Home charging: 120v-->240v 30amp--> 240v 50amp

Home charging: 120v-->240v 30amp--> 240v 50amp

So, just getting the hang of this electric car.
Bought the S75D from a neighbor for 42k...think that was a good deal.

Went to plug it into my 240v air compressor outlet, but of course wrong plug. Plugged it into standard 120v and added 3-4 MPH charge. Slooooow.
Bought an adapter for the 240v outlet (30 amp service) and charge at 24amp and it adds some 16-17 MPH charge. Most the wife uses is half of the 200 mile range (set to 80% charge) and most she has ever needed is about 7 hours of charge to get back to 80%/200miles. Seven hours is fine if she plugs in at 5-6-7-8:00 at night to leave by 7:00 am.

So I think what I have is good enough.

But missing the compressor being plugged in whenever working on something in the garage. Sure, it holds some PSI for a bike tire top off. But for air tools and such, gotta swith out car and compressor. Not really a big deal. Once a week at most.

But an electic buddy will grab 6 gage wire and 14-50 outlet from work and add a dedicated outlet for Thor. Will be in right spot so she doesn't have to back in.
So guessing then I can bump up the charge rate to 40amp. Guessing we will get some 30MPH charge rate? Will be able to fill up the 100miles needed in 3 hours instead of 4 or 5 or 6. But why? Who cares what time of the middle of the night it is full....we are sleeping.

Am I right on all my assumptions? Is there any merit to charging at 24amp instead of 40?
Just wanted to post what I'm learning and learn more.


CooHead | August 6, 2019

Oh, 2016 S75D with 55,000 miles it is/was for $42,000.
First thing I did wasreplace the "slicks" with new tires.....$1100?!

reed_lewis | August 6, 2019

Charging at 24 amps vs 40 amps makes no difference except 40 amps is faster of course. I actually charge at 32 Amps which is adequate to add the range I need in a few hours.

Tessnme | August 6, 2019

If the compressor cycles while you're charging the car, you'll probably trip the breaker and your wife will not be able to go to work the next day. Also, make sure you're on a 50 amp breaker before attempting to charge at 40 amps.

reed_lewis | August 7, 2019

@Johnc, if the new outlet is on a dedicated breaker, then you will be fine. If it shares the same breaker, then of course you will have issues.

CooHead | August 7, 2019

Gotcha, thanks all.

Will be proper 50amp breaker with 6ga wire.
Will be it's own breaker, just for the car.

will probably set it to charge at some 30-35amp as no need to fill it up in 3 hours instead of four is the middle of the night, who cares when it is full!? Midnight or 2:00a,m.
30-35 amp is better than my present 22amp. hell could keep it at 22-24amp for all we care. Just want my compressor plugged in all the time.

She took her road bike out for a ride and every week or two she tops off the tires (110PSI?!?!?). Sure enough, tanked had leaked some PSI over the past week+ and and there was not enough to add PSI to bike tires. All she did was release bike tire pressure to equalize to tank (guessing 80-90PSI).
"hey honey, it is cause your car is taking the electricity instead of the compressor plugged in. Its your car's fault!" Haahha.


Techy James | August 7, 2019

@Johnc You will gain 2 benefits by having a Separate Nema 14/50 Wall outlet put in on it's own separate breaker:
1) Ability to charge car and run Compressor at same time.
2) Ability to charge car about 57% faster.
Since your current Outlet charges at ~17 mph the new dedicated could potentially charge at ~ 27 mph assuming the Tesla you got can maintain a steady rate of 42 AMP charging rate.

reed_lewis | August 8, 2019

How often do you use the air compressor to get air out of it? Keeping it plugged in 24/7 seems like a waste of power if you only get air from it once every few days.

i have an air compressor for my Whac-A-Mole arcade game in my basement. I only turn it on when I want to play the game.

kelder | August 8, 2019

Piggy backing onto this thread: Is there an advantage to having a Wall Charger vs. just using a Nema 14/50 outlet? Just bought my first (M3) and I want to set up charging at my work where I can easily get a dedicated 240.

jimglas | August 8, 2019

Wall charger is faster

Techy James | August 9, 2019

@Kelder The advantages of a Wall Charger over a Nema 14/50 Outlet are 2 fold:
1) No need to unplug your included Gen 2 Mobile Connector to have it available when not at home.
2) Depending on the Model 3 you can charge it at a max of 48 AMP which it the highest charge rate the Model 3 LR can support. Two side notes here: A) the Gen 2 Mobile Connector even with the 14/50 adapter max charge rate is 32 AMP. Also the SR and SR+ also tops out at 32 AMPs. So this only is a benefit for LR variants of the Model 3.