Which electrical charger installation proposals should I pick?

[twoblackdogs]

Hi all, I live in Chicago and am looking for electricians to install a 240V outlet in my detached garage for a Model Y expected at EOY. I got several proposals and eliminated them to two of the ideal ones. I know nothing about electricity so I am looking for some advice on which one to pick:

Background: Total 100 AMP with limited to no extra spaces in the panel.

First Proposal: $1,500 for a panel swap with a new Siemens 100 AMP, 32-space panel, and $2,500 for the power brought to the garage via underground pipe. Total: $4,000

Second Proposal: Install a new sub-panel and power brought to the garage through the roof. Total: $3,352

Based on my research, I should choose the second proposal because it is safer and cheaper to install a sub-panel; however, I do have a problem with my current panel where occasionally my lights dim or flash during the winter when my furnace is on, so I am debating on the first proposal as well. Can someone please give me some suggestions?

 

[Corndart]

Your electrician should be providing you with load calculation information. If you're already experiencing light "dimming" with the furnace cycling, how is going from an existing 100a panel to a new 100a panel with more breakers going to solve that issue? The means by which you get the wall connector powered seem a lot less important than solving a more fundamental issue, which I'd 100% do before introducing an EV into the mix...

 

[ATPMSD]

Totally agree with @Corndart, you have a much bigger problem. To begin with a 100-amp service panel is marginal for adding an EV outlet and the fact that you are see “dimming” indicates it is not sufficient to power what you have. You can upgrade to a 150- or 200-amp service but this involves the Utility company and is a big ticket request, say $5-10K and sometimes more.

 

[twoblackdogs]

Your electrician should be providing you with load calculation information. If you're already experiencing light "dimming" with the furnace cycling, how is going from an existing 100a panel to a new 100a panel with more breakers going to solve that issue? The means by which you get the wall connector powered seem a lot less important than solving a more fundamental issue, which I'd 100% do before introducing an EV into the mix...

@ATPMSD Got it. Thank you so much for bringing up the load calculation. Let me reach out to the electricians to see if they can provide me with that information. The electrician who gave me the first proposal said that I don't need to upgrade to a 200 AMP in order to install a 50AMP breaker. The things he did was look at my panel, and then asked me briefly whether my washer/dryer and stove are using electricity, to which I responded with no to all questions. Does that consider a load calculation?

Also, if it happens that I cannot install a 50AMP charger, should I give up on my Model Y? I feel like upgrading it to 150-200 amp services is quite expensive.

 

[jcanoe]

You don't "need" a 50 amp charging circuit. Many Tesla owners use a 30 amp dryer circuit or even a 20 amp circuit. As long as you have 6 or more overnight hours to charge each evening then you will be fine. (The Tesla vehicle does not perform any differently whether charged at 3 miles per hour charging rate or at a 30 miles per hour charging rate.)

The typical vehicle owner drives 30 miles per day. How many miles per day do you drive?

240 Volt charging, amperage *:

20 amp circuit adds up to 14 miles per hour while charging
30 amp circuit adds up to 21 miles per hour
40 amp circuit adds up to 29 miles per hour
50 amp circuit adds up to 36 miles per hour

* Charging amperage is always limited to 80% of the rated circuit amperage.

 

[ATPMSD]

no extra spaces in the panel.

BTW, there are ways of making room in a “full” breaker box, such as by using Tandem Breakers

Search Results for tandem circuit breaker at The Home Depot

Search Results for tandem circuit breaker at The Home Depot

www.homedepot.com

 

[twoblackdogs]

You don't "need" a 50 amp charging circuit. Many Tesla owners use a 30 amp dryer circuit or even a 20 amp circuit. As long as you have 6 or more overnight hours to charge each evening then you will be fine. (The Tesla vehicle does not perform any differently whether charged at 3 miles per hour charging rate or at a 30 miles per hour charging rate.)

