So, with the money that The General is putting on the hood of the 2020 and 2021 Bolts, combined with the average age and mileage on the current fleet, I'm thinking about dipping my toe in the the water of the whole EV experiment.
While I would love a Tesla Model 3 Performance, purely for the party trick of being able to engage hyperdrive and beat a Porsche 959 0-60, I tend to develop 'alligator arms' when it comes time to reach for my wallet and spend money on a new car. If I can snag a new Bolt for what I think I can, after all incentives, rebates, yadda, yadda...I'll consider it buying "carbon credits" and save the need for speed stuff for the track.
All that said, Mrs Rotaryracer is also open to considering a Tesla when she parts with her CX-5 in a couple of years....probably a Model Y, or whatever Dr. Evil has dreamed up by then. I have enough other dinosaur-burners in the fleet to solve for the #ZOMGigottadrivetocalifornianonstop worries, but am wondering how much juice each charger expects to draw. Based on limited Googling, I'm thinking 32A for the Bolt and up to 80A for the Tesla? If I were to power both (off my 250A main panel), that feels like a pretty healthy subpanel in the garage...especially when I also want to run at least 100-125A out to a yet-to-be-built pole barn in the future.
I know the easy button is just to charge one car at once, and unless I want to upgrade my house power quite a bit, maybe that's the plan. That said, with EV adoption increasing, I'm assuming that someone has considered there could be more than one EV in the garage at any time.
Thoughts? Rough math? I will reach out to an electrician to do the work, but was hoping for general guidance.
Thanks!
Make sure you drive them first. I have just come off a couple weeks in Teslas for work and they are not what you expect to drive or ride like. I'm sure Keith will chime in on his Model 3 experiences. I have no experience with a Bolt though. But yeah, definitely get some seat time to make sure you can live with one.
You really only need enough power to recharge overnight. The mobile charger that comes with a Tesla tops out at about 32A. You can get chargers that will pump in more juice, but that 32A is enough to add roughly 30 miles of extra range every hour, or around 240 miles for an 8 hour sleep. So while you can probably find a charger that will deliver 80A, it may not actually get you anything useful. This will likely not change much across different EVs unless you get yourself a real electricity hog.
Give yourself a 50A circuit for each and I think you're in a pretty safe place. Remember that these chargers will most likely be pulling most of their load at night when the rest of the house is sleeping, that 250A main panel is referring to peak load.
The Teslas (and probably others, but I only know the Teslas in this regard) do modulate their charging somewhat to match your schedule. Kinda like the latest phones, they'll time the charging and preconditioning to suit your scheduled or typical drive times. You can also tell the car when the off-peak rates are so it will try to only charge during those times - you could use that to prevent both EVs from charging at the same time if that became a problem.
This is not a "which EV should I buy" answer, this is a "how do I prepare for EVs living in my house" answer :)
PMRacing said:
Make sure you drive them first. I have just come off a couple weeks in Teslas for work and they are not what you expect to drive or ride like. I'm sure Keith will chime in on his Model 3 experiences. I have no experience with a Bolt though. But yeah, definitely get some seat time to make sure you can live with one.
Thanks PMRacing. I've been reading Keith's Tesla thread and Tuna55's Bolt thread, but yeah...haven't spent time behind the wheel of either yet. My EV experience is limited to driving a P90D once for a short distance, but didn't get a chance to really get a good sense of it. Given that my current daily drivers are driven by "order of least broken", having something that is more of an appliance is kinda intriguing and might save more time and money for the "fun" cars. That said, I'll be spending a hell of a lot more time in this than I will in the road race Camaro, so definitely need to make sure it's a change I can live with.
I'm already trying to prepare myself for the onslaught of questions from my gearhead friends...."wait, you bought a what?".
In my experience, real gearheads find them interesting.
Not trying to derail this as I'm interested in EV's and expect to own one once I get the rest of my life squared away.
I was casually looking at new Bolts back March or early April and all the new ones had something in the ad that you could reserve it, but not actually buy it then due to some recall. As I'm not ready to buy yet I did not dig into what the recall was. Prices with all the incentives & discounts seemed appealing for the Bolt at that time.
secretariata (Forum Supporter) said:
Not trying to derail this as I'm interested in EV's and expect to own one once I get the rest of my life squared away.
