries will not harm the charging system or starter.

A bad or weak battery causes more stress on a charging system or starter and can cause premature failures due having to compensate the voltage or current. If you replace a battery, alternator, voltage regulator or starter, you should test the other components for latent or permanent damage.

14. Once formed, batteries will not change polarity.

If a battery is fully discharged and continues to have a load, for example, leaving the headlights on, it is possible for one or more cells to reverse polarity. This is referred to as "cell reversal". To change reversed polarity, fully discharge the battery and recharge it with the correct polarity.