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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keepthetips t1_j1skbwy wrote

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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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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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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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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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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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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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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_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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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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neildmaster t1_j1t6mzk wrote

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

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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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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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RWCK1 t1_j1ugzw8 wrote

LPT: Find a good 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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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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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_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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