Adjusting charging amps remotely?

[Target]

I have a 2015 Tesla Model S 85. For some reason it defaults to 30 AMPs on the car charging screen even when I change it to the MAX of 40 AMPS even when the charge port is NOT connected. I have 50 AMPS circuit breaker.

Any suggestion to fox this problem?

In the car software, location matters for charging rate. If I had my station set to 25A the previous time the car was plugged in at a GPS location, it will default to 25A at that location the next time I pull up. Once I plug in it will then update to the current available from the station. If the car previously charged at 30A at your house, that is what it will show you before you plug in. So long as you didn't manually set that number at some point, if you manually set it to 30 in that location, then it will retain that because you manually overrode the car.

If the car is lowering the charging rate every night when you charge, it is doing that for a reason. Usually it is seeing some sort of voltage drops when it increases the current that scare it. I would contact an electrician, or, if your capable, check the torque on all of the connections in the path to your station and on the station itself. If it's plugged into an outlet, I would check that the outlet still feels tight on all the pins.

I have had this happen, and stuff was loose and getting hot. Left unfixed, bad things will happen.

I usually suggest to people that they bring the electrician back out after one year of use to go over the entire path and tighten everything back up again. Alternately the spring is also a good time to do this in places where it gets cold, because the thermal cycling on the connections loosens them much faster in the winter. I had to do this at my parents house last spring, and I had only charged there a few times over the previous year since the outlet was installed. One connection on the breaker was slightly loose, and one side of the outlet was scary loose. I didn't do that install, I paid a local electrician to do it, so I have no idea of the beginning torque. If you are doing this I suggest finding a proper torque measurement tool to accurately tighten these connections.

 

[MorrisonHiker]

I have a 2015 Tesla Model S 85. For some reason it defaults to 30 AMPs on the car charging screen even when I change it to the MAX of 40 AMPS even when the charge port is NOT connected. I have 50 AMPS circuit breaker.

Any suggestion to fox this problem?

If the car senses a problem, such as a large voltage drop, it will reduce the amps by 25% as a safety precaution. Since yours is dropping 25% from 40 to 30 amps, I would suggest you watch the voltage and see if it drops when checking after you have reset the amps. You should also check the connections in the 14-50 outlet and confirm the plug and chargeport look fine.

 

[RobK]

Thank you @ Target and @MorrisonHiker for yoru good suggestions.

Good news! After I jiggled the connector the car held 40 AMPS setting. Last night I set the car to charge at midnight and it had finished charging at 4:50 AM.

Have anyone been able to charge at 50 AMPs at home?

 

[tga]

Thank you @ Target and @MorrisonHiker for yoru good suggestions.

Good news! After I jiggled the connector the car held 40 AMPS setting. Last night I set the car to charge at midnight and it had finished charging at 4:50 AM.

Have anyone been able to charge at 50 AMPs at home?

Not on a 14-50 outlet (or a wall connector on a 50A breaker). You can never charge at >80% of the circuit rating.

In North America, circuits are rated for intermittent usage. Continuous loads, like EV charging, must be limited to 80% of a circuit's intermittent rating, per National Electric Code. This is to avoid overheating/fire risk.

You generally don't run into this 80% limit in residential electric systems except for EV charging, as there generally aren't any other continuous loads found in residences. Electric heating elements (dryers, ovens, electric furnaces) aren't considered continuous, since the heating elements cycle on/off to maintain temp. EV charging is usually the most "stressful" load a home electrical system will see.

 

[RobK]

Not on a 14-50 outlet (or a wall connector on a 50A breaker). You can never charge at >80% of the circuit rating.

In North America, circuits are rated for intermittent usage. Continuous loads, like EV charging, must be limited to 80% of a circuit's intermittent rating, per National Electric Code. This is to avoid overheating/fire risk.

