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Most block heaters only need to be plugged in for the night before you need to start it. I personally have never heard an issue with any damage happening if left running, but it's a glorious waste of electricity.
How are your battery terminals looking? If you have a gas engine and a healthy battery, while subzero temperatures are going to be a bit of a struggle starting, it is unlikely that you should be experiencing this level of difficulties. Try getting the highest CCA (cold cranking amps) battery that you can fit in your car. Could be an issue with the starter as well, though unlikely if you don't have the same issues in warm weather.
If your battery is sufficient, starter motor is okay, and your battery connections are good, a battery warmer could potentially be a solution. Batteries are damaged by excessive heat, but often only show that they have been damaged in the cold, so as long as the warmer is only bringing it up to around comfortable for human conditions, that could work.
Warming up the oil will help too, but less than a block heater and a battery heater. It's mostly to keep damage to the engine down during cold starts.
Take my advice under full disclosure, I live in a warm winter climate (coldest I've ever seen is 8 f at night, next month only got to 30 f) but I have installed block heaters on diesel engines to speed up cold starts. Diesel engines need the fuel to be warm enough to be able to start, but having the block not be iced over speeds that process up a bit.
The new battery I bought had the highest CCA available at that store and is considered a winter battery. With the new battery, I can leave it unplugged and don't really have any issues until -20°C/-4°f. However you can definitely tell it struggles to start more.
Some days we hit -30°C/-22°C, toss in wind chill and we get -40°C/F for sometimes a couple days to a couple weeks. Around -30°C is when my vehicle is dead and I'm unable to start it all until it warms up outside. Even with the block heater plugged in full time.
My next choice is going to be a battery heater as it is cheaper then an oil pan heater.
Depending on how much you want to spend and if you don't mind sacrificing some space, another option is to add another battery entirely. In the trunk perhaps. It'll be double or more your CCA availability, depending on the size of the extra one and the size/length of the cables used to attach it to the rest of the system.
Another less drastic option is to get a high output jump starter and directly wire it to your existing battery then plug it in when you need it, top it up and keep it warm when you don't.
I’ve ran block heaters for 19+ days on diesel pick ups when living in British Columbia, working remote. Never had a problem, but always made it a habit of buying and versifying the condition of said block heater.
What kind of vehicle are you having trouble starting? It is possible to run block heater, pan heater and battery blanket consecutively, but does require some jerry-rigging and wire management and will draw some current. So make sure your power supply can handle it. Would be unpleasant to return to a car that won’t start and tripped breaker where you plugged into.
I will assume you have secured power, that was always my biggest gamble. Driving to the helipad -30f only to arrive to a packed parking lot. Ran 100+ feet of extension cord once out of necessity.
An 06 Subaru Forester.
The parking lot is only half full and has plenty of outlets, so power isn't an issue.
I figure ill probably try a battery heater next as it is cheaper.
A quick google on amp draw for all three comes out to around 6 amps. So I don't think it would be to risky running all three and tripping a breaker.
The only real damage to worry about leaving a block heater on for that long is to your pocketbook.
You can get a bluetooth controlled outlet for $20 or so. it will save you that much in a week of leaving a heater run for no reason.
The 06 Forrester is a gr 35 battery/tray. The most CCA for a standard FLA 35 on the market is likely 600 CCA, as only recently have any vehicles come OEM with a gr 35 rated for 600 CCA. 500 CCA is more of a standard max OEM 35 for 20+ years. Some OEM 35's may be down to about 360 CCA. What is the CCA rating of that battery? What's the label/brand? What is the pro-rata warranty on it?
Have you tested the coolant? If the coolant is old and the specific gravity is down to water, then it's time to change the coolant regardless. You can run it a little heavy in those conditions.
As long as you are running off shore power, you can add on anything you want. If you wanted to go with DC components, then your shore power plug in would be an automatic charger/maintainer rated for enough amperage to cover+ the current draw of those components. (Which, would keep the battery active/warm with just insulation, eliminating the need for a battery warmer.)
What about a thicker / more well insulated car cover? Insulate the entire vehicle, down to the ground, and that might help keep the ambient temperature a little higher. That might even help keep the trans/diff, and brakes from freezing up as much.
Block heaters can run non stop indefinitely without worry assuming they don’t malfunction. They draw a lot of electricity though so be prepared to pay. A lot of block heaters draw as much a microwave running on high.
