Max charging amp on 240v60a circuit without wall charger

[doublede]

Unfortunately, it doesn't work that way. You need to get a dedicated EVSE (Juicebox/HPWC). The car needs to 'communicate' to the EVSE for safety, and a piece of wire won't have that, so the car won't start charging.


Yes, you'll need to purchase Juicebox 48 Pro or Tesla Wall Connector.

If you're putting in a brand new 60A (48A continous) circuit in your garage, please consider installing a NEMA 14-60R (recepticle) instead of a 14-50R. The 14-60 outlet is rated for 60A (48A continous) and can be used with the Juicebox Pro 48 or Tesla Wall Connector to get the full 48A of current. You will just need to install a NEMA 14-60P (plug) on the EVSE. Alternatively, you can just hardwire the EVSE to your 60A circuit and forgo the receptacle altogether, but this will mean that you won't be able to unplug it and take it with you (if that matters to you). I doubt many people take their Juicebox/HWPC with them as they're large units with heavy cables.

Some options for the NEMA 14-60R (recepticle):
Leviton
Bryant
Hubbell
Eaton

Some options for the NEMA 14-60P (plug):
Leviton
Hubbell
Eaton

Lastly, you can install a 50A circuit with the NEMA 14-50R as you suggested. However, then you're limiting yourself to only 40A continous, so if I were putting a new circuit, I'd make it 60A to get the full current and to make the installation cost worth it.


That's right. Even though you're using a 14-50 plug which should in theory give 40A continous, the Tesla EVSE that comes with the car is limited to 32A, so the plug is coded to pull no more than 32A.

Thanks for the explanation on the plug that comes with the car..

 

[TomServo]

I get 40 amps (37 mph) from a Clipper Creek EVSE plugged into a NEMA 14-50 outlet.

 

[hill]

........snip.....
The Gen 1 Wall Connector provides up to 80 amps, but no current 'on menu' model can utilize the full current. The ones that can were special ordered with twin on-board chargers, a configuration made obsolete by Superchargers...... snip........

our model X could charge at a Max of 72 amps. both 72 and 80 amp charge rates are nice on multiple accounts. you may get home, be miles away from a supercharger, but need to still get out and about in short order. at 72 amps, though we only use it sporadically comes in handy when you have that situation but less than 50 miles local running around.
equally important, charging at over 20kW (ie - NOT using DC/QC) means we never activate the algorithm that counts supercharging ... ultimately reducing max capability after so-many sessions.

 

[MD-2000]

Just a note - I bought this on Amazon.ca:

General Electric WX09X10037 4-Feet 50-Amp 4 Wire Range Cord​

This allowed me to not have to hard-wire the Gen2 charger directly, I keep the 14-50 plug in my garage. No electrician needed. So if I have a problem with the charger, I can fall back on the portable one that came with the car. And if I every get into using industrial tools, I have a place to plug them in...
Since my circuit is on a 50A breaker (6Ga), max I can do is 40A continuous anyway. (There's a rotary switch in the Gen2 to set max amps - in Gen3 chargers, I think this is set with wifi configuration)
Just, when installing this cable be sure to screw everything down firmly to ensure good connections. With the amount of power flowing, this is very important.

 

[MN-MS100D]

The lugs on the wall connector are not rated for fine stranded wire. Terminations can heat up and go into thermal runaway.

 

[Rocky_H]

Yep, and this is why I cringe when people just think they know better, and they are going to go out and buy some appliance cord, and use it, instead of hardwiring it, like the instructions say. They don't know what they don't know--like appliance cords being extra flexible because they are fine stranded wire, and why that is not appropriate for this device.

 

[PorthosJon]

Personally I have my home charging dialed back to 24 amps for efficiency. It has been more than sufficient. The only time I need faster charging is when on road trips.

Be careful with low & slow. One of the things is that we are talking about very large amperage and the length of the cable both for the charger and to the outlet have loss from resistance. The longer the cable and time of use, the more loss, and that realizes as heat.

I cannot remember where (but I'm sure Google could dredge it up) but I saw the data from someone who tested all the way from a standard 120 Edison Outlet up to a Gen 3 Wall Charger at 48A as to costs. Bottom line is that charging for the same mileage at the standard Edison plug rate (about 4 Miles per hour of charge) ended up costing nearly twice as much in $ because of all the power lost to resistance. The difference between 24A and 48A is less, but it is still appreciable, and over time can have a real impact.

Never discount that pesky 2nd law of thermodynamics, entropy can be a real pain.

 

[nwdiver]

The difference between 24A and 48A is less, but it is still appreciable, and over time can have a real impact.

