Everyone's been asking me for details on supercharger speeds.
I think it's time to do an FAQ on this and break things down on the technical side.
Post your Model S/X supercharging questions below, and I'll update this top post with as many answers as possible. I'll also add in some additional ones.
(Hopefully can make this work with my TMC account as it sits.)
Keep non-supercharging related stuff out. No range loss stuff, lawsuit talk, NHTSA stuff, etc.
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Q/A: (Will sort these eventually. Don't worry if I skipped you, just getting simple stuff initially)
kWh is a measure of energy capacity. Some algebra:
kWh = Ah * nominal_voltage
Ah = kWh / nominal_voltage
nominal_voltage = kWh / Ah
(Ah = amp-hours)
kW is a measure of power. Specifically, kilojoules per second... where 1kJ = ~0.278 Wh.
kW = (volts * amps)/1000
So if you're charging at home on 240V at 40A, you're getting 9.6 kW of power into the charger (and some amount less than that into the battery after conversion losses). In 1 hour you'll have added 9.6kWh (minus losses) of energy into the battery pack.
For supercharging, the same applies. If you're getting 350V at 300A, that's 105 kW. Alternatively, you can algebra this to get amps from amps = (kW*1000 / volts).
Unfortunately Tesla hides this data on vehicles now, so you can't easily calculate current/voltage anymore without CAN tools.
For most electrical things, including batteries, things are limited by current, not by power. For supercharging, the peak is around ~375A for non-gen3 units... which means in practice most vehicles will never hit that 150kW mark.
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Buy a P100D.
Jokes aside, the early 90 packs are pretty horrible. Your low mileage is helping you, but you'll eventually get lower charge speeds the more the pack is used and/or supercharged. The chemistry of the early 90 packs is just really bad, degrading twice as fast or worse than 85 or 100 type packs (or late 90 packs that use 100-type cells).
In short, there's not much you can do except limit use and hope for the best.
---------------------
All cars with the automatic charge port have decent thermal sense at the port. Superchargers have sensors in the handle itself also. Older magnetic ports (2014 and older, some 2015) have only one thermal sensor and... well, it's pretty bad and no helpful.
The charge port and associated components are definitely a bottleneck for high current charging. They're original testing was for about 200A continuous, and they're now pushing 375A+ into them peak, which is pretty crazy.
In short, most likely cause of dipping from peak that doesn't fit with the battery's capability is thermals at the charge port either in the port, the handle, or the pins themselves.
---------------------
More soon as time permits.
I think it's time to do an FAQ on this and break things down on the technical side.
Post your Model S/X supercharging questions below, and I'll update this top post with as many answers as possible. I'll also add in some additional ones.
(Hopefully can make this work with my TMC account as it sits.)
Keep non-supercharging related stuff out. No range loss stuff, lawsuit talk, NHTSA stuff, etc.
---------------------
Q/A: (Will sort these eventually. Don't worry if I skipped you, just getting simple stuff initially)
kWh is a measure of energy capacity. Some algebra:
kWh = Ah * nominal_voltage
Ah = kWh / nominal_voltage
nominal_voltage = kWh / Ah
(Ah = amp-hours)
kW is a measure of power. Specifically, kilojoules per second... where 1kJ = ~0.278 Wh.
kW = (volts * amps)/1000
So if you're charging at home on 240V at 40A, you're getting 9.6 kW of power into the charger (and some amount less than that into the battery after conversion losses). In 1 hour you'll have added 9.6kWh (minus losses) of energy into the battery pack.
For supercharging, the same applies. If you're getting 350V at 300A, that's 105 kW. Alternatively, you can algebra this to get amps from amps = (kW*1000 / volts).
Unfortunately Tesla hides this data on vehicles now, so you can't easily calculate current/voltage anymore without CAN tools.
For most electrical things, including batteries, things are limited by current, not by power. For supercharging, the peak is around ~375A for non-gen3 units... which means in practice most vehicles will never hit that 150kW mark.
---------------------
Buy a P100D.
Jokes aside, the early 90 packs are pretty horrible. Your low mileage is helping you, but you'll eventually get lower charge speeds the more the pack is used and/or supercharged. The chemistry of the early 90 packs is just really bad, degrading twice as fast or worse than 85 or 100 type packs (or late 90 packs that use 100-type cells).
In short, there's not much you can do except limit use and hope for the best.
---------------------
All cars with the automatic charge port have decent thermal sense at the port. Superchargers have sensors in the handle itself also. Older magnetic ports (2014 and older, some 2015) have only one thermal sensor and... well, it's pretty bad and no helpful.
The charge port and associated components are definitely a bottleneck for high current charging. They're original testing was for about 200A continuous, and they're now pushing 375A+ into them peak, which is pretty crazy.
In short, most likely cause of dipping from peak that doesn't fit with the battery's capability is thermals at the charge port either in the port, the handle, or the pins themselves.
---------------------
More soon as time permits.
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