Car question - dead battery

Morpheus

My wife’s car wouldn’t start this morning. I immediately checked to see if the lights were left on and they were not. I called AAA out, they jumped it and when the car came on, I noticed the turn signal was on. My assumption is that she must have accidentally hit the turn signal when she parked last night. The tow truck driver said the alternator was testing fine and the battery was definitely drained. I went to autozone where we purchased the battery back in August 2022. The girl working there said it was under warranty and offered me a new battery which I accepted. My question is this, can leaving a turn signal on drain your battery? My thought is no but I see no other reason that the battery should have drained unless it was really just a faulty battery.

In any car in the last 20 or 30 years, leaving the turn signal on it will not actually blink unless you leave the keys in the ignition. Regardless, a turn signal blinking all night would not drain the battery unless it was right at the very end of its life. You can leave a lot of things (not headlights though probably lol) on all night and it won't completely drain a battery except when it's near the end of its life

Morpheus

@donhulio

I agree with your statement. What do you think? Battery just died?

Could be, if it was a cheaper battery with shorter warranty when you bought it

timbear50

Hey @Morpheous - sadly I’ve drained many car batteries with similar tactics, so I’ve learned that yes a turn signal left on can certainly drain it, especially overnight. Also autozone / oreilly / advance and Walmart all have batteries that are left sitting around a long time, while most dealers or good repair shops give you a batter that will last much longer, good luck

achetocuddle

I am glad to be learning all this. Thank you.

@timbear50 That's interesting and disappointing. I seem to leave a dome light on in my car overnight every month or so and have yet to have that drain the battery.

Interesting observation about source of batteries... how do dealers and shops manage to get better turnover of their stock than the big box stores?

robroo

Turn signals should only work if the ignition is on. Could possibly be the battery, unless something else is draining it.

Morpheus

I’ve googled left and right and it seems like half of what I find says no to the turn signal left on and half say yes 🤦🏻‍♂️

Morpheus

@timbear50

autozone / oreilly / advance and Walmart all have batteries that are left sitting around a long time

Good point, I’ve actually heard that before.

timbear50

@donhulio I bought batteries at Autozone for years and they only last about two years. Then I had my car in a repair shop, someone I trust, and he explained why theirs was much more expensive than big box batteries. Basically the big box batteries are already half drained when you get them, due to being fully chanrged sometimes months earlier, then warehousing, transport, and local inventory processes - all that time passes and the battery slowly losing charge. On average I read they start at about 65% and never fully get much higher after that initial extended drain. The battery I bought from my repair shop was taken off a charger the day before it was installed in my car. It’s also much stronger so everything works better. I can’t recall the cost exactly but I want to say it was closer to $225 installed. I hope this helps - I’m not a huge car person and so there’s probably many others on here who can shine more light on the subject ..

LionsFan

A little logic is in order. If the turn signal was powered, you'd likely see it working as you exit the car.

I suspect something like an overactive keyless entry system, Bluetooth search, or GPS system. AND a sub standard battery. A competent shop can test what system is draining.

CuddleDuncan

Batteries can be a bit mad, or rather they are quite individual.

Leaving an indicator on overnight definitely could drain a battery, but not necessarily. The fact that the lamp is not flashing is irrelevant: what matters is whether current is flowing in a circuit, and if something is on it probably is. The weather, especially damp and cold, can have a significant effect.

And sometimes, they are like hamsters. They just .... die.

Morpheus

@LionsFan

I totally agree with what you say. Example, if your car is off and the hazards are on, they stay on, right? I’m pretty sure the turn signal does not though. I’ve read in several places however that even though you don’t physically see your turn signal on, if it’s left in the on position, it still drains your battery. That doesn’t seem right though. Overall, I don’t think there is an issue that’s draining the battery because this hasn’t been an ongoing issue. I think there’s either some truth to the turn signal thing or the battery just died.

CharlieBear

I left my hazards on overnight and my battery died. I started getting my batteries from Costco and def make use of their warranty because buying new batteries is costly.