You generally don't run into this 80% limit in residential electric systems except for EV charging, as there generally aren't any other continuous loads found in residences. Electric heating elements (dryers, ovens, electric furnaces) aren't considered continuous, since the heating elements cycle on/off to maintain temp. EV charging is usually the most "stressful" load a home electrical system will see.

Thanks. Excellent explanation.

 

[Target]

@RobK
I routinely charge at 80A, but I have a hardwired setup that is built on a 100A circuit.

IMG_20180815_141454

• Target
• Jul 9, 2019

Charging station and fused disconnect, side view

Does your car have the twin charger / high power charger? Those bring you up to a max of 80A or 72A. If you have the new nose car then you either have a 48 or 72 amp charger. If you have an old nose car you have either one or two 40A chargers in your car enabling 40A or 80A charging.

 

[RobK]

@RobK
I routinely charge at 80A, but I have a hardwired setup that is built on a 100A circuit.

IMG_20180815_141454

• Target
• Jul 9, 2019

Charging station and fused disconnect, side view

Does your car have the twin charger / high power charger? Those bring you up to a max of 80A or 72A. If you have the new nose car then you either have a 48 or 72 amp charger. If you have an old nose car you have either one or two 40A chargers in your car enabling 40A or 80A charging.

@Target - That is impressive. You must drive your Tesla a lot.
Our 2015 Tesla S 85 has less than 20,000 miles but we love every-driven mile. Would love to upgrade to the new Model S but want to see FSD in action first.

 

[r1200gs4ok]

In the car software, location matters for charging rate. If I had my station set to 25A the previous time the car was plugged in at a GPS location, it will default to 25A at that location the next time I pull up. Once I plug in it will then update to the current available from the station. If the car previously charged at 30A at your house, that is what it will show you before you plug in. So long as you didn't manually set that number at some point, if you manually set it to 30 in that location, then it will retain that because you manually overrode the car.

If the car is lowering the charging rate every night when you charge, it is doing that for a reason. Usually it is seeing some sort of voltage drops when it increases the current that scare it. I would contact an electrician, or, if your capable, check the torque on all of the connections in the path to your station and on the station itself. If it's plugged into an outlet, I would check that the outlet still feels tight on all the pins.

I have had this happen, and stuff was loose and getting hot. Left unfixed, bad things will happen.

I usually suggest to people that they bring the electrician back out after one year of use to go over the entire path and tighten everything back up again. Alternately the spring is also a good time to do this in places where it gets cold, because the thermal cycling on the connections loosens them much faster in the winter. I had to do this at my parents house last spring, and I had only charged there a few times over the previous year since the outlet was installed. One connection on the breaker was slightly loose, and one side of the outlet was scary loose. I didn't do that install, I paid a local electrician to do it, so I have no idea of the beginning torque. If you are doing this I suggest finding a proper torque measurement tool to accurately tighten these connections.

my issue is dropping from 40a to 30a....voltage is constant at 235v.....the electrician came back and looked.....everything was tight in the Nema 14-50.....panle was tight but he did change the Sieman’s breaker just in case.....still get the dropping of current on every charge....this happens on both cars......Tesla was sent pictures of the charging progress from the Teslafi app.....they sent me a new Wall Charger, but it is the old Gen 2. which is black and has no pig tail......have not got an answer as to whether I can use the old pif tail.....

I measure the heat at the plug when charging and is was only 98F....it dropped to 75 going into the charger and at the car plug it was 78F...The new black charger is heavier because the cable is much thicker than my grey Gen 2 unit....only question now is, “Can I use the old pig tail with the new Black Gen 2 charger"

 

[tnt1971]

Electric heating elements (dryers, ovens, electric furnaces) aren't considered continuous, since the heating elements cycle on/off to maintain temp.

Also, electric motors, which are in just about every other high draw item in a household (dryer, refigerator, pumps for heat, fans, etc.), use about twice the energy draw to start the motor as when they are running. You get a quick spike when you first start one of these motors.

