Home/mobile charger challenges

[twnt70s]

Hello to all,

I am hoping to get some ideas from you all to solve my home charging issues. We have a model 3 LR and I have been using a 75ft extension cable to charge at home using mobile charger. Until about 5 months or so ago would usually get 24 mi/hr and now its reducing amps to 12 and getting only 11-12 mi/hr.
The charger begins flashing red and the adapter end of the mobile charger and extension becomes hot. I recently purchased a new 10-30 adapter and that didn't seem to fix the issue. I have tried unplugging and plugging the cable on the car but it quickly reduces charge from 24-12 mi/hr.

Some more information, the wall plug (dryer) is nema 10-50, cable has 10-50 adapter on one end and other end is 10-30. Not sure if this is an issue with mismatching 10-50 and 10-30. My next plan is to upgrade the wall outlet, just unsure which would be a good choice as an upgrade.

Never had charging issue with same extension cable but both ends were same in the past, 10-30. Unsure if mobile charger itself is crapping out.

Please feel free to provide feedback.

 

[ucmndd]

The red flashes are telling you something - how many times does it flash?

Something in your setup is overheating, sounds like the connection between the mobile connector and your extension cord. You need to figure out why and fix that. When the mobile connector detects high temps at the plug head it backs off current for safety.

What are the specs of your extension cord? This is really not a great setup for permanent charging..

 

[Mercimek]

The red flashes are telling you something - how many times does it flash?

Something in your setup is overheating, sounds like the connection between the mobile connector and your extension cord. You need to figure out why and fix that. When the mobile connector detects high temps at the plug head it backs off current for safety.

What are the specs of your extension cord? This is really not a great setup for permanent charging..

Agree. Any way you can get an electrician to create a plug closer to the car so you don’t have to use extension?

 

[Rocky_H]

There are a few things in this that concern me.

Some more information, the wall plug (dryer) is nema 10-50, cable has 10-50 adapter on one end and other end is 10-30.

That would be highly unusual. Dryer outlets are almost always 30A type--either 10-30 or 14-30. Are you sure this is a 10-50 and was it there for something else? Posting a picture of it would help because we might be able to identify it for sure.

Not sure if this is an issue with mismatching 10-50 and 10-30.

In the other direction, it very likely could be, but in your direction, that part should be fine. It is the Tesla adapter that sets the current by the plug type, and since that Tesla plug you are using is a 10-30, it will announce to the car to only use 24A maximum, and that should be fine for this outlet, regardless of whether it's a 10-50 or 10-30.

I think this is much more likely an issue of the large length and extra amounts of plug connections. Those are added resistance factors and can cause extra heat buildup and hotspots and if the car detects the high resistance drop, it will drop down the current for safety (which is a very good thing).

Using a 75 foot extension cord isn't a great long term thing. It would be good if you could get some kind of circuit out nearer to the car. But with what you've got, if it's already throwing errors at 24A, and reducing itself to 12A, maybe you should try to stick with 12 to 15A or so, because of the extra length and plug connections.

 

[twnt70s]

it flashes 4 times which I believe means high temp on outlet. Wall outlet is never hot only the end of the extension where it meets the tesla adapter.

The extension cord is 10awg, 105*c 500v vw-1 c(ul) STW 3x5.26mm

 

[twnt70s]

Agree. Any way you can get an electrician to create a plug closer to the car so you don’t have to use extension?

I have been contemplating asking landlord permission to install wall charger but haven’t yet pursued that.

 

[twnt70s]

There are a few things in this that concern me.


That would be highly unusual. Dryer outlets are almost always 30A type--either 10-30 or 14-30. Are you sure this is a 10-50 and was it there for something else? Posting a picture of it would help because we might be able to identify it for sure.


In the other direction, it very likely could be, but in your direction, that part should be fine. It is the Tesla adapter that sets the current by the plug type, and since that Tesla plug you are using is a 10-30, it will announce to the car to only use 24A maximum, and that should be fine for this outlet, regardless of whether it's a 10-50 or 10-30.

I think this is much more likely an issue of the large length and extra amounts of plug connections. Those are added resistance factors and can cause extra heat buildup and hotspots and if the car detects the high resistance drop, it will drop down the current for safety (which is a very good thing).

Using a 75 foot extension cord isn't a great long term thing. It would be good if you could get some kind of circuit out nearer to the car. But with what you've got, if it's already throwing errors at 24A, and reducing itself to 12A, maybe you should try to stick with 12 to 15A or so, because of the extra length and plug connections.

