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For those questioning the feasibility, 100% electric school buses are already on the road in Montreal. I see them frequently, and they seem to handle our crappy

For those questioning the feasibility, 100% electric school buses are already on the road in Montreal. I see them frequently, and they seem to handle our crappy roads and winters fine.

wolverine876 5y ago
Why would electric buses have more problems on winter roads than ICE buses?
- ajford 5y ago
  Cold air impacting heath & capacity on the Li batteries, perhaps? Lithium batts tend to be finicky about their temperatures. Even my PHEV chevy volt de-rates the capacity if the ambient air temps hit less than 36*F.
  - wongarsu 5y ago
    Heating the batteries and passenger compartment is quite expensive energy-wise, you certainly have to calculate that in when determining an appropriate battery size for such an application.
    - ajford 5y ago
      Definitely something to consider. I wonder if there's some value to a secondary/supplemental seasonal battery that can be added for part of the year to handle the extra load. Would come down to whether the installation/removal (to lower the "dry" weight for the warm seasons) would be worth the energy savings of not hauling around the supplemental battery weight. Other options might be to use some kind of thermal mass for heating, perhaps a large heated mass or fluid tank? Not sure if there's any benefit there though beyond being able to swap out the fluid tank between runs faster than charging a battery.
    - Broken_Hippo 5y ago
      You don't need to heat the entire passenger compartment unless folks are in there, though. You just heat the bits that could benefit. This is the same sort of thinking behind the engine block heaters (for combustion engines) folks use when it is cold and a similar theory to trucks that heat their diesel tanks to keep the diesel from turning to gel, though I don't know if that's an issue anymore with modern diesel blends.
      - wolverine876 5y ago
        Where do the trucks get the energy to heat the tanks, assuming they are off? Electricity - is there enough in the battery? Keep the ICE running?
  - jillesvangurp 5y ago
    There's an effect on range for sure. But there are also ways to mitigate that by for example heating the battery. There are plenty of EVs operating under arctic conditions in Norway, for example. And not just in Oslo where temperatures are mild. Here's a story about a Norwegian with a model 3 that lives on the north coast of Norway in the arctic circle: https://electrek.co/2020/02/11/tesla-model-3-arctic-circle-winter/ https://electrek.co/2020/02/11/tesla-model-3-arctic-circle-w... It seems that that particular car has some features that are genuinely nice to have when it is minus 32. Like the ability to warm it up before you get into it. That costs energy of course and that explains most of the range hit you get. Most recent EVs have ways to cool (high temperatures are also a problem) and heat batteries, which older cars and phevs would have lacked. And of course the process of charging and discharging batteries actually warms batteries up as well. That's why heat is a problem and probably a bigger problem from an engineering point of view. Yet nobody ever complains about Tesla's not working in the desert. It's kind of a solved problem. Extreme temperatures affect range and you need to plan accordingly. But otherwise the battery will work fine.
  - hedora 5y ago
    Sorry to be the bearer of bad news, but that's mostly because it's a Chevy, not because managing lithium batteries in cold weather is an unsolved problem: https://news.yahoo.com/cold-hard-truth-evs-winter-103037566.html https://news.yahoo.com/cold-hard-truth-evs-winter-103037566.... If you are in a climate where freezing weather is common, you might want to swap it for a different brand. There are comparably priced options that work well in the cold (just look at the chart in the article).
    - rootusrootus 5y ago
      My Tesla definitely lost range in the cold, too. I don't think it's just that Chevy (LG, you mean) doesn't know how to make a good battery pack.
    - ajford 5y ago
      While I don't doubt other manufacturers have taken steps to charge better at cold temperatures, since theoretically you can do this if you have the charger warm the pack up to temperatures above freezing, this isn't just an issue with my Chevy. All battery chemistry suffers from degraded performance in cold temperatures, because they all rely on chemical processes that are hampered by cold. Lithium batteries are in some ways more susceptible because they are just a more finicky battery chemistry overall, being far more sensitive to charging currents, temperatures, and voltages. There's tons of articles and references out there about the cares that must be taken with batteries of various chemistries, and they all talk about the low temperature issues. - https://www6.slac.stanford.edu/news/2021-08-24-how-extreme-cold-can-crack-lithium-ion-battery-materials-degrading-performance.aspx https://www6.slac.stanford.edu/news/2021-08-24-how-extreme-c... - https://www.fluxpower.com/blog/the-importance-of-industrial-battery-temperature-control#:~:text=What%20Happens%20to%20Lithium%2Dion%20Batteries%20at%20Low%20Temperatures%3F https://www.fluxpower.com/blog/the-importance-of-industrial-... - https://batteryuniversity.com/article/bu-410-charging-at-high-and-low-temperatures#:~:text=Below%205%C2%B0C%2C%20the%20charge%20current%20should%20be%20reduced%2C%20and%20no%20charging%20is%20permitted%20at%20freezing%20temperatures%20because%20of%20the%20reduced%20diffusion%20rates%20on%20the%20anode https://batteryuniversity.com/article/bu-410-charging-at-hig.... - https://relionbattery.com/blog/the-best-battery-for-cold-weather#:~:text=Does%20cold%20weather%20affect%20lithium,80%25%20of%20its%20rated%20capacity https://relionbattery.com/blog/the-best-battery-for-cold-wea....
- krallja 5y ago
  It’s cold in the winter.

