Charging options for Model 3

[shauna]

I have one electrician that installed a 30 amp 220 outlet in my outdoor electrical panel and say I can use this with my mobile charger and an adapter just fine and he will install a gfi outlet incase moisture gets in. This would allow me to charge at 22miles/hour.

Another electrician told me he can install the wall charger with a 50 amps, and down grade to 40 if it gets overloaded. I have a 125 amp panel (the first electrician told me I am using 124 amps and would need to pay $5,000 to upgrade the panel to 200 amps). My question is, is it worth the $500 for the wall charger and $750 for installation, how fast will my car charge then? Is there anything I should know about using the first method which would only cost $150? I drive up to 60 miles/day.

 

[Sophias_dad]

I have one electrician that installed a 30 amp 220 outlet in my outdoor electrical panel and say I can use this with my mobile charger and an adapter just fine and he will install a gfi outlet incase moisture gets in. This would allow me to charge at 22miles/hour.

Another electrician told me he can install the wall charger with a 50 amps, and down grade to 40 if it gets overloaded. I have a 125 amp panel (the first electrician told me I am using 124 amps and would need to pay $5,000 to upgrade the panel to 200 amps). My question is, is it worth the $500 for the wall charger and $750 for installation, how fast will my car charge then? Is there anything I should know about using the first method which would only cost $150? I drive up to 60 miles/day.

Tesla shows the speeds-of-charge...

If you have a 30 amp breaker and the plug supports 30 amps, in theory the 3 can take 28 amps, giving a 26 m/hour charge rate. In reality, you aren't supposed to do that because its considered a continuous-use appliance, and you are only allowed to use 80% of the rating of the wire/breaker(24 amps, which is where you get the 22m/hour).

If you go HPWC, you'll get 44/37/30 m/hour at 48/40/32 amps(circuit breakers would be 60/50/40 amps).

Note also that all these mi/hour rates are 'optimal' rates. In reality I never see the quoted 37 with my 40 amp HPWC, and I get somewhat less than the expected mileage out of my electrons.

It doesn't sound like you need a HPWC at all. You are looking at 3 hours per night of charging, and best case, you'd be looking at halving that time with the HPWC.

While I'm pretty skeptical that the first electrician was correct about not being able to get more power out of the panel without an upgrade, its entirely possible he's correct, and also not worth the bother or money.

Note that you probably should have not only a GFCI outlet installed, but a weather-safe cover/enclosure for it.

 

[Eno Deb]

Another electrician told me he can install the wall charger with a 50 amps, and down grade to 40 if it gets overloaded. I have a 125 amp panel (the first electrician told me I am using 124 amps and would need to pay $5,000 to upgrade the panel to 200 amps). My question is, is it worth the $500 for the wall charger and $750 for installation, how fast will my car charge then? Is there anything I should know about using the first method which would only cost $150? I drive up to 60 miles/day.

Purely looking at your daily driving the 30A outlet is plenty fast for overnight charging (you can recover 60 miles in about 3 hours). I charge from a 30A dryer outlet in my garage and it works very well. Of course there may be practical issues to take into account (Is the outlet exposed to the elements? Do you need to frequently unplug the charge cable because you need the outlet for something else as well?). If nothing else stands in the way, I'd save the $750. You might consider buying the wall charger (which is outdoor rated) anyway and have the first electrician connect it to the 30A circuit.

 

[David99]

Been charging my Model S for 5 years on the mobile connector now. No issues. 100% reliable.

Regarding the panel limits. All breakers combined can't be higher than the total of the panel. Worst case is that there is a full load on all lines maxing out the capacity of the panel. In reality that's never happening. For example I have a 200 Amp panel. Two ovens, a hot tub, AC, dishwasher, washer and everything else. I added all thing up (if they were all switched on at the same time) and it comes out to 120 Amp. So even in the worst case adding 40 Amp for charging the car would not max out the panel. The electrician said I would need another panel. I sent him home and installed the 50 Amp breaker and the NEMA 14-50 myself for a total of $60 materials.

I only charge at night to get the cheaper off peak rate. At those times the average load from the entire house is around 0.5 to 2 kW. If the AC is running it's 5 kW more. Charging the car brings it up to 17 kW which is 70 Amp. Way below the 200 max of the panel. So even if I had a 100 Amp panel I'd be fine.

 

[Sophias_dad]

Been charging my Model S for 5 years on the mobile connector now. No issues. 100% reliable.

Regarding the panel limits. All breakers combined can't be higher than the total of the panel. Worst case is that there is a full load on all lines maxing out the capacity of the panel. In reality that's never happening. For example I have a 200 Amp panel. Two ovens, a hot tub, AC, dishwasher, washer and everything else. I added all thing up (if they were all switched on at the same time) and it comes out to 120 Amp. So even in the worst case adding 40 Amp for charging the car would not max out the panel. The electrician said I would need another panel. I sent him home and installed the 50 Amp breaker and the NEMA 14-50 myself for a total of $60 materials.

I only charge at night to get the cheaper off peak rate. At those times the average load from the entire house is around 0.5 to 2 kW. If the AC is running it's 5 kW more. Charging the car brings it up to 17 kW which is 70 Amp. Way below the 200 max of the panel. So even if I had a 100 Amp panel I'd be fine.

