Tesla charger

JDB3 said:
Thanks for all of the comments. As this is an older house (big house, don't know square footage), with a 200 amp service, I'm starting to wonder about the service size? Best that I remember, it has 2 electric water heaters, electric range & dryer, electric furnace (older one), etc. What do you'll think ?? Thanks, again !
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Not sure about the furnace but the other loads you mentioned typically add up to between about 84 and 100A. And it's unlikely they all run simultaneously and the code doesn't strictly require the service to allow them to. Lighting and electronics are rarely very much. So if the electric furnace isn't more than 48A itself, and there's nothing else you left out, it should all be just fine.
 
To the OP...

Apologies in advance if you know everything below...

If you or the client is at all nervous about the long term impact of the 48A Tesla EVSE to the existing service, you can of course easily use it at less than the "Full Beans" 48A.

You indicate an existing customer and what I assume might be the purchase of a first Electric Vehicle? If so, maybe they are unaware of some of the details concerning vehicle charging. And they might be thankful for any education / guidance you can provide?

Lets assume this EV gets 3.5 miles per khw. That's likely a little low for a new Tesla 3 or Tesla Y, but lets also be pessimistic on purpose.

At 240 VAC and 48A, that's 11.5 KW (what I consider pretty substantial for L2 home charging). That charging rate would put back ~40 miles in the battery for every hour of charging.

The average daily commute in the US is going to be right around that 40 mile range. So... do they need to replenish an entire days use in about an hour? Likely not. Maybe Texas is more spread out and they travel 100 miles per day, that's still 2.5 hours of charging. Does the car need to be ready again that fast?

Now maybe your client is an Uber or Lyft driver, or maybe a traveling salesperson. Then that use case might be calling for the fastest charge possible at home. But if they are not...

It's a classic case of "Just Because You Can, Doesn't Mean You Have To".

More than likely they would be fine with charging rates from 16A to 24A. For a Tesla, it's all adjustable - even on the fly - from the car or on the phone app. Charging at 16A would put back 100 miles in 8 hours, so easily accomplished overnight.

For the occasional long trip recovery, they can dial it up to 48A assuming you wire it for that. But for everyday "short mileage" charging, there is no need for that rate. The premise's wiring will thank you, as will your local POCO.

And be sure to check with that POCO, many have substantial rebates or discounts for things like off-peak charging. Again, maybe something your client was unaware of.

Good luck and sorry for all the words!!
 
nizak said:
As a 50A breaker is relatively common, I would have to guess that there are a lot of 48A chargers out there being supplied by them.

My thought would be a great deal of these chargers are installed and wired by homeowners with help from a YouTube video.

Just my useless .02 worth.
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Sadly I see a lot of these installed by electricians the same way.
 
Jaybone812 said:
Yes. 625.42 says evse charging loads are continuous loads and 625.41 says the ocpd is factored at 125% of kw rating . Your 50 amp ocpd is not sized correctly for a 48 amp continuous load


Sent from my iPhone using Tapatalk
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I recently looked at one of the 48amp Tesla chargers to see that it only has a 50amp rated plug on it instead of a 60 ampthat you would think it would have to have when considering the continuous load at 125%
 
mopowr steve said:
I recently looked at one of the 48amp Tesla chargers to see that it only has a 50amp rated plug on it instead of a 60 ampthat you would think it would have to have when considering the continuous load at 125%
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Tesla Wall Connectors are designed to be hardwired only. They do not come with cord/plugs.
 
mopowr steve said:
Hmmm,
I guess I’ll have to ask the homeowner that installed it, if he put the cord on it.
Seems odd that he found a ~10’ factory made 50a cord/plu
mopowr steve said:
Hmmm,
I guess I’ll have to ask the homeowner that installed it, if he put the cord on it.
Seems odd that he found a ~10’ factory made 50a cord/plug
Click to expand...
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my prior comment was a typo I meant to just say 50 amp range cord/plug not “4 wire 50 amp range cord/plug” there’s no neutral connection for a tesla wall connector
 
Last edited by a moderator:
MD Automation said:
To the OP...

Apologies in advance if you know everything below...

If you or the client is at all nervous about the long term impact of the 48A Tesla EVSE to the existing service, you can of course easily use it at less than the "Full Beans" 48A.

You indicate an existing customer and what I assume might be the purchase of a first Electric Vehicle? If so, maybe they are unaware of some of the details concerning vehicle charging. And they might be thankful for any education / guidance you can provide?

Lets assume this EV gets 3.5 miles per khw. That's likely a little low for a new Tesla 3 or Tesla Y, but lets also be pessimistic on purpose.

At 240 VAC and 48A, that's 11.5 KW (what I consider pretty substantial for L2 home charging). That charging rate would put back ~40 miles in the battery for every hour of charging.

The average daily commute in the US is going to be right around that 40 mile range. So... do they need to replenish an entire days use in about an hour? Likely not. Maybe Texas is more spread out and they travel 100 miles per day, that's still 2.5 hours of charging. Does the car need to be ready again that fast?

Now maybe your client is an Uber or Lyft driver, or maybe a traveling salesperson. Then that use case might be calling for the fastest charge possible at home. But if they are not...

It's a classic case of "Just Because You Can, Doesn't Mean You Have To".

