Hey! My Model Y is on order and planned for delivery in Jan/Feb. I'm trying to figure out some charging options ahead of time because I won't have a garage until at least June/July. For now, I'll be parking the car on the street and wiring an extension cord from a 120V outlet. My landlord said he'd be ok with installing a NEMA outlet if I pay and estimates that it will cost $800-$1200. Is it worth paying for this to maintain the battery life/quality over the next 6-18 months? The other option is just to use the 120V outlet for now until I relocate to an apartment with better EV charging/a garage.
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Keeping car outside & charging with 120v
- Thread starter traxion
- Start date
Charging in winter using 120V can be challenging. When the battery is being warmed there is little power available to charge. Charging using 120V in very cold weather will take longer, perhaps so long as to be impractical as the Tesla vehicle would spend almost as much time warming the battery as actually charging the battery. When you are charging at 120V/12A (the maximum amperage when charging using a 15A circuit) the available power is not that great, just 1.4kW so there is little power to spare to warm and charge at the same time.
By NEMA receptacle do you mean the NEMA 14-50 (240V/50A) receptacle. If you can't install the receptacle close to the Tesla vehicle you would have to use a 50A extension cord (These exist but are expensive, not all that long.)
There is no issue with using a Supercharger, the main downside is the cost. Urban Superchargers (the type usually found in parking garages) are limited to a 72kW charging rate. This is significantly lower than the V2 (120kW or 150kW) or V3 (250kW) Superchargers' maximum charging rates. The 72kW maximum charging rate of an Urban Supercharger is a good balance of power and charging time without stressing the Tesla vehicle's battery.
When the Tesla vehicle's battery is already partially charged, perhaps at 50% and the battery is not sufficiently warm the charging rate of an Urban Supercharger would be lower, i.e. 36kW. Even so, this is 25X more power than is available from a 120V/15A circuit. You might only need 30 minutes to 1 hour charging time a few times a week using the Urban Supercharger.
You don't have to leave the Tesla vehicle plugged in (even though Tesla recommends always leaving the Tesla vehicle plugged in.) The Tesla vehicle will stop charging once the battery has reached the desired maximum charge level (up to 90% for daily driving), then stop charging. The Tesla vehicle does not warm the battery unless the vehicle is charging or the vehicle is preconditioning prior to being driven. Unplugged, with Sentry Mode and Summon turned off, the Tesla vehicle's battery will lose less than 1% charge per day. If the Tesla vehicle's battery is charged to at least 50% the vehicle can be parked, unplugged, for an extended period with no issue. Some Tesla owners choose to leave their Tesla vehicle parked at airports, sometimes for weeks, with no issue even if there is no way to charge while parked.
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jasonh4451
Member
Great comments from jcanoe above. I would just add that it depends on how much you drive. I lived with just 120v charging for two years before renovating our home and adding a wall charger. It was ok because I have a short commute and had faster charging available at my gym and office. If you drive a lot then your calculation will be different. Love the wall charger now though. Wouldn’t go back
I've heard it can damage your battery. Is this a myth? If not I might just rely on supercharging 99.9% of the time. I'd hope the 120V would atleast be able to keep me charged or warm enough to charge up over 2-3 days/week with the 50A extension cord. Yes, I'm talking about the NEMA 14, but sounds like ill be good to do 120V charging if I have some V3 supercharger nearby and keep it charged on the 120V 2-3 days a week (those days are off days). What do you think?
Also, side question but if I leave the car charging and it rains, I assume this would be a hazard right?
I only plan to drive on weekends and maybe once a week to drive up to the store. I work remotely so it won't be as frequent as others.
The lower powered Urban Supercharger (72kW Maximum) would be less stressful to the battery than seeking out the V3 Supercharger (250kW Maximum). With lithium batteries the capacity of the battery is termed C. When charging or discharging a lithium battery it is best to limit this to no more than 1X C. Since the Tesla Model Y's battery capacity is currently 82kWh an Urban Supercharger at 72kW is well matched to the Tesla Model Y's battery (just under 1C) when charging. If you charge using a V2 or V3 Supercharger then for part of the time while charging the charging rate can well exceed 1XC, even 2X C. Even using a V2 or V2 Supercharger the Tesla vehicle's battery management system will manage the charging cycle to protect the battery while charging and prevent excessive charging rate from potentially harming the battery.
Charging in the rain is no problem, the charging connector is designed to be used in all weather conditions. (I don't recommend charging during electrical storms.)
