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Confession: I know very little about how battery systems work, but something I've picked up in the last year or so of getting into EVs is that the actual speed you get at a DC Fast Charger can vary a lot depending on the temperature of your battery.

I assume the Ultium vehicles will be pretty sophisticated about this, like Teslas and other higher-end EVs that precondition their battery packs when you navigate to a fast charger, but one wrinkle that dawned on me specific to the Silverado (and Hummer EV), is whether the size of the pack makes a big difference in the amount of energy required to do this.

Does anyone know about this? Is it fair to say that (for simplicity sake) a 200 kWh pack takes 2x the energy to heat or cool as a 100 kWh pack, or does it not scale like that?

Canadian winters are famously cold and I'm wondering if it will be more difficult to see peak charging speeds on big-battery trucks like these.
 

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Confession: I know very little about how battery systems work, but something I've picked up in the last year or so of getting into EVs is that the actual speed you get at a DC Fast Charger can vary a lot depending on the temperature of your battery.

I assume the Ultium vehicles will be pretty sophisticated about this, like Teslas and other higher-end EVs that precondition their battery packs when you navigate to a fast charger, but one wrinkle that dawned on me specific to the Silverado (and Hummer EV), is whether the size of the pack makes a big difference in the amount of energy required to do this.

Does anyone know about this? Is it fair to say that (for simplicity sake) a 200 kWh pack takes 2x the energy to heat or cool as a 100 kWh pack, or does it not scale like that?

Canadian winters are famously cold and I'm wondering if it will be more difficult to see peak charging speeds on big-battery trucks like these.
As a general rule, the larger the pack the more power it can accept for a given charge level. Yes it takes more power to heat/cool the larger mass, but the larger capacity offsets that. Further, even if a pack is throttled to half of it's potential intake by temperature, a pack twice as large will be throttled to half of that potential; or twice what the smaller pack was taking.

My brother used to have a Tesla with a smaller pack than the one I drive. Un-conditioned supercharging speeds were much lower with his smaller pack than on my larger one.

Moral of the story: Bigger is better... even more so when it is cold. My brother traded his car for one with a larger pack.
:cool:
 
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