Plug In or Not While on Vacation?

[Ulmo]

I COULD ask to park it in my parent's garage and have it connected to a standard 120V outlet, BUT both of my parent's cars are expensive cars which they OBVIOUSLY would PREFER to keep inside the garage. Additionally, my Dad is kinda crazy with energy conservation(EVERY SINGLE TV is on a power strip including the cable box and is immediately powered off when the TV is off) so I don't know how he would feel about the car being plugged in for 30 days!

1. Set your car's charging schedule to start during cheapest electricity charging time. (If you have ample solar, you could alternatively set it to very low amps during peak excess sunlight, perfect for long term storage, especially since this will require the automatic battery BMS system to do less battery preconditioning to get it up to proper heat level. By very low amps, I mean super low, like 5 amps or so, to use only 600 watts; depends on battery age, but a 70kWh battery that depletes 2% every day could be recharged from 11AM to 2PM sunlight for 3 hours at 466 watts, so 4 amps is OK, whereas an older battery that loses 5% per day for a 85kWh would require 11AM to 3PM sunlight at 1000 watts which is about 8 or 9 amps; similar numbers at night, but you aren't worried about staying under excess solar use to avoid peak charges, but you do want to charge it fairly quickly to avoid having to keep the battery heated for as long while charging which uses more electricity).
2. Of course, like discussed here already, set your charge level to 50%. (The day that is before the last charge scheduled charge before you expect to arrive home, you can remotely set your charge level higher if you expect to go futher than the 50% will allow.)
   
3. Plug your UMC into a beefy exterior-rated extension cord (such as a 10AWG (usually listed as "10/3") 25 foot or even a 50 foot outdoor extension cord, available from Home Depot for over $100 for the longer variety) to a GFCI 120VAC 15amp or 20amp normal household outlet near to your parking spot that is the minimum comfortable length to reach out to your car in an inconspicuous location so no one tampers with it. Set your UMC to charge at 12 amps or less during this time; I think it will enforce this. This is really slow and not fast enough for daily commutes, but for just long term storage, I think it may be enough in most climates. Obviously, raise the connection between the beefy (10AWG is best) exterior rated extension cord and the UMC plug off the ground a bit so that water doesn't go in and trip it, and so that rain will drain away. Cover it with something that will keep rain off, too. Also, make sure the socket you plug into at the house is new and well installed with the circuit and screws well connected and no bad wiring, so it doesn't burn the house down in the middle of the night (electricians can verify that).
   
   Ideally, your parking spot at your parents' will be within UMC distance of a qualified 15AMP or 20AMP GFCI outlet that is safe to use, so you wouldn't need an extension cord at all. Otherwise, see my buying list below for good extension cords.
   
4. Regarding your dad being kind of crazy, that's an issue you will have to negotiate: I just told you the correct way to save your car. If you do not do that, you will potentially lose tens of thousands of dollars of battery prematurely, it will be your fault, and it is not covered by warranty; tell your dad that penny-pinching on one end to end up spending WAY MORE MONEY AND ELECTRICITY on the other end makes no damn sense. Then again, I don't get along well with a lot of people, so there's that ...

This is what you want for heavy duty extension cords for 120VAC 12amp: look for the 10/3 (which is rare but I will tell you where to get it; don't get 14/3 or not as bad but still not as good 12/3 (higher AWG is worse)), which will keep the resistence much lower, and the total amps used lower, and the total heating of the wiring in your house lower, and contact distortion and wear and tear lower, and much much safer (get the shortest one that makes sense on the end of your UMC which already has its own length); note that thieves love to steal these since they are great extension cords, so you need to hide these away from sight or awareness; note also that these are not suitable for daily commute charging of a Tesla, only for long term storage charging needs in climates that are not super-cold (or if you are a professional contractor, for running large compressors on the end of extension cords which is usually not possible with regular extension cords):

• Southwire 25 ft. 10/3 SJEO Outdoor Extension Cord with Lighted Plug-1787SW0002 - The Home Depot
• Southwire 50 ft. 10/3 SJEOW Outdoor Heavy-Duty T-Prene Extension Cord with Power Light Plug-17880002 - The Home Depot
• RIDGID 50 ft. 10/3 Heavy-Duty Contractor-Grade Indoor/Outdoor Extension Cord-HD#729-706 - The Home Depot
• Southwire 100 ft. 10/3 SJEO Outdoor Heavy-Duty T-Prene Extension Cord with Power Light Plug-017990002 - The Home Depot
  