I was casually looking at new Bolts back March or early April and all the new ones had something in the ad that you could reserve it, but not actually buy it then due to some recall. As I'm not ready to buy yet I did not dig into what the recall was. Prices with all the incentives & discounts seemed appealing for the Bolt at that time.
There was a small issue of a few examples of the 2017-2019 Bolts sorta kinda catching on fire just a little bit. Evidently they use the same batteries as in the Kona EV (LG) and there was an issue with batteries made in Korea. At some point in 2019, the Bolts moved to batteries sourced from LG's plant in Michigan and the tendency for them to go en fuego went away. There's now a "permanent fix" introduced for the affected cars, but 2020+ should be good.
At least the Internet says so, and the Internet is never wrong.
In reply to Keith Tanner :
I think the Model 3 would find greater acceptance than the Bolt, purely for the face-melting POWAHHHHH. The Bolt isn't quite as sleek looking as the 3, and is probably more "quick" than fast...fine for the daily grind, and quicker than anything I currently own save the road race car. Ironically, 20 years ago, if you told me I could have an econobox that got the equivalent of all the MPGs and still hit 0-60 in less than 7 seconds, I would've asked for some of what you were smoking. :)
It's been my experience that more of the questions are about the day-to-day things, like charging and what they're like to live with and what it's like on the highway etc. I mean, the "punch it and everyone loses the ability to breathe for a moment" trick is always good, but I'm talking about the parking lot sort of conversation. I think the real game-changer for a lot of people is the fact that they're just always full of fuel when you're parked at home, and that's a bit of a change of mindset.
I ran 8-2 wire with an 80 amp service to the wall between my garage doors for my compressor. Overkill, but I knew I was about to insulate and drywall the garage and that way I'd have the power budget available for when we (or whoever) owns this house ends up with electric cars.
You may be considering the wrong question...
I think the question you should be asking is what is the OTHER electric load on your house during evening hours when the cars will be charging.
You are not adding 120A of load (for the cars) plus 125A of load (for the shop) to your existing 250A load on your existing service. You have a total capacity of 250A around the clock. If your primary heat source fuel is something other than electric, then it is very likely that the load on your house will be minimal while you are sleeping. It is also unlikely that your shop will be operational when your cars are charging.
If you pulled a 125A subpanel for the car chargers, you could also pull an additional 125A subpanel for the shop with no increased load on the service, because the shop and chargers will not run at the same time.
If you DO run into a capacity issue with the 2 cars, there are smart chargers available. They basically charge both cars on the same circuit (at half power), then have the ability to redirect full power to one of the cars when the other is not charging.
You have several options, but what you need to do is determine the actual loads you are drawing around the clock, not the individual combined peak loads.
I have a 100A sub-panel in my garage for a welder, etc. That sub-panel has a 100A breaker in it feeding another sub-panel in my back yard wood shop. Why? Because there is only 1 me, and the wood shop and garage will never be utilized at the same time.
SVreX (Forum Supporter) said:
You may be considering the wrong question...
I think the question you should be asking is what is the OTHER electric load on your house during evening hours when the cars will be charging.
While in theory you can talk yourself into that logic you should really have a chat with a licensed electrician. I doubt hanging 375A worth of load on a 250 panel would meet code. Usually they will give you something like an 80% usage allowance which would mean that you'd need a 300A panel.
I went through this dance when I had the subpanel installed in my garage. I have a 200A service. It was loaded to 160A. The AC has a 60A circuit and the oven has a 30A. I argued that we don't use our oven if its hot enough to have the AC running. It would also be pretty hard for me to simultaneously run the lathe, CNC mill and compressor to their max rated current too. In the end he gave me 10A over the rated current for the panel.
In reply to CAinCA :
"Meet code" and "Make sense" and "Be safe" are not always the same thing.
Signed
-A licensed contractor
In reply to CAinCA :
The correct way is to actually do a measured load calculation.
