Building new garage- 100amp or 200amp service

[richkae]

After 6 years and 75000 miles of EV ownership I have never arrived at home with an empty battery and needed to charge it to full as fast as possible so I could drive off again. I've almost never *needed* to charge at anything more than 24 amps or so at home ( enough to refill overnight ).
I have discovered a few times that my wife hasn't plugged her car in for days and that the battery is low. Then I wanted to charge faster.

Nor do I believe there will be home EVSEs of greater than 80 amps anytime in the near future. I don't believe there will be a market for a car with an onboard charger big enough to need that, and installing it in most homes will be impractical.

Still I would absolutely pay the $350 for 200 amp service. Having multiple EVs, or multiple guests with EVs, and needing to charge them simultaneously is increasingly likely.
It is very inexpensive future proofing.

 

[jcaspar]

For that price, go 200Amp. Also, if you are sheet rocking the walls, think about all the locations you could possibly need outlets. This can avoid having to string tons of ugly conduit all over the walls which is what most electricians want to do because it is cheap and easy.

 

[brucet999]

Building an oversized one car garage. We are running dedicated service to then garage - it is $350 more to do 20amp service vs 100amp.

My ride doesn't have duals chargers, but I want to leave that option open. If we do 100amp service, can we run a 100amp circuit to an HPWC? Should we pay the extra just to be safe/have flexibility down the line? I don't foresee needing more capacity than 100amp, but who knows (our house was constructed in 1922 before the need for central air was conceived for example).

It is only a one car garage and there isn't much of a driveway (alley) so us having an second EV plugged in regularly is unlikely. However, I want to see if I can provide a secondary outlet on the outside of the garage for someone to use if they are in a pinch. That would be a NEMA 14-50 and I'd shut it off at the panel if I didn't want people using it. I really don't know how I can pull this off with the garage layout, but I want to be a good citizen. It really wouldn't cost much to put it in.

Inside, I have to decide on the HPWC vs NEMA 14-50. I guess I will do the latter and see if it is annoying to not have the convenience of a HPWC.

Why not 150A panel? That would enable dual-charging a Tesla and NEMA 14-50 charging another vehicle or operating power tools while charging.

You did not say, but is the dedicated service designated as EV charging only with its own meter from the PoCo at a special rate? If so, you may not want other outlets on the system. If it is a sub panel off the house meter, then you are limited by the capacity of the hose service panel.

 

[jerry33]

Why not 150A panel?

I thought that too. Then when I needed more than 150 amps, I had to rip the 150 out an put in a 200. It would have been better to do the 200 in first place (by a couple of thousand). Put in as much as you can afford, you won't regret doing so.

 

[ibxspeedracer]

ibxspeedracer - will you share some more details on your install and how this is fed into your system? Any diagrams/brands/models/costs that you are willing to share would be appreciated - private message is fine.

chriSharek - this is new service for the garage, completely independent of the service to the house.

...tmc2015: i will try you on direct messaging basis...

Choosing charging capacities is subjective and a derivative of our personal economics in conjunction with practical and personal preference(s) in convenience and excess capacity. My preference is predicated on the fact that most of us are early adopters, technology enthusiasts, driving $125k+ cars so spending a few hundred to even a few thousand dollars more on this investment, specially since the $ spent can have many additional other advantages, made it a no brainer for me to having done all I did.

 

[m6bigdog]

Complete install included: a 14kW solar panel system along with upgrading main panel from a 200amp to a 400AMP (required utility company to bring a new feed from the street into my main panel); added a new 150amp sub-panel branched off my new 400amp main panel off into the garage where a dedicated 100amp breakers is now alloted to the HPWC for my dual charger MS while the other 50amp shared between spare a 14-50 and a 10-30 for future/alternative use. Future proof, making charging MS as fast as possible (short of a SC, of course), scalable to provide aboundant power to charge 1-2 more EV's, and still keeping the utility's power used to a minimum, this has been pricey commitment but the best way...and very happy with my investment.

