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That doesn't sound very practical; keeping the batteries of all cars warm 24/7 would require immense amounts of electricity on a country-wide scale. It's not l

by 2000UltraDeluxe 4y ago

That doesn't sound very practical; keeping the batteries of all cars warm 24/7 would require immense amounts of electricity on a country-wide scale. It's not like everyone have heated garages, and outdoor temperatures often reach -30c or below in arctic climates.

lazide 4y ago
1) the batteries are insulated 2) you don’t need to keep them warm 24/7, just above freezing when charging them or and/or when you want more efficiency or maximum power (like a longer trip, or midway through a drive). ICE engines are quite inefficient when ‘cold’ (and diesel may refuse to run at all), this isn’t a new problem. The batteries don’t need to be warm by human standards, and the vehicle will still work even when quite cold, just not very well.
- 2000UltraDeluxe 4y ago
  How much energy does it take to heat a battery pack from -30c to 1c? ICE engines definitely have their own set of cold-related issues, but I can't imagine heating a 150 kg engine block would require the same amounts of energy required to heat 500 kgs of battery twice (charging and before driving). Mind you, I'm not arguing against EV's or anything; I'm just saying it sounds like there's an engineering problem that needs to be solved before EV's can replace ICE cars in very cold climates, which incidentally, also tend to be where the most range is needed.
  - lazide 4y ago
    Nope. It isn’t that much energy compared to losses in ICE engines/existing inefficiencies. Feel free to do the energy calcs - there is no engineering challenge here for EVs that is currently unsolved.
    - 2000UltraDeluxe 4y ago
      I prefer practical tests. Right now, however, the authorities here encourage people to avoid using electric pre-heaters in order to save electricity, so I'll take your word for it. :) Ideally, things like this wouldn't be a problem, but where I live EV's is simply not an option during winter. Charging from a regular 240V/16A outlet takes too long, the nearest proper charging station is over 25km away, and the grid out here won't handle the load of everyone getting proper chargers at home. Adding additional load to heat batteries of thousands of cars probably won't be a viable option until the grid has been modernized. Luckily, this shouldn't be a problem in warmer, more densly populated areas anyway. Better to roll out EV's where it's viable, and sort out the fringe cases later.
      - lazide 4y ago
        Some specifics - Assuming Cp = 0.32 kJ/kg•K, which seems about right, you’re talking about 3kwh to heat up a 75kwh sized pack from -25C (-13f) to 25C (77f), or about 4% of the pack capacity. Which about lines up with my experience ‘warming up’ ICE vehicles. It’s not great fuel economy wise to do so. If you have a block heater, seems like those can be as much as 750-1500 watts. If a diesel, that block needs to get pretty warm, and it’s not like a ton+ of steel/cast iron doesn’t take a lot of energy to heat up either. And that’s ignoring transmission heaters, battery heaters, etc. Is it 3kwh worth? That would depend on a lot of factors not specified, but it wouldn’t surprise me if it was close. A 240V/16A outlet (16A is a bit unusual? Usually it’s multiples of 5), is 3.8KW Peak. That would indeed be limiting, as assuming something like 90% efficiency a full charge is 20+ hours. It’s an odd number to pick though, as unless someone has a very undersized utility feed, more shouldn’t be a big deal? I know, some places have only a 50 amp panel and blow fuses anyway, but compared to buying a new car that’s a cheap problem to fix. Even a not shitty welder is going to want 240v/20A, and an old 50 amp panel can barely handle a space heater and other usage. A typical electric stove is 240v/30A (or more) same with an electric dryer or AC. If using a typical electric dryer type connection, that’s 7200 watts, and at 90% efficiency could recharge a fully discharged 75kwh pack in 11 hrs, which is ‘overnight’ in most situations. Most newish residential construction has 150 or 200 amp, 240v split phase service and panels, or 36-48kw, which provides a lot of headroom. Of course to your point, out in the sticks things are different, and I don’t know your situation or the local counties power infrastructure. Just supply chain issues would be a show stopper for me in a remote area. Couple in frequent power outages and that it could be life threatening not having a vehicle during one, also an issue.

