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I have a 2011 Toyota RAV4 and this past weekend I came home probably around 3 am on early Sunday night. This morning when I started my car I realized that I stupidly had my headlights on for 24+ hours. Luckily for me my car did start and driving to work it was fine.
I need to go on a road trip and I wanted to know if a new battery was needed or not. I don’t know much about cars but I’ve heard that if your car starts after leaving your headlights on then it will be fine. I however did get a new battery probably like 3-4 years ago so the battery is somewhat new. Would you recommend I get a new battery or is it fine as is?
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No - just take it for a good long run to charge up the battery fully. It was probably just the sidelights, as the headlights left on for 24 hours would have flattened the battery completely.
Good old Toyota!
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Sounds like your battery is fine. As Avant stated, headlights would have completely flattened it. Even sidelights for 24 hours can flatten a weak battery but yours seems to have taken it ok with plenty of capacity to spare. If you aren't doing a reasonably long run soon give it a trickle charge if you can (just in case you do it again) BTW does the RAV have a warning chime if you take out the key with any lights on?
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You left your lights on for 24 hours and the car started ok.
I think you have a very good battery there that does not need replacing!
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Time will tell. Batteries, like tomatoes, all look much the same but vary greatly in quality and longevity. In 2006 the 6 year old battery in our Focus gave up. Its replacement was completely flattened in Luton airport long-stay in 2014 by my foolishly hurriedly turning off the lights...into the 'parking light' position. (Jump started for free on our return!). Battery is now 12yrs old and still OK! But - shortly after buying an 8yr old Audi A8, it needed a new (large and expensive) battery, which I also managed to flatten after a few months. Despite allegedly zillions of amp hours, it never held charge from then on. Halfords replaced it for free, no questions asked.
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That's often the difference between good batteries and the cheapos. No car battery likes to be flattened completely. The plates can warp and the oxide falls off. The quality ones have better secured plates. If you are planning on keeping the car for a few years it pays to splash out a bit on a premium product and if you shop around they not need to cost a vast amount more. It always bugs be that so called reviews consist of nothing more than comparing specification and price. How do they perform after the equivalent of a few hundred cold starts and the occasional night with the side lights left on?
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Once upon a time headlamps left on would have been glow-worms in a couple of hours and not a snowball's chance of car starting after 8 hours never mind 24. Experienced that a few times when I was a train commuter. Car park attendants had a battery pack to provide start up assistance.
Last few cars have an alarm if you open door with engine off and lights on. I think most will also shut down stuff before the battery goes flat. Both Berlingos go into a power saver mode and turn radio off after around 20mins if you're listening with engine off, same if interior lights are on.
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The car may well have turned the lights off itself to preserve the battery - like the auto turn off for radios on some cars I've owned.
This was an annoying feature of our last smart car, if you left the sidelights on when parked they would go out after about 10 minutes.
Fine if you want to save the battery, not so fine if you are parked and need to keep the car illuminated.
Toyota may be more sensible and have maybe a 60 minute period before they turn off.
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My Hyundai automatically turns all lights off when the ignition is turned off and the key taken out. They come on again when the ignition is turned on.
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Same as my Forester. To activate parking lights after you remove the key, you turn the sidelights on.
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Battery is now 12yrs old and still OK!
The original battery in my Pug 207 is now 11 years old and still performing its job, which I reckon is pretty good considering it has to start a diesel engine. I don't think it is quite as vigorous as it once was, but equally it doesn't owe me much. I have only needed to recharge it once. after leaving the ignition on to inflate the tyres. It goes into Economy Mode fairly readily.
Edited by Andrew-T on 02/04/2019 at 16:54
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Avant said, “just take it for a good long run to charge up the battery”.
That is what I always thought but recently I left the lights on in a hire car – not sure how as I parked in the dark – but the Europcar got the AA out to me in 20 minutes, so good service from both.
Now, the AA man said that the battery would recharge as fast at idling as on a run; was he wrong?
I knew that dynamos did not charge at low revs but thought that alternators still charged more at higher revs.
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If you jump start a car with a completely flat battery, it's advisable to switch something, eg side lights or similar, on, so the alternator has something to power up.
I've known cars left running in compounds for hours after being jump started, and because nothing was switched on to trigger the alternator no charge was put into the battery.
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Avant said, “just take it for a good long run to charge up the battery”.
That is what I always thought but recently I left the lights on in a hire car – not sure how as I parked in the dark – but the Europcar got the AA out to me in 20 minutes, so good service from both.
Now, the AA man said that the battery would recharge as fast at idling as on a run; was he wrong?
I knew that dynamos did not charge at low revs but thought that alternators still charged more at higher revs.
Yes, he's wrong - alternator outout increases as rpm increase to some extent
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An alternator will charge at tick-over (unlike a dynamo), but requires a few more revs to fully meet its maximum output. I understand some alternators are now over driven to produce more output at lower engine revs, but have a clutch arrangement to prevent them being driven too fast at high engine revs.
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More complicated that you might think. Most modern alternators work "on demand" with their output controlled by the engine management computer. Coupled with an "oap " to give better loading and fuel economy. www.youtube.com/watch?v=fv7IMqjvCaY
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More complicated that you might think. Most modern alternators work "on demand" with their output controlled by the engine management computer. Coupled with an "oap " to give better loading and fuel economy. www.youtube.com/watch?v=fv7IMqjvCaY
Oap? Is their a small retiree living in there?
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Oap? Is their a small retiree living in there?
We need something to keep us occupied.
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Grandkids.....works for us, no chance of our cars battery running flat with all the running about we do, as for my battery, pretty discharged I would say...
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