• RIDGID 100 ft. 10/3 Extra Heavy-Duty Contractor-Grade Indoor/Outdoor Extension Cord-HD#866-886 - The Home Depot

Don't listen to anybody who says "oh 14 guage is fine!". Those will be more dangerous, heat up more, and use more electricity, period. It's plain physics. There's a reason they sell 10/3 extension cords. Also, old worn out wall sockets are dangerous, as are miswired, damaged, or poorly wired anything in the home wiring. Yes, a good extension cord will set you back some money, so find a good place to store it where it won't get damaged or mishandled or lost when not in use. Ideally, good home wiring will be close enough to your parking spot to just use the UMC directly. But if you're adding wiring to the permanently installed home electrical circuits, you really should get a Tesla HPWC set up for where you park and charge daily, properly wired by an electrician. (I also have a screed about your primary place of charging should be your work solar-energized inexpensive J1772 charger or equivilent during high sunlight hours, since using solar direct at collection point is the right way to own an EV, but it will be decades before that's commonplace, and does not apply to long term home storage as we're discussing now, except insofarasmuch you already have your own large home solar array with excess power available for EV charging.)

 

[matto]

1) give it a full charge and leave it unplugged

Good lord no. Did you RTFM?

 

[Ulmo]

Coming up we will be away from home for 2 1/2 weeks, leaving our Model 3 at home. Do I:

1) give it a full charge and leave it unplugged

GAAAAH NO!!!!!! I'm very glad you asked ! That has the potential for two horrible things: (1) it being left at a high state of charge (very bad, super awful, could highly damage your battery), and (2) it running down to a very low state of charge (very very bad, could completely ruin your battery), and (3) both (ugggh).

 

[mongo]

This is what you want for heavy duty extension cords for 120VAC 12amp: look for the 10/3 (which is rare but I will tell you where to get it; don't get 14/3 or not as bad but still not as good 12/3 (higher AWG is worse)), which will keep the resistence much lower, and the total amps used lower, and the total heating of the wiring in your house lower, and contact distortion and wear and tear lower, and much much safer (get the shortest one that makes sense on the end of your UMC which already has its own length);

A lower gauge cord will dissipate more heat in itself, and the extension cords plug/socket and house socket quality are also important. An undersized cord will cause charging to take longer and use more total power. Or even result in the Tesla reducing current due to voltage drop.

However, the usual issues in power draw due to running motorized power tools and such via extension cords do not apply to Tesla charging. The Tesla's charger will limit the amperage based on the type of plug attached to the UMC. A UMC with 15 Amp outlet plug will cause the car to only draw 12Amps maximum. Extension cord type will not impact house wiring or amperage draw (beyond the plug/socket interface).

 

[Jeffcm3]

FWIW, I think the manual is available online.

I wonder if they have a report they run daily on all the cars in the inventory to make sure they don’t run out of battery. Eventually they will need to pay people to go grab those cars and charge them.

Based on my model 3 delivery (9/9/2018, in Fremont) i would say probably not.
Our car was delivered with 165 miles of range. About 50%.
They said they didn’t have the capacity to fully charge all the cars.

 

[eprosenx]

Based on my model 3 delivery (9/9/2018, in Fremont) i would say probably not.
Our car was delivered with 165 miles of range. About 50%.
They said they didn’t have the capacity to fully charge all the cars.

Yeah, I was mostly calling out that they need a way to keep them from running totally flat while in storage.

For most people delivering without a full SOC is not the end of the world, but if you have to drive a long way home or you don’t have home charging setup yet it might leave a poor taste in your mouth.

The service centers must be fantastic power company customers. Normally auto shops don’t use a ton of power, but the service centers do! I wonder how many cars are charging at any given time there? I know based on what my phone tells me that they seem to plug them in at any time they can while undergoing service.

