You can't expect your vehicle's battery to last forever. Research shows that the batteries inside most cars, trucks and SUVs lasts for just three to five years on average. Once your vehicle's battery has reached this mark, it may fail to hold a charge, in which case you won't be able to start your vehicle. You can, however, jump-start your vehicle by connecting the dead battery to a good battery of another vehicle, but you should follow these safety tips to protect against injury.
#1) Remove Jewelry
It's always a good idea to remove any jewelry -- especially jewelry on your wrists, hands and fingers -- before jump-starting a vehicle. Why is this necessary? Well, jewelry is often made of conductive metals. If it's near the battery terminal, it may pull a charge, resulting in shock. By removing your jewelry, you won't be taking this risk.
#2) Turn Off Both Vehicles
Contrary to what some drivers believe, you shouldn't leave either vehicle running when jump-starting a dead battery. You obviously won't be able to start the vehicle with the dead battery, but you should keep the other vehicle turned off as well. With both vehicles turned off, there won't be fluctuations in battery charge that could otherwise lead to failure or damage.
#3) Connect Positive Cable
When you're ready to jump-start your vehicle, connect both batteries with the positive cable. Place one end of the positive cable on your vehicle's dead battery, at which can you clamp the opposite end of the positive cable on the other vehicle's battery. Just remember to make sure the metal part of the clamps is touching the metal post on both batteries.
#4) Connect Negative Cable
After connecting the positive cable, you can connect the negative cable. Keep in mind, though, that the negative cable shouldn't be connected to both batteries. Rather, you should connect one end of the negative cable to the good battery and the other end to a bare-metal surface someone in your vehicle's engine bay. The negative cable is simply a ground cable, so it doesn't have to be connected to both batteries.
#5) Wear Eye Protection
Finally, you should wear eye protection when jump-starting your vehicle. According to the National Highway Traffic Safety Administration (NHTSA), eye injuries account for nearly three in four battery-related injuries. Automotive batteries can discharge their electricity, or they can completely explode, either of which can result in severe eye injury. Wearing eye protection, however, lowers the risk of eye injury should a catastrophic battery failure occur when jump-starting your vehicle.