Wall charger install issue HELP!

[MidnightPerfAZ]

So bummed. Im handy but not with electrical work so i dont have much detail here and i couldnt find a similar thread surprisingly. I had an electrical company approved on Teslas website come out this morning to install the wall charger i bought from Tesla.

they told me that my breaker box panel is only 150amps which is ‘not enough’. They also told me after calculating a ‘load calculation’ that my breaker box has 146 of the 150 used.

this drives me nuts because i have a newish townhouse with a ‘Premium builder’ and they put this crap in here.

the electrician is basically quoting me $3500 to put a 200 amp box in.

anyone run into this issue? Is there a simpler known fix? Does the local electrical company do anything about this? Is there maybe a non tesla brand wall charger that works? Any info or direction would be appreciated as i dont know much and dont want to just rely on whatever this electrician tells me.

Thanks

 

[Sophias_dad]

They probably didn't do a load calculation for real. You can do one yourself and see what you come up with. Its possible that 150 amps is already near the limit, but unlikely.... You might not be able to get the full 48 amps from the HPWC....

IIRC, there are two ways to do the calculation...here's the site I used for my math...

Residential Service Calculations in the National Electrical Code - IAEI News magazine

 

[davewill]

Sounds a little suspicious. I would think the 150a would be plenty for a townhouse. You don't just add up the breakers in the panel. You add up the actual appliances plus an amount for lighting and general use that's dependent on square footage. Do you have any unusual electric appliances?

If you have truly maxed out your panel, there's a box that cuts off the car if the house pulls too much current:

DCC Electric – Simplifying Electric Vehicle Charging In Condos

They're not cheap, but it is a solution.

 

[Fossil Fool]

I'm in Tempe and have two Tesla wall mounts if you want to visit and see my electrical set up. I have 100amps on one line and 80amps on the other one. I did have to install a 100amp box, only because my original panel was full.

 

[Webeevdrivers]

Something doesn’t sound right. We have a townhouse with a 100 amp service. The electrician did his calculation and was able to add two 240 amp EVSE’s consisting of.

A 14-50 receptacle with a 40 amp Juicebox EVSE connected to it.

A hardwired 15 amp 240 circuit with a 12 amp clipper creek EVSE.

Mind you our heat and water heater are both natural gas. Electric stove and central air though. Is your heat and hot water electric?

 

[powaking]

This sounds a little fishy, as if once he knew you wanted a Tesla HPWC installed he was seeing $$$. Can you provide a photo of your panel (with the circuit breakers) and a list of appliances that you have (stove, number of fridges, water heater type and furnace). I have a 100amp service with 50amp breaker for my HPWC. I do have gas furnace/water heater/stove. My only larger energy use besides the HPWC is the fridge and mini freezer and even in the summer with 3 AC window units I can charge the car (I usually drop it down to 20amps at that time). So having a 150amp service I can’t see why you couldn’t put the HPWC even on a 40amp breaker (or smaller).

 

[RonAz]

Do you have any gas appliances? If you do then this calculation might not be correct.
I am supplied by SRP and they have a reduced rate from 11:00 pm to 5:00 am for EV charging. During these hours I have a very small amount of other demands. I see this as a time of use application, not a total load application. Sure someone could plug in the Tesla, walk around the house and turn on everything electric and overload the panel. That's why panels have breakers. I don't see that as a reason to not charge my car at night when I am asleep.
If you have an electric dryer plug you can use your mobil connector on it for a good overnight charge. I did this for months when I got my car. 30 amps is 30 amps.

 

[animorph]

We just barely fit a 100A HPWC circuit (with two HPWC's) within our 200A limit according to our load calc. We have mostly gas appliances, and a 4000sf two story house with upgraded insulation.

Go ahead and get a couple more quotes and see what they say. There's some slop in the calculations. The HPWC is flexible enough to be dialed down to whatever amps are available.