Never discount that pesky 2nd law of thermodynamics, entropy can be a real pain.

The Equation is (I^2)(R) so 48A generates 4x as much heat as charging at 24A.

 

[Fourdoor]

Be careful with low & slow. One of the things is that we are talking about very large amperage and the length of the cable both for the charger and to the outlet have loss from resistance. The longer the cable and time of use, the more loss, and that realizes as heat.

I cannot remember where (but I'm sure Google could dredge it up) but I saw the data from someone who tested all the way from a standard 120 Edison Outlet up to a Gen 3 Wall Charger at 48A as to costs. Bottom line is that charging for the same mileage at the standard Edison plug rate (about 4 Miles per hour of charge) ended up costing nearly twice as much in $ because of all the power lost to resistance. The difference between 24A and 48A is less, but it is still appreciable, and over time can have a real impact.

Never discount that pesky 2nd law of thermodynamics, entropy can be a real pain.

Isn't the car at least partially awake during charging? I know that for the Bolt, it uses more power to charge on 120v 12 amps than it does on 240V 32 amps because even though the cooling system doesn't have to work hard at a slow charge rate, it does run on a hot summer day fairly often during charging... and charging at 120V 12 amps takes much longer so you end up with much more battery cooling time taking power away from what is actually accomplishing charging so the efficiency is lower compared to faster charging. So, you have less intrinsic efficiency charging at low power, AND you have more vampire load on the car so the cost of low power charging is noticeably worse.

Keith

 

[jcanoe]

It has been a while since I read the information but for the Chevy Volt charging at 120V/12A was ~between 80% and 85% efficient while charging at 240V/16A was ~90% efficient. Over a year, charging at 240V could save you somewhere around $30 assuming that you charge at home.

 

[DonaldBecker]

Be careful with low & slow. One of the things is that we are talking about very large amperage and the length of the cable both for the charger and to the outlet have loss from resistance. The longer the cable and time of use, the more loss, and that realizes as heat.

I cannot remember where (but I'm sure Google could dredge it up) but I saw the data from someone who tested all the way from a standard 120 Edison Outlet up to a Gen 3 Wall Charger at 48A as to costs. Bottom line is that charging for the same mileage at the standard Edison plug rate (about 4 Miles per hour of charge) ended up costing nearly twice as much in $ because of all the power lost to resistance. The difference between 24A and 48A is less, but it is still appreciable, and over time can have a real impact.

Never discount that pesky 2nd law of thermodynamics, entropy can be a real pain.

You might have drawn the wrong conclusion from that story.

Charging from 120V is significantly less efficient than charging with 240V. Both because of resistive line losses, and because the on-board charger has to boost the voltage more. Higher boost ratios tend to be less efficient.

Charging very slowly from 240V might incur more total losses because of the fixed charging overhead, but charging at 24 amps is well past where that is a concern.

I doubt that you can set the charge current low enough to encounter the bad effects of very slow trickle charge, which is a problem with small electronics.

 

[PorthosJon]

You might have drawn the wrong conclusion from that story.

Charging from 120V is significantly less efficient than charging with 240V. Both because of resistive line losses, and because the on-board charger has to boost the voltage more. Higher boost ratios tend to be less efficient.

Charging very slowly from 240V might incur more total losses because of the fixed charging overhead, but charging at 24 amps is well past where that is a concern.

I doubt that you can set the charge current low enough to encounter the bad effects of very slow trickle charge, which is a problem with small electronics.

Not really. As I said, the trickle charge is definitely a more dramatic loss & cost differential. However, the loss difference between 48amps & 24amps is not insignificant. I'm sure you can find the real world differential study that I found on Google (can't find the link right now), but if you know about electrical engineering, this paper does an excellent job demonstrating that there is an up to 20% differential in power loss when you double the amperage [Measurement of power loss during electric vehicle charging and discharging].

 

[DonaldBecker]

Not really. As I said, the trickle charge is definitely a more dramatic loss & cost differential. However, the loss difference between 48amps & 24amps is not insignificant. I'm sure you can find the real world differential study that I found on Google (can't find the link right now), but if you know about electrical engineering, this paper does an excellent job demonstrating that there is an up to 20% differential in power loss when you double the amperage [Measurement of power loss during electric vehicle charging and discharging].

That was an interesting paper, but it doesn't apply here.

They were talking about their own grid-integrated system. They had designed the car's inverter, one that both charged the EV battery and supplied power back to the power grid. Part of the paper was writing about how efficient their own design was, and where the losses were.

