Alternators and Batteries 101

Charging and starting system issues? If you’re battery is decent, they may stem from your alternator. Uh oh.

First of all, what is an alternator? 

Generally speaking, an alternator is part of the charging and starting system in cars. Two other components to the charging system are the voltage regulator and the battery. 

These three components work together in your vehicle. The alternator, specifically, is where the electrical energy is created. And the alternator has a lot to do with keeping the battery charged so it can start the engine.

When could an alternator be the issue? How will I know?

Let’s say you’re driving down the road and you start to lose power and the lights come on. Let’s say you then stop the car and turn it all the way off, but then it won’t turn back on. That could potentially be an alternator that is not charging the battery.

Or if you’re car, truck, or SUV won’t start and the battery is a fairly new one, you may have an alternator that’s not able to keep the battery up to the needed power.

Another issue happens  when your alternator belt is slipping, it can cause the alternator to not produce optimal power.

The right voltage

We’ve seen how a bad alternator can also damage electrical components in the computer and make the vehicle run bad, such as if you have too much AC voltage in the system, rather than the DC voltage that everything’s designed to run on. 

How can you preserve your alternator?

Replace the batteries regularly. 

The alternators and batteries are especially important in newer vehicles with all the electronics that are built into modern cars. 

Let’s walk through another hypothetical scene: you’re going down the road and you’ve got all the lights on and the wipers on, the radio, everything. It’s all drawing from the battery. 

Your alternator is trying to keep the battery up to a certain level to maintain all that you’ve got going on in the car over time. Let’s also say that you usually drive with everything on, all the time. 

Once your alternator starts getting weak and not be able to keep that voltage up, that’s when the battery starts to go because it’s working too hard and can’t keep up to that needed level of charge.

Then, when you keep driving a vehicle with weakening batteries, well, that makes the alternator charge too much. This is when your alternator is going to get too hot and fail prematurely. 

People don’t want to believe that they need a battery because they feel it’s too expensive. 

They feel this way up until the moment they learn they have to put a new alternator in their car.

Costs context:  battery vs. alternator

A $150 battery may feel like a pinch, for sure, but let’s compare that to a $700+ alternator replacement cost. 

Which would you rather pay?

If you have a borderline battery and you decide you’re going to sit in your car and listen to the radio and charge your phone while your kids are playing baseball during the summer season. Well, that’s a good way to take your battery out. 

You’re going to be frustrated because your battery’s dead. And it’s not going to give any warning. You’re going to attempt to start the car and won’t turn over… nothing. We tell people all the time is your average life expectancy of a battery in the Seattle area is between 52-60 months. 

Please don’t ignore the recalls

We’ve recently had a few cars in our shop with some frightening alternator replacement needs. A few makes and models have been under safety recall and people have ignored the notifications only to have their alternator catch fire.

Really scary. Please, don’t ignore the recalls!

Regular maintenance and priority checklists will save you money over time. 

This is part of the expert service we offer at Tom’s Automotive Services, located just a few blocks off of the West Seattle Bridge. 

We’d love to help keep you and your family safe on the roads with regular, guaranteed vehicle maintenance and repairs. Schedule your next service with us today.

Our Reviews

Tom's Automotive Service
Reviewed from Google

4.7 out of 5 stars

Denny and Jim
Denny and Jim

5 out of 5 stars

posted 1 week ago

I got a flat tire across the street from Tom's Automotive. Although they don't repair tires, they immediately sent over a technician to change my tire. They also filled it with air so I could make it safely to a tire shop, all free of charge. Thanks Adam and the friendly staff at Tom's Automotive for your great service!

Bethany Manahan
Bethany Manahan

5 out of 5 stars

posted 2 months ago

My bosses were the ones that recommended me to see Tom's when I had my 'check engine' light on some time last year. They were very helpful, and kindly, turned the light off as there wasn't anything particularly wrong with my car. However, recently, my car was being looked at by them (as I've had other things happen to my car), and the staff helped me walk through the process of either furthering the fix or getting rid of my car. As someone who doesn't know anything about cars (oh boy), they really did a great job of explaining things to me. Thanks!

TJ Rawlinson
TJ Rawlinson

5 out of 5 stars

posted 2 weeks ago

I had a great experience with Tom's. We had a good dialog, lots of great communication, and I am happy with the work done. Prices were as expected and no work was done that didn't need to be. I will be going back as needed.

Michael Mizell
Michael Mizell

5 out of 5 stars

posted 1 week ago

I always take both my company vehicle and personal vehicles directly over to Tom's whenever I need issues taken care of...except for that one time I had to change a headlight in my Yukon. After struggling with trying to figure out how to take it out, I watched a YouTube video and followed all the steps. It turns out that you cannot simply take the headlight casing out, but you need to take the grill off first, then take the wheel well liner off (which I successfully completed) and then there is a hidden screw that needs to be removed. You cannot see this screw because it is tucked away behind the frame, and a standard socket wrench head is too large and will not work to remove. Feeling defeated, I called Tracy. He said to come on by and they took the screws out for me and helped replacing the headlight. I told him I wanted to at least pay something for the service but he refused to accept anything. These guys have always been good to me, and I appreciate their hard work and honesty.

Kt McVeigh
Kt McVeigh

5 out of 5 stars

posted 3 weeks ago

They were very professional and helpful at all times - even when I didn't have time to use their services before I headed out of town, Casey spoke with me on the phone for upwards of 15 minutes to figure out what was wrong with my car, so I could get help elsewhere. Really stand-up place!