Is This a Reasonable Charging Strategy?

[JMatt]

First - yes, I've searched and read dozens, if not hundreds of threads on this topic in general. My question relates to pre-conditioning the battery each morning now that it's getting colder (Michigan). My daily schedule is too irregular to rely on the car figuring out an automatic pre-conditioning schedule. So I was thinking of setting the car to charge to 80% each night. Then as soon as I get up for work in the morning, I use the phone app to increase my charge to 90% (and turn on the cabin heat). The car won't charge much by the time I'm ready to head out the door - maybe 84% since the heater is also running. Is this a reasonable strategy for overall long term battery health?

As an aside, has there been a consensus on negative affect of 90% compared to 80%? My commute is 36 miles a day round trip. Add some miles to go to lunch and I'm still under 50 each day, so range isn't an issue at all. Car is a 2015 Model S P85D.

Thanks all.

 

[brkaus]

IMHO - pre-conditioning does the following -
- increases range in case of cold weather, because battery warms off shore power.
- makes cabin more comfortable without loosing range, due to shore power
- cold battery limits regen, so warming makes better driving experience (and on shore power)

If one isn’t in serious need of max range, I don’t see the need to put too much thought into it. Turn on the heat 10 min before leaving.

 

[djgarrett21]

This is pretty similar to what I do using teslafi

 

[whitex]

Sounds reasonable, keep in mind the heating of the battery is not going to be very much from 80 to 84%. Cabin heater does not heat the battery (I once had it on high for almost 2 hrs, had to restart it via the app because it timed out), managed to melt some chocolate in the car but battery was still frozen such that when I drove a couple of miles to a supercharger, it charged at 6
KW for the first 5 or 10 minutes.

We've been charging our Teslas to 90% (max daily) and the oldest Tesla is ow 3.5 years old, not much degradation (90% charges to 227miles, which is pretty much the same as when it was new, maybe 1 or 2 miles less, I honestly don't remember).

 

[JMatt]

Sounds reasonable, keep in mind the heating of the battery is not going to be very much from 80 to 84%. . . .

What's the best strategy for pre-heating the battery given that A.M. departure time isn't real regular?

 

[Kruegmeister]

Also interested in this thread (also in Michigan)
This is why it took me so long when I wanted to supercharge up leaving Gaylord MI when visiting one of my Employees Cabin... I thought "man the SuperCharger here sucks, next time I'll get a better charge in Bay City"

I have my good charger at my Office 72 amps. But I get only like 23 at my house (Breaker Box getting full)

So I'm thinking if I start charging when I wake up, shower etc...
Won't add much charge, but Battery & the Cabin will be toasty...

 

[whitex]

What's the best strategy for pre-heating the battery given that A.M. departure time isn't real regular?

The (relatively) new firmware claims it will automatically pre-heat when turning on climate, but not sure if it works on older cars (it's supposed to show you a battery icon in the app). I also tried charging for a 20+ mins at 80A (dual-charger) with limited success. Also, some spirited driving can help, but may be hard in freezing weather. The most reliable way I found was to plan to finish charging in the morning, so starting your charge so it finished before you leave.

 

[Snowstorm]

Ever since early 2018, pre hearting the cabin will also pre heat a cold battery. However, it won’t fully heat up the battery, instead, it gets it to a point so you get some but still limited regen with about 30kw charge acceptance. If you drive it for another 30 minute or charge for about an hour it will heat it up to full regen and charge acceptance rate. Guess they figured out a full on battery heat is too energy wasteful.

To the OP, I won’t worry about charging a bit more, I would just turn on the heaters 10 minute before.