Drastic reduction 110V charging

[Siciliano]

I can't find this anywhere else on the forum...sorry if it's already been posted. I was consistently getting a 4-5mi/hr charge on my 110V for almost a year since I bought the car in Sept 2020. Even last winter I was getting a bare minimum of 3mi/hr.

Now for the past 4-6 months I haven't been getting *anything* above 1 mi/hr, regardless of time or outside temp. I'm getting a 14-50 installed later in the spring, but honestly this is driving me crazy right now.

Nothing has changed as far as what I'm running electrically inside the garage or inside the house. It's very strange. It's there some trick to get back the 5mi/hr??

TIA.

 

[GtiMart]

Forget about "miles per hour" as a charging rate and look at the voltage and amperage, which mean kW, which is a better measure of charging rate. What are you seeing in the car when you charge? You should ideally see 120V and 12A which is the maximum for such a 5-15 plug.

 

[SpaceKat]

As I recall, the manual says that the current draw is adaptive. If the system detects the voltage dropping as it draws charging current, it automatically backs off and then remembers the lower current setting. Just speculating, but perhaps you have had power fluctuations and the car backed-off from its normal 14A power draw and remembered that setting?

 

[GtiMart]

14A? On a 5-15 plug (normal 120V plug in America) the maximum the mobile charger will pull is 12A. That is so it stays within 80% of the circuit.

 

[Siciliano]

Forget about "miles per hour" as a charging rate and look at the voltage and amperage, which mean kW, which is a better measure of charging rate. What are you seeing in the car when you charge? You should ideally see 120V and 12A which is the maximum for such a 5-15 plug.

Currently as per the app, I'm getting 8/12A and 115V. I'm not sure why since I haven't changed a single thing. I wonder if unplugging it from the outlet would reset it??

 

[Siciliano]

I unplugged and replugged and nothing changed... I didn't think that would work, but this is very strange. I was getting 4-5 mi/hr every time I plugged in...

 

[SpaceKat]

Can you adjust the current to 12A manually on the charging screen before you plug in?

 

[RayK]

Is there anything else plugged into an outlet which is on the same breaker?

 

[GtiMart]

Try going in the car and changing the amps back to 12. Sometimes changing from the app doesn't "stick" it seems. If the car goes back down to 8A after a few minutes then you have a voltage drop and the car does that for safety.

 

[Rocky_H]

Currently as per the app, I'm getting 8/12A and 115V.

Now that's more informative. So now we know what probably caused it and what you can do about it.

The car checks the voltage level at the beginning, before beginning to ramp up the current for charging, and compares that to after it has turned the current up. If there is excessive voltage drop from the load there, it will back off the current to three fourths of the amps it was using. The 8 out of 12 seems to indicate that's what happened.

When the amps are changed, either by that safety check, or by the user, that setting is set in memory, tagged to that location. So it will continue to use 8 when you charge at that location until you turn it back up on the screen. (It is a separate issue that there is a stupid bug in the mobile app that it doesn't seem to recognize or work well changing the amps through the app. Just do it on the car's screen while you are plugged in.)

But now for the future: If there was some high voltage drop, there may be some weak connections in that circuit, or other things plugged into other outlets on it. If you turn it back up to 12A, it may work fine some more times, but may run into this again and turn back down to 8A. So if you want to try somewhere around 9 to 11 amps, it may be able to hold steady there, without tripping down to the lower level.

 

[swiftd03]

As others have mentioned, check and see what else is on that circuit. We had a Pacifica plug in hybrid before we had a vehicle charger and found out that the power outlet by our front door was the same circuit as the one in the garage so when we plugged in our christmas lights there like we did every other year we started tripping the breaker. The Tesla's are smarter and would back down the draw before the breaker would kick. If you are plugging into a garage you might have a refrigerator or freezer in there, a garage door opener, computer of some sort, water heater that is gas powered with a powered controller (like a tankless). Anything new in there in the last year?

 

[toolman335]

Eliminate a variable and plug in somewhere else.

 

[Frank99]

Listen to Rocky_H.

The car tries hard to keep your house from burning down. If it's charging, and notices a large voltage drop, it'll reduce the amount of current (Amps) that it uses to charge. I didn't realize that it stores that as a charging limit for that location, but let's go with that.

The reduction in charging current is intended to prevent overheating in your house wiring. If there's a bad connection (say, the wire isn't tightly screwed onto the outlet), high current will generate a lot of heat at the loose connection, which in the worst case would start a fire. It's a Bad day if that happens.

There are several reasons why the car might detect a voltage drop while it's charging:
- The electric company is having issues, and lowered the voltage to your house (a "brownout") for a few seconds. You may not even have noticed this happen.
- There's a loose connection in your house wiring between the circuit breaker and the outlet.
- Perhaps someone knocked the Mobile Connector's plug loose; not enough to stop charging, but enough to create a weak connection between the plug and the outlet. Easily fixed by pushing the plug in fully.
- Perhaps something else is on the same circuit (Garage Door opener, pool pump, air compressor, spare freezer), and started up while the car was charging, generating enough of a voltage drop to piss off the car.
- There are probably a dozen others...

Anyway, I'd do as Rocky_H suggested, and verify on the screen that charging current is set to 12A. If it reduces again in the future, I'd strongly encourage a call to an electrician to have them inspect the circuit to check for loose connections. If it doesn't happen again, I'd just call it a random event (for example, a momentary brown-out), and go on with life. Your 14-50 install should eliminate the issue, certainly (BTW, make sure the electrician uses an industrial quality outlet).