LPT: After every mechanic visit, drive your vehicle around for 10 to 15 minutes extra before going back home.

Submitted by TheMasterBaker01 t3_zw388w in LifeProTips

Just got burned by not doing this on Christmas day: took my vehicle in, got it back the next day, and drove it home and parked it. Woke up to a dead battery and it was a whole ordeal.

When your car's getting worked on, there's a non-zero chance your doors are being left open, leaving your lights on and running your battery down, so give it the extra time to get home so your alternator can charge it back up.

It'll also give you more time to sus out any potential issues with the work they did.

EDIT: Removing the part about idling because, as some people pointed out both kindly and not-so-kindly, idling will charge your car battery.

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Solid-Question-3952 t1_j1szbpu wrote

My husband has been in various positions in the auto repair industry for 15+ years. I asked him how many times he has heard of a good battery being dead, as you described, due to mechanics leaving doors open or letting the vehicle idle. His answer : "never. That wouldnt happen. Maybe if you had a bad battery or your car was from the 1990's. But no, thats not a thing."

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LegendaryRed t1_j1vuv8h wrote

What happened to OP sounds like plain bad timing. His battery decided to crap the bed at that moment, it just happened to coincide with a visit to the mechanic.

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Solid-Question-3952 t1_j1wem83 wrote

Its amazing the amount of things that happen like that. And then people get a case of the eversince's. "Eversince you changed my oil my back tire leaks." "Eversince you changed my door handle my mpg have dropped."

As I said to OP somewhere else, people typically go to a mechanic because they dont know how to do the repair themselves. Yet they always seem to know more than the mechanics do.

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beefy1357 t1_j1x6e17 wrote

And sometimes you know how, you are just too lazy to do it.

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SirHerald t1_j1sl41f wrote

That extra driving won't do much for the battery. Especially compared to the effects of cold on an old battery.

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superseriousaccount5 t1_j1smxtb wrote

How long does the alternator need to recharge a battery normally?

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phwe9774 t1_j1snudt wrote

Normally, not very long because you don't use the battery much except to start the engine. If you do anything to draw the battery down (listen to the radio or leave your lights on without the engine running), it only takes a few minutes if you have a good battery. If your battery is getting weak, it takes a little longer but still not very long

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tossaside555 t1_j1v4uuk wrote

Battery usage is essential for normal car operation - not just ignition.

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Solid-Question-3952 t1_j1wf3pi wrote

Once your car is running, typically, your alternator is charging your battery enough to keep it fully powered.

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tossaside555 t1_j1z4s9m wrote

Unless you have a bad battery.

Then the car will shut off - even with a good alternator.

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Solid-Question-3952 t1_j20gfp8 wrote

Correct. A bunch of us keep saying that OP has a battery issue. This LPT is stated as if this is something everyone should be doing. Its 100% unnecessary unless you have a bad battery. In which case, LPT: get a new battery.

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SirHerald t1_j1so5lp wrote

I've heard it's about 30 minutes for a good alternator running solid on the highway. 2 hours or more just driving on small roads.

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Solid-Question-3952 t1_j1sy95u wrote

Highway or small roads dont make a big difference these days with virable alternators. They will change depending on your speeds. If you are trying to charge a battery from dead, you need to put it on a charger. If its sat with the door open for a couple minutes, driving from your house to the grocery store will be fine

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SirHerald t1_j1t0ep1 wrote

It was dead the next morning. It needs a lot more than meandering for 15 minutes.

If worried, turn off all possible electrical and run the speed up. I keep a charger at home for all that though

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ForceOfAHorse t1_j1tzepl wrote

If you can start a car, drive home and next day battery is dead, your battery is just bad.

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Solid-Question-3952 t1_j1wfaag wrote

This seems to be a lost idea on this LPT. Its mind blowing how many people know so little about cars but keep speaking like the mechanics are the ones in the wrong

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Colonelfudgenustard t1_j1tdwoc wrote

Don't drive immediately home, and certainly not near a school or playground, if you suspect the mechanic might have attached a bomb to your vehicle.

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RWCK1 t1_j1ugzw8 wrote

LPT: Find a good mechanic

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Solid-Question-3952 t1_j1sxmk5 wrote

LPT: your engine idling doesnt effect your batteries so its clear you dont fully understand cars or the way mechanics work. Also, the vast majority of mechanics warranty their work and if you have an issue that is actually caused by their work they will fix it. You have no idea how many "ever since" people they deal with everyday complaining about problems that have nothing to do with the work they just did and they try to help them out anyway. Example: "eversince you changed my oil my rear brakes squeek." "Eversince you replaced my rear axel my front tire leaks."

If you are worried about the battery let it idle before you turn it off, no need to drive around putting more wear and tear on your vehicle.

Edit: In almost all cars in the last 15 years, any power from your doors being open cuts after a few minutes to avoid an accidentally drained battery. So mechanics working with your doors/trunks open wont matter. If your car started when you picked it up, driving home should have been more than enough to charge it battery (unless you like 3 minutes away). If you had a dead battery the next day either you have a bad alternator or most likely, your battery is going bad. Keep an eye on it.