 

[Target]

my issue is dropping from 40a to 30a....voltage is constant at 235v.....the electrician came back and looked.....everything was tight in the Nema 14-50.....panle was tight but he did change the Sieman’s breaker just in case.....still get the dropping of current on every charge....this happens on both cars......Tesla was sent pictures of the charging progress from the Teslafi app.....they sent me a new Wall Charger, but it is the old Gen 2. which is black and has no pig tail......have not got an answer as to whether I can use the old pif tail.....

I measure the heat at the plug when charging and is was only 98F....it dropped to 75 going into the charger and at the car plug it was 78F...The new black charger is heavier because the cable is much thicker than my grey Gen 2 unit....only question now is, “Can I use the old pig tail with the new Black Gen 2 charger"

You have a "range cord" that you plug into the 14-50 outlet and wire up into your Tesla Wall Connector?

Assuming that is the situation, make sure the range cord is 6 ga on the hot leads and 8ga on the ground only. I believe there are a few of those floating around that only have 8ga on the hot leads, leading to more heating than you want.

Assuming you are measuring 98F on the plastic/rubber surface of the plug, is more temp then I would want to detect on a surface, because that means the pins of the outlet are probably much hotter. The pig tails aren't usually the issue, so long as they are the proper gauge wire and well attached to the charging station. Pigtails are usually fine strand wire, and that is a challenge for many connections to get a very good connection. My fine stranded wire always get wire ferrules. That is the only way to be sure you have gotten a good bond to all of the small strands.
https://www.amazon.com/Ruikarhop-Ferrules-Connector-Insulated-Terminal/dp/B07V3VX2S5
To install I strip back as close to exactly the ferrule depth as possible, so you can clearly see where you are once it is inserted. Insert the copper into the ferrule, and then insert the ferrule into the connection point and tighten down, while making sure the copper doesn't escape the ferrule. This will provide a secure connection as the clamping force will crush the ferrule and form it to a good fit of the inside of the wall connector terminals.

Wire used in a normal hard wire application only has a few large strands and doesn't need a ferrule, but a cable like a pigtail is typically much more flexible and finely stranded making a ferrule a really good idea.

From my perspective that is one possible issue, and the other is that the springs that maintain contact in your outlet are starting to age and weaken. You can try to guess at how much strength they have left by inserting the plug and seeing how much force it takes, but this isn't a very accurate test. I don't know of an accurate test, but I am sure one exists. In general those springs wear out far faster than anything else in a normal install. This has lead me to only use outlets for occasional use, and to suggest being hardwired for any full time use.

On the Gen 2 unit you just received, just make sure you set the amperage dial to 40A to the car / 50A circuit.

 

[Target]

@Target - That is impressive. You must drive your Tesla a lot.
Our 2015 Tesla S 85 has less than 20,000 miles but we love every-driven mile. Would love to upgrade to the new Model S but want to see FSD in action first.

I used to drive quite a bit, but I built my charging setup for the long haul. I have four stations in my garage plus two NEMA14-50's for occasional use beyond just 4 cars. I am actually selling my Tesla, because it is just collecting dust, and will drive the Bolt or i-Miev for the next year or so. Once this virus thing sorts itself out, I will look to buy another Tesla again. No point paying for a car to sit around collecting dust.

 

[r1200gs4ok]

You have a "range cord" that you plug into the 14-50 outlet and wire up into your Tesla Wall Connector?

Assuming that is the situation, make sure the range cord is 6 ga on the hot leads and 8ga on the ground only. I believe there are a few of those floating around that only have 8ga on the hot leads, leading to more heating than you want.

