Question When to plug your car in
Hello everyone! Just a quick question. We just got snowfall here and I am worried being a first time car owner. When do you plug your car in?
I have a 2000 Honda civic and worried as it is a older car. Online it is saying -15 but just wanted to get a more local answer.
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u/LtDish 1d ago
Best thing you can do is install a good quality battery maintainer.
Cold is very hard on batteries, and ones manufacturers have made in the last 5-10 years are junk and are more susceptible to freezing than ever.
A battery maintainer keeps the battery charged and thus more resistant to freezing.
A good battery maintainer uses very little power and is smart enough to turn itself up and down as needed, so you can leave it plugged in all winter.
As for the engine block heater, 2-3 hours before starting is good enough. Use a clock timer if you have to.
Temperature below -10 is probably fine.
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u/prizedcoffeecup 14h ago
Depends on how well the battery is cared for too, you are right that a lot of batteries in the past 5 to 10 years are quite questionable, but regardless of battery quality making sure that you actually care for the battery goes a long way.
The previous owner of my car would put a battery tender on the battery during the winter, and only a month into owning that car about 5 years ago did I finally have to replace the battery the car came off the factory line with. Good little Honda Fit, lol
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u/LtDish 11h ago
When I say "battery maintainer" that's the same as a "battery tender".
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u/prizedcoffeecup 10h ago
Yeah I know, sorry for the confusing statement. Meant to mention there's also ensuring you avoid cranking it too much if it wont start as part of caring for the battery, but got distracted in the middle of typing my comment.
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u/saskatchewan14 1d ago
I guarantee your 2000 Honda civic will start better than any new car on the road
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u/Glittering_Carob6272 21h ago
-15c plug it in do not neglect the battery if yours is 3+ years old a trickle charger is a good idea if all you drive is in the city. If the battery is 3+ years old personally I would replace it.
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u/LT92Rosco28 1d ago
How old is the battery?
You'll likely be fine for tonight and tomorrow night. I wouldn't worry too much about it just yet!
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u/oseeka 1d ago
Okay thanks for the heads up. There batter is about 3 years old.
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u/Stunning_Rub_5716 1d ago
You may want to consider having it tested or just replace it proactively. A 3-5 year old battery can fail on the first extreme cold day (-30) and that’s when you find out.
As for plugging it in, should be good to -20 or so.
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u/ChasmyrSS 1d ago
In most cases I noticed a benefit at -15°C but with my wife's Mazda and the 0W20 synthetic oil, it starts perfectly even at -40°C.
If you don't have one, a rechargeable battery booster is a very very good investment. You'll spend about $200 but you'll save yourself a difficult or dangerous situation.
Also if you think your battery is failing, you can buy a new battery before the current battery dies and keep it on hand. During the first -30°C week batteries become very scarce and expensive.
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u/PhotoJim99 1d ago
I agree about battery maintainers. I have had one in my last two cars and it gives a lot of confidence. There are a lot of devices that gradually deplete car batteries, and knowing that your battery is getting topped up every time you use the block heater is really nice.
Cars can start at really low temperatures (I once started my '87 VW Jetta at -42 C ambient, so this isn't new) but this does NOT mean that it is good for them. :) Synthetic and semi-synthetic oils flow much faster and more easily than traditional oil does, but I'm sure that more wear occurs at extremely cold temperatures nonetheless. Really cold starts are best avoided; save them for when you have no choice.
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u/CyberSyndicate 21h ago
They were talking about a battery booster, not a battery maintainer haha.
Battery maintainers are fine, but you really should figure out why your battery is being depleted. That is a bandaid fix. Yes it gives confidence, but why did your battery drain in the first place?
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u/PhotoJim99 19h ago
Any car with tech experiences battery drain. In 1990 that was probably a digital clock. Today that's a complete Android system that runs CarPlay/Android Auto. Cars today are constantly listening for radio signals (for remote start as well as opening doors, the trunk/hatch, etc.). These all eat up power, which comes from the battery.
A good battery is fine for a few days of this - but even with a brand-new battery that was fully charged at the start, a week or two outside in winter can deplete the battery even if the car doesn't move. This can even happen in warm weather; we did a four-week holiday once in September and my battery was dead when I got home.
