As everyone knows that, after turning off the car, the car battery may fail to jump start the engine because of forgetting to turn off the headlights or letting the stereos on for several hours.

Some cars’ headlights can be extinguished automatically in ten minutes, even though they were forgotten to be turned off. However, the power of car batteries is generally 12V/60Ah (that is, 720Wh), and the headlights power rate is about 60 Watts. It should only consume a little electricity in such short time. But, how about the battery is not in good condition and on the verge of retirement? The power consumption may be enough to make the car battery fail to jump start the engine. In addition, there are still many cars without automatic turning off system, which would let the car battery drained to flat. So, after turning off the car, remember to check and make sure the headlights are off.

Talk about the consumption of battery by audio system. Some experienced drivers know the conditions about their cars very much, they usually listen to the radio and play music when waiting for friends or customers in the car, and they are full of confidence to turn off the stereos before that the battery is too low to jump start engine in time. However, the time for entertainment always runs very quickly, and a little carelessness will cause the battery slip over and fail to jump start.

So, after turning off the car, how long can we keep the speakers working?

First of all, the power of the audios are different for each car. For example, Volvo Baohua Weijian is very famous in automotive industry, which maximum power is up to 1100W or 1400W. And the audios power of standard car are generally about 200W-400W . If the car battery is in new state totally and fully charged, you can play music 2-4 hours (ps: new battery). 

Actually, it is impossible to last for such a long time:

First, the battery is generally unlike to be very new and full charged 100%. Second, the battery capacity will gradually shrink after using for a period. Third, while car battery capacity level is below 11V, it would impossible to jump start the car.

So, how can we solve these problems?

A. You can call for help from a nearby car, and use battery cables to recharge your car battery.

B. Preparing a portable car jump starter in your car is a good choice, you can jump start engine even if the car battery is flat totally in few seconds by yourself, it is very easy. And you will never need to worry about the extreme cold weather which may cause you car battery frozen any more.