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That is interesting to see the difference the manufacturers bake into their battery designs as far as software control goes. Tesla seems to quite tightly contro

That is interesting to see the difference the manufacturers bake into their battery designs as far as software control goes. Tesla seems to quite tightly control pack charge and discharge through their bms, and limit things in software rather than hitting chemical limits of the batteries like some other manufacturers seem to be allowing.

brianwawok 4y ago
It also matters who has heat pumps and who doesn’t. Keeping the meat bags warm is a lot of energy.
- jeffrallen 4y ago
  The heat pump is for the batteries. If there's some heating/cooling left over, it's for the meatbags.
  - brianwawok 4y ago
    I don’t think many people are driving around in winter with a 30 degree cabin temp. IME meat bags get priority at all times except while supercharging, when the temp can go pretty wild while it focuses on the battery.
    - jeffrallen 4y ago
      I drive a Renault Zoe which has a heat pump and air-cooled batteries, and I can tell you that the Renault engineers were very protective of the battery. I've never had a problem with the cabin temperature, but it's clear that the HVAC system is sized and optimised for the batteries. For example, when charging cold batteries, the blower revs up much higher than it would ever go for the cabin.
- galangalalgol 4y ago
  Looking back into the source article some of the more better performers do actually have heat pumps. It seems one of the mistakes is that some of them do not start heating the batter in advance, while others spendnpower to keep it warm while plugged in.
ajross 4y ago
It's not a chemical thing, it's just temperatures. Cold batteries have lower cell voltage, so the current available drops into the non-linear ("off") range at a lower state of discharge than a hot battery. The energy is still there[1], you just can't get it out without warming it up. Teslas[2] (and a handful of other models) have heat pumps to warm the batteries. It's as simple as that. The same system is integrated with navigation too, because even on warm days unused/empty cells will be colder, and you want those to be warm when you reach the supercharger. [1] Which is to say this isn't strictly a change in "range", if you can drive somewhere warm you can keep going to the rated distance. [2] Ones built over the last three years anyway -- older ones didn't have this. I think Y's and all but the oldest 3's have heat pumps, but older S/X models might not. Something to be aware of when buying on the used market.
- Tostino 4y ago
  You are absolutely correct that temperature has those effects...but that doesn't change the fact that the underlying reaction inside the batteries is a chemical in nature. That chemical reaction inside the batteries is what gets slowed down as the temperature drops.
aetherspawn 4y ago
Hitting the chemical limits of the batteries is what causes 1/ rapid aging and 2/ catastrophic cell damage and/or short failure and runaway, so if what you say is true (I don’t think it is) then the other manufacturers have implemented poor state of function control (SOF) and it would be a good idea to avoid. Proper SOF control is loosely required for ECE R100 which most manufacturers would have, but OTOH I am convinced that it’s possible to fudge that certification. Source: battery controls engineer.

brianwawok 4y ago

It also matters who has heat pumps and who doesn’t. Keeping the meat bags warm is a lot of energy.

jeffrallen 4y ago
The heat pump is for the batteries. If there's some heating/cooling left over, it's for the meatbags.
- brianwawok 4y ago
  I don’t think many people are driving around in winter with a 30 degree cabin temp. IME meat bags get priority at all times except while supercharging, when the temp can go pretty wild while it focuses on the battery.
  - jeffrallen 4y ago
    I drive a Renault Zoe which has a heat pump and air-cooled batteries, and I can tell you that the Renault engineers were very protective of the battery. I've never had a problem with the cabin temperature, but it's clear that the HVAC system is sized and optimised for the batteries. For example, when charging cold batteries, the blower revs up much higher than it would ever go for the cabin.
galangalalgol 4y ago
Looking back into the source article some of the more better performers do actually have heat pumps. It seems one of the mistakes is that some of them do not start heating the batter in advance, while others spendnpower to keep it warm while plugged in.

ajross 4y ago

It's not a chemical thing, it's just temperatures. Cold batteries have lower cell voltage, so the current available drops into the non-linear ("off") range at a lower state of discharge than a hot battery. The energy is still there[1], you just can't get it out without warming it up. Teslas[2] (and a handful of other models) have heat pumps to warm the batteries. It's as simple as that. The same system is integrated with navigation too, because even on warm days unused/empty cells will be colder, and you want those to be warm when you reach the supercharger. [1] Which is to say this isn't strictly a change in "range", if you can drive somewhere warm you can keep going to the rated distance. [2] Ones built over the last three years anyway -- older ones didn't have this. I think Y's and all but the oldest 3's have heat pumps, but older S/X models might not. Something to be aware of when buying on the used market.

Tostino 4y ago
You are absolutely correct that temperature has those effects...but that doesn't change the fact that the underlying reaction inside the batteries is a chemical in nature. That chemical reaction inside the batteries is what gets slowed down as the temperature drops.

aetherspawn 4y ago

Hitting the chemical limits of the batteries is what causes 1/ rapid aging and 2/ catastrophic cell damage and/or short failure and runaway, so if what you say is true (I don’t think it is) then the other manufacturers have implemented poor state of function control (SOF) and it would be a good idea to avoid. Proper SOF control is loosely required for ECE R100 which most manufacturers would have, but OTOH I am convinced that it’s possible to fudge that certification. Source: battery controls engineer.