Prepare your Battery for Winter – How to clean a battery connector

clean a battery connector prevents frozen carsIt’s no secret that we are getting close to winter. The Handy Millennial would guess that the average car owner has thought more about Christmas than whether their car would reliably serve them through the winter.

This is a problem. It’s a problem because we all hate standing next to a frozen pile of metal hoping that the tow truck is around the corner.

Today the Handy Millennial would like to help you plan ahead a bit so that you don’t become one of the unfortunate souls that’s slowly turning into an icicle around February 11th or so.

This post continues the Handy Millennial’s series on car care. In previous posts the Handy Millennial described how he changes his own oil, keeps his air vents nice and clean, how he has replaced his own brakes, and even why financing a car might make sense. Today, we will discuss your car battery; more specifically, how to clean a battery connector.

As usual before I get too much into the details of what one could do, let’s begin with the typical and sadly necessary disclaimer. The Handy Millennial is not responsible for any damage, injury, or loss (of life or property) resulting from you performing similar work on your own vehicle. The Handy Millennial is an enthusiast showing people a recent job performed and is in no way encouraging readers to perform their own repairs. All information is provided for entertainment purposes only.

Why do we have a battery?

You car battery is very important because it keeps you from having to manually crank your car to start it. You see, before the car battery and the electric starter was invented, people would have to stand outside and literally crank the engine over until it started. Don’t believe me? Check out this photo from the Library of Congress (public domain images).

A clean a battery connector is necessary to replace the car hand crank

Pretty cool, huh? Or depending on your point of view, maybe not so cool.

Now this approach to starting a car wasn’t fun. It was miserable in the cold and rain. It was dangerous once the engine started moving. And it wasn’t practical for some people, and cold cars were hard to start.

So along came a new invention: the electric car starter. This allows you to snuggle inside the car while your engine starts and gets ready to carry you in a blanket of warmth to your destination.

The trouble is that as nice as this all sounds, it does require a battery, which is just one more thing to maintain.

Check your battery at Advance/AutoZone/Pep Boys/O’Reilly’s

Car batteries used to be hard to maintain. Just like all other technology, batteries started as something complicated and we’ve spent the better part of the last hundred years making them simple enough that you don’t need any actual knowledge to use them. Here is a 1913 model, courtesy of Argonne National Labs:

definitely not how to clean a battery connector

Today, we have a much nicer model: typically lead acid and sealed. Sealed means that you do not need to open it. Lead Acid means that it contains lead and acid. Duh! More specifically, lead plates with acid in between.

Because the battery is sealed, you cannot actually fix a battery that has deteriorated to the point of failing to start your car. We say a  battery is dead when it can no longer source enough current to turn over your engine.

There is an interesting game of opposites that happens with car batteries. The heat of summer reduces the battery’s performance, sometimes killing it, while the cold increases how much power is needed from the battery and therefore may reveal that it is dead. So summer is the battery killer, but it isn’t until the winter that we realize it.

Luckily, it’s actually free to check! On your way back from work (or while you are driving to the store in panic mode about the upcoming holidays), stop by any car parts store: Advance / AutoZone / Pep Boys / O’Reillys. They can check the state of your battery and give you a definitive yes or no answer on whether you battery will survive the winter.

In case you are too busy, two signs that your battery might be dying are:

  1. Your car engine takes a few cranks to start. A car with a good battery and a good starting system should start instantly.
  2. Your lights dim when you start the car.

Look Under the Hood

If your car battery has passed the test, or you feel that you don’t need a test, then take just one more step to make sure things are in good functioning order – look under the hood!

Look under the hood to clean a battery connector

This is always a good step in any season, but as a last check before the cold bears down, it’s worth a look to see how things are faring in there. Things to note while your nose is under there:

  1. Look around carefully for any wet areas. Leaks tend to happen as the temperatures fall, especially in the winter.
  2. Look carefully at any rubber hoses you see. Do they look nice and healthy?
  3. Look at the rubber belt carefully. Does it look cracked or fraying?
  4. Look at your battery (obviously the point of this post :P).

These are all quick visual inspections that you can do to make sure things are alright. For the most part your mechanic would do the same. Only he would charge you $99.99 to do it.

Make Sure Your Battery Terminals Are Clean

When it comes to the battery, what you are looking for is clean terminals. The terminals are those two little posts on top where cables connect to. If they are clean, then your battery is charging well. If they are not clean then either your battery is getting old or your charging system has a problem.

Let me show you what I mean. These are clean terminals (yes, you need to pull off the red cap to check):

how to clean a battery connector

Dirty corroded terminals:

Clean a battery connector thats this dirty.

See that mess of white? That’s a dirty connector. Now you could run to your mechanic in panic and likely spend a couple hundred dollars in the process, or you could take one simple step – clean it and observe. It will either:

1. Come back fast – battery or charging problem.

2. Come back slow – likely a small battery vent leak. Consider replacing the battery.

Clean a Battery Connector

Now in either case, you should clean the battery connector. Doing so will prolong the life of your battery, increase the charging efficiency (critical on shorter drivers), and increase your chance of not having to deal with a car that won’t start on the coldest day of the year.


If you work in an engineering company, you probably chuckled at the mention of PPE. That’s because PPE (personal protective equipment) is something that gets drilled into you day in and day out. This job we have here today requires some protective equipment. Mainly:

Safety glasses:

clean a battery connector but protect your eyes


Safety Gloves:clean a battery connector with protected hands


And something to cover your mouth and nose.

clean a battery connector but watch out for yourself!


Tools to Make Time Fly

Now normally people will recommend to you that you use one of these to clean the corrosion.

