Slow charging car after power wall installation

[Wesfromohio]

I recently had solar and two power walls installed by a third party installer. The house has two panels so each power wall is on its own panel with its own gateway. I have a Model 3 that I charge via the mobile connector on a NEMA 14-50 outlet.

Since the installation when I charge my Model 3 it charges at normal speed at first (~34 mph) drawing from both the power wall and/or solar/grid as necessary. This all seems to be working appropriately. However after an hour or so of charging the rate of charge halves to 17 mph and stays that way for the rest of the charge. Sometimes it stops drawing from the grid and sometimes the PW runs out and it’s only using the grid, but either way the rate of charge is reduced to 17 mph.

Any suggestions on what the issue may be?

 

[jjrandorin]

I would suggest getting your installer back out to look at it. Your install itself sounds strange (2 panels with 2 gateways and only 2 powerwalls) so there are obviously some considerations that are not readily apparent.

Charging speed shouldnt change, normally. What would change is where the power is coming from, not charging speed.

Check the car for error messages. There should be a message in there when it drops the speed as to why.

 

[getakey]

there's a setting in the app for Car charging from the PW. Have you looked at that?

 

[jjrandorin]

there's a setting in the app for Car charging from the PW. Have you looked at that?

That setting only applies if you are off grid. If you are on grid, there is no interaction between that setting and charging.

 

[yblaser]

I have read that the cars will back off on their charging rate if it senses the line voltage starting to droop. I don't know what the threshold voltage is when it start to back off, but you should monitor what voltage the car is sensing during charging in the car section of the app.

 

[jjrandorin]

I recently had solar and two power walls installed by a third party installer. The house has two panels so each power wall is on its own panel with its own gateway. I have a Model 3 that I charge via the mobile connector on a NEMA 14-50 outlet.

Since the installation when I charge my Model 3 it charges at normal speed at first (~34 mph) drawing from both the power wall and/or solar/grid as necessary. This all seems to be working appropriately. However after an hour or so of charging the rate of charge halves to 17 mph and stays that way for the rest of the charge. Sometimes it stops drawing from the grid and sometimes the PW runs out and it’s only using the grid, but either way the rate of charge is reduced to 17 mph.

Any suggestions on what the issue may be?

OP, since you are charging from a mobile connector and a 14-50, what size circuit / breaker was configured for you? The maximum charge speed in that setup (with a 14-50 and a 50 amp breaker) is going to be 32 amps, because its limited by the mobile connectors max charge speed.

All mobile connectors that came / come with model 3s max out at 32amps. Old ones that came with model S and X can max out at 40 amps but the ones that came with model 3s max out at 32amps.

Your charge speed cutting in half is likely either your cars onboard charger going out (the "charger" is in the car actually, and model 3s either have 2 or 3 16amp chargers in them), or, for some reason, your car throttling back charging speed because of a detected issue.

Of those two things, the most likely one is the second one (car throttling back charging speed), either because of heat at the outlet, or voltage or something like that. There should be an error message in the car, but you may have to poke around for looking at past error messages to find it in the Car UI.

 

[Wesfromohio]

OP, since you are charging from a mobile connector and a 14-50, what size circuit / breaker was configured for you? The maximum charge speed in that setup (with a 14-50 and a 50 amp breaker) is going to be 32 amps, because its limited by the mobile connectors max charge speed.

All mobile connectors that came / come with model 3s max out at 32amps. Old ones that came with model S and X can max out at 40 amps but the ones that came with model 3s max out at 32amps.

Your charge speed cutting in half is likely either your cars onboard charger going out (the "charger" is in the car actually, and model 3s either have 2 or 3 16amp chargers in them), or, for some reason, your car throttling back charging speed because of a detected issue.

Of those two things, the most likely one is the second one (car throttling back charging speed), either because of heat at the outlet, or voltage or something like that. There should be an error message in the car, but you may have to poke around for looking at past error messages to find it in the Car UI.

Thank you, very helpful. I just noticed that the charging drops from 32/32A to 16/16A when the charging slows. Voltage remains around 235V the whole time. Would that suggest one of the chargers in the car going out like you described? Maybe this has nothing to do with the solar/power wall installation?

 

[jjrandorin]

Thank you, very helpful. I just noticed that the charging drops from 32/32A to 16/16A when the charging slows. Voltage remains around 235V the whole time. Would that suggest one of the chargers in the car going out like you described? Maybe this has nothing to do with the solar/power wall installation?

Check the car for error messages. There should be a message in there when it drops the speed as to why.

Try looking for the error message in the car.

1. Tap car icon in bottom left hand side of screen to pull up car menus
2. Tap SERVICE menu item
3. Select NOTIFICATIONS in the service menu item.

This menu should have the notifications your car has generated. See if there are any notifications in there that can give you more information.

