I suspect a software engineer coded the limitation in without a good understanding of the true engineering limits. Similar to how the original Model S would limit itself to 20A charging from 120V sources. That limit made no sense, and neither does this one.
dhanson865
Active Member
Seems reasonable to me.
My Leaf has a 16a charger and I often see over 240v in my garage. So the charger starts pulling at x.5a and then floats around up to x.7a sometimes depending on the voltage. I see the same even if i limit x to 14 or 12 or 10. It doesn't care about the max limit it seems to try to honor the pilot signal request or float around the starting KW as the voltage varies. I'm not sure the logic but it sure isn't power limited (on a 50a circuit, 14-50 socket, 30a evse, 16a on board charger and it'll still floats around between 11.5a and 11.7a when my voltage varies from 241 to 246). Leafspy shows 2.5 or 2.6KW on a 12a setting for the EVSE (some rounding or truncation there).
I'd be fine with it pulling 12a no matter what and the KW fluctuating instead but it doesn't.
so if 72a x 240v = 17,280 watts aka 17.28 KW I wouldn't be surprised if the charger floats around 17.3 KW or less even if the hardware could handle more.
flankspeed8
Member
Another poster mentioned the 72amp charger is now a $1500 upgrade. This again does not make the single charger argument any stronger.
Price hikes
Price hikes
pvogel
Member
Depends on your state of charge on the batteries. Lithium battery charging involves two phases: Constant Current (deliver a steady current to the batteries) and Constant Voltage. During the Constant voltage phase the voltage from individual cells is checked and cells whose voltage is at the desired voltage have alias applied to them while cells below the desired voltage do not (this is called balancing and is absolutely critical to the life and safety of the pack) the amps are slowly ramped down during the CV phase until there is at most a 1-2mV (usually 0 mV) difference in the tested voltage of each cell in the pack.
The charger is designed for whatever maximum current it is designed for and/or set for by the installer based on the load calculation for the available supply. It won't go above that load no matter what you ask for or how fluctuations in the supply voltage would or would not allow based on watts. When considering what's acceptable AC use in any install, AMPs, not watts, are the figure of relevance.
Axmann Philippe
Member
Apparently, it does not work in Europe (or in France at least). When I type "charger" or "chargeur" in french, nothing change. Do you know if the charger is different from country to country?
satheesh.net
President | Tesla Owners Club Norway
All Model X' delivered to Europe has 16,5kW charger. Nothing more, nothing less. And you can only get this option, there is no other option to choose from - unfortunately.
Axmann Philippe
Member
So if I understand correctly, it correspond to the 72amp charger right?
16,500 / 230V = 71,7amp! or I'm missing something?
WarpedOne
Supreme Premier
andrewket
Well-Known Member
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ecarfan
Well-Known Member
how do you know that with such certainty?
Unless you work for Tesla, you do not have access to that information.
satheesh.net
President | Tesla Owners Club Norway
Weren't all Signatures in the US offered with 72A only as well? Then all production models offered with the smaller charger as standard?
Cyclone
Cyclonic Member ((.oO))
If I recall correctly, in the US, Founders got 72 amp by default, Sig got 48 amp by default with 72 amp a free upgrade if you request it. Production is a paid upgrade for 72 amp.
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dhanson865
Active Member
Model X is 48a or 72a. No 40a chargers in Model X anywhere. 48a is 20% more power, but more than 20% faster charging if you are on a HPWC that can do the KW.
If you wonder how can 20% more power exceed 20% faster charging, that comes down to net vs gross. It's 20% more gross, the overhead/vampire drain is fixed, so the additional energy goes straight to the battery (minus charging inefficiencies) and the Net increase is more than 20%.
Mark Z
Active Member
The early Model X Signature vehicles came with the 72 amp charger by default. I never read that any Signature had a 48 amp charger. We paid for a fully optioned vehicle, so it wouldn't make sense to ship 48 amp chargers for any Signature buyer.
Not sure what the "Design Studio" options would show today for the remaining Signatures that have yet to configure.
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Cyclone
Cyclonic Member ((.oO))
On the Wall Connector instructions for electricians the table says it’s possible to charge Model X at 45 miles/hour with a 100amp circuit and 40mph with an 80amp. If the onboard charger is 72amp why is there a difference?
https://www.teslamotors.com/sites/default/files/downloads/charging_wall_connector.pdf
https://www.teslamotors.com/sites/default/files/downloads/charging_wall_connector.pdf
Its the source circuit amp. 80% of 80 amp = 64 amps < 72 amps (the max that the X upgraded charger can take). The 100 amp can deliver 79-80 amps to a dual charger Model S, a little more than the Model X upgraded charger can handle, but will only take max 72 from it. Hope that helps!
Circuits are derated at 80% with continuous loads so a 100 amp circuit will supply 80 amps (slightly exceeding the 72 amp onboard charger) while the 80 amp circuit will supply 64 amps (slightly below the 72 amp onboard charger).
64 / 72 = 0.88
0.88 * 45 mph = 39.6 (or ~40 mph)
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