Model 3/Wall Connector charge current limited to 16 Amps?

[gfunkdave]

So, what about a workplace with a single 2-headed ChargePoint? Or 2 of them (4 heads)? What's the side-effect? Voltage is <208 V so assuming it is 208Y/120V ?

That would be fine. The issue is that the installing electrician will do his/her best to spread the potential load evenly among phases. But if you're only installing one charger of course you wouldn't be able to split it among three phases. The goal is to keep the demand on all three phases roughly in balance throughout the power grid, which enables generators to run more efficiently, with less wear and tear, and also lets the utility run thinner neutral lines (since neutral just carries the imbalance between phases).

Same as when you put in a generator transfer switch and try to keep the load roughly equal between the two legs of the split phase.

 

[eprosenx]

So, what about a workplace with a single 2-headed ChargePoint? Or 2 of them (4 heads)? What's the side-effect? Voltage is <208 V so assuming it is 208Y/120V ?

Yeah, you just try to balance the phase loads as equally as possible. Sometimes you can't and that just means you have excess capacity on one phase that is under utilized (you had to size things for the max loaded phase).

I would have to look at the ChargePoint units, I think some of the dual head units may have both cars share one circuit, others have two supply circuits (which you can permute on different phase pairs). But yeah, from a pure optimal standpoint you would install units in sets of three...

 

[yuhong]

That was my understanding as well. So presumably they put in some kind of switch to allow one of the chargers to switch from one phase to a different phase (so two chargers can be tied to a single phase).

My further question is: Can you charge at 48 amps single phase if you found a single phase charger that could provide that? Or is that not a "thing" in the EU? Does the standard (plugs/receptacles) even support that as an option? (my guess is no, I am guessing 32a per phase would be the limit).

Also- Tesla's in the US have a proprietary Tesla connector. Due to the fact that residential in the US is all single phase (well, split single phase) they optimized all the charging designs around large ampacity single phase charging. There are only two current carrying conductors in the cable itself. So when you install chargers in commercial locations you end up needing to split them up so they equally use all three phases. Typically in commercial installs, the phase to phase voltage is 208v and the phase to neutral is 120v. So the EV charging is nearly universally hooked up phase to phase which gives you 208v (residential setups are 240v phase to phase). You have to permute your chargers to have equal numbers on L1-L2, L2-L3, and L3-L1.

The Wall Connector in the US can take up to 80a of current and deliver it to a car (on a 100a breaker). All current production US model Tesla's though only can do 48a (except for SR/SR+ which only does 32a).

There is a 3x63A option in the Type 2 standard, but that is commonly used only by the Zoe. Many European utilities have a limit on how much single phase load can be served.

 

[EfficientWatts]

That was my understanding as well. So presumably they put in some kind of switch to allow one of the chargers to switch from one phase to a different phase (so two chargers can be tied to a single phase).

My further question is: Can you charge at 48 amps single phase if you found a single phase charger that could provide that? Or is that not a "thing" in the EU? Does the standard (plugs/receptacles) even support that as an option? (my guess is no, I am guessing 32a per phase would be the limit).

Yes I found this post! I knew someone asked if one could do > 32 amp single phase on a 3ph car...

This is anecdotal evidence, but I ran across a youtube video of an Australian model 3 owner who had a HPWC that apparently did 40A single phase but has the Type 2 connector. (https://www.tesla.com/sites/default...ts/Wall_Connector_Install_Guide_Australia.pdf) I noticed in his video that at home the model 3 reported a possible 40 amp max setting. I asked if his model 3 could charge at the full 40 amps and he said yes.

The only thing I wonder is if on the connector side there's some funny commoning or bonding going on, but if not then the car is internally able to bond and go higher than 32 amps on a single phase.

Still doesn't answer your 48 amp question but it seems like we can at least go above 32 amps...

 

[eprosenx]

Yes I found this post! I knew someone asked if one could do > 32 amp single phase on a 3ph car...

This is anecdotal evidence, but I ran across a youtube video of an Australian model 3 owner who had a HPWC that apparently did 40A single phase but has the Type 2 connector. (https://www.tesla.com/sites/default...ts/Wall_Connector_Install_Guide_Australia.pdf) I noticed in his video that at home the model 3 reported a possible 40 amp max setting. I asked if his model 3 could charge at the full 40 amps and he said yes.

View attachment 549811

The only thing I wonder is if on the connector side there's some funny commoning or bonding going on, but if not then the car is internally able to bond and go higher than 32 amps on a single phase.

Still doesn't answer your 48 amp question but it seems like we can at least go above 32 amps...

So the question is:

Does the EVSE have all the “hots” tied together externally, or do the onboard chargers have the ability to flip between phases? And if they can flip between phases, can just one of them flip or cans two of them?

Also, I realized if you tie the hots together (internally or externally) you could overload the neutral in the cord since the current won’t cancel from multiple phases (it will be additive). So that must be accounted for.

The more I think of it, due to the neutral overload issue you can’t just externally tie things together and expect it to be OK. The switchover must be done inside the Tesla and the question is if only one module can switch over, or if two are capable.

 

[EfficientWatts]

So the question is:

Does the EVSE have all the “hots” tied together externally, or do the onboard chargers have the ability to flip between phases? And if they can flip between phases, can just one of them flip or cans two of them?

Also, I realized if you tie the hots together (internally or externally) you could overload the neutral in the cord since the current won’t cancel from multiple phases (it will be additive). So that must be accounted for.

The more I think of it, due to the neutral overload issue you can’t just externally tie things together and expect it to be OK. The switchover must be done inside the Tesla and the question is if only one module can switch over, or if two are capable.

It does seem to be on the car side, especially since based on the wiring diagram I don't see any indication of any funny business going on into the handle.

I kinda assumed that in NA cars that the chargers operate in some form of bonded mode all the time, and originally thought that only 2 of the 3 chargers were in EU cars. However it probably makes sense to leave that capability in there for all 3 chargers even in EU as if 1 of the 3 modules fails you can still charge at a full 32A single phase, you can rotate usage if you want to balance wear and tear, and in terms of production you don't have to worry about shipping a 2 out of 3 bonded AC charger for EU cars and 3 out of 3 bonded for NA cars.

(I am kind of making up some terms here and do not know the technical names for whatever I'm describing above, but I think you get the jist).

 

[eprosenx]

It does seem to be on the car side, especially since based on the wiring diagram I don't see any indication of any funny business going on into the handle.

I kinda assumed that in NA cars that the chargers operate in some form of bonded mode all the time, and originally thought that only 2 of the 3 chargers were in EU cars. However it probably makes sense to leave that capability in there for all 3 chargers even in EU as if 1 of the 3 modules fails you can still charge at a full 32A single phase, you can rotate usage if you want to balance wear and tear, and in terms of production you don't have to worry about shipping a 2 out of 3 bonded AC charger for EU cars and 3 out of 3 bonded for NA cars.

(I am kind of making up some terms here and do not know the technical names for whatever I'm describing above, but I think you get the jist).

Several thoughts: Even in the US we have some cars with 2x16a modules and some with 3x16a modules depending on which one you paid for. The theory is that they just don’t populate the electronics on the PCB for the lower end version.

The “European” cars need to be able to handle three phase power (so each of the two or three modules that they have are connected to different phases), but those same cars need to have some switching mechanism so that at least one of the chargers can flip phases to parallel up with another charger so they can do 32 amp single phase charging.

I wish I knew more about how Tesla is building the European cars!

The two or three US car chargers are always paralleled up since the cars never accept three phase.