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Tesla Home Charger. Redundancy. (Poll included)

How Do you Charge Your Car At Home?


  • Total voters
    192
  • Poll closed .
Hi,

I am awaiting my LR AWD M3. So far we are preparing for the car by installing a home charging setup. A friend of mine has agreed to sell me a Tesla wall charger for a very good price since he has an extra one and I have a construction electrician coming by this weekend to set up our box. We have talked about putting in an 80 amp breaker, but he will look at our home and probably lock it down to 60 amps, which would probably mean only 40-45 amps available (since according to him, we never go full throttle on the circuit).

We discussed adding a back up plan in the event that the device fails. He agreed that this would be a very good idea, not only for redundancy in the event that the device fails, but especially if we moved. I wouldn't want to leave the Tesla wall charger behind if it was still working. However the new occupant would have another way to charge their EV (or run an oven :)). So we are planning on also installing a a NEMA 14-50 set up? It would reside right next to the Tesla dedicated charger as a back up. (Pity we couldn't use the NEMA 14-50 Dedicated Tesla plug in wall charger - Sold Out and way too expensive).

One question I was asked at work by a few who have M3's was why not just do a NEMA 14-50 and just use the supplied cord to attach it? My answer was simply that I got a really insane deal on the wall charger and the electrician is not charging anything extra to do the additional installation, so why not? Additionally, it adds an extra layer of calmness for me knowing that if the Tesla charger breaks down I have something else to fall back on (as long as there's electricity of course :)).

Would love to hear the thoughts of others on doing this and/or what you have set up at home.
 

brkaus

Well-Known Member
Jul 8, 2014
8,507
7,141
Austin, TX
I have a WC on a 50a breaker (40a charging). I would have done 60a (48a charging) but I have a special EV rate that has a nice price for 50a.

I personally see no reason to invest in a backup.

1) I have a regular outlet that would give me some charge and likely cover the majority of my daily commute.

2) I know a number of people nearby that have Tesla WC

3) superchargers, destination chargers.

4) pretty easy to pop off the WC and mount a 14-50 if the stuff hit the fan.


Sure, if I had space in my main panel and if I could do it for $50 (or 100)... all in, inspection included I would do it. But I have a 200a panel, 3 AC systems, electric dryer, 2 ovens...

I easily charge a 3 and an S with this single WC. We drive about 40-60 miles a day each.
 
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I use the UMC that came with the car and a NEMA 14-50 outlet, it has a wall mount to relieve strain. I bought a spare UMC to carry in my trunk when I travel as I got tired of unplugging it from my garage wall. Having two UMC's also gives me a backup in case one fails.
 

MrMassTransit

Member
Supporting Member
Mar 7, 2019
299
515
Washington, DC
If you've got a great deal on a HPWC, then I'd use it. It looks nice, charges faster and allows you to leave the mobile connector in the car if you want it as a backup on road trips. There is no need for a 240v "backup" in your home in my opinion. The backup is the 120v outlet in your garage - if for some reason something failed, just plug into the 120v outlet and limp along until you get the HPWC fixed. But HPWCs don't fail with any frequency, so I wouldn't worry about it.

Unless you plan on driving 150-200 miles per day, multiple days per week and have no superchargers anywhere near you, then there's really no way to justify a 240v backup. You could go a week or two charging on 120v and falling back on superchargers if needed and be total fine. The only reason it would make sense is if you planned to get an RV, do some welding, or had another high power 240v need in your garage in the future.
 
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jjrandorin

Moderator, Model 3, Tesla Energy Forums
Moderator
Nov 28, 2018
14,305
18,115
Riverside Co. CA
Hi,

I am awaiting my LR AWD M3. So far we are preparing for the car by installing a home charging setup. A friend of mine has agreed to sell me a Tesla wall charger for a very good price since he has an extra one and I have a construction electrician coming by this weekend to set up our box. We have talked about putting in an 80 amp breaker, but he will look at our home and probably lock it down to 60 amps, which would probably mean only 40-45 amps available (since according to him, we never go full throttle on the circuit).