+1,
Yeah Baby!! 14kw Solar!! that makes electricity inexpensive for sure. I have a 8.5 kWac system and my electricity typically cost me $4-5 a month and that is the grid hookup cost.

With EV charging it is also good to install dual meters on an upgraded service entrance; one meter/disconnect for EV charging to get a better rate and a meter/disconnect for the residence.

That is what I'm talking about - however most would object to hanging the large 400 amp meter/disconnect equipment on the side of their house.

Soon we must all take personal responsibility for EV charging, solar power generation and residential battery storage systems to ensure the slow growth rate of the public utility power grid remains viable to handle what will be a huge increase in the growth to EV's as every EV added will impact the grid to the tune if 10-15kWh a day and hopefully most of that will be during non Peak overnight electrical use periods. However, I can see the day when my nightly electrical usage charging EVs will exceed the remainder of the homes daily electrical use.

 

[dsm363]

Agree. Minimal cost to do it now vs a lot more in future. Could always run a second NEMA 14-50 to second garage spot as well.

 

[jerry33]

Soon we must all take personal responsibility for EV charging, solar power generation and residential battery storage systems to ensure the slow growth rate of the public utility power grid remains viable to handle what will be a huge increase in the growth to EV's as every EV added will impact the grid to the tune if 10-15kWh a day and hopefully most of that will be during non Peak overnight electrical use periods.

My understanding is that at least 50% of the fleet (not just the new car fleet, but every car out there) would have to be electric before a problem would begin to arise because of the excess overnight capacity that already exists. (Assumes most EVs charge at night.) Even in the best case situation, that won't happen for many years.

 

[CHG-ON]

Without a doubt, 200Amp.

 

[tmc2015]

Am I reading into some of the language here or is there a different rate from the utility company for EV charging? I guess it depends on the company, but I didn't see anything when I googled - maybe I was using the wrong key words. I also saw something in the forum about a tax incentive for installing EV charging equipment, but I didn't find anything specific when googling. Maybe I just suck at googling.

Is is there anything we need to do during this install to facilitate the addition of solar panels in the future?

 

[kuttakamina]

Am I reading into some of the language here or is there a different rate from the utility company for EV charging? I guess it depends on the company, but I didn't see anything when I googled - maybe I was using the wrong key words. I also saw something in the forum about a tax incentive for installing EV charging equipment, but I didn't find anything specific when googling. Maybe I just suck at googling.

Is is there anything we need to do during this install to facilitate the addition of solar panels in the future?

Utility company - very location speciific, call your utility company, and look for other utility companies in your area. I did not have any serious benefits going offpeak.
Tax incentive for EV charging - dependent upon state. You'll have to check your state laws.
Solar panels - AFAIK, you connect solar to your house, and it powers everything, including your car. You can add a battery as well, most people do, to get the max benefit out of solar.
I will be adding solar cells to my house, I've spec'ed out a 5KW panel for about 10K. But only so many "projects" I can juggle at once.

 

[Kbsilver]

Why not split the difference and run a 150 to the 1-car garage? That should provide plenty to an HPWC if you need the full 100 amps and then have some for your outlets, lights, saws, etc.

The bigger question should be - what is the service running to the property? Mine is only a 150, so running a 100 amp sub-panel service for my HPWC didn't make sense (plus the fact that I'm not getting the dual chargers).....

Same position as I am in which may be common in some areas with a house that has gas service. I also only have 150 amp main service. With all underground wiring and the transformer across the street, upgrading would cost almost as much as the car. My single largest electrical load is the A/C system of about 25 amps. I ran some worksheets and came up I could safely run a 70 amp service for car charging. So if I were to be a Tesla owner, my plan would be to run #2 or #3 (100 amp capable) to a sub panel in the garage but connect to a 70 amp breaker. Wire is oversized to minimize voltage drop (about a 75' run). If I were to get dual charges it would only be for destination charging, is never needed at home.