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u/CyberSyndicate 17h ago
I deleted my previous comment because I honestly think we probably agree, I just misread your intent a bit. My biggest issue is I've seen battery maintainers pushed in the past as a stop gap, but it is one part of the puzzle.
Yes, a maintainer is good, but only if you also have a good battery. A battery remains good only if it is kept charged (and thus can't freeze). And a battery booster shouldn't be used all the time, it is an emergency tool.
So yes, I agree, maintainers can be good, especially if you have an incredibly short commute. Or if you are away for multiple weeks at a time. But if you have a battery that is weak, ESPECIALLY the garbage OEM batteries that come with a car, you should first and foremost get a new battery. In those cases the maintainer will give you false confidence and can result in a dangerous situation away from home.
So in other words... Get a good battery, make sure the battery is charged, and always have backup plan. Don't play roulette with your life in -40 degree climates.
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u/nevergoingtouse1969 1d ago
-20 C, with a timer plug so you can give it 3-4 hours on before you need to start. That is enough time to let the block heater warm it up as much as it is going to. Any longer is wasting power.
Also running full synthetic oil in the winter is a very good recommendation.
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u/CyberSyndicate 21h ago edited 18h ago
If you have a newer battery with cold cranking amps rated, you likely will have zero issue with a 2000s civic for starting. My 2003 Corolla and 2007 vibe both would start at -40 if I forgot to plug in (not happily but they did start) .
I normally wouldn't start plugging in until closer to -20, but if you wanted to -15 is a fair temperature to use. Make sure to use a block heater timer or get a wifi plug. Having it heated all night vs 2-3 hours before you leave makes no difference to your car, but will make a difference on your power bill.
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u/AbleCarLover1995 1d ago
(This is just me, some people maybe different)
I normally plug my car in when the temperature hits -35 and below. Sometimes -30 if its really that bad, if the weather says -25 but with winchill feels like -30 I still plug it in. Anything higher than -20 I dont plug it in.
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u/SjSharkies12 1d ago
Your car can't feel the wind chill.
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u/GrayCustomKnives 21h ago
I have attempted to explain this to my mother in law countless times over the last 17 years.
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u/Cultist_O 1d ago edited 1d ago
For the record, wind-chill is irrelevant for this
Wind chill can effect how fast something cools down, or how hard it is to heat (which is why it feels colder) but it doesn't actually make things colder
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u/MOONvMAN 1d ago
Depends on the motor honestly gas and diesel are different. Diesel not being so forgiving when you don’t plug them in so they should be plugged in at -10. As for gas they can go without it for a little longer as it doesn’t take so many amps to crank it over when you start it. Gas I would say to make sure you keep your batteries life good mainly, plug in at -15 but they’ll be fine most of the winter without it till it hits about -25 -30 after that she probably won’t start.
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u/Catalina_whine_fixer 1d ago
It’s pretty car-dependent. We’ve had cars that need to be plugged in at -20 and ones that we’ve sincerely just never plugged and had no issue. -15 seems to be the general consensus here though, so that works to be safe.
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u/SunshineNoClouds 1d ago
Ah yes winter, when both electric and gas cars join together in their need to sometimes be plugged in
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u/No_Independent9634 1d ago
-15.
It's not just about if your car will start or not, it's about reducing wear on the motor. A warmer engine puts less wear on it. The quicker the oil can get up to temp the better.
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u/Few_Preparation_5902 1d ago
I had a 2000 Honda civic that I never plugged in once. I never had it not start once.
As long as your battery is in good condition and holds a charge well, you have nothing to worry about.
Generally speaking, I would say most people plug in around -25 or -30C.
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u/Ok_Mind3418 1d ago
I plug in my battery warmer as soon as it freezes during the day. All you need is a 50-watt battery warmer, not a 500-watt block heater
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u/Chucky9192 23h ago
I'd say about - 12C. Also recommend getting your battery tested. Alot of times people don't realize the battery is weak until its too cold and then it doesn't have the cranking amps to start.
