Accidentally leaving your headlights on, faulty relays, and extreme weather conditions are just some of the things that can drain your car battery and leave you with a car that won’t start.
While newer vehicles will kill the headlights after a certain amount of time to save the battery even if you leave the headlights on, most older cars won’t do this.
Luckily, jump-starting your car shouldn’t be too hard to do by yourself as long as you don’t forget any of the steps and have some really good jumper cables.
Warning: Don’t ever work around a car battery without eye protection regardless of how often you’ve done it before or how many other people you see doing it. Batteries can explode without warning and you can sustain serious injury. Wear wrap-around safety glasses or protective goggles.
Jumping a dead battery is a relatively easy task. However, you’ll need another vehicle with a functional battery and jumper cables. You also need to be able to properly identify the positive and negative terminals on each battery. This is very important.
Here are tips on how to jump-start your car:
Ideally, the two vehicles should be face-to-face. You need to know where the battery is on each vehicle and you can tell by opening the hood how you need to position the vehicles so your jumper cables will reach.
Before popping open their hoods, turn off both cars first. Of course, the car with the dead battery will already be turned off, so there’s that. Letting the vehicles run while jump-starting the dead battery can cause explosive hydrogen gas from the battery’s electrolyte to ignite.
Warning: If you smell a rotten egg smell coming from the dead battery, don’t try to jump the vehicle off, because the battery may be internally shorted and jumping the vehicle can be dangerous.
If you smell a rotten egg smell coming from the dead battery, don’t try to jump the vehicle off, because the battery may be internally shorted and jumping the vehicle can be dangerous.
– Richard McCuistian, ASE Certified Master Automobile Technician
A car battery has two terminals: the positive terminal and the negative terminal. You can identify these by looking at the top of the battery next to each post, where you’ll see a + on the positive side and a – on the negative side. Do this on both vehicles.
Take one end of the red jumper cable and connect it to the dead battery’s positive terminal. Then, connect the other end of the red jumper cable to the donor battery’s positive terminal.
Similarly, connect one end of the black jumper cable to the negative terminal of the donor battery. However, do not connect the other end to the dead battery.
Connecting the black jumper cable to the dead battery’s negative terminal can cause the battery to spark and explode. To complete the circuit, you’ll have to connect it to a good engine ground, but choose a place that isn’t painted or extremely rusty metal.
Let the vehicle with the functional battery idle for around 10 to 15 minutes, so it can charge your car’s dead battery. This is especially important if you suspect that your jumper cables are not the best kind. If you have really good jumper cables, you can simply start the car with the dead battery immediately. With jumper cables, you get what you pay for. Good ones will be heavy, with thick wires and good clamps.
After a while, you can go ahead and start your vehicle and you should be able to disconnect the jumper cables immediately. If the dead battery car dies, the alternator isn’t charging and that needs to be dealt with.
Here’s how to take the jumper cables off correctly:
After jump-starting your car, you have to keep it running to let the alternator charge your battery. Some recommend letting it idle, while others recommend driving your vehicle around instead.
Connected to the engine’s crankshaft, the alternator creates an electrical current that powers various electrical systems in your vehicle. It also charges the battery, allowing your vehicle to operate properly.
How long a car battery takes to charge after jump-starting will depend on several factors, such as the battery’s condition, size, and the amount of charge it had left before it was jumped. Usually, if the battery is good, just idling the car for 10 minutes will allow the alternator to deliver enough power to restart the car, but some recommend driving for 30 minutes to around an hour.
If your car won’t start even with a successful jump, then your battery might be dying or damaged. Here are signs of a dying battery:
If your headlights start to flicker or dim, then it might be time to get a new battery. A dying battery won’t have enough power to keep your headlights on.
An illuminated check engine light can be caused by different issues, including a dying battery. If it’s accompanied by unusual clicking noises, then it’s likely a dying battery.
If you catch a whiff of rotten eggs, then it might be hydrogen gas being created by boiling electrolyte due to an internal battery short circuit.
After jump-starting your car, don’t forget to take good care of it. Here are tips on proper car battery maintenance:
Letting your car sit for weeks at a time can cause your battery to die. To prevent this, you should drive your vehicle every day or let it run for at least 10 to 15 minutes.
If driving your car regularly isn’t an option, then you’ll have to use a mobile charger instead. You can use a trickle charger that connects your car battery to a power outlet in your garage.
Depending on your vehicle, you might have to charge it every month. Just be careful not to overcharge your car battery, or it might end up leaking.
Most car batteries typically last three to six years, which means it might be time for a replacement if your vehicle’s battery is over three years old.
A battery is like an electrical gas tank that gets smaller every year until it is too small to hold any cold cranking amps (CCA). There are inexpensive tools you can buy to check cold cranking amps and keep track of how they’re fading away as your battery gets older.
You can test the voltage, but a CCA test as mentioned above is the best indicator of battery health once the battery is charged.
When testing the voltage, it’s recommended to test your battery’s resting, crank cycle, and idling voltage every six months. Here are the ideal voltage readings for a healthy battery:
If your battery tests lower than these numbers, then you likely need a replacement.
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.