I'll be getting my LR AWD M3 in a couple of weeks and from what I've been reading I've been looking at three different home charging options. My daily driving during the week will be around 40 miles per day. Of course, the first option is to stick with the basic 120V house plug in that probably gets about 2-3 mrph. Second option is to convert one of the regular garage outlets into a 5-20 NEMA outlet (20A circuit, so 80% would be 16A) which probably gets me around 5-6 mrph and, even though I haven't got an estimate for that option, I am guessing it's probably no more than $100. The third option would be the 14-50 NEMA outlet, probably 30-35 mrph, and I received an estimate for this option at around $700. So, even though I'm hearing good things about having a 14-50 NEMA installed in garages I'm thinking the 5-20 NEMA outlet may work just fine for my situation. Any other pros or cons in converting a regular 120V garage outlet into a 120V 5-20 NEMA outlet? Appreciate any info or advice for those in the know. Thanks!
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Three home charging options
- Thread starter NuttyM3
- Start date
Bite the bullet and get NEMA 14-50 (or at least 14-30), so you could fully enjoy your car and not worry about slow charging.
Don't waste time and money on any partial and temporary solutions.
However, do shop around. Get more quotes from electricians. $700 sounds rather high!
Don't waste time and money on any partial and temporary solutions.
However, do shop around. Get more quotes from electricians. $700 sounds rather high!
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Is your 5-20 outlet on a dedicated circuit? If so you can convert it to a 6-20 (240V) outlet and get close to 16 MPH charging.
Yes - I would agree - I installed a Nema 14-50 and have found it useful in the situation where I am returning from a road trip and have say 30-40% charge when I get back home. With the 14-50 - I will be back up overnight easily to my 80% typical charge threshold - while if I had stuck with regular 120 wall outlet that would take many days to recover back to 80% while accommodating my daily commute of 50 miles or so. One other point with that scenario is that I would also be able to easily recharge during the window where my electricity is at its lowest cost overnight. With the regular wall outlet - that may not be possible as you will need 12 - 14 hours (assuming 3-4 miles avg charge rate) to just recover what I use each day. Something to keep in mind as depending on how your electric rates work - that 700 install cost may actually be recovered in part due to the lower rates you could charge at.
Yeah, this is what I've been leaning towards for a while now especially if I can get it installed closer to $500 or less.
No, I don't believe so. The breaker lists 20A circuit for the three garage outlets and a couple of breakfast nook outlets since it buts up against the garage.
A dedicated circuit, whether 5-20 or 14-50 shouldn’t cost all that different, just a different gauge wire. Outlets and breakers are roughly the same cost. I guess converting a dedicated circuit, a 5-15 into a 5-20, only requires changing an outlet, so that’ll make it cheap.
I had a 6-20 for the Volt, which I changed out for a 14-50 for my Model 3. Materials cost about $75. If you put the dedicated 14-50 box next to the panel, it can be quite cheap, since it’s the 6gauge wire that can be expensive.
I had a 6-20 for the Volt, which I changed out for a 14-50 for my Model 3. Materials cost about $75. If you put the dedicated 14-50 box next to the panel, it can be quite cheap, since it’s the 6gauge wire that can be expensive.
ucmndd
Well-Known Member
Switching out a receptacle to a 5-20 is easy and essentially free - I think you’ll eventually want a faster charging solution but there’s no harm in trying things out on a slower/cheaper option first.
Start with 120V 15A. With weekend and maybe some Superchargers, that should get you started.
Then take the time to figure out what works best for you
Then take the time to figure out what works best for you
Do the 14-50 NEMA.
1. Reduce the charge anxiety and range anxiety.
2. More efficient way to charge meaning more kw of power going into the car and not lost as heat.
3. Don't charge to 80% every day as you will lose range. Charge 250 miles once a week in your case.
4. If your electric company offers a demand meter, you can schedule a full charge in the cheapest hour.
That last point is huge. Our electric company publishes predicted rates that are usually really close.
It may be $0.16/kw at the peak times but usually $0.02/kw sometime between 12:00 AM and 5:00 AM.
About once every couple of weeks, we get PAID to take their power, often --$0.01/kw.
No Lie. Com Ed has paid me to take their power.
And not charging every day is really important. Let the battery get down to under 50 miles.
