How to Jump-Start a Car
There’s a right way and a wrong way to jump-start a vehicle. Doing it wrong can damage your battery or other electrical components. Learn how to do it correctly in this Les Schwab Quick Tips step-by-step video. We show you:
- The proper order for connecting and disconnecting jumper cables.
- How to keep the cables clear of hot engine areas.
- What to do once the dead car starts.
The main safety concern around jump-starting isn’t the electrical current. Jump-starting your battery in the rain, for example, doesn’t put you at risk of shock. Passing vehicles are a bigger issue. Be sure to stay out of the path of traffic and use flares or reflective triangles if you have them when it's rainy or dark out.
How Your Auto Battery Works
Here’s a simple guide to understanding how car batteries work, from the alternator to cold cranking amps to different types of car batteries. Find out:
- How a battery starts your car
- How the battery provides power
- What cold cranking amps are
- How the battery recharges
- Why car batteries die
- What the different types of auto batteries are
How a Car Battery Starts a Car
The first purpose of an auto battery is to provide power for starting your vehicle. It also acts as a surge protector for the car’s computer and provides power for short-term use of things like lights, stereo, GPS or wipers when the engine is off.
The car battery is part of the starting system. There are three main components in this system:
- The ignition switch is either the starter button you press or where you insert your key.
- The switch controls the starter relay (also called a solenoid). When you turn the ignition, it sends a small electrical current to the starter relay. This causes a pair of contacts to close.
- When those contacts close, the battery sends voltage to the starter motor, which turns some gears to start the car.
How the Battery Provides Power
The two types of auto batteries—flooded and AGM batteries—use lead-acid technology. A typical lead-acid car battery contains plates of lead alternating with plates made up of other materials, all immersed in an electrolyte solution of about one-third sulfuric acid and two-thirds water.
Turning the ignition triggers the acid in the liquid electrolyte solution to react with the active material on the plates (active material refers to any substance in the battery that reacts with the solution to discharge or recharge the battery). This generates a bigger electrical current. The current travels through the starting system in a chain of reactions that cues the engine to start.
What Are Cold Cranking Amps?
Cold cranking amps (CCA) refers to the amount of power a battery can supply for 30 seconds even at low temperatures. Larger engines require more power to start, as does starting the car for the first time on a cold day.
A high CCA rating is important for standard auto batteries in areas with subzero temperatures, since deeply discharged wet cell batteries can freeze solid in such weather.
How the Car Battery Recharges
The alternator is responsible for recharging your car battery as you drive. This part also supplies power for your car’s electronics when you’re underway. It is driven by the alternator belt from the engine. As the belt goes around, it generates electrical current to run your vehicle's electronics. It also sends some current back to the battery to recharge it.
A voltage regulator controls this flow of electricity to keep it even and deliver the right amount of charge to meet needs like running the AC or heater. It also protects the battery from overcharging, which can damage it.
Why Does My Battery Die?
Over the life of a battery, discharge-recharge reactions happen thousands of times. Each cycle wears out the plates a bit, and over time the lead deteriorates. As your car battery loses capacity, cold cranking amps decrease.
Deep discharging, which happens when you use the battery to run the stereo, lights or other electrical systems in your car when the engine is off, is responsible for a good portion of battery failures. Discharging most of your battery’s capacity by using it in this manner for too long and then recharging it through driving can cause the sulfur in the electrolyte solution to stick to the lead and create other damage to the plates in the battery.
What Are the Different Types of Auto Battery?
The two most common auto batteries for sale today are standard wet cell batteries and absorbed glass mat (AGM) batteries. Both use lead-acid technology. The differences are in the needs of the car.
Standard Wet Cell Batteries
These are also called flooded, conventional or SLI (starting, lights, ignition) batteries. Some standard batteries have vents that allow for airing out corrosive gases, steam and condensation (these may be called vented batteries). They have removable caps for adding fluid. Other wet cell batteries are closed systems, with no removable caps.
- Service needs: Occasional simple maintenance including cleaning off corrosion on terminals and topping off fluid with distilled water if the battery has removable caps. Battery should be visually checked every year. Battery charge should be checked before road trips and after summer before temperatures fall.
Absorbed Glass Mat (AGM) Batteries
These are a type of VRLA battery, which stands for valve-regulated lead-acid. They're sometimes called regulated valve, dry cell, non-spillable or sealed batteries. They are called sealed because they have no removable caps, don’t vent gases and can’t leak any acid. They do have pressure-activated relief valves that open only if the battery overheats during recharging.
Some newer cars, such as those with start-stop technology, require AGM batteries. These batteries will continue to deliver power to a car’s computer and electronics even when the engine isn’t running.
AGM batteries hold a charge longer than standard wet cell batteries. They can tolerate periods of disuse and repeated deep discharging and recharging cycles better than flooded batteries. They have a short recharge period but they can be easily damaged by overcharging. They also perform well in harsh climates with extreme heat or cold.
