Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Need advice on temporary charging solution until HPWC arrives

Merle Corey

Member
Apr 1, 2016
66
98
Brambleton
Slight problem.. I got my invite a couple days ago and configured. ETA is 3-6 weeks. That’s the good news. Problem is that I don’t have my charging situation taken care of yet! I am buying a black signature HPWC from one of the other members here, but it won’t be here until June. In the meantime, I was just going to have an electrician wire up a temporary 220v plug so that I can plug in that way. I’m assuming that he can come back when the HPWC is here and then use the existing wiring that he installed to connect it. Does that work? Or are they two separate installs and he can’t reuse the 220 wiring/connection?
 

eSpiritIV

Member
Mar 24, 2016
434
229
Portland, OR
The difference in time for an electrician to connect one or another cant possibly be more than a half hr. You will want to pull your #6AWG THHN wire in conduit, and 50A circuit breaker. Only difference is to install a 4 square electrical box and NEMA 14-50 Plug to connect to vs just connecting into the HPWC.

Pulling the wiring is the hardest part.

If you think you have no other charging options till your install, you can always just wait for the HPWC to arrive in the mail
 

Galve2000

Active Member
May 20, 2013
1,036
300
NYC
Should work fine as long as the electrician uses the correct wire gage for the amount of current you want the HPWC to pull when it eventually gets installed. Otherwise it is a simple swap from whatever NEMA plug you are installing to the hard-wired HPWC.

In the very olden days before the HPWC was available this is what Tesla recommended be done by the 1st batch of lucky owners.
 

boaterva

Supporting Member
Supporting Member
Apr 2, 2016
7,574
3,746
Northern Virginia, USA
Right, an HPWC can run on any circuit from 240 V 15 Amps to 100 Amps (12 to 80 effective). If you are going to end up with 50 Amps (40 usable), install a 14-50 and use that; easy to switch over.
 
  • Like
Reactions: dhrivnak

jaguar36

Active Member
Apr 10, 2014
2,085
1,639
NJ
Once you've got a 14-50 installed you may find there is no need to buy a HPWC.

We've got two S's and have never had a problem with just a single 14-50 outlet.
 

Derek Kessler

Active Member
Apr 15, 2016
1,193
1,806
Cincinnati
Depending on how much you drive in a day, you might be able to get by charging off of just a NEMA 5-15 outlet (that's your standard 15-amp 120-volt household 3-prong outlet). Model 3 should do 4-5 miles/hour off that.

Once you get the NEMA 14-50 installed, there's not a compelling case (in my opinion) for a HPWC, aside from that it looks nicer (or if you really need the charging speed). Your Model 3 will top out at 48 amps (which requires a 60-amp breaker), while 14-50 will deliver a continuous 40 amps.

Circuit BreakerMax ampsModel 3 charge speedFull charge time
15 amps, 120 volts (UMC)12 amps5 miles/hour2:13:55
50 amps, 240 volts (UMC)40 amps37 miles/hour8:22
60 amps, 240 volts (HPWC)48 amps44 miles/hour7:03

Source: Tesla
 
Last edited:

rhaekar

Member
Nov 9, 2017
455
367
San Diego
Once you've got a 14-50 installed you may find there is no need to buy a HPWC.

We've got two S's and have never had a problem with just a single 14-50 outlet.

Charge rate shouldn't matter that much if you're charging over night. It really comes down to if you want to always have your UMC in your car then you have to unpack it and pack it up whenever you home charge.
 

brkaus

Well-Known Member
Jul 8, 2014
8,047
6,525
Austin, TX
Charge rate shouldn't matter that much if you're charging over night. It really comes down to if you want to always have your UMC in your car then you have to unpack it and pack it up whenever you home charge.

Yes, overnight charging is great!

And there really isn't much need for a UMC in the car, unless one travels to visit family, etc. I've used my UMC away from home one time in 1 year / 20k miles.

Most charging around town is J1772, which only needs the adaptor.
 
  • Like
Reactions: jaguar36

drawfour

Member
Mar 10, 2018
774
709
Seattle, WA
It really comes down to if you want to always have your UMC in your car then you have to unpack it and pack it up whenever you home charge.
You can buy a second UMC for cheaper than the HWPC, right? So then you have one in your car for when you need it and one at home. Bonus: if one of them breaks for some reason, you have a replacement right away (unless you're actually out on a long trip when that one breaks).
 

rhaekar

Member
Nov 9, 2017
455
367
San Diego
You can buy a second UMC for cheaper than the HWPC, right? So then you have one in your car for when you need it and one at home. Bonus: if one of them breaks for some reason, you have a replacement right away (unless you're actually out on a long trip when that one breaks).

$300 for a gen2 UMC, $500 for a HPWC. For $200 extra, you get a better looking charger and faster charging rate if ever needed in case of an emergency. You can also get the HPWC in 24' vs 20' of the UMC.

It's really just a preference. I went with the HPWC.
 

Merle Corey

Member
Apr 1, 2016
66
98
Brambleton
Depending on how much you drive in a day, you might be able to get by charging off of just a NEMA 5-15 outlet (that's your standard 15-amp 120-volt household 3-prong outlet). Model 3 should do 4-5 miles/hour off that.

Once you get the NEMA 14-50 installed, there's not a compelling case (in my opinion) for a HPWC, aside from that it looks nicer (or if you really need the charging speed). Your Model 3 will top out at 48 amps (which requires a 60-amp breaker), while 14-50 will deliver a continuous 40 amps.

