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Tesla Model 3 LR - can onboard charger do 22 kW

Hello all,

apparently, when charging Model 3 LR from 3phases, it can only charge with 11 kW (230V x 16A x 3). But, when it is being charged through UMC, it can take up to 7 kW (230V x 32A x 1). What I know about the onboard charger on Model 3 (
), it consists of three identical AC to DC converters. I assume only one is used when charging from 1phase. This would mean, when charging from 1phase, single converter is allowed to draw 32 amps, but when charging from 3phase, it is only allowed to draw 16 amps.

I see only two possible reasons why. Either there is really some limit, possible due to thermal losses, that if all three converters would draw 32 amps at the same time, the charger would overheat. Or the other more likely reason, that it is just a limit set in software?

Does anybody know the answer?

Thanks
 

Rocky_H

Well-Known Member
Feb 19, 2015
8,577
11,127
Boise, ID
Yes, we know the answer. The onboard charger does basically have a limit of about 11-12 kW. That's it. That's all it can do. So no, it can't ever do 22 kW.

Internally, it is built with three modules. It is configured a bit differently for the North American cars, where they can only do single phase electricity. There just isn't any 3 phase charging infrastructure readily available here, so the charger isn't built to take that. So all three part of that are set to divide the total amps.

On the European cars, they can operate to have those three internal modules each run on one of the phases for 3 phase charging, with still having about a 12 kW total power limit. But I am not sure how it can adapt if you're giving it only single phase. I think it can dynamically switch to take more than just one third of that if you connect it to a single phase source.
 

miimura

Well-Known Member
Aug 21, 2013
7,397
7,400
Los Altos, CA
The Gen1 UMC with Type-2 Connector that was provided with Classic Model S in Europe bridged the 3 phases on the vehicle side from one phase on the plug adapter. I think later vehicles including Model 3/Y can do that internally - switching between native 3 phase and higher amperage single phase.
 
Thanks for the replies.
I see, so the UMC is most likely connecting the single phase, 32 amp capable source, to 2, possibly all the 3 converters.
That makes sense.
When I saw the video I attached in my original post, it seemed like a single 32 amp phase could not be simultaneously connected to more than 1 converter.
But it makes sense that this can be done within the UMC.
Thanks again, I guess I will sleep better knowing that the onboard charger cannot physically do more than 11kW and it is not just locked by SW.
 

miimura

Well-Known Member
Aug 21, 2013
7,397
7,400
Los Altos, CA
Thanks for the replies.
I see, so the UMC is most likely connecting the single phase, 32 amp capable source, to 2, possibly all the 3 converters.
That makes sense.
When I saw the video I attached in my original post, it seemed like a single 32 amp phase could not be simultaneously connected to more than 1 converter.
But it makes sense that this can be done within the UMC.
Thanks again, I guess I will sleep better knowing that the onboard charger cannot physically do more than 11kW and it is not just locked by SW.
I'm not saying that they still use the UMC to distribute the one phase power to multiple converter phases any more, just that when the Model S was first introduced in Europe with the 3 phase charge port, that was the way it was done. At some point even the Model S was able to internally distribute the single phase power to multiple converter phases somewhere between the charge port and the OBC.
 

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