I am thinking of purchasing the Tesla Wall Charger for my Model 3. It says it delivers up to 48 amps. I think ideally a 60-amp breaker would work best. But I live in a condo so the installation is crazy expensive. In order to cut costs, would I be making a big mistake by installing a 40-amp breaker? I would be charging in the overnight hours so I don't need the charging to be fast. The wiring used would be for 8-AWG which costs less than 6-AWG. Any thoughts would be greatly appreciated.
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Tesla Wall Charging
- Thread starter Taikos
- Start date
No reason you have to install a 60 amp breaker for the wall connector. Install what meets your needs. If you install a 40 amp breaker, you’ll get 32 amps to the car and get 30 miles per hour. For most people, 30 miles an hour is plenty.
I had a 30 amp outlet and just used the mobile connector for 2 years to charge my Model S. I only got 18 miles per hour, but it met my needs. I installed a wall charger on a 50 amp breaker once I picked up a Model Y.
No need to install 60 amps unless you really need it. It’s just a waste of money if you don’t need it.
I had a 30 amp outlet and just used the mobile connector for 2 years to charge my Model S. I only got 18 miles per hour, but it met my needs. I installed a wall charger on a 50 amp breaker once I picked up a Model Y.
No need to install 60 amps unless you really need it. It’s just a waste of money if you don’t need it.
No, you would not be making a mistake at all to consider that. Any sort of 240V charging is good, and even 20 or 30amp is supported by the wall connector, and would likely be enough to charge overnight.
One thing that people tend to do that drives the cost of these installs up is to ask an electrician "Whats it going to take for me to get a 60amp breaker in here for my new EV?", and the answer to that could be $ or $$ or $$$ or even $$$$$$$$$$$.
Instead, a better question is "What does a load calculation show I can add as far as a 240V circuit that I want to use for charging an EV?"
fholbert
Active Member
Short answer no. The chart below should help. At 240v/40a you'll add 30 miles of range an hour.
Keep in mind, you'll want to charge during off peak.
Thanks! I'm going to need approximately 200 feet of cable so buying a smaller diameter of wire would be a substantial savings.
fholbert
Active Member
Wow, a 200’ run may require a larger diameter cable. I’ll let the licensed electricians respond to that.
Assuming the overall price of installing a charger is $4k plus the cost if electricity. What’s the pay back on installing a wall charger vs using a Super Charger?
That's exactly where I was going with this... you can't run 8AWG wire over 152 ft. Even 6AWG will only get you 188 ft, so you're looking at 4AWG as a default. You'll definitely want to do a break-even analysis between the cost to do this (and then your electric rate) vs just building in a SuperCharger visit as needed to keep your car in the 20% to 90% battery range.
That’s the beauty of using a 40A breaker and only charging at 32A. 8 gauge can support up to 50A, so you are already dropping the amps significantly from what the wire normally can support. So, makes sense to me to use 8 gauge at 40A for a long run like that.
And no, you don’t want to rely on Superchargers if you can at all avoid it. Cost, convenience, etc.
fholbert
Active Member
Don't know who's right, but you guys crack me up.
- FWIW, a friend of mine has owned a MS since new, gets free super charging and that's all he uses.
- Another friend has a 2 yo model Y, he charges with a 110v 20a which meets his needs.
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Thanks guys for the very valuable information. I'll be sure to discuss all these issues with my electrician when the time comes. And no wonder he is proposing a 50-amp breaker! I think I'd better listen to him.
Yes, I want to see if I can install a 40-amp breaker instead of a 50-amp. But from what I'm hearing, the 200 feet distance might not be feasible for 8-AWG wiring. Maybe that's why the initial proposal from my electrician is calling for a 50-amp breaker.
That's why I'm confused. You normally would use 8 gauge for both 40A and 50A breakers, assuming you use conduit and are pulling wires (which you would do in a condo garage situation).
Now for a 200' run, you'd want to use smaller gauge than "normal" and indeed the proper way to do it is to use the Southwire voltage drop calculator (Voltage Drop Calculator | Southwire).
So let's see, for a 40A breaker, 32A charging, the calculator says you'd need 6 gauge.
You'd be able to use 8 gauge if you charged at 24A which might be fine for you.
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