Optimal battery temps for Level 2 charging

[boulder.dude]

As we head into our first winter for many of the new Tesla owners on this site…

What is the optimal temperature range for Level 2 (I.e. HPWC) charging, so the car doesn’t need to heat or cool the battery (thereby losing charging efficiency)?

As we roll into winter and my garage temp drops into the 30s, I wonder if I should change my charging habit from “in the middle of the night” to “as soon as I get home.”

 

[Sophias_dad]

Yep, as soon as you get home.

 

[chriswood]

I haven't seen an authoritative source (other members, please link if you have one), but various threads here seem to converge on ~50°F as the threshold below which the car needs to proactively heat the battery. Unless you're paying a lower off-peak rate, it's best to charge when it's warmer.

This is also an argument towards installing the highest-capacity charging circuit as is practical, particularly if you live in a cold-weather area - the faster the charge, the less power wasted keeping the battery warm.

Side question - does the charging process itself also generate heat which helps here? I know my laptop and phone get warm when they're charging, but obviously a Tesla is not an iPhone.

 

[boulder.dude]

Side question - does the charging process itself also generate heat which helps here? I know my laptop and phone get warm when they're charging, but obviously a Tesla is not an iPhone.

At 48A, the charge cord gets noticeably warm from waste heat, so I would assume the guts inside the car are being warmed by waste heat as well.

 

[Pstreicher1]

At 48A, the charge cord gets noticeably warm from waste heat, so I would assume the guts inside the car are being warmed by waste heat as well.

I noticed after reducing the charge current down to 30a from 48a, that I don't hear the relays clicking off and on nor the fans turning off and on like I used to. I usually spend a bit of time cleaning the Florida bugs off the front of the car each evening after the wife returns from her day, and polishing the chrome trim and any other obvious spots or dirt or grime I see. I think my next project will be to download the raw data at different charging times to see the differences in battery temp using 30a versus 48a. Not that that will matter much from many posts from more educated owners than myself here and elsewhere. But, I am seriously interested in battery makeup and how best to get longevity out of them. A happy battery is a charged battery is what I've learned over the years of cell phone and tablet usage though.