I live in Alberta, Canada, and lately it has been very cold (-20s degrees Celsius at night). I don't drive often; for example I'll drive once a week (sometimes less due to COVID restrictions, but I'm aiming to drive more during cold snaps to ensure the battery charges). When should I plug in my block heater? Only 4 hours before driving? Less? My car wouldn't start (after plugging in for an hour) and the roadside assistance technician told me I should be plugging it in all the time (when not driving), considering my situation, during these cold temps (-15 degrees Celsius and below) to ensure the car is always ready to go, even in emergencies (e.g. I unexpectedly must go to the hospital, but I didn't plug it in beforehand). Any suggestions? I've also thought about getting a battery tender, but maybe the block heater is sufficient?

 

Never used a block heater as super cold temperatures are pretty rare here. But my cars always started fine, in fact the last few weeks were about -15 to -20c at night too and I had no issues starting either the Fit or the Miata. So my somewhat educated guess is that this is more of a battery issue, perhaps it's old/worn out or it really doesn't get charged enough on your infrequent drives.

A block heater would certainly help (though it wouldn't warm up your battery) but seems like it would be wasteful to run it the whole week just in case you'd drive it once. So I think I'd go with a battery tender, but take this with a grain of salt.

 

If your Fit doesn't start below -15 C it's probably time to replace the battery. It should easily start well below -30 C. In Finland it's commonly stated that 2 h pre-heating with a block heater is sufficient and more than 4 h is definitely not increasing anything else than your electricity bill. However, if you want or need to keep it plugged all the time it's good idea to check coolant level time to time.

 

When I was young many decades ago and driving my first car, the general rule was that you could plug a block heater in for up to 4 hours but after that natural heat loss to the cold air would prevent it from warming up any further. Since 4 hours was optimum many people including me installed exterior timers which would come on 4 hours before you had to go to work and the car would be at optimum temp when you turned the key. The timer cut down on unnecessary heating and saved some money on the electrical bill.

In Slug's situation where he's on call and may have to head for work at any time, when the weather is really cold there's not much choice but to leave it plugged in all the time. Fortunately the Fit's block heater is not that large and does not draw a lot of power.

I've also always put an electric battery blanket around my batteries to warm them up. It doesn't draw much power and does make a huge difference when starting up. The car turns over like it was the middle of summer. It fits snugly around the OEM battery type 151R, but when I have to replace that I'll be going to the larger size the 51R and I suspect that it will no longer fit because there will be much less clearance around the battery.

And of course we all have 0W20 synthetic oil in our Fits which is extremely thin and great for cold weather starting.

I don't actually plug my Fit in that often since it will start at just about any temperature and due to ground heat the garage is about 5°C to 7°C warmer than the outside air, which has been running at -32°C to -40°C overnight for the last two weeks.

 

Slug - does your Fit have the standard 151R battery? If so, consider replacing with a 51R. I did this on mine couple months ago. The tray was big enough to accommodate the bigger battery without any surgery.

You get a lot more cranking power. It might be the difference in getting it started vs. the standard smaller 151R.

 

That's smart!

 

Thanks for the tips. I talked to Honda dealership staff, too, and got their recommendations for ensuring optimal Honda Fit health during extreme cold. Some suggested leaving the block heater plugged in whenever it's really cold (-20C or below), especially at night, even if I'm not planning to drive it anytime soon. I was told it'll keep the fluids warm and prevent the engine from freezing, and make it easier for the battery and engine to work together to get the car started. It sounds like it's really up to me on how long I plug it in, and may involve trial and error. I wish there was a manual, but there seem to be so many factors, as even shown in all of your helpful suggestions.

Mobby_6kl seems to drive often, so probably their battery won't ever have a charging issue. And their location doesn't seem so cold (-15/-20 C in EU vs -20 to -40 C here in Alberta).

TnTkr: Thanks for suggesting to check the coolant levels; I hadn't thought of that. The dealership told me it probably shouldn't be an issue, but at temperatures of -30C a block heater should be plugged in all night (and even when I'm not using it). Maybe Fins don't need to plug in, but some Canadians do? Maybe it's a different kind of cold there (or microclimates create warmer/sheltered environments for cars? - my car is out on the street, exposed to the elements, with no shelter), or their battery is just charged better from daily use (at long runs and high speeds)?

woof: I wish I had your heated garage, or a garage period. I haven't used a battery blanket, but heard the battery tender is a good (and maybe better) option to ensure the battery starts on those bone-chillingly cold days.

bargainguy: My Fit has a standard 151R battery, so I suppose I could replace it with a more powerful battery. But if it ain't broke...

I've had people tell me block heaters aren't required if you have synthetic oil, but dealerships and AMA highly recommend them. As for block heater charging times, I've been advised it should be anywhere from an hour (before driving) to 4 hours to overnight/ all the time (when not driving and it's super cold). I think in my case, I need a longer time for charging, especially if the car has been sitting in the cold for a long time, as was my case: After 3 days in the -30s (degrees Celsius at night, but -20s during the day) and not driving or plugging in the block heater, I plugged in for a short time (maybe an hour), but couldn't get the car started. The car sounded like it was choking, as I tried to get it started. A boost worked, though. The roadside service agent told me my battery was just slightly below the threshold needed to start the car, but my battery was fine.

