Charging Speed Challenge

[JTexDal]

Hi everyone,

Thanks for the help here. New Tesla owner. Just bought a used 2018 Model S, 100D. Had a NEMA 14-50 outlet installed today. I’m getting 32/32A, 246v, but it’s only charging at 7kw. That seems very low compared to what it’s supposed to. I haven’t been able to test on another plug yet to determine if it’s the plug or mobile charger. All connections feel tight. Any thoughts on why I’m seeing such a low rate?

 

[andydandy14]

I think there is a limitation in some of the newer mobile chargers. I have the same challenge with my mobile charger that I got with my 2021 Model 3, but my old mobile charger from the Model S goes up to 40A/9kW. Sorry

Edit: did you check the amperage that your circuit breaker is allowing? That can be the other limiting factor.

 

[JimmyB]

246 x 32 = 7,872, so your 7kw is about right (esp if the car is rounding down and / or allowing for efficiency losses). @andydandy14 is right that the Gen2 mobile connector only goes up to 32A.

Does your car have the 72A charger? If so, the wall connector might be a worthwhile investment. I get 16kw charging at 80A - alas the stone-age infrastructure here means I'm limited to 208v, at 240v I'd be at 19kw.

 

[LoudMusic]

If the car is doing anything else it will consider that power usage removed from the charging speed. Aircon, heater, sentry, ... I don't know what else uses big power But the HVAC systems could easily knock off 1kw of charging power.

 

[JTexDal]

Sorry, I believe I misread the manual. It said it charges at 23 miles per hour. I was thinking 23 kWh so 7 kW is probably equivalent or close to 23 miles then. Sorry for the post.

And no I don’t have the 72A charger. Was using the NEMA 14-50 plug with the gen 2 mobile charger.

 

[ucmndd]

And no I don’t have the 72A charger. Was using the NEMA 14-50 plug with the gen 2 mobile charger.

Then 32 amps and 7kw is precisely what you should be getting. Enjoy the new car!

 

[airborne spoon]

Sorry, I believe I misread the manual. It said it charges at 23 miles per hour. I was thinking 23 kWh so 7 kW is probably equivalent or close to 23 miles then. Sorry for the post.

And no I don’t have the 72A charger. Was using the NEMA 14-50 plug with the gen 2 mobile charger.

how do you know you dont have the 72kW charger? have you tested to see? The charger is inside the car under the rear seats and aint small. The UMC that came with the car is what you are talking about a Universal Mobile Connector not a charger.

with the gen 2 UMC that you have the max charge speed it will give is 32A which is 7kW. if you had a gen 1 cable like those of us with older cars then you could charge up to 40A on that cable.

To test if you have the 72A charger you need to go to a destination charger that is listed as 16kW on the screen like the example pic here. To find one you can use the cars nav screen or you can use the find us website.

If you plug into a destination charger and you get all 16kW at 72A then obviously you have the 72A onboard charger if it stops at 40A you have the standard charger. However if it does 40A just for the sake of verifying results I'd go to another station that was also listed as 16kW and see if it goes past 40A because they could've mislabeled it or there could be a power issue at that location. Also i dono about the 72A ones because i have the dual chargers in mine that go to 80A but there is a pause when it gets to 40A where it takes like 30 seconds or so to start kicking up past 40A so plug in and sit for a few minutes.

Lastly if you do have a 72A charger and you have the need to fast charge at your home you can look into buying a gen 2 HPWC which will max out at 80A (even though your car will only accept up to 72A) someone correct me if I'm wrong but i think the gen 3 HPWC is the one that nerfed the speed to like 48A or some lame ass *sugar* like that.

 

[ucmndd]

how do you know you dont have the 72kW charger? have you tested to see? The charger is inside the car under the rear seats and aint small. The UMC that came with the car is what you are talking about a Universal Mobile Connector not a charger.

with the gen 2 UMC that you have the max charge speed it will give is 32A which is 7kW. if you had a gen 1 cable like those of us with older cars then you could charge up to 40A on that cable.

To test if you have the 72A charger you need to go to a destination charger that is listed as 16kW on the screen like the example pic here. To find one you can use the cars nav screen or you can use the find us website.

If you plug into a destination charger and you get all 16kW at 72A then obviously you have the 72A onboard charger if it stops at 40A you have the standard charger. However if it does 40A just for the sake of verifying results I'd go to another station that was also listed as 16kW and see if it goes past 40A because they could've mislabeled it or there could be a power issue at that location. Also i dono about the 72A ones because i have the dual chargers in mine that go to 80A but there is a pause when it gets to 40A where it takes like 30 seconds or so to start kicking up past 40A so plug in and sit for a few minutes.

Lastly if you do have a 72A charger and you have the need to fast charge at your home you can look into buying a gen 2 HPWC which will max out at 80A (even though your car will only accept up to 72A) someone correct me if I'm wrong but i think the gen 3 HPWC is the one that nerfed the speed to like 48A or some lame ass *sugar* like that.

View attachment 757590

Or instead of all that effort, you can just look at the charging screen on the car when not plugged in, and it will say either “0/48 amps” or “0/72 amps”.

 

[airborne spoon]

Or instead of all that effort, you can just look at the charging screen on the car when not plugged in, and it will say either “0/48 amps” or “0/72 amps”.

perhaps you have a different screen than i do in my 2014. If i have the 14-50 plug on the UMC it says x/40A even though i have dual chargers. the only way my car will show more Amps is to plug into something that gives more juice like the HPWC i installed at my moms house for when i visit her or to use a destination charger that can go to 80A, even if i plug into a destination charger that's set to 40 A it still says 40/40A. like i often charge off a 120v wall outlet so the car says 10/12A not 10/80A

 

[ucmndd]

perhaps you have a different screen than i do in my 2014. If i have the 14-50 plug on the UMC it says x/40A even though i have dual chargers. the only way my car will show more Amps is to plug into something that gives more juice like the HPWC i installed at my moms house for when i visit her or to use a destination charger that can go to 80A, even if i plug into a destination charger that's set to 40 A it still says 40/40A. like i often charge off a 120v wall outlet so the car says 10/12A not 10/80A

When UNPLUGGED, the car will show the max amps supported by the onboard charger(s), like so:

When plugged into an EVSE, the car will show whatever the negotiated max current is between the car and the EVSE, like so when plugged into my Gen 1 UMC:

This is on v11, although the information has always been displayed somewhere in a similar form.

 

[airborne spoon]

When UNPLUGGED, the car will show the max amps supported by the onboard charger(s), like so:

When plugged into an EVSE, the car will show whatever the negotiated max current is between the car and the EVSE, like so when plugged into my Gen 1 UMC:

This is on v11, although the information has always been displayed somewhere in a similar form.

Mine still has the bug for V11 where it doesn't show *sugar* on the charging screen. I don't recall what it said on the old version, if it does then that is pretty convenient

 

[Rocky_H]

Mine still has the bug for V11 where it doesn't show *sugar* on the charging screen. I don't recall what it said on the old version, if it does then that is pretty convenient

I have an old 2014 car, and it doesn't have V11 (thank goodness). But this is how the cars have always worked. Whenever the car is UNPLUGGED, you can always go to the charging screen, and it will show the maximum amps of your onboard charger(s) on the screen.