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Just use a mobile charger with 5-15 (at least initially)?
- Thread starter Brian_2024
- Start date
E90alex
Active Member
Depends how much everything else draws in your house. To give you an idea, charging the car on 120V would be like having a hair dryer or toaster oven running for 12 hours.
You can also set the car to not start charging until you sleep when all other major appliances are off but of course that will reduce how much range you will gain from plugging in when on 120V when every hour you can be charging matters.
If you can put in a 240V circuit then you can wait to start charging in the dead of night when everything else is off and it will be done in a couple hours.
You can also set the car to not start charging until you sleep when all other major appliances are off but of course that will reduce how much range you will gain from plugging in when on 120V when every hour you can be charging matters.
If you can put in a 240V circuit then you can wait to start charging in the dead of night when everything else is off and it will be done in a couple hours.
It's a sub panel. The main panel has a 200A capacity and is connected to things like the HVAC. The range is on a 40A circuit and dryer is 30A.
50-60A
Dial back your expectations and ask for a 40A circuit (A 40 amp circuit would enable charging at 32 amps.) This would add 10% charge to the battery per hour, approximately ~29 miles of driving range added per hour. A 30 amp circuit would charge at 24 amps and add 7% charge per hour and add ~21 miles of range per hour.
Quick update: A couple of the licensed electricians said they could add the circuit to the 100 amp panel in my garage and quoted around $1,500. The last electrician said that would trip the breaker (I was wondering the same), said they'd have to update the panel to the outside of the house and quoted $6,800
Hmmm, I know I'm not paying $6,800 to have a charger put in, but am wondering if that electrician was correct....say charging the Tesla, running the stove and running the dryer would be too much for 100 amp panel?
What normally happens in these cases is someone says "I got a new Tesla, how much is it to add a 60 amp circuit to what I got so I can charge my new Tesla at 48amps?" and a company happily quotes what that would take, even if it takes panel upgrades etc.
Its the wrong question (in my opinion). The "right" question is, "I got / am getting a new EV. What is the largest 240V circuit I can put in that does not require major upgrades? What does a load calculation say I can install in my current panel?" (or something close to that).
Perhaps a load calculation says you can only add a 240V 30amp circuit, which in actuality is probably fine for most people. You wont really know unless a load calculation is done.
You can probably live with just about any 240V circuit as far as it pertains to getting enough charge on a daily basis.
GalacticHero
M3-AWD+
I used 120V charging for over a year when I bought my 3. I'd plug it in and start it charging when I got home from work. Since my round trip commute is 50 miles, I'd lose a bit of range every day. Then I'd have the weekend to top it back up. Occasionally if I drove it a lot on the weekend I'd stop by a Supercharger and add some mile that way.
That being said, it was going to be more convenient to have 240V charging; so, I got a quote. It turned out I had panel space and enough spare amperage. The quote ended up being only(?) $600, plus there was a tax benefit for doing the EV charging install. I went with an outlet and using the Mobile Charger. It delivers plenty of power to ensure even a full charge overnight. I've unplugged the charger maybe once since the outlet was installed; so, not too concerned about not using a super expensive outlet. Also, if I want to run a welder or plasma cutter, I can use the outlet for that.
That being said, it was going to be more convenient to have 240V charging; so, I got a quote. It turned out I had panel space and enough spare amperage. The quote ended up being only(?) $600, plus there was a tax benefit for doing the EV charging install. I went with an outlet and using the Mobile Charger. It delivers plenty of power to ensure even a full charge overnight. I've unplugged the charger maybe once since the outlet was installed; so, not too concerned about not using a super expensive outlet. Also, if I want to run a welder or plasma cutter, I can use the outlet for that.
exxxviii
Member
What he said... I would add one minor tweak to the question for your scenario..."What would be the biggest EV circuit (and cost) they could run directly to the 200 A main panel and bypass the 100 A sub panel, without any panel upgrades?"
Based on your high-level information, I think Electrician #3 is probably more qualified than #1 and #2. Seems like that 100 A panel would be overloaded with a typical 32 A to 48 A charging load. But #3 may have massively overengineered his solution.
It seems that whoever installed the 5-20 receptacle should have installed a 5-15 receptacle, the wire behind that 5-20 is probably only rated for 5-15. So you can't even use a 5-20 Mobile Connector there (only the 5-15) or it will trip the breaker when it tries to draw 16 amps. Plus, seems like lots of stuff already hanging off that shared 15 amp breaker, so adding the Tesla to it might cause lots of nuisance tripping.
Short term, you might think you can make this work by plugging in and charging every day on that 5-15. But that's going to start getting old really quick. It will quickly become a nightmare trying to squeeze enough juice into your Tesla with that incredibly slow rate. And then you plug in at night, and come out in the morning to find the 7-outlet daisy chained 15-amp circuit tripped the night before and you have no charge in the morning.