The typical vehicle owner drives 30 miles per day. How many miles per day do you drive?

240 Volt charging, amperage *:

20 amp circuit adds up to 14 miles per hour while charging
30 amp circuit adds up to 21 miles per hour
40 amp circuit adds up to 29 miles per hour
50 amp circuit adds up to 36 miles per hour

* Charging amperage is always limited to 80% of the rated circuit amperage.

Hey @jcanoe, thank you so much for the information! This gives me a lot of confidence. I rarely drive; in fact, Model Y is my first vehicle. On average I drive about 20-40 miles a day and 60 miles at most.

 

[jcanoe]

Hey @jcanoe, thank you so much for the information! This gives me a lot of confidence. I rarely drive; in fact, Model Y is my first vehicle. On average I drive about 20-40 miles a day and 60 miles at most.

Look into getting the Tesla Wall Connector as it has a longer charging cord (24 ft) and can be configured for any circuit from 15 amps up to and including 60 amps. There are probably quite a few Wall Connectors that are provisioned on 30 amp circuits. The Wall Connector is designed to be hard wired into the circuit so there is no plug or receptacle. This means you can have the electrician install 2 wires (plus the ground wire) insread of 3 wires as would be needed for the receptacle (saves you a little money.)

 

[andy00778]

Your lights dimming on the existing panel is immediate concern. You didn’t specify what type of furnace ( gas, electric?) but in any case it’s an indicator of a loose connection or possibly a bad breaker. This should be checked into no matter what option you take.

 

[SkyDog]

I agree with others, that the lights dimming needs to be investigated. But just fyi, I have 100 amp service to my house, I had a Wall Connector installed on a 40 amp breaker and it's working great - the car charges more than fast enough, and it hasn't caused any problems in the house, like lights dimming or anything. Hopefully you can do the same, but it really depends on your own situation.

Also fyi, I had similar options presented to me: add a sub-panel to my detached garage, or else run a line directly from the main panel to the wall charger. I went with getting a sub panel added to my garage because I felt that it gives more flexibility. If the next owner of this house wants to do something else with the garage, the circuits off of the sub panel could be changed easily.

 

[240vPlug]

Lots of good suggestions here. You need a proper load calculation done. As others have stated you don't have to use the maximum charging rate.

A 30 amp circuit would allow you to charge at 24 amps which is half speed on a Tesla wall connector which maxes out at 48 amps on a 60 amp breaker.

If upgrading to 200 amp service is not an option this sounds like the best plan provided of course your not overloading it. Dimming lights are a concern and should be addressed asap.

With a 100 amp panel you shouldn't be pulling more than 80 amp continuous. A 50 amp charging at 40 amps will use half your available capacity.

I wouldn't give up on the car. Just figure out a temporary solution and budget for upgrading your service to 200 amps in the future.

 

[twoblackdogs]

I agree with others, that the lights dimming needs to be investigated. But just fyi, I have 100 amp service to my house, I had a Wall Connector installed on a 40 amp breaker and it's working great - the car charges more than fast enough, and it hasn't caused any problems in the house, like lights dimming or anything. Hopefully you can do the same, but it really depends on your own situation.

Also fyi, I had similar options presented to me: add a sub-panel to my detached garage, or else run a line directly from the main panel to the wall charger. I went with getting a sub panel added to my garage because I felt that it gives more flexibility. If the next owner of this house wants to do something else with the garage, the circuits off of the sub panel could be changed easily.

Thank you @SkyDog ! I am happy to hear that you make 100 amp service works! I really like the insight into the decision you make. I think my plan moving forward is to have the electrician do a proper load calculation, and if they said it's fine, then I may as well go with the second proposal on a sub-panel. It is also cheaper too!

 

[twoblackdogs]

Lots of good suggestions here. You need a proper load calculation done. As others have stated you don't have to use the maximum charging rate.

A 30 amp circuit would allow you to charge at 24 amps which is half speed on a Tesla wall connector which maxes out at 48 amps on a 60 amp breaker.