For those questioning the feasibility, 100% electric school buses are already on the road in Montreal. I see them frequently, and they seem to handle our crappy roads and winters fine.

wolverine876 5y ago

Why would electric buses have more problems on winter roads than ICE buses?

ajford 5y ago
Cold air impacting heath & capacity on the Li batteries, perhaps? Lithium batts tend to be finicky about their temperatures. Even my PHEV chevy volt de-rates the capacity if the ambient air temps hit less than 36*F.
- wongarsu 5y ago
  Heating the batteries and passenger compartment is quite expensive energy-wise, you certainly have to calculate that in when determining an appropriate battery size for such an application.
  - ajford 5y ago
    Definitely something to consider. I wonder if there's some value to a secondary/supplemental seasonal battery that can be added for part of the year to handle the extra load. Would come down to whether the installation/removal (to lower the "dry" weight for the warm seasons) would be worth the energy savings of not hauling around the supplemental battery weight. Other options might be to use some kind of thermal mass for heating, perhaps a large heated mass or fluid tank? Not sure if there's any benefit there though beyond being able to swap out the fluid tank between runs faster than charging a battery.
  - Broken_Hippo 5y ago
    You don't need to heat the entire passenger compartment unless folks are in there, though. You just heat the bits that could benefit. This is the same sort of thinking behind the engine block heaters (for combustion engines) folks use when it is cold and a similar theory to trucks that heat their diesel tanks to keep the diesel from turning to gel, though I don't know if that's an issue anymore with modern diesel blends.
    - wolverine876 5y ago
      Where do the trucks get the energy to heat the tanks, assuming they are off? Electricity - is there enough in the battery? Keep the ICE running?
- jillesvangurp 5y ago
  There's an effect on range for sure. But there are also ways to mitigate that by for example heating the battery. There are plenty of EVs operating under arctic conditions in Norway, for example. And not just in Oslo where temperatures are mild. Here's a story about a Norwegian with a model 3 that lives on the north coast of Norway in the arctic circle: https://electrek.co/2020/02/11/tesla-model-3-arctic-circle-winter/ https://electrek.co/2020/02/11/tesla-model-3-arctic-circle-w... It seems that that particular car has some features that are genuinely nice to have when it is minus 32. Like the ability to warm it up before you get into it. That costs energy of course and that explains most of the range hit you get. Most recent EVs have ways to cool (high temperatures are also a problem) and heat batteries, which older cars and phevs would have lacked. And of course the process of charging and discharging batteries actually warms batteries up as well. That's why heat is a problem and probably a bigger problem from an engineering point of view. Yet nobody ever complains about Tesla's not working in the desert. It's kind of a solved problem. Extreme temperatures affect range and you need to plan accordingly. But otherwise the battery will work fine.
- hedora 5y ago
  Sorry to be the bearer of bad news, but that's mostly because it's a Chevy, not because managing lithium batteries in cold weather is an unsolved problem: https://news.yahoo.com/cold-hard-truth-evs-winter-103037566.html https://news.yahoo.com/cold-hard-truth-evs-winter-103037566.... If you are in a climate where freezing weather is common, you might want to swap it for a different brand. There are comparably priced options that work well in the cold (just look at the chart in the article).
  - rootusrootus 5y ago
    My Tesla definitely lost range in the cold, too. I don't think it's just that Chevy (LG, you mean) doesn't know how to make a good battery pack.
  - ajford 5y ago
    While I don't doubt other manufacturers have taken steps to charge better at cold temperatures, since theoretically you can do this if you have the charger warm the pack up to temperatures above freezing, this isn't just an issue with my Chevy. All battery chemistry suffers from degraded performance in cold temperatures, because they all rely on chemical processes that are hampered by cold. Lithium batteries are in some ways more susceptible because they are just a more finicky battery chemistry overall, being far more sensitive to charging currents, temperatures, and voltages. There's tons of articles and references out there about the cares that must be taken with batteries of various chemistries, and they all talk about the low temperature issues. - https://www6.slac.stanford.edu/news/2021-08-24-how-extreme-cold-can-crack-lithium-ion-battery-materials-degrading-performance.aspx https://www6.slac.stanford.edu/news/2021-08-24-how-extreme-c... - https://www.fluxpower.com/blog/the-importance-of-industrial-battery-temperature-control#:~:text=What%20Happens%20to%20Lithium%2Dion%20Batteries%20at%20Low%20Temperatures%3F https://www.fluxpower.com/blog/the-importance-of-industrial-... - https://batteryuniversity.com/article/bu-410-charging-at-high-and-low-temperatures#:~:text=Below%205%C2%B0C%2C%20the%20charge%20current%20should%20be%20reduced%2C%20and%20no%20charging%20is%20permitted%20at%20freezing%20temperatures%20because%20of%20the%20reduced%20diffusion%20rates%20on%20the%20anode https://batteryuniversity.com/article/bu-410-charging-at-hig.... - https://relionbattery.com/blog/the-best-battery-for-cold-weather#:~:text=Does%20cold%20weather%20affect%20lithium,80%25%20of%20its%20rated%20capacity https://relionbattery.com/blog/the-best-battery-for-cold-wea....
krallja 5y ago
It’s cold in the winter.