This is my first harsh winter with the car. I lived in areas with milder winters, so I'm not sure what is advisable, but appreciate all of the advice. I read that a battery tender may not work at low temperatures (below -20C). My friend told me if I'm not driving for a few days, and it's cold, I could remove the battery and bring it indoors. I've never done that before, and am not sure if I should since it sounds like a bit of a hassle. I wish the car would just speak to me and tell me exactly what it needs (keep me warm all the time when it's below -20C! drive me at least once a week! and we must go fast non-stop for 1/2 an hour).

 

What a load of hooey!
Tell that to my dad who recently (last fall) picked up a Volvo S60 with no block heater.

After the last cold snap his car has been rendered useless and he's had to resort to renting a car from Enterprise to get around.
Since they live in Regina there's no Volvo dealership to sell him a $300 block heater (parts, not including labor), and the closest dealer is in Saskatoon

I told him several times to not purchase that thing...but my parents just don't listen.
They seem to think because it's a "Volvo" it'll be as reliable and simple to operate as the old 240 series cars we had in the 80s.

 

Many people here in Finland use block heater continuously or overnight, there is nothing to worry in that. There are also kits to permanently mounted battery charger connected to block heater supply to ensure engine is warm and battery charged. I think that would be very recommended if you are driving short distances. Even in temperatures not requiring pre-heating for starting the car, it has significant benefits reducing the engine wear and fuel consumption right after a cold start already at 0 C (32 F).

The issue about coolant disappearing when using block heater is very seldom an issue, and it's very often related to existing small leakages in the system. It's easier to remember checking coolant when you get driving but easy to forget if car is just staying block heater connected.

 

When I had my 2015, I had a block heater installed. It was around $40 for the parts. I did not have a garage, and certain times in winter it would get to -10 degrees F or -23 C. I rigged up what others have stated using a timer. The block heater was on the timer circuit in addition to a battery blanket that essentially warmed the battery up. The only aspect with constant power was a small battery maintainer which was plugged in using quick connects where the block heater port was on the car. Ironically set it to 4hrs before I had to leave for work, and never had an issue. It only got to -20C a few weeks out of the year, but a car being outside all the time it made perfect sense to me. Now I have a house with a two car garage and my 2017 does not have a block heater. I do keep a battery maintainer on my car since being a remote employee before the pandemic the car simply does not get driven all the time.

 

Here in Alberta, I believe all new vehicles come with a block heater, probably because it gets so cold here. I think that here in Alberta (or at least Edmonton), not many people plug in the block heater continuously when it's very cold; I think overnight plugging or using a timer is the norm, but I want to do what's best for my car and within my constraints. I think the battery tender/minder/charger sounds like a good idea. I would plug in continuously (during cold temperatures) and even at temps not requiring pre-heating to start the car (since as TnTkr says, it reduces engine wear/fuel consumption at 0C; I don't think lots of people do this, but dealership staff recommended this, too), but there are concerns about electricity costs. Any idea how much electricity/energy is used by: a block heater? a battery tender? I have a 2017 Honda Fit. Also, is it recommended to get a battery tender installed at the dealership? (to ensure warranties aren't voided)

 

A block heater typically uses about 400 watts for a typical car. Could be a bit less for the small Fit engine.
A battery tender an easy guess of 50 watts or less. Maybe a lot less if the battery is fully charged and doesn't draw much power as a result.

 

Sadly, that's not the case (but it should be).
Try building any new car online and you'll see the added option of a "block heater".

A great example of new Canadian vehicles without them are rentals.
Since the rental company strives to keep purchase prices as low as possible, most fleet purchased vehicles are not equipped with them.

 

Most people flying in and renting a car probably wouldn't know what a block heater is - or bother using it - anyways.
Same in Manitoba. New cars are generally equipped with a block heater automatically.

 

haha, that's true.

So which manufacturers offer free block heaters on the prairies?
I'm very interested to know

 

How long would you plug in the block heater in such cases when the outside temperature is at 0C or a bit below?

 

I'd say 30-45 minutes at 0 C would be good. My Jazz has a Defa block heater with 500 W electric power.

 

Free???? If you were familiar with car companies you wouldn't have to ask that question. The answer is: obviously none of them. The cost of the block heater and installation is tacked onto the list price of the car. You pay for it, along with a lot of other crap the dealer slaps on any new car arriving at his lot.

 

Oh I am familiar...from years selling cars, to fixing them.
All manufacturers either add it without you knowing (and charge you for it), or are like Honda where ALL their vehicles have optional block heaters that you don't have to purchase - if you don't want to.

 

Optional???? Well I bought a Fit and there was no optional about it. The first dealer slapped a block heater on car the instant it hit their lot, along with Honda floor mats, mud flaps, and several other things including a $600 "tire insurance" policy which they absolutely insisted couldn't be removed. Nothing could be removed, not even the mats. I walked and bought at another dealership which didn't have "tire insurance". The block heater was never an issue since I was going to get that installed anyways. I had heard that in Manitoba it was a government requirement to put block heaters on all new cars but I've never found anything to confirm that. It does make sense though, and equal sense in other Provinces with milder weather to just make them optional.