Usually charge to 250 miles but occasionally you will do 100%. Charging from 40 miles to 310 miles on a
5-20 NEMA is 54 hours. You will end up hating the car and probably pay a lot extra for the power.
40 miles to 310 miles on a 14-50 NEMA is 9 hours which means charging from 10 PM to 7 AM
and paying a lot more for power to start early and end late. That's why the 44 MPH wall charger pays for itself.
If tonight from 3AM to 5AM will be -$0.01/kw, let them pay you for 88 miles.
1. Reduce the charge anxiety and range anxiety.
2. More efficient way to charge meaning more kw of power going into the car and not lost as heat.
3. Don't charge to 80% every day as you will lose range. Charge 250 miles once a week in your case.
4. If your electric company offers a demand meter, you can schedule a full charge in the cheapest hour.
That last point is huge. Our electric company publishes predicted rates that are usually really close.
It may be $0.16/kw at the peak times but usually $0.02/kw sometime between 12:00 AM and 5:00 AM.
About once every couple of weeks, we get PAID to take their power, often --$0.01/kw.
No Lie. Com Ed has paid me to take their power.
And not charging every day is really important. Let the battery get down to under 50 miles.
Usually charge to 250 miles but occasionally you will do 100%. Charging from 40 miles to 310 miles on a
5-20 NEMA is 54 hours. You will end up hating the car and probably pay a lot extra for the power.
40 miles to 310 miles on a 14-50 NEMA is 9 hours which means charging from 10 PM to 7 AM
and paying a lot more for power to start early and end late. That's why the 44 MPH wall charger pays for itself.
If tonight from 3AM to 5AM will be -$0.01/kw, let them pay you for 88 miles.
FlatSix911
Porsche 918 Hybrid
Here is a handy guide for the Tesla model charging rates using a NEMA receptacle vs. the Telsa HPWC.
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Or you can follow the owner’s manual and plug the car in when you get home every time. (If charging costs are less for you at night, you can set the car to start charging at night, but still just plug the car in when you get home.)
About the Battery
Model 3 has one of the most sophisticated battery systems in the world. The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it. This is particularly important if you are not planning to drive Model 3 for several weeks. When plugged in, Model 3 wakes up when needed to automatically maintain a charge level that maximizes the lifetime of the Battery.
Note: When left idle and unplugged, your vehicle periodically uses energy from the Battery for system tests and recharging the 12V battery when necessary.
There is no advantage to waiting until the Battery’s level is low before charging. In fact, the Battery performs best when charged regularly.
We got both. Have a 14-50 and also use the 5-15 (we have two Tesla’s) and no variable power pricing. Net, net, we live with the 5-15, but the 14-50 is much more convenient for the occasional longer trips as you dhave not have to do multi day planning to get up to 95%. And we normally leave plugged in every night. Didn’t realize that was the reco 
As an aside your mobile wall connector is limited to 32A or 7.2kW (so to get the full 40A you need a Tesla Wall connector to get to 10kW.) but 14-50 is more flexible and it their standard plug.
As an aside your mobile wall connector is limited to 32A or 7.2kW (so to get the full 40A you need a Tesla Wall connector to get to 10kW.) but 14-50 is more flexible and it their standard plug.
The manual from the company that makes the car specifically says there is no benefit to doing what I bolded there. Do what you want to your car, but dont give recommendations to new owners that directly contradict the information that comes from the people who make the car.
XLR82XS
D M C
edigest
Member
This statement
is contradicted by so many other sources, including the manufacturer, that it isn't worth listing citations.
Range loss is inevitable in LiON batteries, but charging to 80% every day (or 90% every day) is not the primary cause any significant range loss.
There may well be an advantage to keeping the car plugged in when not in use, if only to allow the BMS more opportunity to level the battery cells.
is contradicted by so many other sources, including the manufacturer, that it isn't worth listing citations.
Range loss is inevitable in LiON batteries, but charging to 80% every day (or 90% every day) is not the primary cause any significant range loss.
There may well be an advantage to keeping the car plugged in when not in use, if only to allow the BMS more opportunity to level the battery cells.
XLR82XS
D M C
The owners manual states at least twice to leave the car plugged in when not in use. I will use scheduled charging when it's in the garage overnight.
FlatSix911
Porsche 918 Hybrid
You are both correct... feel free to keep you Tesla plugged in, but do not charge over 90% every day or you will see a dash warning.
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