Limited to 33 Amps?

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beantownrich

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#1
I was looking at my charge menu today. Normally it shows 48 amps as max charge current. Today when I looked it said 33 amps and the plus button was greyed out. I'm at 251 miles (~80-something percent charge) does it always go down while charging and I never noticed it before or is something up.

Recently updated to 32.2 and before that had the BMS campaign performed while at service.
 

garsh

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#2
The Mobile Connector that comes with the car is limited to 32 amps. If you're currently using it to charge, that's probably why it won't allow you to adjust the charge current higher.
 

GDN

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#6
If you were already charged to 80% doesn't the charging slow down at the top of the battery? Or is that only at a Supercharger? Doesn't a WC or even UMC do the same thing at the top end of the battery?
 
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#7
The manual states that if variances in line voltage to the charger are detected, a 25% reduction in current will apply. I'm guessing there was a transient power anomaly that triggered this for you.
 

rsbell

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#8
I’ve run into this same issue today. My HPWC is on a 40 amp circuit, and it has always charged at 40 amps. Today, running 32.2, it wouldn’t charge above 32 amps. I got an error that charging was slowed. Tesla checked and there was definitely a fault. I know the issue isn’t with the charger because it charged our X at 40 amps.

Now’s not a good time for me to take the 3 in to the service center, so I’m going to give it a few days and see if it resolves.
 

Jason F

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#9
I’ve run into this same issue today. My HPWC is on a 40 amp circuit, and it has always charged at 40 amps. Today, running 32.2, it wouldn’t charge above 32 amps. I got an error that charging was slowed. Tesla checked and there was definitely a fault. I know the issue isn’t with the charger because it charged our X at 40 amps.

Now’s not a good time for me to take the 3 in to the service center, so I’m going to give it a few days and see if it resolves.
A 40A circuit should only draw at 32A, which is 80% of max rating. A 60A circuit is needed for 48A charging. Not sure if the new sw is enforcing that for the first time or not.
 

beantownrich

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#10
The manual states that if variances in line voltage to the charger are detected, a 25% reduction in current will apply. I'm guessing there was a transient power anomaly that triggered this for you.
This is the most helpful thing I've read in a while. I never noticed it in the manual. It's interesting I came off a superchager as a previous charge, so it's their own fault :)

You'd think they'd throw a warning in the car to let ya know!
 

rsbell

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#11
A 40A circuit should only draw at 32A, which is 80% of max rating. A 60A circuit is needed for 48A charging. Not sure if the new sw is enforcing that for the first time or not.
Hmmm.

It has shown 40/40 when charging before-and it shows 40/40 in the wife’s Model X...

I haven’t drained it enough to have to recharge. I’ll check it in the next day or so.
 

Jason F

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#12
I
Hmmm.

It has shown 40/40 when charging before-and it shows 40/40 in the wife’s Model X...

I haven’t drained it enough to have to recharge. I’ll check it in the next day or so.
It probably isn't the sw being that smart, but who knows. But you really shouldn't let it charge at 100% of the circuit rating.
 
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#13
A 40A circuit should only draw at 32A, which is 80% of max rating. A 60A circuit is needed for 48A charging. Not sure if the new sw is enforcing that for the first time or not.
While I agree in general that a 20% derating is needed based on the breaker capacity, the OP stated this is a HPWC that has previously delivered 48amps. For that reason, I suspect his breaker is at least 60 amps and that his HPWC is configured for delivery of at least 48 amps continuous (max rate for model 3).