Assuming you are measuring 98F on the plastic/rubber surface of the plug, is more temp then I would want to detect on a surface, because that means the pins of the outlet are probably much hotter. The pig tails aren't usually the issue, so long as they are the proper gauge wire and well attached to the charging station. Pigtails are usually fine strand wire, and that is a challenge for many connections to get a very good connection. My fine stranded wire always get wire ferrules. That is the only way to be sure you have gotten a good bond to all of the small strands.
https://www.amazon.com/Ruikarhop-Ferrules-Connector-Insulated-Terminal/dp/B07V3VX2S5
To install I strip back as close to exactly the ferrule depth as possible, so you can clearly see where you are once it is inserted. Insert the copper into the ferrule, and then insert the ferrule into the connection point and tighten down, while making sure the copper doesn't escape the ferrule. This will provide a secure connection as the clamping force will crush the ferrule and form it to a good fit of the inside of the wall connector terminals.

Wire used in a normal hard wire application only has a few large strands and doesn't need a ferrule, but a cable like a pigtail is typically much more flexible and finely stranded making a ferrule a really good idea.

From my perspective that is one possible issue, and the other is that the springs that maintain contact in your outlet are starting to age and weaken. You can try to guess at how much strength they have left by inserting the plug and seeing how much force it takes, but this isn't a very accurate test. I don't know of an accurate test, but I am sure one exists. In general those springs wear out far faster than anything else in a normal install. This has lead me to only use outlets for occasional use, and to suggest being hardwired for any full time use.

On the Gen 2 unit you just received, just make sure you set the amperage dial to 40A to the car / 50A circuit.

Thank you......my set up with the Nema 14-50 is only 6 months old.....I have replaced the breaker just to eliminate that from the equation....My current unit is set for 40a on my 50a breaker and I am sure that the Romex coming from the breaker to the Nema is 6awg..........I believe I am going to just hard wire......I think that is why Tesla stopped using the Grey pig-tailed units because the wiring in the pig tail was not working out.....when charging it starts at 40a and drops to 30a and this cycle continues until the charge is complete...the temp is within limits and the hottest is at the pig tail which was around 98F.....the temp was taken at the back of the plug....everywhere else is was 85F or less......so, bottom-line, I will hard wire and see if that will eliminate my issues......thanks for the help

 

[Target]

Thank you......my set up with the Nema 14-50 is only 6 months old.....I have replaced the breaker just to eliminate that from the equation....My current unit is set for 40a on my 50a breaker and I am sure that the Romex coming from the breaker to the Nema is 6awg..........I believe I am going to just hard wire......I think that is why Tesla stopped using the Grey pig-tailed units because the wiring in the pig tail was not working out.....when charging it starts at 40a and drops to 30a and this cycle continues until the charge is complete...the temp is within limits and the hottest is at the pig tail which was around 98F.....the temp was taken at the back of the plug....everywhere else is was 85F or less......so, bottom-line, I will hard wire and see if that will eliminate my issues......thanks for the help

I think you will find that to be a stable long term solution. I wish you the best of luck!

 

[r1200gs4ok]

I think you will find that to be a stable long term solution. I wish you the best of luck!

thanks my friend.......take care and be safe

 

[r1200gs4ok]

I think you will find that to be a stable long term solution. I wish you the best of luck!

Just got call from Colin at Tesla charging team....The unit he sent me with pig tail is the same as the grey without pig tail....both have thicker cables and perform the same.....the issues is with the pig tail....I causes a temp sensor to trigger and lowers the amperage.....so, he sent me another unit with pig tail today...I am going to return it and use the black Gen 2 with pig tail......hopefully this will solve my issues with amperage.....COlin told me there was no issue with the pig tail but they discontinued them because of lack of sales, but the found one for me.....hehehehe

So, bottom line, I am going to go with the hard wired black unit....I will change the face place out for the Grey one and should be good to go....I was told to send them the invoice and they will send me a check for the install......got to say, Tesla reacted to my problem and furnished excellent customer service response...they sent me 2 units....one each and basically told me to take my pick....tomorrow or Thursday I will install the new charger......and then charge my Model S because it is down below 30%

have a great day

 

[Target]

Removing the outlet and it's springs is a good thing in my opinion, and it sounds like they agree that is where the problem was. Hardwired is the answer!