Circuit BreakerMax ampsModel 3 charge speedFull charge time
15 amps, 120 volts (UMC)12 amps5 miles/hour2:13:55
50 amps, 240 volts (UMC)40 amps37 miles/hour8:22
60 amps, 240 volts (HPWC)48 amps44 miles/hour7:03

Source: Tesla

Thanks for the helpful chart!

$300 for a gen2 UMC, $500 for a HPWC. For $200 extra, you get a better looking charger and faster charging rate if ever needed in case of an emergency. You can also get the HPWC in 24' vs 20' of the UMC.

It's really just a preference. I went with the HPWC.

Hmm.. making my decision harder. Was all set on the HPWC, but I guess it does only offer better looks. I'll be doing less than 40 miles a day on average, so speed of charging is not important.

If anyone has some pictures of their HPWC and or NEMA outlet in their garage, that would be good to see. I guess I'm just trying to convince myself to get the nicer looking charger since I'll literally be using it everyday! LOL
 

drawfour

Member
Mar 10, 2018
774
709
Seattle, WA
I guess I'm just trying to convince myself to get the nicer looking charger since I'll literally be using it everyday! LOL
If you think a non-Tesla EV might be in your future, then the NEMA 14-50 will work for both your Tesla and the other. I'm debating that right now - I doubt my wife will want a Model 3 - expensive plus she's really not all that "gadgety". But she might upgrade her 2010 Prius to an EV or plugin hybrid. If she did that, we could have one charging port and satisfy our needs. Or get the Tesla one and have a NEMA 14-50 installed next to it, so we each get our own. Who knows.
 
  • Like
Reactions: AlanSqB

Derek Kessler

Active Member
Apr 15, 2016
1,193
1,806
Cincinnati
If anyone has some pictures of their HPWC and or NEMA outlet in their garage, that would be good to see. I guess I'm just trying to convince myself to get the nicer looking charger since I'll literally be using it everyday! LOL

Here's my UMC (Gen 1) setup:
C0BF0855-3991-45FE-808E-B0CC658B4CA9.jpeg
 

SageBrush

REJECT Fascism
May 7, 2015
12,507
15,521
New Mexico
$300 for a gen2 UMC, $500 for a HPWC. For $200 extra, you get a better looking charger and faster charging rate if ever needed in case of an emergency. You can also get the HPWC in 24' vs 20' of the UMC.

It's really just a preference. I went with the HPWC.
The car comes bundled with a UMC. You only spend $300 to have another.

For reasons that are not clear to me, electricians tend to charge a lot more to hard-wire an HPWC than to install a 14-50 outlet. Perhaps it is that Tesla brand at work.
 
  • Like
Reactions: Galve2000

drawfour

Member
Mar 10, 2018
774
709
Seattle, WA
The car comes bundled with a UMC. You only spend $300 to have another.
That's what we were talking about. Keep your UMC that comes with the car in the car at all times so you have it when on the road. Have another plugged into your NEMA 14-50 at home at all times so it's available. No worries about unplugging it at home and leaving it there and not having it with you. It was for the convenience, just like installing a HPWC is for the convenience...
 

Moderatefan

Member
Dec 20, 2017
902
841
Denver, CO
Thanks for the helpful chart!



Hmm.. making my decision harder. Was all set on the HPWC, but I guess it does only offer better looks. I'll be doing less than 40 miles a day on average, so speed of charging is not important.

If anyone has some pictures of their HPWC and or NEMA outlet in their garage, that would be good to see. I guess I'm just trying to convince myself to get the nicer looking charger since I'll literally be using it everyday! LOL
From me reading other threads...
- the new UMC gen2 can charge @32amp, which is below 40amp (continuous) capability of NEMA 14-50 receptacle.
- the old UMC gen1 can charge @40amp, but is unsafe/prone to failing, which is why Tesla switched to gen2, so don't buy.
- HPWC is safer due to no plug/unplug cycles & can charge @80amp, but you'll be limited by car's charger - LR @48amp and SR @32amp
A lot of info here: Home Charging Installation

In my opinion, HPWC probably makes sense if you expect to have multiple Tesla vehicles charging significantly - then you do the wiring once @100amp and later just add more HPWCs to the same curcuit. (consider how likely you are to buy Y in the future :) )

On the other hand, you may have one Tesla used for longer commutes, road trips etc. that needs significant daily charging and other Tesla for short local trips - I see many people report successfully using NEMA 14-50 + UMC and a regular CGFI 110V outlet + UMC for 2nd car in this scenario.

See nice pictures from Daniellane here: HPWC plugged into 14-50 - is this ok?
 
Last edited:
  • Informative
Reactions: brkaus

dhrivnak

Active Member
Jan 8, 2011
4,495
3,762
NE Tennessee
Thanks for the helpful chart!



Hmm.. making my decision harder. Was all set on the HPWC, but I guess it does only offer better looks. I'll be doing less than 40 miles a day on average, so speed of charging is not important.

If anyone has some pictures of their HPWC and or NEMA outlet in their garage, that would be good to see. I guess I'm just trying to convince myself to get the nicer looking charger since I'll literally be using it everyday! LOL
It is also VERY easy to add a plug to an HPWC and plug into a NEMA 14-50. If you do this make sure you dial it back to 40 amps. Easy to do.
 

Moderatefan

Member
Dec 20, 2017
902
841
Denver, CO
It is also VERY easy to add a plug to an HPWC and plug into a NEMA 14-50. If you do this make sure you dial it back to 40 amps. Easy to do.
This is illegal as a permanent solution per thread I referenced, specifically
A suggestion was made that Tesla note in the instruction/installation manual that permanent wiring methods are required, which would then be required by the NEC per section 110.3.
 

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top