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TheMasterBaker01 OP t1_j1sz37r wrote

The idling point is fair even though you're being a dick about it, so I edited my post. My point isn't that mechanics are doing shotty work, but that sometimes through their work it can leave your battery low, so driving it around will give it an efficient charge as well as test out what they fixed to confirm things are running smooth.

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Solid-Question-3952 t1_j1szr9v wrote

Happy cake day.

No, shotty work wont cause that. And driving around another 10 minutes wont fix it. Im sorry you disagree. Customers always know more than the mechanics they bring their vehicles to. Its amazing. Im not trying to be a dick. Yeah, there are shitty mechanics just like crappy people in every profession. But the vast majority of mechanics and shops are good people who actually like fixing vehicles and want to help. And what you're saying just isnt a Life Pro Tip because its not true.

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TheMasterBaker01 OP t1_j1t0469 wrote

I'm speaking from the experience of having this happen twice now that I've either gotten my car back with a weak battery or dead altogether. Last time I was there they had to jump me. It's just a part of the job that they can leave doors open or stuff going while they're working. I'm not holding that against all mechanics or saying they're bad for doing it, just that if you go to the mechanic, give your vehicle some extra time on the road to be safe and sure as possible. Otherwise you end up like me having to jump my car on Christmas in >10 degree weather.

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Solid-Question-3952 t1_j1tw9nt wrote

You probably have a battery issue. Unless your car is 20 years old (and maybe it is) if they leave a door open, your car will automatically cut the power and all the lights will go off and stop using your battery. You can leave your car door open for 3 days and start it perfectly. Thats how cars have been designed for years. If you needed to be jumped when you left a mechanic and they didnt try to figure out why or suggest you need to replace a battery (or alternator) please dont go back there.

You dont know how to fix your car, so you bring it into people you must trust to do the job for you. And you are assuming these people who know more about cars than you, dont think about or realize what drains the battery and what that will cause? Im sorry you had it happen to you so many times but this isnt something that happens on a normal or even semi-normal basis for people.

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Crepuscular_Oreo t1_j1wktgd wrote

>Unless your car is 20 years old (and maybe it is) if they leave a door open, your car will automatically cut the power and all the lights will go off and stop using your battery.

I wasn't going to comment because I was a mechanic back when cars were not rolling computers and there weren't so many power-sucking components. I haven't kept up on the technology over the years.

I did the math once (back then) and calculated you would have to run your radio and dome light for something like a week to use the same amount of power you use to start your car once. I don't remember the exact numbers, but it was a long time.

Most cars can start the engine multiple times in rapid succession. Think about when you park at a store, shut off your engine, and find yourself too close to a pole to open your door so you start it up again and move a few inches and try to get out again. Then you get back in the car and start the engine to drive to the gas station next door, shut the car off and fill up, then start the engine again to drive somewhere else. If your car won't do that, you need a new battery.

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NecessaryPen7 t1_j1wayj4 wrote

That means your battery was shit or dead.

Virtually zero mechanical shop is going to have any effect on a newer battery.

Obvious life tip: find a good mechanic

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ForceOfAHorse t1_j1tzjt0 wrote

Just because somebody points out your lack of knowledge on a subject while you give tips on this subject doesn't make they "are dick about it".

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PlsRfNZ t1_j1spvrs wrote

If the car is idling in the workshop that is still charging the battery. Alternator works as long as the engine is running.

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Zedd2087 t1_j1swoby wrote

At idle your alternator does not produce enough to keep your engine running and charge your battery.

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keepthetips t1_j1skbwy wrote

Hello and welcome to r/LifeProTips!

Please help us decide if this post is a good fit for the subreddit by up or downvoting this comment.

If you think that this is great advice to improve your life, please upvote. If you think this doesn't help you in any way, please downvote. If you don't care, leave it for the others to decide.

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neildmaster t1_j1t6mzk wrote

What about turning off your interior lights when you drop it off?

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Solid-Question-3952 t1_j1wi4kf wrote

You dont need to. Unless the car is really old cars are built to cut the power after a few minutes of having a door/trunk open to avoid this exact situation.

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bemest t1_j1st4mr wrote

This is a good tip. I picked up my F-150 from a dealer after a power cut out problem. Every warning light would come on. They said I needed a new accelerator. $500. They drove it and said it was fixed. I didn’t get a half mile from the place and the problem recurred.

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LegendaryRed t1_j1vuiju wrote

Electrical problems are notoriously difficult to diagnose and fix. Many sensors share the same power cable so it's not unheard of to misdiagnose a sensor.

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bemest t1_j1xewta wrote

I know. I formerly owned an aircraft maintenance business. This dealer didn’t do much in!the way of diagnosis. Of course the errors reset so it took a little driving for them to act up and the problem to recur. I took it to another dealer that found a wire bundle chafing. If I had continued with the first dealer it would have been more parts swapping. Related to the OP it is advisable to do a good shake down run immediately.

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Solid-Question-3952 t1_j1wibqv wrote

You're spot on. Also its not uncommon for a problem to hid behind another code. So you fix the first code, think its good and then the real code pops up.

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