Your information is incorrect. All breakers combined can, and frequently are, higher than the main breaker of the panel. Theres a whole slew of calculations done to predict concurrent loads and try to avoid overloading the main breaker, and frequently-running or continuous loads count for much more in that. Notably working the opposite way, if there are continuous loads that are never going to be used at the same time(giant central air conditioner and electric baseboard heat, for instance) the lower of those two loads can be essentially ignored. The individual breakers are there to protect the wiring (to the outlets) from overheating in case of overload, not to protect the main breaker(or panel itself) from overload. The main breaker protects both the wiring coming from the pole and the panel itself from overload, although its not gonna protect the wiring(from the pole) from overload if something goes awry on the way to the panel.

 

[David99]

Your information is incorrect. All breakers combined can, and frequently are, higher than the main breaker of the panel. Theres a whole slew of calculations done to predict concurrent loads and try to avoid overloading the main breaker, and frequently-running or continuous loads count for much more in that. Notably working the opposite way, if there are continuous loads that are never going to be used at the same time(giant central air conditioner and electric baseboard heat, for instance) the lower of those two loads can be essentially ignored. The individual breakers are there to protect the wiring (to the outlets) from overheating in case of overload, not to protect the main breaker(or panel itself) from overload. The main breaker protects both the wiring coming from the pole and the panel itself from overload, although its not gonna protect the wiring(from the pole) from overload if something goes awry on the way to the panel.

I understand all of that. The issue are electricians that take advantage of clueless EV owners and charge them for work and upgrades they do not need. The average person doesn't have the knowledge to verify what is suggested to them. I understand electricity well enough to add up all loads and know there is no need to spend $4000 for a new panel.

For the last 5 years I have been reading messages from new owners that just got their estimate from an electrician and it's disheartening to see how people are ripped off. They see a $100k Tesla and think, 'hey that guy has money, let's get the most out of this job'. Like so many others here, I got the most ridiculous estimates and that's why I ended up doing it myself. Of course I don't recommend to install your own outlet if you don't understand what how and what. But the way electricians take advantage of new EV owners is really frustrating.

 

[Sophias_dad]

I understand all of that. The issue are electricians that take advantage of clueless EV owners and charge them for work and upgrades they do not need. The average person doesn't have the knowledge to verify what is suggested to them. I understand electricity well enough to add up all loads and know there is no need to spend $4000 for a new panel.

For the last 5 years I have been reading messages from new owners that just got their estimate from an electrician and it's disheartening to see how people are ripped off. They see a $100k Tesla and think, 'hey that guy has money, let's get the most out of this job'. Like so many others here, I got the most ridiculous estimates and that's why I ended up doing it myself. Of course I don't recommend to install your own outlet if you don't understand what how and what. But the way electricians take advantage of new EV owners is really frustrating.

I totally agree with all those sentiments. I'm sure there are many electricians who are quite honest, maybe we only hear about the bad ones here because not many people are going to go out of there way to write "Is my quote too low? My electrician wants to charge $250 to install a $20 breaker and 40 feet of 6AWG"

 

[David99]

I totally agree with all those sentiments. I'm sure there are many electricians who are quite honest, maybe we only hear about the bad ones here because not many people are going to go out of there way to write "Is my quote too low? My electrician wants to charge $250 to install a $20 breaker and 40 feet of 6AWG"

True, forum messages are usually not a good and neutral average.

 

[RandyS]

The real question, OP, is whether you want a legal (permitted) installation that was done by an installer that knows how to apply the National Electrical code load calculations to determine if your existing panel can handle this new load (and what to recommend if you need additional capacity), or whether you are okay with using a lesser qualified electrician who might charge less but doesn't have the knowledge or experience to assess your situation and just makes a recommendation based on the fact "that it should work" or something similar.

For many people, the installation of a Wall Connector or NEMA 14-50 receptacle to charge a car could very well be one of the largest loads you have in your house. Don't you want to make sure that you get it done correctly? Neither one of your two electricians are giving me the warm and fuzzy feeling that they have much experience with this type of installation...

 

[David99]

The real question, OP, is whether you want a legal (permitted) installation that was done by an installer that knows how to apply the National Electrical code load calculations to determine if your existing panel can handle this new load (and what to recommend if you need additional capacity), or whether you are okay with using a lesser qualified electrician who might charge less but doesn't have the knowledge or experience to assess your situation and just makes a recommendation based on the fact "that it should work" or something similar.

I think the original question is not between a good and a not so good electrician. The question is if the smaller 30 Amp outlet is enough to charge his car for his daily needs and doing the math shows quickly: it is plenty fast for his 60 mile daily driving needs. On an average 10 hour night he could charge well over 200 miles if he needed. Adding a second 200 Amp panel for $5000 is a waste of money.

 

[animorph]

Doesn't seem like you need the HPWC.

The price for installing the HPWC seemed good. If you liked it's convenience and don't mind the price you should be able to replace the existing socket with the HPWC. No more amps, unless your electrician says your load calc and wiring would allow it, but no bothering with the outlet.