This is the dryer plug that already came with the house.

I have used this extension for years with a previous model 3 and this one prior to our move to current home in November. Never had a charging issue. So it’s all kinds of curious for me.

 

[FLRifleman]

it flashes 4 times which I believe means high temp on outlet. Wall outlet is never hot only the end of the extension where it meets the tesla adapter.

The extension cord is 10awg, 105*c 500v vw-1 c(ul) STW 3x5.26mm

There's no way for the charge cord to know the temperature on the outlet side of your extension cord (Obviously). You have an overheating issue at the end you're plugging the charge cord into. As others have said, that's not a good setup. In the short term, you want the length of the extension cord to be as short as possible, and you should look at replacing the female end. The contacts may be worn, or you have some other resistance issue on the female end.

 

[ucmndd]

it flashes 4 times which I believe means high temp on outlet. Wall outlet is never hot only the end of the extension where it meets the tesla adapter.

The extension cord is 10awg, 105*c 500v vw-1 c(ul) STW 3x5.26mm

So the connection between your mobile connector plug and the extension cord is overheating. You need to figure out why. Oxidation, worn contacts, etc etc...

 

[Rocky_H]

This is the dryer plug that already came with the house.

Well I'll be. I see the writing on the side: 50A and 125/250V, so it sure is a 10-50. Those aren't usually used for dryers.

I have used this extension for years with a previous model 3 and this one prior to our move to current home in November. Never had a charging issue. So it’s all kinds of curious for me.

But it's not curious to all of us. You've been doing something risky that pushes the envelope here for a long time. It may run fine for quite some time, but it is very likely that it will eventually have a problem. High continuous current through extension cords is a high chance of getting worse and developing hot spots, and it is fortunate that the safety mechanisms of the charging cable were able to catch this in time.

 

[twnt70s]

Well I'll be. I see the writing on the side: 50A and 125/250V, so it sure is a 10-50. Those aren't usually used for dryers.


But it's not curious to all of us. You've been doing something risky that pushes the envelope here for a long time. It may run fine for quite some time, but it is very likely that it will eventually have a problem. High continuous current through extension cords is a high chance of getting worse and developing hot spots, and it is fortunate that the safety mechanisms of the charging cable were able to catch this in time.

It does make sense since this setup isn’t optimal long term.

Going to have to pursue a more appropriate setup like wall connector moving forward.

 

[twnt70s]

Thank you all for your feedback

 

[Eric33432]

Most likely the problem is that the contacts in the NEMA 10-30R connector on the end of the extension cord have developed a high resistance and are causing the heating problem. It is not easy to clean them. Or they also could be worn and are no longer making a tight connection.

You said you purchased a new Tesla adapter but I suggest you also check that the prongs on the Tesla adapter are clean. You could try cleaning them with some steel wool if they are not bright metal, which they likely are not if they have been overheating.

While this is not an optimal situation, and you should try and get an outlet (or better a Tesla Wall Connector) installed in the garage, as a landlord I understand this might not be easy to do.

In the mean time, my recommendation is to simply replace the extension cord with a good quality 10 gauge copper wire cord, with a NEMA 10-30P and 10-30R and use an adapter like this to enable plugging it in to the NEMA 10-50R outlet:

Amazon.com

 

[davewill]

Most likely the problem is that the contacts in the NEMA 10-30R connector on the end of the extension cord have developed a high resistance and are causing the heating problem. It is not easy to clean them. Or they also could be worn and are no longer making a tight connection.

You said you purchased a new Tesla adapter but I suggest you also check that the prongs on the Tesla adapter are clean. You could try cleaning them with some steel wool if they are not bright metal, which they likely are not if they have been overheating.

While this is not an optimal situation, and you should try and get an outlet (or better a Tesla Wall Connector) installed in the garage, as a landlord I understand this might not be easy to do.

In the mean time, my recommendation is to simply replace the extension cord with a good quality 10 gauge copper wire cord, with a NEMA 10-30P and 10-30R and use an adapter like this to enable plugging it in to the NEMA 10-50R outlet:

Or replace the receptacle on the end of the cord (since 75ft, 30a extension cords are not cheap). If you've been in the habit of unplugging the mobile connector often, I'd stop doing that as it's a likely cause of your problem.