 

[Chisale]

I agree with what everybody else is saying. Get somebody else in there for a 2nd opinion. Unless you have a hot tub AND a tankless electrical water heater or some other combination of very high wattage appliances then you'll be fine. They may have just done a square footage calculation which means nothing. Or they're just trying to upsell you. Worst case scenario you have to go with a sub 40A service that is still sufficient for many owners needs.

 

[Sophias_dad]

I should add that $3500 seems pretty high for a panel replacement, unless they need to run a new feed line or somesuch. If a significant portion of that is for adding a far away high amp HPWC, maybe its more reasonable. It also might be impossible or difficult to get 200 amp service there, depending on the utility and distribution situation.

 

[srs5694]

they told me that my breaker box panel is only 150amps which is ‘not enough’. They also told me after calculating a ‘load calculation’ that my breaker box has 146 of the 150 used.

In addition to what others have said, note that Tesla's Wall Connector can be set to deliver anywhere from 16A (IIRC) to 80A (again, IIRC). These are both to-the-car figures, which are 80% of the rated capacity of the circuit, so that'd be 20A to 100A in breaker sizes, and wiring to match. If the electrician was assuming setting the device to its maximum value, then few homes would have the capacity to spare without a bigger breaker box and service inlet. You don't say what Model 3 variant you have, but the SR/SR+ and MR both max out at 32A (so a 40A circuit), and the LR variants top out at 48A (so a 60A circuit). You can go lower than this with any of these vehicles, though. If you find that your current electrical needs consume, say, 120A, leaving only 30A free, you could always set your Wall Connector to provide 24A. You'll charge a little more slowly than you would if you had more capacity, but that's probably an acceptable compromise to save $3500.

I should add that $3500 seems pretty high for a panel replacement, unless they need to run a new feed line or somesuch.

I'd assume that's exactly what's involved. If the residence is fed by a 150A line from the utility pole, then that would need to be replaced to upgrade to 200A. I needed to have this done when I had my solar panels installed, both because I wanted to upgrade from 100A to 200A service and because the installer was nervous about the condition of the existing 100A feed. That said, I don't know what sizes of feed lines are available. If there's no such thing as a 150A feed line, then the residence likely has a 200A feed line and a 150A breaker box.

One more twist: As this is a townhouse, it may have a 208v feed, rather than 240v. I don't know how this would affect load calculations or whatnot. One practical consequence is that the charge rate, in kW or miles of charge per hour, will be lower than on a typical 240v residential configuration. This may be important if @MidnightPerfAZ is looking for some charge rate in miles of charge per hour.

 

[MidnightPerfAZ]

Hey guys, thanks for all the input. Greatly appreciated. Most of it is jibberish however. I took some pics below of the electrical box and the load calc done by the Tesla approved electrician. Based on load calc methods mentioned above and on internet, this seems to make some sense to me. Any thoughts?

 

[user212_nr]

Hey guys, thanks for all the input. Greatly appreciated. Most of it is jibberish however. I took some pics below of the electrical box and the load calc done by the Tesla approved electrician. Based on load calc methods mentioned above and on internet, this seems to make some sense to me. Any thoughts?

100+60+60+70+100+20*100+15*6 = 2480 amps @120, 1240 @240 if you add all the breakers together.

If you assume that the lights and the outlets are 0 and count only the large appliances at their breakers, that's 195 amps.

Maybe you can install a new panel and new service, just for the garage. Won't save any money, but you'll have room to grow.

 

[ZOMGVTEK]

If thats 150A service, it is a little light to be adding a wall connector at 48A. It would work, but in a worst case with the car charging while the A/C is running, water heater heating, dryer running, and stuff on the range, its undersized. I don't know your specific install so its hard to say the complexity to move to 200A service. Moving to a gas range or water heater would be sufficient though if thats possible. Or dial the wall connector in at ~20ish amps @ 240. That service was sized to be sufficient for the loads when it was built. 200A service barely costs more to put in when new, but more is more so its not done often enough.

