You should expect jumpstarting a dead battery to take five minutes, but in harsh conditions, it could take up to thirty minutes to jumpstart your car. You need to drive for at least fifteen minutes after a jumpstart to fully recharge the battery.
If it’s not working, it’s easy to figure out why. To find the problem, start by checking your cables. Make sure the red, positive clamps are connected to the positive terminals on each battery. Then check the negative clamps. One should be connected to the good battery’s negative terminal, and the other should be grounded on a piece of fixed, unpainted metal.