It is common for the total breakers to add up to more than the main. Often twice as much.
The amperage number on the breaker can be meaningless in many situations. For example, most houses have 15A or 20A lighting circuits. But owners have since converted the fixtures to LEDs and reduced the actual load by 85%. But they never changed the breakers. So the actual circuit load can't ever come close to the breaker capacity.
They also upgraded all the appliances to newer more efficient models, and perhaps even upgraded the HVAC unit to a higher SEER rating. Still didn't swap the breakers or derate them.
Do the math of the actual loads.
In reply to CAinCA :
He's not hanging 375A of load on a 250A panel.
He's hanging 375A of breakers, with a load that never comes close to 250A.
The breakers are simply distribution. They are not load.
I mean, the breakers are really protecting the wiring itself more than whatever is plugged in. 15A breaker with 14ga wire, 20A with 12ga, 30A with 10ga, cuz that's how much those wires can handle continuously for the type of distances you're usually talking about for household stuff. If something at the end shorts out and wants to let the smoke out, better to have said thing burn up then have the wires hidden in the walls heat up, melt, catch fire, and burn the house down.
Note - I'm NOT an electrician, although I've done a lot of home wiring, including a lot that successfully passed inspection, and haven't burned the house down (yet).
In reply to SVreX (Forum Supporter) :
I agree with everything you said.
That said different local authorities may have a different attitude about it.
NorseDave said:
I mean, the breakers are really protecting the wiring itself more than whatever is plugged in. 15A breaker with 14ga wire, 20A with 12ga, 30A with 10ga, cuz that's how much those wires can handle continuously for the type of distances you're usually talking about for household stuff. If something at the end shorts out and wants to let the smoke out, better to have said thing burn up then have the wires hidden in the walls heat up, melt, catch fire, and burn the house down.
Note - I'm NOT an electrician, although I've done a lot of home wiring, including a lot that successfully passed inspection, and haven't burned the house down (yet).
Yeah AC sets the wire on fire while DC kills the component.
I am working on a new building that has 4 electric panels. I just checked, out of curiosity...
The plans as designed by the electrical engineer (in accordance with the National Electrical Code) show the following:
Panel 1: 1200A with 1310A worth of breakers
Panel 2: 400A with 360A worth of breakers
Panel 3: 400A with 990A worth of breakers
Panel 4: 225A with 850A worth of breakers
The breaker rating is not the load.
Keith touched on it far better than anyone else, but I have to ask; why do you think you need the 80A for a charger? 220v Chargers are where the residential side maxes out, anything more than that and you're talking about installing your own Tesla Supercharger at home.
I just checked my new panel that was installed by a licensed electrician, with permits and signed off by the city.
200a panel, 900a worth of breakers 
Wouldn’t the main breaker trip if you are drawing more power than allowed?
Let's say in my case above, I know they did a load calc. and they determined it was ok. But if I were to turn every single thing on, once the draw is higer than 200 amps from the panel, wouldnt the main breaker trip?
Slippery said:
Wouldn’t the main breaker trip if you are drawing more power than allowed?
Let's say in my case above, I know they did a load calc. and they determined it was ok. But if I were to turn every single thing on, once the draw is higer than 200 amps from the panel, wouldnt the main breaker trip?
It's supposed to. If that fails, listen for smoke detectors. :)
In reply to GIRTHQUAKE :
Thanks Girthquake. Admittedly, my Google Fu is weak and more investigation is required, but this is one article I found mentioning "up to 80 amps". I had a subpanel with 50A breaker in my old garage that my Dad was able to charge his Model S off of and it seemed to work well...and as Keith mentioned, if it charges overnight, do I care if it takes 6 hours or 8 hours, as long as Mrs Rotaryracer is topped off in the morning? :)
How many amps is a Tesla charger? (theelectricconnection.com)
The level 2 charge is a 240V outlet installed by a professional electrician as a dedicated home EVSE. It has the capacity to power tough power-hungry machines like your dryer. This charge is more powerful than the previous option and delivers on up to 80 amps. This translates to anywhere between 9-52 miles of Tesla range per hour charging.