As previously noted, leaving the Tesla vehicle plugged in in cold weather the Tesla vehicle's battery management system will not continuously warm the battery pack. The only time the battery is warmed is when is actively charging or while preconditioning before being driven and while being driven as required.
My landlord said he can install a 240v 20amp for $450. For that price would it be more worth it to have him install the NEMA 14-50?
The 240V/20amp charging circuit would be a good option, faster and more efficient than charging using 120V. The 240V/20amp charging would add 12 to 14 miles of range to the battery per hour of charging so most days, depending on how far you need to drive, you might only be charging for about an hour or two when you return home.
If you park the Tesla Model Y unplugged, as long as you turn off Sentry Mode and Summon (a Full Self Driving feature) then you would lose less than 1% per day. A week parked outside would not be a problem as long as you park starting with a reasonable charge ~40%. Then as long as you refrain from regularly connecting to the Tesla Model Y via the Tesla app (which wakes up the Tesla Model Y) you would lose just a couple of % of the battery in a week's time. (Miles are not really a good indicator, state of charge (SOC) of the battery is the better measure.)
Most of the cost of installing an electrical circuit is the electrician's labor. There would be some additional cost for a heavier gauge wire for a 240V/50A circuit but not much more. If the rental property's electrical service does not have capacity for adding a 50A circuit then the service and panel upgrade would be an additional expense. In that case the 240V/20amp circuit addition would be a good alternative. If it only costs a little more $ then the 240V/50A circuit and a NEMA 14-50 receptacle for EV charging would be a good long term improvement to the rental property.
The NEMA 14-50 receptacle can be used on either a 50amp or 40amp circuit (when there is not sufficient capacity for a 50amp circuit.) Using the Tesla Gen2 Mobile Connector that comes with the Tesla Model Y and the optional Tesla NEMA 14-50 power plug adapter ($45 from the Tesla online store) you would be able to charge twice as fast as with a 240V/20amp circuit. (Tesla claims up to ~29 miles per hour when using the 14-50 power plug.) I am setup to charge at home using a NEMA 14-50 receptacle and a 50amp circuit. I currently charge at 240V/32amp, this adds between 25 and 26 miles per hour of charging to my 2020 Long Range Model Y.
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Thanks for such detailed answers! So helpful. If I left sentry mode on throughout the week, what’s the average battery drain with no charge?
1-2 miles per hour (thats not a typo), so 24-48 miles per day. People without home charging (thus on the street parking, usually) are almost always also the ones who want to use sentry mode, but this is not something you should be planning on doing unless you plan on hitting up that supercharger VERY often.
Nothing wrong with hitting the supercharger
maybe it’ll get me out of the house more often lolThis depends on your daily milage. If you commute under 25 miles per day you should be able to get away with a regular outlet in the summer and probably under 15 miles per day in the winter.
Is there any possibility to charge at work?
As noted, Sentry Mode and also Summon (if equipped with FSD) cause the Tesla vehicle to remain powered on, i.e. never enter a sleep state. The power drain when powered on, before any climate control power use, is ~230W (almost a quarter of a kilowatt.) By comparison, when in a sleep state the power drain is just ~25W, so leaving Sentry Mode active will use almost 10X as much power from the battery as the Tesla vehicle is never able to enter a sleep state.
When Sentry Mode is not active and the Tesla vehicle is locked the vehicle alarm remains active. The alarm system, door locks, BT modem and LTE modem are included in the 25W power usage when the Tesla vehicle is in a sleep state.
Nothing wrong with hitting the supercharger
Sure.. but keep in mind that the cars battery uses "energy" to move it (bear with me, there is a point here). What I mean is, lets say you decide "i dont mind going to the supercharger a lot, I will use sentry mode anyway", and your car uses a very average amount of energy when sentry mode is used, of " 25 miles) worth of energy a day.
Thats 25 "miles" a day, 175 "miles" a week worth of energy, "just sitting there", but the equivalent of being driven, to your battery. Thats 9,000 miles a year "just sitting there". Not including all your extra time spent running back and forth to the supercharger, and possibly spending more money at wherever the local supercharger is, out of boredom in sitting there, you would be putting 9k more miles on your battery, which could be more miles than you actually drive in a year.
Just food for thought, as it were. The car was not designed with Sentry mode in mind, as it was bolted on "later" due to a rash of break ins in san francisco. Its best usage is "while Im at the restaurant, or at the store". Using it 24 X 7 can be done, but is an incredible amount of energy to be using, just sitting there.
Its kind of like letting a bathroom water faucet at home that has a "fast drip" just continue to drip, forever, and how much water that would end up wasting, even though it doesnt look like much to begin with.
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