Adding the breakers together isn't how a load calculation is done, and i'm getting 340A.

 

[msm859]

Hey guys, thanks for all the input. Greatly appreciated. Most of it is jibberish however. I took some pics below of the electrical box and the load calc done by the Tesla approved electrician. Based on load calc methods mentioned above and on internet, this seems to make some sense to me. Any thoughts?

I would get a second opinion. It is not a matter of simply adding up breakers - with gas you add up all the potential loads, not with electricity. Further, the reality is you are going to be charging at night - cheapest rates and Not when you would be using cooktop, oven, microwave etc. i.e. heavy load items.

 

[user212_nr]

Further, the reality is you are going to be charging at night

He can charge whenever he likes. Quite the opposite, he may come home from work and plug in while the range and the microwave are running.

 

[MidnightPerfAZ]

Yeah unfortunately i have no gas appliances and Teslas website suggests 60amp breaker for performance 3 charging. I would probably primarily charge at night of course but it may also be worth noting that i live in AZ and during the summer the AC definitely runs at night!

 

[Big Earl]

Yeah unfortunately i have no gas appliances and Teslas website suggests 60amp breaker for performance 3 charging. I would probably primarily charge at night of course but it may also be worth noting that i live in AZ and during the summer the AC definitely runs at night!

Just because a Tesla suggests 60 amps doesn’t mean you need to install 60 amps. Most people would be just fine charging on a 30 amp circuit overnight. 30 amp circuit (dryer plug, for example) will support 24 amps of load, which is good for about 22 miles of range per hour. Based on your setup, I would recommend not using the range and the dryer together while charging.

 

[srs5694]

Just because a Tesla suggests 60 amps doesn’t mean you need to install 60 amps. Most people would be just fine charging on a 30 amp circuit overnight. 30 amp circuit (dryer plug, for example) will support 24 amps of load, which is good for about 22 miles of range per hour. Based on your setup, I would recommend not using the range and the dryer together while charging.

+1 on this.

The reason Tesla suggests a 60A circuit (I presume) is that this produces a 48A (60A * 0.8, which is required by US electrical code) charge rate to the car, which is the maximum that the Model 3 LR varieties can handle. (Note that the SR/SR+/MR varieties max out at 32A charging.) There's no technical requirement that you charge at the car's maximum rate. The main disadvantage to charging at a lower rate is that it'll take longer; in particular, charging at a slower rate will not harm the car in any way. (In theory, charging faster may be a little more efficient because the car will stay awake less, but that's a pretty small effect.) A 48A to-the-car connection will regenerate about 45 miles of range per hour. If you use a 30A circuit, for 24A charging, it'll get the 22 miles of range per hour that Big Earl notes. In most cases, that's plenty fast. Even if you arrive home from a road trip with next to no charge and need to leave six hours later for work, you'd have 132 miles of range when you leave at that rate. The next morning, you'd probably be back to your "full" (80-90% -- whatever you set as your daily limit) charge. If the choice is between making do with a 30A circuit and paying $3500 to put in 200A service, I think I'd opt for the 30A circuit.

FWIW, I have a LR RWD Model 3, and I charge with a Clipper Creek HCS-40, which provides 32A to my car. I bought the Clipper Creek for use with a Chevy Volt that I drove before buying my Model 3. The Clipper Creek was over-sized for the Volt, but it's "under-sized" for my Model 3. I've owned the Model 3 for just under 8 months, and I have yet to come close to wanting, much less needing, a faster charge rate, so I'm keeping my Clipper Creek rather than wasting $500 (plus installation) to upgrade to a Tesla Wall Connector.

IMHO, the biggest advantages to faster at-home charging relate to people who need to charge multiple vehicles off of one EVSE or to those who frequently put many miles on the car in a single day (those who take frequent road trips, say). With an LR Model 3, you have enough range to spare that it probably won't be a big deal if you can't fully charge after returning from a road trip once or twice a year.

 

[woodguyatl]

Deleted.