Can someone explain this, I’m

[moswissa]

Hey guys, new Tesla wonder. I recently in installed the 14-50 NEMA outlet drawing 220v and was getting 32a, charging speed of 26-27mph. It would take 8-10 hours to full charge.

With the 120 it would charge 3mph and say “+24h remaining” because of how slow it is.

today, I plugged it in to the 14-50 and it’s only charging at 2mph and reports 6 hours and 20 min left. That doesn’t make send to me if it’s charging that slow, how is it going to complete charging that soon? Is it going to eventually speed up later? I attached a pic for reference.

thanks

 

[jbcarioca]

If you checked immediately after connecting, it does take some time for the charge rate to rise. Further, if there are other loads on the same circuit available amperage will be lower anyway. Amperage and voltage vary under load, but amperage much more so. It should not be so dramatic as you report unless the charge is just beginning.

 

[NYCR160]

Is your A/C on or off.

 

[ilyak]

Cold battery/climate in use - the car is using a bunch of the energy it is drawing from the outlet to warm it up. After an hour or so the number should go up.

 

[Rocky_H]

Cold battery/climate in use - the car is using a bunch of the energy it is drawing from the outlet to warm it up. After an hour or so the number should go up.

It's this, but probably sooner than an hour. It is diverting most of that 32A to just warming up the battery at first, so there is very little going toward the actual charging, so you see that 2 miles per hour charge rate. But then over the next 10, 15+ minutes, it will continue to ramp up the charging speed as the battery gets warmer and it can shift more current from warming to charging.

 

[ilyak]

It's this, but probably sooner than an hour. It is diverting most of that 32A to just warming up the battery at first, so there is very little going toward the actual charging, so you see that 2 miles per hour charge rate. But then over the next 10, 15+ minutes, it will continue to ramp up the charging speed as the battery gets warmer and it can shift more current from warming to charging.

Yeah, an hour or so would only be required if it's very cold out. I've seen several hours before any meaningful charging on a cold-soaked battery in -25F weather but, given that it's April, that's probably not very common now.

 

[Puddles]

It can be a real eye-opener to see how much draw the cabin heater alone can take away from the charging.

 

[Rocky_H]

Yeah, an hour or so would only be required if it's very cold out. I've seen several hours before any meaningful charging on a cold-soaked battery in -25F weather but, given that it's April, that's probably not very common now.

The person asking is in Los Angeles, so I was not figuring extended extreme cold.

 

[rjt!]

It's also possible that the amp setting in the car for that charger got dropped by the car because it detected a fault. Even a transient would be enough for the car to decide it can't get all 32 amps. Check the charge screen when you are plugged in and make sure it is not limited to something lower than 32 amps. You might have lost a 'leg' in your new 240V circuit; that might make the car think it is only a 120 outlet and you might see the same sort of thing - tho I'd hope the car would see an open hot or neutral and refuse to charge at all.

 

[Rocky_H]

It's also possible that the amp setting in the car for that charger got dropped by the car because it detected a fault. Even a transient would be enough for the car to decide it can't get all 32 amps.

Not that, because the picture posted of the display shows that it IS pulling the full 32/32 amps. It just shows a low charging rate in mi/hour because it is not using all of that current for recharging.

You might have lost a 'leg' in your new 240V circuit; that might make the car think it is only a 120 outlet and you might see the same sort of thing - tho I'd hope the car would see an open hot or neutral and refuse to charge at all.

Circuits don't work like that. It has to have a complete loop, and it only uses those two lines for the incoming voltage connection. If one side gets disconnected, you get a broken circuit, and you get nothing, not seeing as if it's 120V. This could be a different matter in European scenarios when using 3 phase that has multiple circuits, but that's not relevant here.

 

[ilyak]

It's also possible that the amp setting in the car for that charger got dropped by the car because it detected a fault. Even a transient would be enough for the car to decide it can't get all 32 amps. Check the charge screen when you are plugged in and make sure it is not limited to something lower than 32 amps. You might have lost a 'leg' in your new 240V circuit; that might make the car think it is only a 120 outlet and you might see the same sort of thing - tho I'd hope the car would see an open hot or neutral and refuse to charge at all.

Screenshot is showing 32/32A and 236V. When the car reduces the current for any reason, it's reflected in the app. It's pulling the full 7.5 kW but using a bunch of it for HVAC or battery heating, perfectly normal.

 

[moswissa]

You guys were all correct! It got up to speed after 15 min and charged in promised time.