We discussed adding a back up plan in the event that the device fails. He agreed that this would be a very good idea, not only for redundancy in the event that the device fails, but especially if we moved. I wouldn't want to leave the Tesla wall charger behind if it was still working. However the new occupant would have another way to charge their EV (or run an oven :)). So we are planning on also installing a a NEMA 14-50 set up? It would reside right next to the Tesla dedicated charger as a back up. (Pity we couldn't use the NEMA 14-50 Dedicated Tesla plug in wall charger - Sold Out and way too expensive).

One question I was asked at work by a few who have M3's was why not just do a NEMA 14-50 and just use the supplied cord to attach it? My answer was simply that I got a really insane deal on the wall charger and the electrician is not charging anything extra to do the additional installation, so why not? Additionally, it adds an extra layer of calmness for me knowing that if the Tesla charger breaks down I have something else to fall back on (as long as there's electricity of course :)).

Would love to hear the thoughts of others on doing this and/or what you have set up at home.

The "cord that comes with the car" will only charge at 32 amps. That would likely be enough for your commute but would not be using the circuit that you are having installed to the fullest. I dont see this as being much different than putting in another dryer plug close to your first one just in case the dryer plug stops working.

I would likely just install the wall connector you are getting and put the mobile cord that comes with the car into the trunk.

Also, as mentioned, if you are getting a AWD or Performance tesla, it will charge at a maximum of 48 amps. To hit that, you need a 60 amp circuit, as electrical code does not let you max out the charge rate (simplified explanation but works). If you are getting a SR or SR+ tesla, it wont even charge that fast... it will charge at 32 amps. The larger you make your circuit , the more expensive the wiring and stuff tends to be. Unless you are trying to future proof and plan on having multiple teslas connected to multiple wall connectors, there is no current reason to size a circuit larger than 60amps for this purpose.

its likely that your electrician is suggesting putting an outlet on the same circuit next to the wall connector just in case the all connector goes out. Nothing wrong with that, as long as you (nor anyone else) ever tried to use that plug to power something the same time you were charging your car. I doubt very seriously that he is recommending two separate circuits right next to each other in your garage for redundancy.
 

RoBoRaT

Zero Farts Given!
Nov 22, 2018
1,768
1,726
NorthSoCal
Hi,

I am awaiting my LR AWD M3. So far we are preparing for the car by installing a home charging setup. A friend of mine has agreed to sell me a Tesla wall charger for a very good price since he has an extra one and I have a construction electrician coming by this weekend to set up our box. We have talked about putting in an 80 amp breaker, but he will look at our home and probably lock it down to 60 amps, which would probably mean only 40-45 amps available (since according to him, we never go full throttle on the circuit).

We discussed adding a back up plan in the event that the device fails. He agreed that this would be a very good idea, not only for redundancy in the event that the device fails, but especially if we moved. I wouldn't want to leave the Tesla wall charger behind if it was still working. However the new occupant would have another way to charge their EV (or run an oven :)). So we are planning on also installing a a NEMA 14-50 set up? It would reside right next to the Tesla dedicated charger as a back up. (Pity we couldn't use the NEMA 14-50 Dedicated Tesla plug in wall charger - Sold Out and way too expensive).

One question I was asked at work by a few who have M3's was why not just do a NEMA 14-50 and just use the supplied cord to attach it? My answer was simply that I got a really insane deal on the wall charger and the electrician is not charging anything extra to do the additional installation, so why not? Additionally, it adds an extra layer of calmness for me knowing that if the Tesla charger breaks down I have something else to fall back on (as long as there's electricity of course :)).

Would love to hear the thoughts of others on doing this and/or what you have set up at home.

I had exactly what you have in mind.
Had my licensed electrician neighbor install a HPWC and backup NEMA 14-50 next to it.

My power company basically paid for the HPWC and install/material cost, rebated $1000.

And, another Air Quality county dept provided $500 - like paying the cost of NEMA 14-50 and mobile charger.