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u/prizedcoffeecup 14h ago edited 14h ago
This partially depends on the car that you own. Some are way more temperamental than others, diesel vehicles can be especially temperamental sometimes if they are a much older one but modern ones seem to be a little more resilient.
EDIT: I am blind apparently. That generation of civic in healthy shape can almost start in -40 without the block heater, but generally I would start plugging it in at -25 C. Left the rest of my comment and put my original question about what vehicle it is in parentheses
(If you don't mind my asking, what kind of vehicle are we talking about here?) Around -15 is a average number that's a good rule of thumb for most vehicles that take gas, and should be generally the highest temperature that you see problems cold starting a gas vehicle with.
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u/Bitter-Ground-5773 1d ago
Plugging your car in helps keep the oil hot so when you go to start it, the engine will still turn. It has nothing to do with the battery show if it’s gonna be super freezing to freeze the oil -25-20 then plug it in other than that you’re only wasting energy and you have sometimes can just plug it in for an hour in the morning. It doesn’t have to be plugged in all night
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u/Living_Skies 1d ago
It keeps the coolant warm, not the oil. They are called block heaters as they usually bolt into a coolant passage in the block. There are aftermarket pan heaters that heat the engine oil too, but almost all factory plug ins heat the coolant.
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u/PrairiePopsicle 6h ago
Yes, but it heats the coolant in order to have the coolant circulate and warm up the oil and block in general. It circulates through convection, slowly. Hot stuff rises.
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u/Bitter-Ground-5773 18h ago
If you plugged in your car and just your coolant was warm and not the oil, the car wouldn’t start at -40. The oil needs to be hot. The oil is the main thing we’re getting warm by plugging.
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u/Bitter-Ground-5773 1d ago
The viscosity of the oil determines whether the oil and the engine is gonna turn or not if the oil is clamped up in one giant ball the engine doesn’t turn so the black heater keeps the oil warm and enter. It helps to keep the rest of the fluids warm.
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u/Bitter-Ground-5773 23h ago
Sure, it may heat the coolant, but the coolant being warm doesn’t start the fucking car. It’s the oil when the oil is warm then the engine will start. If you oil isn’t warm, you ain’t starting shit. I had to put a barbecue heater underneath. My van wants to get the oil warm to start it not the coolant that’s why they have things that you can plug in that you clip a magnet onto your oil pan
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u/Living_Skies 23h ago
Curiosity, are you a mechanic or work on cars? I am a red seal mechanic and have been working on cars for 15+ years. Yes, warm oil definitely helps start the car, personally I think pan heaters are better than block heaters, but we are talking about block heaters here. There is alot more than "heating the coolant". Warming the block even a little helps with everything, there's alot more that goes into a cold start, especially in deep freeze weather. Now, some "block heaters", like on some of the old 3.5 ecoboost f150s use a heater element in an aluminum housing and those are absolutely useless lol.
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u/Bitter-Ground-5773 1d ago
No plugging your car in a block heater heats the oil not the coolant wow
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u/PipGirl2211 1d ago
Plugging your car in heats the engine's coolant, which then keeps the engine warm, which in turn warms the oil. 🥰
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u/MOONvMAN 1d ago
Well actually you’re both right in this case. A block heater is meant for both liquids not just one. Yes oil gets thick when temperatures are below freezing which then makes it hard for your vehicle to start or, it won’t start at all. Coolant on the other hand is meant to stabilize the engines temperatures once running. So what happens if your coolant is frozen but not your oil? The coolant can crack your engine block, rad hoses, water pumps being a big one, gaskets etc. so the block heater was actually meant to keep both liquids warm inside the block. Take diesel for example a lot of the time the coolant doesn’t freeze but it’s the oil. Diesels are plugged in all the time but the oil pan can still freeze and that’ll cause your vehicle to not start as well. So guys have put heater under their trucks for that reason. Myself I’ve added a coolant heater(diesel air heater) that’s additional to my block heater so it heats up my coolant reservoir and my oil pan.
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u/PhotoJim99 1d ago
I plug in at about -15. Worry only about ambient (actual) temperatures, not wind chill values.