Morpheus

@CharlieBear

Of autozone hadn’t replaced it for free, I was going to head to Costco 💯

LionsFan

@CuddleDuncan

This wasn't a British car with an all Lucas (Prince of Darkness) electrical system. A flashing light is relevant as it indicates current is flowing. The absence of light indicates an OPEN CIRCUIT which has zero drain.

LionsFan

Don't batteries have a manufacturing "date of birth" stamped in the top? This came about when batteries came sealed...no filling with acid at point of sale.

Morpheus

@LionsFan

Good point, I’ll look at the battery and see what the date is.

LionsFan

@Morpheus

Do a little test. There may be signal lights in your side mirror, or elsewhere, that work in tandem with your main front facing turnsignals. An incredibly bad design if these are on a live circuit with ignition off.

Bear

Johnson Controls makes batteries for Auto zone , Kirkland which is Costco and Die hard and motor craft and interstate.

There are about 2-3 major car battery manufacturers.

@Morpheus what year is the car ?

My blinkers don’t work without the key in the ignition. Hazards will work regardless if I remember right. Headlights and dome lights turn off automatically after a while in my vehicle. I have a 2010 Dodge grand Caravan.

You could have an internal drain in the vehicle. Or just aYou could have a internal drain in the vehicle. Or just a bad battery.

Bear

Check your car operation manual or look it up on line. To see if it stays on over night. You could also possibly try auto zone to see if they have an electric test or mechanic.

wilderdude

Most vehicles the signal won't work if ignition isn't on. Every semi truck I've owned was the opposite, signal is activated regardless of if the switch is turned to on position.

Was there a lot of corrosion buildup on the battery? That can affect charging, not getting a good connection to the alternator which is supposed to charge the battery.

Yeah sometimes they just die, there's no rule of thumb, sometimes batteries will die very early in their life.

liveninpjs

Had the car just been driven on a short trip? Auto batteries lose noticeable charge starting the car...but the alternator charges them right back up...if it has time to do so. This could could have exacerbated things, along with all the automatic functions cars have these days, like lights coming on and staying on for a time, powered doors or rear hatches, etc.

And like people have said, if the battery was on its way out this might have just finished it off.

May the new battery live and serve many years!

Morpheus

I checked the battery that I got from autozone today and it says July 2024 on it.

panda619

I had a short commute for 10 years and went through more batteries than average. Hope that offers some insight !

LionsFan

I haven't bought a battery in 50 years.

UREverything

Maybe the starter is going bad, maybe a door was left ajar slightly or something left in the charger that drained it or the visor was left down with the light on or the trunk was slightly ajar or gremlins were fed after midnight and got to it. Maybe the battery posts are crusty and caked up. Used to be your could put water in the old batteries but now its pay pay pay for a cheaper product.
No to the turn signal.

Morpheus

After all the comments here plus talking to friends and family, I’m gonna officially go with ut wasn’t the turn signal.

Just to share.... I had a friend who purchased a used car. It's security system, for whatever reason, had been modified/cut out. It's like there was still some sort of signal that was being sent to the security system, that kept draining the battery! Even though it had been disconnected, the system was still acknowledging--and powering-- it. Cars! Love to look at 'em, hate to work on 'em! lol

Falco

Cars in US are very different from Europe, but here there are some brands which dimly turn on two lights according to which side the lever is. This is to make others see that the car is there when parked parallel to the road. For example, you park it at right side, turn lever left and left light turns on. It's a low consumption mode, but of course not zero. It seems NOT to be your case, though.

I had a short commute for 10 years and went through more batteries than average. Hope that offers some insight !

That makes sense. When igniting the motor, a lot of current is drained from the battery, stressing it. While motor is on, the alternator converts the rotation of the motor, powered by gas, into electricity and puts the charge into the battery. If you have short commutes, you stress a lot (every ignition), but recharge little (few miles/time in which motor is on). If your use is like that, you should check the voltage of the battery every now and then and use an external charger when it is low (unless you want to drive until the battery is charged, of course!).