But, the main reason is redundancy. I drive 160 miles daily - so if the HPWC fails, i have the 14-50 to get by the next day.

HPWC was installed with 80A breaker initially (my electrician neighbor did not charge extra for running bigger gauge wire that is harder to bend/work with), but had to change breaker to 60A due to load reduction to allow Solar/Battery install. HPWC with 60A breaker still gets you the 48A max input for a LR AWD M3 charger. It has been flawless for 9 months ownership at 30K miles, and have given me peace of mind.

20190209_110438.jpg
20190917_060935.jpg
 

Zaxxon

Active Member
Supporting Member
Dec 11, 2012
4,705
22,079
Colorado
We've got 2 load-sharing HPWCs for our 2 vehicles, with a UMC on a 120V outlet as a backup in the event that the HPWCs or their circuit ever has an issue. I don't ever really expect that to happen, but I did charge one of the cars via that 120V setup for a few days to verify everything works just in case.
 
I've a bit surprised that alternate 240 outlets (e.g. 6-20) get so little mention. In my case I didn't want to install a 14-50 because I knew I was moving in under 2 years, and I had a crowded breaker box. As it turned out I had an unused 240v 20 amp circuit that could easily and cheaply be wired to a 6-20 outlet with ordinary 12-2 wire. Although it only charges at about 15 MPH, my normal day's drive is under 100 miles so its never been a problem.

A cold New England winter day is a bit of a challenge since the car uses more juice and time is wasted heating the batteries, but as long as I don't have back to back long drives with a short layover it works out. The only issue I've ever had had is when I forgot to plug in, causing a bit of anxiety the next morning - I've learned to check the charge when I wake up!

That said, in the new house I'm putting in a 14-50, taking a 240v slot from an unused stove outlet.
 

Big Dog

Active Member
Mar 7, 2016
1,815
1,989
Irvine, CA
I've a bit surprised that alternate 240 outlets (e.g. 6-20) get so little mention. In my case I didn't want to install a 14-50 because I knew I was moving in under 2 years, and I had a crowded breaker box. As it turned out I had an unused 240v 20 amp circuit that could easily and cheaply be wired to a 6-20 outlet with ordinary 12-2 wire. Although it only charges at about 15 MPH, my normal day's drive is under 100 miles so its never been a problem.

A cold New England winter day is a bit of a challenge since the car uses more juice and time is wasted heating the batteries, but as long as I don't have back to back long drives with a short layover it works out. The only issue I've ever had had is when I forgot to plug in, causing a bit of anxiety the next morning - I've learned to check the charge when I wake up!

That said, in the new house I'm putting in a 14-50, taking a 240v slot from an unused stove outlet.

I also have a "crowded breaker box" so the electrician installed a sub-panel to feed the HPWC at 60 amps (the max for a Model 3). Since we almost always charge at night, there is no issue as nearly every other electrical appliance is off.

And for 'redundancy' should the WC die, I'll just use the cord that came with the car and plug it into a 110 garage receptacle until the WC can be repaired/replaced. And if that fails, I can head over to a SuperCharger if a true emergency.

When we sell the house, I'll just disconnect the WC, flip the breaker off, clip/cap the wires in the wall and screw on a cover plate (from Home Depot) over the hole.
 
Unfortunately (but not really) my dryer is upstairs so I didn't have a dryer outlet when I bought the Model 3. I did have lots of panel space with the panel right next to the Tesla parking space though so I had my electrician install both a wall charger and a dryer plug. That way I have the Tesla charger for now and the 14-50R for future. I keep the UMC in the sub trunk just in case. I thought about doing just the 14-50R but given the cost of a 40 amp charger unit from Tesla figured I may as well get the wall charger and an extra 8 amps.
 
I do not like plugging and unplugging the mobile connector. I also like to keep a charging cord in the frunk, in case I go t a place with no destination or superchargers nearby.