lazide 4y ago

1) the batteries are insulated 2) you don’t need to keep them warm 24/7, just above freezing when charging them or and/or when you want more efficiency or maximum power (like a longer trip, or midway through a drive). ICE engines are quite inefficient when ‘cold’ (and diesel may refuse to run at all), this isn’t a new problem. The batteries don’t need to be warm by human standards, and the vehicle will still work even when quite cold, just not very well.

2000UltraDeluxe 4y ago
How much energy does it take to heat a battery pack from -30c to 1c? ICE engines definitely have their own set of cold-related issues, but I can't imagine heating a 150 kg engine block would require the same amounts of energy required to heat 500 kgs of battery twice (charging and before driving). Mind you, I'm not arguing against EV's or anything; I'm just saying it sounds like there's an engineering problem that needs to be solved before EV's can replace ICE cars in very cold climates, which incidentally, also tend to be where the most range is needed.
- lazide 4y ago
  Nope. It isn’t that much energy compared to losses in ICE engines/existing inefficiencies. Feel free to do the energy calcs - there is no engineering challenge here for EVs that is currently unsolved.
  - 2000UltraDeluxe 4y ago
    I prefer practical tests. Right now, however, the authorities here encourage people to avoid using electric pre-heaters in order to save electricity, so I'll take your word for it. :) Ideally, things like this wouldn't be a problem, but where I live EV's is simply not an option during winter. Charging from a regular 240V/16A outlet takes too long, the nearest proper charging station is over 25km away, and the grid out here won't handle the load of everyone getting proper chargers at home. Adding additional load to heat batteries of thousands of cars probably won't be a viable option until the grid has been modernized. Luckily, this shouldn't be a problem in warmer, more densly populated areas anyway. Better to roll out EV's where it's viable, and sort out the fringe cases later.
    - lazide 4y ago
      Some specifics - Assuming Cp = 0.32 kJ/kg•K, which seems about right, you’re talking about 3kwh to heat up a 75kwh sized pack from -25C (-13f) to 25C (77f), or about 4% of the pack capacity. Which about lines up with my experience ‘warming up’ ICE vehicles. It’s not great fuel economy wise to do so. If you have a block heater, seems like those can be as much as 750-1500 watts. If a diesel, that block needs to get pretty warm, and it’s not like a ton+ of steel/cast iron doesn’t take a lot of energy to heat up either. And that’s ignoring transmission heaters, battery heaters, etc. Is it 3kwh worth? That would depend on a lot of factors not specified, but it wouldn’t surprise me if it was close. A 240V/16A outlet (16A is a bit unusual? Usually it’s multiples of 5), is 3.8KW Peak. That would indeed be limiting, as assuming something like 90% efficiency a full charge is 20+ hours. It’s an odd number to pick though, as unless someone has a very undersized utility feed, more shouldn’t be a big deal? I know, some places have only a 50 amp panel and blow fuses anyway, but compared to buying a new car that’s a cheap problem to fix. Even a not shitty welder is going to want 240v/20A, and an old 50 amp panel can barely handle a space heater and other usage. A typical electric stove is 240v/30A (or more) same with an electric dryer or AC. If using a typical electric dryer type connection, that’s 7200 watts, and at 90% efficiency could recharge a fully discharged 75kwh pack in 11 hrs, which is ‘overnight’ in most situations. Most newish residential construction has 150 or 200 amp, 240v split phase service and panels, or 36-48kw, which provides a lot of headroom. Of course to your point, out in the sticks things are different, and I don’t know your situation or the local counties power infrastructure. Just supply chain issues would be a show stopper for me in a remote area. Couple in frequent power outages and that it could be life threatening not having a vehicle during one, also an issue.