 

[Phillyasian]

1. Set your car's charging schedule to start during cheapest electricity charging time. (If you have ample solar, you could alternatively set it to very low amps during peak excess sunlight, perfect for long term storage, especially since this will require the automatic battery BMS system to do less battery preconditioning to get it up to proper heat level. By very low amps, I mean super low, like 5 amps or so, to use only 600 watts; depends on battery age, but a 70kWh battery that depletes 2% every day could be recharged from 11AM to 2PM sunlight for 3 hours at 466 watts, so 4 amps is OK, whereas an older battery that loses 5% per day for a 85kWh would require 11AM to 3PM sunlight at 1000 watts which is about 8 or 9 amps; similar numbers at night, but you aren't worried about staying under excess solar use to avoid peak charges, but you do want to charge it fairly quickly to avoid having to keep the battery heated for as long while charging which uses more electricity).
2. Of course, like discussed here already, set your charge level to 50%. (The day that is before the last charge scheduled charge before you expect to arrive home, you can remotely set your charge level higher if you expect to go futher than the 50% will allow.)
   
3. Plug your UMC into a beefy exterior-rated extension cord (such as a 10AWG (usually listed as "10/3") 25 foot or even a 50 foot outdoor extension cord, available from Home Depot for over $100 for the longer variety) to a GFCI 120VAC 15amp or 20amp normal household outlet near to your parking spot that is the minimum comfortable length to reach out to your car in an inconspicuous location so no one tampers with it. Set your UMC to charge at 12 amps or less during this time; I think it will enforce this. This is really slow and not fast enough for daily commutes, but for just long term storage, I think it may be enough in most climates. Obviously, raise the connection between the beefy (10AWG is best) exterior rated extension cord and the UMC plug off the ground a bit so that water doesn't go in and trip it, and so that rain will drain away. Cover it with something that will keep rain off, too. Also, make sure the socket you plug into at the house is new and well installed with the circuit and screws well connected and no bad wiring, so it doesn't burn the house down in the middle of the night (electricians can verify that).
   
   Ideally, your parking spot at your parents' will be within UMC distance of a qualified 15AMP or 20AMP GFCI outlet that is safe to use, so you wouldn't need an extension cord at all. Otherwise, see my buying list below for good extension cords.
   
4. Regarding your dad being kind of crazy, that's an issue you will have to negotiate: I just told you the correct way to save your car. If you do not do that, you will potentially lose tens of thousands of dollars of battery prematurely, it will be your fault, and it is not covered by warranty; tell your dad that penny-pinching on one end to end up spending WAY MORE MONEY AND ELECTRICITY on the other end makes no damn sense. Then again, I don't get along well with a lot of people, so there's that ...

This is what you want for heavy duty extension cords for 120VAC 12amp: look for the 10/3 (which is rare but I will tell you where to get it; don't get 14/3 or not as bad but still not as good 12/3 (higher AWG is worse)), which will keep the resistence much lower, and the total amps used lower, and the total heating of the wiring in your house lower, and contact distortion and wear and tear lower, and much much safer (get the shortest one that makes sense on the end of your UMC which already has its own length); note that thieves love to steal these since they are great extension cords, so you need to hide these away from sight or awareness; note also that these are not suitable for daily commute charging of a Tesla, only for long term storage charging needs in climates that are not super-cold (or if you are a professional contractor, for running large compressors on the end of extension cords which is usually not possible with regular extension cords):

• Southwire 25 ft. 10/3 SJEO Outdoor Extension Cord with Lighted Plug-1787SW0002 - The Home Depot
• Southwire 50 ft. 10/3 SJEOW Outdoor Heavy-Duty T-Prene Extension Cord with Power Light Plug-17880002 - The Home Depot
• RIDGID 50 ft. 10/3 Heavy-Duty Contractor-Grade Indoor/Outdoor Extension Cord-HD#729-706 - The Home Depot
• Southwire 100 ft. 10/3 SJEO Outdoor Heavy-Duty T-Prene Extension Cord with Power Light Plug-017990002 - The Home Depot
  
• RIDGID 100 ft. 10/3 Extra Heavy-Duty Contractor-Grade Indoor/Outdoor Extension Cord-HD#866-886 - The Home Depot

Don't listen to anybody who says "oh 14 guage is fine!". Those will be more dangerous, heat up more, and use more electricity, period. It's plain physics. There's a reason they sell 10/3 extension cords. Also, old worn out wall sockets are dangerous, as are miswired, damaged, or poorly wired anything in the home wiring. Yes, a good extension cord will set you back some money, so find a good place to store it where it won't get damaged or mishandled or lost when not in use. Ideally, good home wiring will be close enough to your parking spot to just use the UMC directly. But if you're adding wiring to the permanently installed home electrical circuits, you really should get a Tesla HPWC set up for where you park and charge daily, properly wired by an electrician. (I also have a screed about your primary place of charging should be your work solar-energized inexpensive J1772 charger or equivilent during high sunlight hours, since using solar direct at collection point is the right way to own an EV, but it will be decades before that's commonplace, and does not apply to long term home storage as we're discussing now, except insofarasmuch you already have your own large home solar array with excess power available for EV charging.)