- Service needs: Charge should be checked before road trips and after summer before temperatures fall.
Wet cell batteries and AGM batteries are not interchangeable—your car requires one or the other.
Batteries for Anything You Drive
Les Schwab is well known for having the West’s largest selection of tires. Here are four reasons to come to us for batteries as well.
1. Vast Selection
We have an inventory of quality batteries to power just about anything that rolls:
- Cars, light trucks and SUVs
- Commercial vehicles and heavy-duty trucks
- Motorhomes/RVs, fifth-wheels and other campers
- Boats, including personal watercraft
- Off-road vehicles (four-wheelers/quads and side-by-sides)
- Farm tractors and equipment
- Golf carts
2. More for Your Money
What we say about tires also goes for our batteries: If we can’t guarantee it, we won’t sell it. Our best-in-the-business battery warranty includes a replacement program. We’ll replace standard batteries that are deficient absolutely free for a period between 12 to 24 months, depending on the battery. For motorcycles, golf carts and the like we provide replacements for failed batteries up to six months after purchase. The period for RV, commercial and marine battery replacements extends for one year.
And if your battery fails any time before its expected life after that, we’ll refund you the difference. For some batteries, that can mean coverage extending up to seven years.
You’ll also get free auto battery and charging system inspections with your purchase. And you can stop by for a free battery charge at any Les Schwab whenever you want.
3. Expert, Friendly, World-Class Service
Our technicians are equipped with state-of-the-art battery diagnostic tools and are well trained in batteries and charging systems. A problem you suspect is being caused by your battery may actually be something wrong elsewhere in the charging system. (Read more.)
We check any vehicle battery charge for free, whether you bought it from us or not. We’ll give you an honest answer on whether you need a new battery. If you do, one of our service techs will help you decide what battery is best for the job, the vehicle and your budget. Then we’ll install it quickly so you can get on your way without delay.
4. Hundreds of Locations
You can buy, get service on or redeem a warranty for Les Schwab batteries at any of our 475-plus locations across the West. Not sure if you need a new auto battery? We’ll check your battery’s charge while you waitfor free.
For a quality battery backed by a great warranty, come to a Les Schwab Tires near you.
Starting Problems? How to Tell If It’s the Battery or Alternator
If your vehicle won’t start, it’s usually caused by a dying or dead battery, loose or corroded connection cables, a bad alternator or an issue with the starter. It can be hard to determine if you’re dealing with a battery or an alternator problem. Here’s how to know which one is the culprit.
Bad Battery Symptoms
If the cranking of the engine is sluggish, like your vehicle is harder to start on cold mornings, it starts inconsistently, or there’s no sound and interior lights when you try to start, suspect a failing battery, a loose or corroded connection or electrical draw. A low battery that has visible corrosion on the terminals is probably damaged.
If jumpstarting works, then you know you’ve got a battery problem. But you also need to figure out whether it’s simply at the end of its life or there are underlying issues. A dead or low battery can be caused by a failing alternator. It can also result from additional draw from auxiliary lights, fuses, sound systems, alarms and such.
Signs of a Bad Alternator
Some of the things to look for are no-starting and trouble starting, dimming lights and problems with stereo system output. If your car starts but stalls when you're underway, your battery is probably not being recharged due to a faulty alternator. A squealing sound coming from the engine that gets louder when drains like the heater or sound system are on may be your alternator bearings.
Another telltale is turning the AM radio to a low number on the dial without music, then revving the engine. If you hear a whine or the sound goes fuzzy when you hit the gas, your alternator is probably failing.
If the vehicle won’t crank or start but the headlights are still working, look to problems with the starter or other parts of the engine.
What the Battery & Alternator Do
An auto battery supplies a big electric charge that travels through the starting system and turns some gears to start the car. Once the car is running, the alternator sends current back to recharge the battery as you drive. It supplies power for your car’s electronics when you’re underway and makes sure the right amount of charge goes back to the battery.
If Your Car Won’t Start
The common signs above should help pinpoint what exactly is going wrong.
If you’re not wanting to do your own diagnostics, get a jumpstart (and keep your vehicle running) and take it in for a technician to check your electrical system. Both the starting and charging systems should be inspected.
Battery checks on standard wet-cell batteries should include inspection of fluid level, the posts (the terminals marked + and -) for corrosion, and cables for snug connection and no corrosion.
An electronic battery test should be done, which gives more information than a standard load test. It measures the voltage and cold cranking amps (CCA). (Battery inspections and charges are free at Les Schwab Tires.)
The shop should also check the alternator’s voltage and current output and look for signs of bad diodes, the components that convert electrical current from AC (alternating current) to DC (direct current). If it’s time to replace it and your vehicle has been customized with power-hungry aftermarket accessories like a sound system, ask if you need a higher-capacity alternator.
If the alternator is working fine, the search for the problem will move to other parts of the starting and charging system.
Got a Bad Alternator?