Best to bite the bullet now, and get something installed that will charge the car in a reasonable amount of time. Dedicated 240 volt circuit with dedicated wire.
The way you do a load calculation is not by adding up breaker sizes. You don't add 40A + 30A and say you've only got 30A left. You instead look at the power draw rating of the appliance itself. Most dryers will draw a maximum of 20A at full high setting. Ranges likewise 30A max. I would feel very comfortable having the electrician use the garage subpanel for a 50A EV charging circuit, which again, doesn't use 50A at full power.
Second $1500 for installing a 50A circuit in the same garage as the subpanel is a high bid. I would ask for a second quote for that particular work. Make sure the electrician understands this is for a dedicated EVSE (presumably you are talking Wall Connector now), so only three wires needed (2 hots plus a ground).
Second $1500 for installing a 50A circuit in the same garage as the subpanel is a high bid. I would ask for a second quote for that particular work. Make sure the electrician understands this is for a dedicated EVSE (presumably you are talking Wall Connector now), so only three wires needed (2 hots plus a ground).
And, @Brian_2024, my earlier comment about, "Check what your State has for incentives" still stands. A lot of states will help with the cost of a hardwired charger, in which case all of this gets much, much cheaper. A 30 second search found this: Alternative Fuels Data Center: Electricity Laws and Incentives in North Carolina.
A brief skim of the text on that page had stuff like, "Level 2" and "Residential". That, sir, is you. Level 2 is 240 VAC charging.
There seems to be a fund or three out there. Have you called/looked/etc.?
A brief skim of the text on that page had stuff like, "Level 2" and "Residential". That, sir, is you. Level 2 is 240 VAC charging.
There seems to be a fund or three out there. Have you called/looked/etc.?
Thanks all, learning a lot as I'm looking into this. If it's a huge pain or expense to charge the car, I'll probably hold off as I'm still on the fence with buying one. I still think mobile charging would work most of the time for our low driving needs (will also have an ICE car on hand) if ever needed and there's a supercharger near by if I needed to top off quickly. But based on responses, it sounds like charging on 5-15 isn't a good way to go (understandably).
I was wondering about the 5-20 being on a 15amp circuit breaker. I just rechecked the panel and the handwriting is really bad on it, but it looks like one 15 amp breaker says: Lights, Garage recept door and another 15 amp breaker says garage gft (I would think it's GFC) and Outside Receptacles. So maybe I wouldn't need to be as concerned with the mobile charger tripping.
If you have low usage, charging off 120V works. I've been doing it on one of my EVs for over a year. a 20A circuit is preferred of course.
You have to have a receptacle tester (if you don't have one, use a handheld device like a hair dryer, or anything that makes noise) and flip breakers until you find the one that turns off the power to the device. Then label it correctly. You might have a 20A breaker for that receptacle.
You would be fine charging using one of the 5-15 receptacles for the 1st year, possibly longer. You can also lower the charging amperage using the charging settings for a 120V/15A circuit from 12A down to 8A (even down to 5A) but this probably won't be an issue as you will find that charging at 120V and 12A meets your daily charging needs and does not trip the breaker.
You should have an electrician inspect the existing wiring and 5-15 receptacles. If the 5-20 receptacle should be a 5-15 it can easily be changed. Change any receptacle you plan to use for EV charging if more than 10 years old as these do wear out over time. Replace with a good quality receptacle.
You should have an electrician inspect the existing wiring and 5-15 receptacles. If the 5-20 receptacle should be a 5-15 it can easily be changed. Change any receptacle you plan to use for EV charging if more than 10 years old as these do wear out over time. Replace with a good quality receptacle.
sub panel, the main panel is outside the house 200 amp
I know my power company has an $1,100 rebates. I haven't seen anything on state tax incentives yet. I believe the federal may be 30% off a level 2 install.
Check that link I put up there. That's a (I think) DoE web site with links to State sites. It's the state sites that'll cough up cash for an install and it likely won't be a, "Wait until next year and get money back on your taxes", like the Fed car rebate is. Note that some of the entries are for commercial entities with, say, electric delivery vans; others are incentives for residential people.
Good call! I just tried this and it turns out that 5-20 amp outlet is on separate circuit with a 20amp breaker. Looks like it's labeled Freezer / Garage. I'm not sure what Freezer means - maybe if I wanted to put a freezer in the garage or something? My refrigerator is connected to a different breaker.
So if that's a dedicated circuit, I could use the mobile charger with 5-20 adapter and get maybe 7 mph. That might be good enough
Only thing you'll need is the Tesla Mobile Connector and the adapter for a NEMA5-20; that's the one with the right-angle blade.
exxxviii
Member
If it is a standalone recepticle, you could convert it to a 6-20 and charge at 24V/15A for 14 miles/hour or 3.6 kWh.
Thanks! I think I'll go this route.
With a 240v upgrade I think I'll be at "Level 2" charging and can get the rebate through my power company - EV Charger Prep Credit - Duke Energy
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