I want to thank you for your detailed advice. I am responding to you right now sitting on a cruiseship in the middle of nowhere in the Pacific Ocean heading towards Fiji. Everything has been going great. My parents graciously offered one of their garage spaces while my moms car is parked at my sister's house nearby. It is plugged into a standard outlet with the SOC set at 60%. Having the app is such a worry saver since I can see the SOC. Looks like it trickle changes when it drops 15 miles below 60%.
Having relatives nearby with access to my parent's home is a godsend. I have already asked my sister twice to go into the car to activate the software update first for 32.6 and then V9 the other day (I received text msgs both times) (Thank God for Satellite WiFi and Wi-Fi calling Capable cell phones).
I still have over 2 weeks before testing out the new software!
Hopefully your advice will be useful for me another time and also for others reading this thread. The whole purpose of forums like this is to share information and advice and to that end you have done so very explicitly!

 

[Vern Padgett]

FWIW, I think the manual is available online.
The battery pack likely comes from the gigafactory nearly fully charged. … I think the average state of charge of vehicles delivered to the delivery center is lower, so now they struggle with getting them all charged for delivery.

We picked up a new Model 3 in March at Marina Del Ray. It was charged only to 47 percent.

 

[R1Fast]

FWIW, I think the manual is available online.
The battery pack likely comes from the gigafactory nearly fully charged. I doubt they have much inventory laying around waiting to be put in a car.

Then I suspect the factory charges them up nearly all the way (if not all the way) before shipping them out.

Nope - the factory charges to 100% for a battery of tests then discharges to ~50% SOC for transit and safety reasons.

Once the pack is in Fremont it's mated to the 'Penthouse' (not a dirty pun) and tested again, then is either sits or is loaded on a carrier. There is variance in this but that's the basic gist. Whether or not the destination SC charges further from there seems totally random.

Mine was charged to 82% but I requested this the morning of delivery as part of my checklist. If you don't ask for a particular charge, you could really get anything between 45-90%. If you're taking delivery soon and reading this - do yourself a favor and ask for them to set the charge limit to ~83%, then rinse and repeat daily unless you're planning an immediate road trip or have an extremely long daily commute. As mentioned, never charge to 100% and let it sit, esp for any extended period of time.

We picked up a new Model 3 in March at Marina Del Ray. It was charged only to 47 percent.

Based on my model 3 delivery (9/9/2018, in Fremont) i would say probably not.
Our car was delivered with 165 miles of range. About 50%.

IMO, ~50% is better to see than 90%+, since with the latter, you really have no idea how long it's been sitting without a discharge, and could have vamp drained from 100% over the last 7-10 days for all anyone knows.

 

[kbecks13]

IMO, ~50% is better to see than 90%+, since with the latter, you really have no idea how long it's been sitting without a discharge, and could have vamp drained from 100% over the last 7-10 days for all anyone knows.

Agreed. When i got my car, it had been sitting at 100% charge for over 24 hours and it was super cringy. Kinda sad that Tesla would do that.

 

[R1Fast]

Agreed. When i got my car, it had been sitting at 100% charge for over 24 hours and it was super cringy. Kinda sad that Tesla would do that.

That is soooo super not cool. I could see a used car dealer goofing that one up but not Tesla. That's just not acceptable. Hopefully once won't do too much damage though.... what's your range like at 100 SOC?

 

[eprosenx]

Mine was just finishing topping off to 100% when they gave it to me. I am guessing (hoping?) they had only charged it to 100% that morning.

 

[ChrisH]

Just wanted to share my experience. I was gone for 7 days Saturday to Saturday temp range where the car was outside high 60’s to high 80’s I lost on avereage 4 miles per day. This was really good in my opinion. There was one day I lost 7 miles and a couple I lost only 2miles per day. Hope this helps anyone, and the battery of the car was 78% when I left it.

Did you leave it unplugged?