Luckily the panel is in my garage and it cost me $80 for an electrician friend to install a NEMA 14-50 below that. For the time being I have attached the UMC with a 14-50 adapter to it. I have ordered a corded WC (in the short time it was available recently) and when it comes it will be permanently plugged in to the 14-50 receptacle and the mobile connector will be put in the frunk with a 110V and 240V adapters. Another mobile connector with a 14-50 adapter would have been $275+$35 and the corded WC was $500, so it was $190 more for a better built charger with higher amperage and no additional electrician service.

When I move to new house and possibly have another Tesla I am future proofing it with one NEMA 14-50 on either side and a WC connected to a 80 amp panel on one side. In the end I will have a 80 amp WC on one side and 50 amp Corded WC on opposite side and 2 mobile connectors ( that came with vehicle) with 2 adapters, one each in the Tesla frunk.

Probably overkill but cheaper to do while the house is being built.
 

Phlier

Bluebird
Jun 12, 2019
2,233
4,222
Utah
If the electrician is doing a "free" installation, you might want to ask if you can pay for just a bit more...

My electrician successfully up-sold me, which is something that isn't easily done.

I went with a monstrous 100 amp breaker, with (of course) the associated wiring, and I even had him pull a neutral line (not needed for a Tesla HPWC). Why? Glad you asked!

1. I can add a second Tesla to the fleet, and two HPWC's will communicate with each other, and share the available energy between the cars. And since they're sharing a 100 amp line, they will each have a higher share.

2. I can put in pretty much whatever NEMA plug I want, as I had him pull a neutral line, too.

3. I can finally look for a welder. :)

4. I can finally put in that mini-split heat pump for the garage that I've wanted for years.

There is a lot of utility to be had in having a high capacity 240v circuit in your garage. How much utility depends on each individual, of course.
 

abasile

TSLA shareholder
Supporting Member
We prefer to always keep the UMC (Universal Mobile Connector) in the car. It's what gives you the ability to charge virtually anywhere, including standard outlets, campsites with RV outlets, relatives' homes, Sierra Club "huts", hospitals with outdoor outlets, etc., etc. Now, if all you ever do is drive around in urban/suburban areas, you might not feel you need to carry the UMC. But if you ever visit the mountains, take overnight trips, drive out to trailheads, etc., then it can be helpful to have it in the car. If you use the UMC for home charging, the danger is that you'll forget to put it in the car before leaving on a longer drive, or that you'll be caught having to make an unexpected trip and you don't have time to return home to fetch the UMC.

Further, the cost of the Wall Connector is quite reasonable and it's nice to be able to charge at the full 48 amps if your car supports it.
 
Hi,

I am awaiting my LR AWD M3. So far we are preparing for the car by installing a home charging setup. A friend of mine has agreed to sell me a Tesla wall charger for a very good price since he has an extra one and I have a construction electrician coming by this weekend to set up our box. We have talked about putting in an 80 amp breaker, but he will look at our home and probably lock it down to 60 amps, which would probably mean only 40-45 amps available (since according to him, we never go full throttle on the circuit).

We discussed adding a back up plan in the event that the device fails. He agreed that this would be a very good idea, not only for redundancy in the event that the device fails, but especially if we moved. I wouldn't want to leave the Tesla wall charger behind if it was still working. However the new occupant would have another way to charge their EV (or run an oven :)). So we are planning on also installing a a NEMA 14-50 set up? It would reside right next to the Tesla dedicated charger as a back up. (Pity we couldn't use the NEMA 14-50 Dedicated Tesla plug in wall charger - Sold Out and way too expensive).

One question I was asked at work by a few who have M3's was why not just do a NEMA 14-50 and just use the supplied cord to attach it? My answer was simply that I got a really insane deal on the wall charger and the electrician is not charging anything extra to do the additional installation, so why not? Additionally, it adds an extra layer of calmness for me knowing that if the Tesla charger breaks down I have something else to fall back on (as long as there's electricity of course :)).

Would love to hear the thoughts of others on doing this and/or what you have set up at home.

14-50 for me. Has flexibility to accommodate another future EV beater ie volt, or kona or Honda.
 

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