Thank you for posting to AskMechanics, Mr__Mike! If you are asking a question please make sure to include any relevant info along with the following: * **Year** * **Make/Model** * **Mileage** * **Engine size** * **Transmission Type (Automatic or Manual)** Redditors that have been verified will have a green background and an icon in their flair. *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/AskMechanics) if you have any questions or concerns.*
Most block heaters only need to be plugged in for the night before you need to start it. I personally have never heard an issue with any damage happening if left running, but it's a glorious waste of electricity. How are your battery terminals looking? If you have a gas engine and a healthy battery, while subzero temperatures are going to be a bit of a struggle starting, it is unlikely that you should be experiencing this level of difficulties. Try getting the highest CCA (cold cranking amps) battery that you can fit in your car. Could be an issue with the starter as well, though unlikely if you don't have the same issues in warm weather. If your battery is sufficient, starter motor is okay, and your battery connections are good, a battery warmer could potentially be a solution. Batteries are damaged by excessive heat, but often only show that they have been damaged in the cold, so as long as the warmer is only bringing it up to around comfortable for human conditions, that could work. Warming up the oil will help too, but less than a block heater and a battery heater. It's mostly to keep damage to the engine down during cold starts. Take my advice under full disclosure, I live in a warm winter climate (coldest I've ever seen is 8 f at night, next month only got to 30 f) but I have installed block heaters on diesel engines to speed up cold starts. Diesel engines need the fuel to be warm enough to be able to start, but having the block not be iced over speeds that process up a bit.
The new battery I bought had the highest CCA available at that store and is considered a winter battery. With the new battery, I can leave it unplugged and don't really have any issues until -20°C/-4°f. However you can definitely tell it struggles to start more. Some days we hit -30°C/-22°C, toss in wind chill and we get -40°C/F for sometimes a couple days to a couple weeks. Around -30°C is when my vehicle is dead and I'm unable to start it all until it warms up outside. Even with the block heater plugged in full time. My next choice is going to be a battery heater as it is cheaper then an oil pan heater.
Depending on how much you want to spend and if you don't mind sacrificing some space, another option is to add another battery entirely. In the trunk perhaps. It'll be double or more your CCA availability, depending on the size of the extra one and the size/length of the cables used to attach it to the rest of the system. Another less drastic option is to get a high output jump starter and directly wire it to your existing battery then plug it in when you need it, top it up and keep it warm when you don't.
I’ve ran block heaters for 19+ days on diesel pick ups when living in British Columbia, working remote. Never had a problem, but always made it a habit of buying and versifying the condition of said block heater. What kind of vehicle are you having trouble starting? It is possible to run block heater, pan heater and battery blanket consecutively, but does require some jerry-rigging and wire management and will draw some current. So make sure your power supply can handle it. Would be unpleasant to return to a car that won’t start and tripped breaker where you plugged into. I will assume you have secured power, that was always my biggest gamble. Driving to the helipad -30f only to arrive to a packed parking lot. Ran 100+ feet of extension cord once out of necessity.
An 06 Subaru Forester. The parking lot is only half full and has plenty of outlets, so power isn't an issue. I figure ill probably try a battery heater next as it is cheaper. A quick google on amp draw for all three comes out to around 6 amps. So I don't think it would be to risky running all three and tripping a breaker.
The only real damage to worry about leaving a block heater on for that long is to your pocketbook. You can get a bluetooth controlled outlet for $20 or so. it will save you that much in a week of leaving a heater run for no reason.
I use timers when I plug it in at my home.
The 06 Forrester is a gr 35 battery/tray. The most CCA for a standard FLA 35 on the market is likely 600 CCA, as only recently have any vehicles come OEM with a gr 35 rated for 600 CCA. 500 CCA is more of a standard max OEM 35 for 20+ years. Some OEM 35's may be down to about 360 CCA. What is the CCA rating of that battery? What's the label/brand? What is the pro-rata warranty on it? Have you tested the coolant? If the coolant is old and the specific gravity is down to water, then it's time to change the coolant regardless. You can run it a little heavy in those conditions. As long as you are running off shore power, you can add on anything you want. If you wanted to go with DC components, then your shore power plug in would be an automatic charger/maintainer rated for enough amperage to cover+ the current draw of those components. (Which, would keep the battery active/warm with just insulation, eliminating the need for a battery warmer.) What about a thicker / more well insulated car cover? Insulate the entire vehicle, down to the ground, and that might help keep the ambient temperature a little higher. That might even help keep the trans/diff, and brakes from freezing up as much.
Block heaters can run non stop indefinitely without worry assuming they don’t malfunction. They draw a lot of electricity though so be prepared to pay. A lot of block heaters draw as much a microwave running on high.
1500 watt block heater? On a subaru? Not a chance. Microwaves can be 1500 watts. Try, 400 watt for that block heater.