It may have damaged your battery. Since the alternator regulates how much electric current gets fed back to the battery during recharging, the battery may have overheated due to overcharging. This shortens its expected life and can make it unreliable. Ask whether you need a replacement if you’re having alternator repairs done.
If it’s your battery that’s bad, it won’t damage the alternator.
Seasonal Car Battery Care: Why and How
An average car battery will last 4 to 5 years, maybe even up to 7. But where and how you drive and what the weather’s like in your area affect its life. Many short trips are harder on batteries than fewer, longer ones. In hot climates, you may only get 2 to 3 years out of a new battery.
Unless you’re having obvious trouble, you may just ignore it. But it’s a good idea to get your auto battery checked every fall. As cold weather arrives, the everyday work of starting up and powering your vehicle gets harder, and summer heat may have taken an invisible toll. Those battery problems you run into in the winter likely started in the summer.
What Does Summer Heat Do to a Car Battery?
Hot weather is the harshest environment for car batteries.
When it’s 90 or 95 degrees outside, it’s 140 to 150 degrees under your hood. These high temperatures can cause the water in your vehicle’s battery to evaporate. High heat can also force some of the fluid out of the battery vents in the form of gases. That will cause a chemical reaction with the lead and other metals on the battery connector. If you see corrosion that looks like white or blue crystals on the nodes with + and – signs (your battery terminals), that’s why.
The inside of a typical lead-acid car battery is like a layer cake made up of plates of lead and other components, with the “frosting” being a solution of about one-third sulfuric acid and two-thirds water. When some of that water evaporates or some sulfuric acid is forced out because it’s hot, there’s not enough fluid to surround the plates. At that point, they start corroding.
About half of premature battery failures are caused by the loss of fluid in the battery. You may not see this damage, but it will reduce your battery’s efficiency.
Then there are the ways you use your vehicle in the summer. A battery can be pushed to its limit with demands from the engine cooling fan, air conditioning, stereo and GPS or other gadgets you charge on your road trip. Deep discharges also speed up the battery’s aging. This can happen whenever you use the car’s electrical system while it’s turned off.
How to Take Care of Your Battery in Summer
Avoid deep discharges. It’s fun to park by a lake and listen to music through your car’s stereo and handy to charge your phone from the 12V socket while you’re camping, but draining the battery significantly can damage its internal parts.
Use the car regularly during heat waves. It’s not just cold weather that can damage a battery left unused—heat is harmful to sitting batteries, too. Park in the shade whenever possible. Keeping the temperature under the hood even a bit lower than it would otherwise be will slow fluid evaporation.
Speaking of battery fluid, faster evaporation in the warm months will increase corrosion. Clean any corrosion off the top of your battery once a year and make sure the cables are tightly connected. Corrosion is caustic, so make sure you wear gloves and proper eye protection to do this. Dissolve some baking soda in a bit of water and use a toothbrush to gently scrub the battery terminals and cable clamps.
Why Won’t the Car Start When It’s Cold Outside?
If it’s worked hard over summer, or the weather was really hot, your car’s battery may not be as efficient come fall, for the reasons above. If it’s not operating right it will have trouble holding a charge and delivering cranking power to the engine.
A telltale sign that your battery needs attention is if you notice your car is slow to turn over on chilly mornings but easier in the afternoon. This happens because all the fluids in your vehicle are thicker when temperatures are lower, like syrup that's straight out of the fridge versus warm. So it takes more power to move the motor oil required to crank the engine. Also, the chemical reactions that happen in the battery are slower in the cold.
With newer cars, you might not even have a slow start—your car simply won’t start.
Simply put, your vehicle’s systems need additional output from the battery to operate in colder conditions. If your battery is old, needs recharging, or isn’t able to hold a charge, it will struggle to perform in the cold weather.
How to Take Care of Your Battery in Winter
First, get your battery tested in the fall, between summer heat and winter cold. A test will tell you if the battery is fully charged, how many cold cranking amps it can provide, and generally how healthy it is.
Keep a battery charger on hand and use it if you’re driving your vehicle less often in the cold months, you make frequent very short drives, or if you’re having trouble starting in the morning. If you live in a very cold climate where temps can get down to 5 degrees F, consider using a block heater or battery blanket.
A block heater will warm your engine so it’s easier to start the car. A battery blanket will, as the name suggests, keep your battery warmer so the fluid keeps moving and it’s easier for the battery to crank the necessary amps when it’s cold out. Depending on where you live, you may want to use both these items—talk to a mechanic to figure out what you need.
Keep jumper cables in your car, as you’re more likely to need them in the winter.
Heading into the cold months, take a few minutes to clean corrosion off the top of your battery and make sure the cables are tightly connected.
We’ve said it twice, but it’s important enough to say one more time: Autumn is the time to get your battery checked to avoid irritating problems in the winter. If your vehicle’s battery is over 4 years old, it’s especially important to get it checked annually.