Post back if it works out?

 

[r1200gs4ok]

Removing the outlet and it's springs is a good thing in my opinion, and it sounds like they agree that is where the problem was. Hardwired is the answer!

Post back if it works out?

agreed....I was wrong when I said earlier "black with pig tail".......I meant to say "black without pig tail".....the new black without pig tail is much hardier than the old grey......So, Botton line, I will be having electrician come and look at my work as I will be had wiring the new black unit.....

thanks to everyone who responded to all me.....I do respect all the advice and help.....I will post after instal and first charge to let everyone know it I can hold 40a on a 50a breaker during the charging process....

 

[tga]

agreed....I was wrong when I said earlier "black with pig tail".......I meant to say "black without pig tail".....the new black without pig tail is much hardier than the old grey......So, Botton line, I will be having electrician come and look at my work as I will be had wiring the new black unit.....

thanks to everyone who responded to all me.....I do respect all the advice and help.....I will post after instal and first charge to let everyone know it I can hold 40a on a 50a breaker during the charging process....

Do a test charge before the electrician leaves. Which the displayed volts as the charge rate ramps up. It will start at close to 240V (+/- around 5V), but will drop a bit as the charge ramps up. If it drops too much, there is a bad connection somewhere. How much is "too much"? 10V definitely, 8V might make me a bit uncomfortable, 5V is no big deal.

If there is a large drop, have the electrician measure voltage at various points on the way back to the main panel to find the high resistance point. There may be a bad connection somewhere. Don't worry if that doesn't make sense - it should make sense to your electrician (if it doesn't, you need a better electrician!)

 

[r1200gs4ok]

Do a test charge before the electrician leaves. Which the displayed volts as the charge rate ramps up. It will start at close to 240V (+/- around 5V), but will drop a bit as the charge ramps up. If it drops too much, there is a bad connection somewhere. How much is "too much"? 10V definitely, 8V might make me a bit uncomfortable, 5V is no big deal.

If there is a large drop, have the electrician measure voltage at various points on the way back to the main panel to find the high resistance point. There may be a bad connection somewhere. Don't worry if that doesn't make sense - it should make sense to your electrician (if it doesn't, you need a better electrician!)

No problem....I am a EE and understand.....I live in Irvine, Ca....the the local code here is always under a magnifying glass so no matter what I do, it needs to be inspected....the electrician will see what I have done and we will test.....

I agree that voltage is at 240v when ramping up. the it draws down a little to around 233v-237v....Average for 5 hours charging is 234v......I checked incoming and it is around 238v-240v.....our power company has an issue but they refuse to fix it.....however, voltage is mostly constant and I see no power issues throughout the house when the load is green during the summer.....we charge mostly at night......I wish I had a 200a panel.....so that may be my next project.....the I can use a 100a sub-panel to run the charging station.....will advise on what happens

 

[tga]

No problem....I am a EE and understand.....I live in Irvine, Ca....the the local code here is always under a magnifying glass so no matter what I do, it needs to be inspected....the electrician will see what I have done and we will test.....

I agree that voltage is at 240v when ramping up. the it draws down a little to around 233v-237v....Average for 5 hours charging is 234v......I checked incoming and it is around 238v-240v.....our power company has an issue but they refuse to fix it.....however, voltage is mostly constant and I see no power issues throughout the house when the load is green during the summer.....we charge mostly at night......I wish I had a 200a panel.....so that may be my next project.....the I can use a 100a sub-panel to run the charging station.....will advise on what happens

You get it... I run ~245V no load (a bit hot). Charging at 24A I drop to around 237V at the car, but most of that is on the utility side of the meter. I see ~238-239 at the main lugs, so only 1-2V drop inside the house. Even after upgrading from 100A to 200A service (with a new drop), it hasn't changed, so I suspect it's at the transformer.