More than likely they would be fine with charging rates from 16A to 24A. For a Tesla, it's all adjustable - even on the fly - from the car or on the phone app. Charging at 16A would put back 100 miles in 8 hours, so easily accomplished overnight.

For the occasional long trip recovery, they can dial it up to 48A assuming you wire it for that. But for everyday "short mileage" charging, there is no need for that rate. The premise's wiring will thank you, as will your local POCO.

And be sure to check with that POCO, many have substantial rebates or discounts for things like off-peak charging. Again, maybe something your client was unaware of.

Good luck and sorry for all the words!!
Click to expand...
Thanks for the replies. This person makes trips to do photograph work/jobs. He has already mentioned that he would prefer faster charging times. He is married with 2 young children. Furnace might be (best I can recall) 15Kw.
 
MD Automation said:
To the OP...

Apologies in advance if you know everything below...

If you or the client is at all nervous about the long term impact of the 48A Tesla EVSE to the existing service, you can of course easily use it at less than the "Full Beans" 48A.

You indicate an existing customer and what I assume might be the purchase of a first Electric Vehicle? If so, maybe they are unaware of some of the details concerning vehicle charging. And they might be thankful for any education / guidance you can provide?

Lets assume this EV gets 3.5 miles per khw. That's likely a little low for a new Tesla 3 or Tesla Y, but lets also be pessimistic on purpose.

At 240 VAC and 48A, that's 11.5 KW (what I consider pretty substantial for L2 home charging). That charging rate would put back ~40 miles in the battery for every hour of charging.

The average daily commute in the US is going to be right around that 40 mile range. So... do they need to replenish an entire days use in about an hour? Likely not. Maybe Texas is more spread out and they travel 100 miles per day, that's still 2.5 hours of charging. Does the car need to be ready again that fast?

Now maybe your client is an Uber or Lyft driver, or maybe a traveling salesperson. Then that use case might be calling for the fastest charge possible at home. But if they are not...

It's a classic case of "Just Because You Can, Doesn't Mean You Have To".

More than likely they would be fine with charging rates from 16A to 24A. For a Tesla, it's all adjustable - even on the fly - from the car or on the phone app. Charging at 16A would put back 100 miles in 8 hours, so easily accomplished overnight.

For the occasional long trip recovery, they can dial it up to 48A assuming you wire it for that. But for everyday "short mileage" charging, there is no need for that rate. The premise's wiring will thank you, as will your local POCO.

And be sure to check with that POCO, many have substantial rebates or discounts for things like off-peak charging. Again, maybe something your client was unaware of.

Good luck and sorry for all the words!!
Click to expand...
Customer already stated the he wants a faster charging time.
 
jaggedben said:
Not sure about the furnace but the other loads you mentioned typically add up to between about 84 and 100A. And it's unlikely they all run simultaneously and the code doesn't strictly require the service to allow them to. Lighting and electronics are rarely very much. So if the electric furnace isn't more than 48A itself, and there's nothing else you left out, it should all be just fine.
Click to expand...
There have been a number of new homes in the last few years that I would have liked to have installed a 320/400A service on. For a number of different reasons they never got installed ( Scoping document didn’t indicate enough load, meter bases were unavailable at the time, cost prohibitive due to upgrades supposedly needing to be made by the Utility)

On a few jobs that I went back to after the home was occupied for some time I found data on the Smart meter that revealed peak Kw usage was FAR less than a load calculation would have suggested.

If I recall, non of the homes ever saw anything over 25/30Kw

These were homes with detached out buildings, electric ranges, dryers , AC, pool equipment, electric unit heaters in the garage, air compressors, outlets for a welder, etc.

Bottom line is unless you’ve got something like back up strip heat for Geo ( 15-20KW)and all the above I’ve mentioned it’s difficult to overload a 200A service.
 
nizak said:
There have been a number of new homes in the last few years that I would have liked to have installed a 320/400A service on. For a number of different reasons they never got installed ( Scoping document didn’t indicate enough load, meter bases were unavailable at the time, cost prohibitive due to upgrades supposedly needing to be made by the Utility)

On a few jobs that I went back to after the home was occupied for some time I found data on the Smart meter that revealed peak Kw usage was FAR less than a load calculation would have suggested.

If I recall, non of the homes ever saw anything over 25/30Kw

These were homes with detached out buildings, electric ranges, dryers , AC, pool equipment, electric unit heaters in the garage, air compressors, outlets for a welder, etc.

Bottom line is unless you’ve got something like back up strip heat for Geo ( 15-20KW)and all the above I’ve mentioned it’s difficult to overload a 200A service.
Click to expand...
Yup that pretty much accords with my experience as well, generally at lower load levels on average. I have a lot of access to data because our systems are installed with CTs and the app provides 15min interval data. I don't think I've seen a house use more than 20kW, most don't typically use more than 10kw. (There is a rebate program I've worked with that shifts funding categories at 10kW and almost no one qualifies for the over 10kW category based on smart meter data.) Most of those houses are not as loaded as what you describe, but that includes many all-electric 2000 sq ft homes with an EV charger. Point is most homes with a 125-200amp NEC load calc would be fine with a 100A service and most with an over 200A load calc would be fine with 200A or even 125A.
 
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