Using auto shut-off vs. turning off headlights when parking car

Hi all,
Any help appreciated settling a bet… My wife’s 2015 Venza has a automatic shut off for headlamps that kicks in about 2-3 minutes after turning off the ignition. She says this is how the car is meant to shut off the lights, and I say its only a safety precaution and if you use it regularly, you will drain the battery a couple minutes several times a day, depending on how many times you use the car. To bolster my argument, we had to replace the battery on this car after 3 years and maybe 30K on the clock. Who is right?

I use auto shutoff all the time, no harm done. 3 years is a common lifetime for batteries. Is this car driven short distances between starts? That could be more of an issue.


3 years in Texas. 7-10 years is norm here in colder climates. But I do agree that the auto-shutoff shouldn’t harm the battery.

Both and neither, I do not use my automatic headlights, I manually turn them on and off.
Using the automatic option should cause no harm.

At less than 5,000 miles per year, I suspect the car is not being driven enough to fully recharge the battery.

BTW, are you doing required maintenance, oil, coolant, brake fluid, etc on the time and/or mileage as required?

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Thanks. The mileage is more like 12K/year on this car. My other car is a 09 Odyssey who’s original battery lasted 120K and 11 years. Thus the surprise with the 3 years on the Venza. Otherwise the car runs great and is regularly maintained.

As long as you don’t constantly short trip the car… and 12k a year means you likely are not… the headlight delay feature won’t hurt the battery.

But cars increasingly rely on the battery to power more and more electrical things heavily stressing the battery.

And heat kills batteries, as @MikeInNH Mike points out. 3 years in the south is common. 5 to 7 up north is normal. 10-11 years is entirely possible. Trunk mounted batteries fare better no matter where the car lives because they are not exposed to engine heat.

If the random web pages that I found are correct, the headlight current (assuming they’re incandescent) would be around 10 A, so in 2.5 minutes they would use 0.4 Ah of charge. If your battery has 50 Ah, that’s 0.8% of its capacity. Although you’re technically right, I think the effect of adding that to the depth of discharge for each cycle will be practically negligible here.

In any event, don’t you want your wife walking in a well-lit area even if it did cost a bit of money?

My 2017 Accord uses automatic headlight shutoff. Even during the COVID-19 remote work months, I didn’t have battery problems. About the only driving I did was picking up dinner on Friday nights.

If you think 2-3 minutes is too long change the delay time. I believe you can set it as low as 0 sec. that way the lights basically turn off with the ignition. You set it using the radio screen, see your manual for specifics.

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2-3 minutes would be too long for me, good to know it can be changed.

Well to be honest on my 2013 Camry it can, so it should be on other newer Toyotas.

Misread the mileage, read it as 30,000 total as of now, but now I see it as 30,000 in the first three years.
As noted above, living in the south, I replace my batteries at 3-4 years, before I have an issue.

OP is correct technically, headlights remaining on will tend to shorten battery life, make alternator work harder, and reduce mpg. But the adverse consequences seem pretty minimal and not enough to worry about. Remember the adage Happy wife means happy life?

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Withdrawn due to my math error!

Yup, I use auto off but set it to more like 15 seconds. Not sure why you need three minutes? I do find myself looking back at the car though to make sure the lights go off.

You’ll need to try your math again.

You’re right, I was wrong!

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