 

[SMAlset]

Haven’t we heard from a member or two on here about a similar lowering of the charging speed and it turned out to be the electrical connection at the outlet (in wall wiring to outlet) like @jjrandorin mentioned? Maybe a search of the Model 3 forum (know I read it on this forum section) will turn it up and be more helpful as to what triggered their issue.

 

[jjrandorin]

Haven’t we heard from a member or two on here about a similar lowering of the charging speed and it turned out to be the electrical connection at the outlet (in wall wiring to outlet) like @jjrandorin mentioned? Maybe a search of the Model 3 forum (know I read it on this forum section) will turn it up and be more helpful as to what triggered their issue.

There has been more than a couple of threads in the model 3 section that have had that cause / effect (outlet overheating). There have also been some with charge port failures etc.

I dont think this is related to "the powerwall or solar" but I do think its possible its related to "the install", assuming that the install of the outlet happened at the same time as the solar + powerwall. Even if the outlet itself was not installed then, its likely the electrical was moved during the install, so, my bet is its something with "the install" but the car should be saying what the issue is in the notifications.

 

[Wesfromohio]

There has been more than a couple of threads in the model 3 section that have had that cause / effect (outlet overheating). There have also been some with charge port failures etc.

I dont think this is related to "the powerwall or solar" but I do think its possible its related to "the install", assuming that the install of the outlet happened at the same time as the solar + powerwall. Even if the outlet itself was not installed then, its likely the electrical was moved during the install, so, my bet is its something with "the install" but the car should be saying what the issue is in the notifications.

Checked the notifications, it is indeed a high temperature at the wall plug. The plug was not installed at the same time as the solar or power walls, I’ve been using it for about 18 months prior. Perhaps they did something with the wiring at the electrical panel around the install. Any idea what they could have done that would cause this? Not like they changed the breaker out or anything, but I am certainly no electrician so not sure what else they may have done. Thanks for your help.

 

[jjrandorin]

Checked the notifications, it is indeed a high temperature at the wall plug. The plug was not installed at the same time as the solar or power walls, I’ve been using it for about 18 months prior. Perhaps they did something with the wiring at the electrical panel around the install. Any idea what they could have done that would cause this? Not like they changed the breaker out or anything, but I am certainly no electrician so not sure what else they may have done. Thanks for your help.

If it wasnt installed when the solar was installed, and the error is overheating at the plug, I would check that outlet for scorching. It may not be related (outlets fail).

 

[SMAlset]

I also gather from reading threads here that the wiring to the outlet can start to lose contact at the terminals and may need tightening.

We had a NEMA 14-50 installed for our vehicles’ charging and decided to go with the corded mobile NEMA 14-50 connector that remains plugged into our wall. Since the plug is permanently attached to the cord and charging unit it had less points of failure. We also didn’t want to remove the unit to put into our car for trips and plugging and unplugging it from the outlet.

When we had our Solar/PW install done last August/September we decided to upgrade the Leviton outlet our electrician originally installed, this after getting “schooled” by members of the forum about using something like the heavy duty Hubbell outlet instead. A member on the forum did a quality comparison of the outlets in photos and it convinced us to do the upgrade. Given the hours, unattended, of charging at these amp rates we didn’t want to risk an in-wall fire one day. Not cheap for the outlet but worth more in peace of mind. Also cost less than replacing our house.

BTW the Hubbell will require a larger box to accommodate it so be sure to order both and the matching cover plate.

 

[SMAlset]

Here’s a couple of threads worth reading:

Need Advice: NEMA 14-50 Sometimes Charges at only 16a

Hello all I need some advice on where to start looking to track down the problem. I have a 2019 SR+ with a little over 40M miles. The vast majority of my charging is on a NEMA 14-50 outlet at work using the original Mobile Connector and the proper adaptor. There is no damage to the cable or...

teslamotorsclub.com

PSA. Another melted NEMA 14-50 receptacle

Just a reminder to make sure the UMC is snug when plugging into the outlet. There shouldn't be any play when plugged in. If you don't have the Tesla recommended NEMA 14-50, (Hubbell/Cooper), minimize plugging and unplugging the UMC. This outlet was installed about a year ago, the loose...

teslamotorsclub.com

PSA: If your Tesla app is giving you "charging interrupted" alerts for no obvious reason, something may be very wrong!!

So quick backstory: I had a NEMA 14-50 outlet installed in my garage a little over 3 years ago as I had just moved into my new house and needed an outlet for my EVSE to charge my at-the-time Bolt. Used the outlet to charge @240V/32A with a Tesla Gen 2 UMC + Jdapter for over 2 years no problems...

teslamotorsclub.com

Temp Rise in plug, outlet, cords, etc.

Hey all -- We just got our M3 a week ago. I got the 14-50 outlet installed on Thursday and have some questions regarding the temp rises I'm seeing while charging at 40 amps. We live in the Central Valley in CA so it gets warm here fairly often. Here are the specs of my install: Tesla Gen 2...

teslamotorsclub.com