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Impact of cost battery on efficiency

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EDIT: Title should be "cold" not "cost"... oops

Thought this might be useful for those living in colder regions...

I have a LR AWD (non-p) with 18" aeros (with the caps off).

Today I had an (unplanned) chance to see the impact of a cold battery. I had to do the exact same 49 mile trip twice, nearly back-to-back. Exact same route in basically the exact same conditions - which were 36 degrees (F), wet roads, and a mix of steady snow and rain. Route was a mix of freeway and side roads.

First trip (553 wh/mile): Car had been sitting overnight in the garage, which was at about 55 degrees. I did start it charging about 30 minutes before we left, and turned on climate as well. Even so, when we set off there was only about 1/2 of regen available. I was surprised that even after the 50 mile trip I STILL didn't have full regen.

Second trip (330 wh/mile): There was only about a 45 minute break between the 2 trips and I was charging that whole time. When I set off on the 2nd trip I did have full regen - I'm assuming, therefore the battery was in a sweet-spot in terms of temp.

Obviously, in spite of the fact that the 2 trips were identical route-wise and basically identical in terms of conditions, obviously the traffic and street light stops were not identical, which might have contributed something. The only other difference I should call out is that on the first trip my son (about 100 lbs.) was with me on the outbound leg (from home to our destination), and on the second trip he was with me on the return leg (from the destination back home). So maybe that might change things a bit?

Anyway, the warm-battery trip was about 7% more efficient...

Closing comment: I read on here all the time about people regularly getting around 250 wh/mile... While I've only had the car for about 7 weeks and it has been abnormally cold for this time of the year, my total wh/mile over that period is closer to 300... hopefully things will be better next spring / summer, but if you live in areas that get cold I would HIGHLY recommend the bigger battery.