They also were measuring the efficiency of the local power grid, including the final transformer (e.g. the "pole pig" for residential service). The one they were testing with was over-sized for their application and had a high base loss. It wasted 274 watts at 10 amps, 602 watts at 30 amps, and only 352 watts at 42 amps. They disclose the numbers in the paper, but you have to read the details and the table to realize that the loss peak at 30 amps, something that is entirely an artifact of their experimental infrastructure, skews the conclusion.

 

[PorthosJon]

That was an interesting paper, but it doesn't apply here.

They were talking about their own grid-integrated system. They had designed the car's inverter, one that both charged the EV battery and supplied power back to the power grid. Part of the paper was writing about how efficient their own design was, and where the losses were.

They also were measuring the efficiency of the local power grid, including the final transformer (e.g. the "pole pig" for residential service). The one they were testing with was over-sized for their application and had a high base loss. It wasted 274 watts at 10 amps, 602 watts at 30 amps, and only 352 watts at 42 amps. They disclose the numbers in the paper, but you have to read the details and the table to realize that the loss peak at 30 amps, something that is entirely an artifact of their experimental infrastructure, skews the conclusion.

Ah. thank you, that part I missed. But I'm still trying to find the real-world testing for $ that showed that because of resistance loss, having to charge twice as long (24A vs. 48A) did show an appreciable difference in kWh/$ billed.

 

[Rocky_H]

You are drawing all kinds of wrong conclusions from that.

Bottom line is that charging for the same mileage at the standard Edison plug rate (about 4 Miles per hour of charge) ended up costing nearly twice as much in $

Yes.

because of all the power lost to resistance.

No.
That's not because of wire resistance. It's just very low power total. And as @Fourdoor was explaining, there is some noticeable overhead power consumption just from the car being awake and the charging process. When your input is very low, that can be consuming around a third or a fourth of what you are taking in, so efficiency is pretty bad.

As I said, the trickle charge is definitely a more dramatic loss & cost differential.

Yes it is, but not because of resistance.

However, the loss difference between 48amps & 24amps is not insignificant.

Right. Once the power is getting up to 6000+ W, that 300W or so of overhead doesn't show up much as a % versus when your input is only 1400 W.

 

[MD-2000]

Yep, and this is why I cringe when people just think they know better, and they are going to go out and buy some appliance cord, and use it, instead of hardwiring it, like the instructions say. They don't know what they don't know--like appliance cords being extra flexible because they are fine stranded wire, and why that is not appropriate for this device.

To clarify - this is NOT "fine stranded". The cable is far stiffer than the charging cable on the Gen2. It was a struggle to get it installed. It's rated for 50A, which is more than a lot of ovens typically. (2 6Ga power and 2 8Ga neutral and ground - and the 8Ga neutral-white is not connected and not used by the charger so cap it off) It's probably about 6 strands of solid copper per wire and the important point I made was to ensure it is FIRMLY screwed down in the terminal block.

 

[MN-MS100D]

Don't be silly; of course it is fine stranded wire. Anything above Class B is considered fine stranded wire. Probably Class K wiring in that appliance cord.

 

[davenlei]

Does anyone know the gauge of wire used in the Tesla wall connector? Want to make sure I have the right gauge wire to connect to the wall connector for the full 48 amps.
My existing 6ga wire length from the panel to the current charger is very short (2 ft. or less) since it is on opposite sides of the same wall.

 

[jcanoe]

Use only the current circuit breaker as it is probably correctly rated for the circuit.

Why change the current charging station when you can use the Tesla J1772 adapter that comes with the Tesla vehicle?

I would ask an electrician if the current 6 gauge wire will support 60A. It will definitely support 50A.

 

[davenlei]

Use only the current circuit breaker as it is probably correctly rated for the circuit.

Why change the current charging station when you can use the Tesla J1772 adapter that comes with the Tesla vehicle?

I would ask an electrician if the current 6 gauge wire will support 60A. It will definitely support 50A.

I am planning on getting a second Tesla in the near future and heard that 'dual' charging with the wall charger would be activated sometime in the future.
When I had this 14-50 circuit installed a couple months ago, the electrician said I only needed 8ga wire for the 50 amp circuit since the length of the run is so short. I insisted he put in 6ga wire because I told him I was likely going to go with the wall charger for the dual charge capability in the future and only wanted to have to install the wall charger and change the circuit breaker from 50A to 60A which is super easy. I was just concerned if I needed to go to 4ga for the wall charger or not if drawing the full 48A. I don't want to get the 4ga wire if that is excessive and pointless from a safety standpoint.

Looking at the chart here for amp and wire length, it looks like 6ga is even overkill for a 48 amp draw since my wire length is about two feet.

Contact

Welcome to American Autowire! We have everything to suit your needs.

www.americanautowire.com