If upgrading to 200 amp service is not an option this sounds like the best plan provided of course your not overloading it. Dimming lights are a concern and should be addressed asap.

With a 100 amp panel you shouldn't be pulling more than 80 amp continuous. A 50 amp charging at 40 amps will use half your available capacity.

I wouldn't give up on the car. Just figure out a temporary solution and budget for upgrading your service to 200 amps in the future.

Thanks @240vPlug ! I bought the mobile connector from Tesla and plan on using that on a 240V outlet. Without using the wall connector, can you still choose how many amps to charge per hour? Or is this only available via the wall connector?

 

[twoblackdogs]

Your lights dimming on the existing panel is immediate concern. You didn’t specify what type of furnace ( gas, electric?) but in any case it’s an indicator of a loose connection or possibly a bad breaker. This should be checked into no matter what option you take.

Definitely @andy00778 . I will have an electrician do a proper load calculation! Thanks!

 

[twoblackdogs]

Look into getting the Tesla Wall Connector as it has a longer charging cord (24 ft) and can be configured for any circuit from 15 amps up to and including 60 amps. There are probably quite a few Wall Connectors that are provisioned on 30 amp circuits. The Wall Connector is designed to be hard wired into the circuit so there is no plug or receptacle. This means you can have the electrician install 2 wires (plus the ground wire) insread of 3 wires as would be needed for the receptacle (saves you a little money.)

Got it. I bought the mobile connector a month ago since Tesla no longer supplies them on delivery. Can the mobile connector allow you to configure how much amp to use for charging?

 

[brkaus]

Got it. I bought the mobile connector a month ago since Tesla no longer supplies them on delivery. Can the mobile connector allow you to configure how much amp to use for charging?

You configure it by purchasing a plug that matches the outlet you have installed. For example, if you have a 14-30 installed you purchase the matching plug.

 

[ATPMSD]

bought the mobile connector a month ago

I would still consider installing a Wall Connector and leave the Mobile Connector in the car. For the mobile connector you will have to spend an additional $45 for the correct adapter, $150+ for a GFIC breaker and let’s say $35 for some sort of cable management system. The Wall Connector is $400 plus $15 for a standard breaker, so the Wall Connector is about $185 more.

 

[dhrivnak]

Can you reduce any loads? If you have an electric hot water heater get a Heat Pump water heater that uses 1/4 the power. If you have any incandescent lights or even fluorescent ones swap to LED. If you have an older heat pump, look at a new inverter driven one. Finally if your panel is old sometimes breakers and bus bars can gain corrosion and a new panel will fix that IF that is your problem.

I am also a fan of NEMA 14-50 or even a 14-30 in the garage as it can easily support other needs. And even a NEMA 14-50 can be set to charge at 20 amps as you make the setting change once in the car and it remembers. I usually dial mine back to 22 amps to better match my solar output.

 

[jcanoe]

Thanks @240vPlug ! I bought the mobile connector from Tesla and plan on using that on a 240V outlet. Without using the wall connector, can you still choose how many amps to charge per hour? Or is this only available via the wall connector?

You can set the maximum charging amperage from the Tesla charging screen or the Tesla phone app. You can't exceed the maximum for the charging circuit as communicated to the Mobile Connector via the power plug adapter. I.e. the 14-50 power plug adapter enables 32 amp maximum; the 14-30 power plug adapter enables 24 amp maximum. The Tesla charging session will default to the maximum for the charging circuit or the Mobile Connector plug. You can reduce the charging amperage or leave at the maximum, i.e. 32 amps.

 

[jcanoe]

Got it. I bought the mobile connector a month ago since Tesla no longer supplies them on delivery. Can the mobile connector allow you to configure how much amp to use for charging?

Keep the Mobile Connector for travel or sell it. Instead of relying on the Mobile Connector for daily use install the Wall Connector at home.