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Is preconditioning necessary before charging in mild climates?

73Bruin

Member
Nov 7, 2020
180
83
Torrance, CA
I live in Southern California about 2 miles from the ocean. It seldom gets below the high 40s at night in the middle of winter. I have noticed that preconditioning before going to a supercharger really uses a lot of energy. It says this is to prepare for rapid charging. I haven't been time constrained. Do I need to precondition before go to a supercharger?

On a related note, Edison has finally changed our home billing plan, so it now makes sense to charge at home. I can charge from 9:00pm to 4:00pm for 16¢ per kWh. I have a Home Wall Charger in the garage. If I lower the charging rate, can I avoid the conditioning? Is there a downside to doing this?
 

jcanoe

Active Member
Oct 2, 2020
2,177
2,153
Maryland
If you arrive at a SuperCharger (SC) with a battery pack that has not been preconditioned then the charging rate will be reduced (it will take longer to charge, this is counter to the benefit of using a SC.) Is it correct to assume that you received free use of a SC for one year? Charging will be less efficient without preconditioning so if you are paying to use the SC it will cost a bit more than it would if you had preconditioned.

At home you do not have to precondition the cabin before driving but the vehicle will be warmer, more comfortable if you precondition for ~10 to 20 minutes before you leave home. If you do not sufficiently precondition battery pack the level of regenerative braking will be reduced until the battery has been sufficiently warmed while driving.

You can set Scheduled Charging and Scheduled Departure within the Tesla Charging settings so that charging ends just prior to the end of your off-peak charging window. You can choose to have your Tesla automatically start preconditioning prior to a scheduled departure time either every week day or all week.

Anytime the Tesla is charging it will precondition the battery automatically as required. Charging is more efficient when the battery is sufficiently warm. At low temperatures (i.e, your overnight low temperature) the battery may have to be warmed prior to charging to avoid damaging the battery. Again the Tesla handles this automatically.

There is no benefit to lowering the Wall Connector's charging rate, some benefit to charging at the highest possible rate. The higher charging rate will be slightly more efficient than a lower charging rate. There are charging overhead losses (heat losses) that accrue the longer you are charging. By shortening the charging time you minimize the charging overhead losses.
 
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73Bruin

Member
Nov 7, 2020
180
83
Torrance, CA
JCanoe: Thank you for the quick reply.

I have been using the supercharger because the 1000 free miles that came with the purchase reference code are going to expire on June 10th. On the tiered billing rate we were on, it was cheaper to use the supercharger miles than charge at home. Given that the miles were going to expire and "cost" less, I thought it made sense to use them. I was just surprised how much energy preconditioning took at the 60° to 65° that is typical of daytime winter weather here. When I looked at the energy usage graphs, preconditioning and the time charging used far more energy than just driving around.

Going forward, I am mainly going to be charging at home. Based upon your post above, I will probably set the MY to start charging at 8:00am as I seldom go anywhere before 10:00 which is enough time to add over 80 miles of range. I rarely use the heater even in winter because the heat gain in a closed car is so large.

Once again, thank you.
 

mswlogo

Well-Known Member
Aug 27, 2018
6,045
4,668
MA, NH
You don’t have to precondition your battery unless its so cold it won’t warm up from normal usage. Which hasn’t happen to be yet in NewEngland. Total nonsense of how much people think they have to precondition to “save” energy. You waste energy but you might save some time.
 
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Fadiawesome

Member
Sep 8, 2019
153
93
IDAHO
if you dont want to precondition, dont navigate to the supercharger, just navigate nowhere close to there. Or, not sure if this works, you can click on the actual preconditioning message and it might go away.
 

Enadler

Member
Nov 29, 2012
406
96
Westchester, NY
if you don't want to precondition, don't navigate to the supercharger, just navigate nowhere close to there. Or, not sure if this works, you can click on the actual preconditioning message and it might go away.

You can navigate directly to the Supercharger, if you choose to bypass preconditioning simply tap the screen where it indicates the car is preconditioning, it will stop. Preconditioning is not intended to save energy but to save time.

Preconditioning before charging at home is not necessary. However, prior to driving in cold weather, it is helpful to warm the vehicle while the car is plugged in, either manually or by using a scheduled departure time. This will warm the battery and the cabin and improve your range as well as the driving dynamics. When your battery is cold your regeneration will be limited or even disabled. This will result in reduced range as well as change your driving experience. In fact, the first time it happens after using one foot driving for a while it is very shocking and can be dangerous.
 

jeremymc7

Active Member
Feb 3, 2013
1,306
580
U.S.
Live in similar area and similar distance to Pacific. Don't need to use it. Especially if you're going to be charging at home from now on.

My cheapest SCE rate is 10PM to 8AM so I charge within those times.
 

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