Clean a battery terminal with a manual brush.

Feel free to take this advice. But if you’re like me, you just don’t have the patience for that stuff. Personally? I got blog posts to write, what about you?

So here is what I use: a rotary tool and some brush attachments. Now when I say rotary tool, don’t freak out! These days you don’t need to spend more than $20 to get a tool that will do this job. If you’re not a power user, go ahead, buy the cheap one, use it once or twice a year, and replace when needed. A tool is NOT an interest earning account.

Use a rotary tool to clean a battery connector.

On the other hand, if you are a frequent/heavy user then go ahead and buy the nice one.

You will also need some attachments. There are two that I use here:

1. A brass wheel – brass is softer than steel and you should start with this one.

Clean a battery connector with a brass brush.

2. A steel wheel – for when the corrosion just won’t come off.

Clean a battery connector with a steel brush.

Cleaning those terminals

Alright, so we are tooled up and ready to go. First! remove the battery. (If you are uncomfortable with this in any way, please stop now. The Handy Millennial is not responsible for your actions or the consequences.)

Removing the battery is actually pretty easy. Always start with the NEGATIVE terminal. In general, the rule when dealing with the electrical system of a car is: Never do anything to short out the positive and negative. For example, do not connect the positive and negative terminal with your wedding ring. You will burn your finger right off! Some older mechanics have gone as far as to say: “Tuck your left hand in your pants behind you, work only with your right.”

So I generally remove the battery like this:

  • Remove the negative wire, place safely out of the way – this means so that it cannot make contact with the battery!
  • Remove the positive terminal, and place safely out of the way (see above).
  • Remove the battery clamp, which is usually present to hold the battery in place.
  • Finally, remove the battery from the vehicle.

You should now be looking at a nice clean tray like this:

Remove the battery to clean a battery connector.

You can clearly see the dirty terminal in the picture. Put a nice rag in there because you don’t want the corrosion to get everywhere. Remember that corrosion is actually some nasty mixture of acid and copper.

Put a rag under the work area to clean a battery connector.

Now stop! Are you wearing your PPE? Well, why not?! Go put it on now!! Never, ever work without first considering your personal safety. You are solely responsible for all lapses in judgment or injuries; every time the Handy Millennial has nicked himself, it was out of rushing or pure stupidity. Be smart!

Now put the brass brush onto your rotary tool. Turn on the tool at medium speed – note the way the wheel turns. Try to hold the wheel and the terminal so that anything that flies off will not be flying toward you!

Carefully maneuver the tool around the terminal to remove corrosion. Remember that you are holding a power tool. This means you do not need to use physical power or rush. Things will move fast. Slow and steady wins the race here. It’s better to do less than to do more.

If you notice that the brass wheel is not removing any corrosion, then stop and replace with the steel wheel. Attempt cleaning again; this time it will come off.

Use your rotarty tool to clean a battery connector.

A word of caution. These brushes are not what I would call top quality. So the bristles will fly off the brush during your job. Simply replace the brush. If you want quality, you’ll have to pony up some more for the brand name.

Now give or take 10 minutes later, you should see this. Look, Ma! Shiny!

Inspect your clean battery connector.

Now all that is left to do is put the battery back in. Here are the reverse steps:

1. Place battery in the vehicle.

2. Lubricate the posts with Dielectric Grease (We haven’t talked about this yet. Batteries tend to give out a little gas. This means some vaporized acid escapes and then attaches itself to the copper terminal. This causes the gunk that we are removing. While the terminal is gunked up, it isn’t charging your battery very well. We put grease on a clean terminal to prevent this gunking and to ensure that the terminal and post stay well connected.)

3. Connect the positive (+) post.

4. Connect the negative (-) post.

5. Enjoy!

Reconnect your clean battery connector.


So you see my dear reader, in the end, this is not a difficult job. It’s quite easy to maintain your battery and to keep your starting system in tip top shape. Good luck and remember… Winter is Coming!

6 thoughts on “Prepare your Battery for Winter – How to clean a battery connector

  1. Awesome detailed post! I had my battery die on me a couple years ago in the middle of a Colorado winter not a fun time. I am guilty of driving an old car which I secretly still enjoy but I make sure I stay up to date on maintenance. It helps to have “a guy” that is a great mechanic and charges a fair price to keep me up and running.

    1. Thanks DM! I appreciate you stopping by! I am proud of driving an old car 🙂 The dirty secret is that cars don’t die of old age. They die of rust. So if you have a guy or are “a guy” you can do quite well for a while. In my particular case I might start running up against no parts soon. That’s one way to kill of car commonly used by manufacturers – stop making parts after 10 years or so. But we will see where it goes. Where are you in Colorado? I hear some parts don’t use salt. This would help keep your hooptie on the road.

  2. You da man!!! Why don’t you move to Minneapolis so you can show me how to do this stuff in real time?

    I hope that when I have the time in early retirement I’ll be able to invest it in doing DIY projects like this. For now, I’m leaning on my trusty Honda Fit to get me through this winter. Already looks like we’ll be “in for it.” Polar Vortex, all that jazz.

    1. Thanks Cubert! I always enjoy your comments! I’ll be sure to let you know if I make my way to Minneapolis 🙂 Oh man, you drive a Honda Fit! I feel like there is a blog post coming – How I survive the Minnesota winter in my Honda Fit! I haven’t paid attention to the Polar Vortex news too much. In my neck of the woods they say we could get more snow, or we could get less snow – 50/50%. So the forecast is super precise!

  3. One of the other posts suggests the handy millennial makes house calls, this is great news 😁

    This was a nice post. I never realized summer is what’s hard on batteries!

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