Has anyone figured out how to change the charge current of a Tesla home charger using their API? I do not have a Powerwall. The current is adjustable with my phone app, but I would like to control it with a non-phone device. I can already control many car functions, but I want to extend that to control the charging current.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Adjusting home charger current using API and NO Powerwall.
- Thread starter clinquist
- Start date
davewill
Active Member
Just for a little clarity, the phone app changes the car's setting not the wall connector's. The car API is documented and can be used.
Um. Got a Gen 2 WC. No web UI. There are, however, a pair of rotary switches with which one can set the configuration of the WC. One of those configuration settings tells the WC what the amperage of the circuit it’s connected to.
At my place, that’s 60A. The car talks to the WC, then more or less sets the max charging current to 80% of 60A, or 48A. Which is correct for the LR Teslas the WC is normally connected to.
However, nothing stops me from setting the circuit limit switches to, say, 40A. In which case the cars hooked up to this WC would pull no more than 32A, that being 80% of 40A. In fact, I think the settings go from 20A to 100A, that last being for certain Model S’s that could pull 80A, back in the day.
My understanding is that the Gen 3 WC doesn’t use switches, but has a “commissioning” step on its GUI that has the same function. And would cause any car hooked up to the WC to limit the car’s current draw to a max of 80% of the limit set.
Two caveats: First, by all that’s holy, never set the WC’s circuit limit higher than the amperage of the circuit it’s actually hooked up to. That way lies madness, popped circuit breakers, and a non-zero chance of a fire, so Be Careful.
Second, if this wasn’t clear: the actual current is the lowest of what the WC says it can supply or what the car figures it can accept, the latter including any fiddling around with the max charge current setting on the car’s GUI.
At my place, that’s 60A. The car talks to the WC, then more or less sets the max charging current to 80% of 60A, or 48A. Which is correct for the LR Teslas the WC is normally connected to.
However, nothing stops me from setting the circuit limit switches to, say, 40A. In which case the cars hooked up to this WC would pull no more than 32A, that being 80% of 40A. In fact, I think the settings go from 20A to 100A, that last being for certain Model S’s that could pull 80A, back in the day.
My understanding is that the Gen 3 WC doesn’t use switches, but has a “commissioning” step on its GUI that has the same function. And would cause any car hooked up to the WC to limit the car’s current draw to a max of 80% of the limit set.
Two caveats: First, by all that’s holy, never set the WC’s circuit limit higher than the amperage of the circuit it’s actually hooked up to. That way lies madness, popped circuit breakers, and a non-zero chance of a fire, so Be Careful.
Second, if this wasn’t clear: the actual current is the lowest of what the WC says it can supply or what the car figures it can accept, the latter including any fiddling around with the max charge current setting on the car’s GUI.
IvesSM
Member
Tronguy. I read your posts. I also installed a Wall Connector @ my house. 60A breaker, car senses 48A available and sets its draw accordingly.
On day one I set the current draw to 24A in the cars ControlPanel->Charging, and it maintains that for each time I plug in at home. I don't remember if it sets based on charging port info or GPS but suffice to say, it charges @ 24A. No rush charging over night and everything runs cooler @ 24A.
I would guess you're aware of this?
-stew
On day one I set the current draw to 24A in the cars ControlPanel->Charging, and it maintains that for each time I plug in at home. I don't remember if it sets based on charging port info or GPS but suffice to say, it charges @ 24A. No rush charging over night and everything runs cooler @ 24A.
I would guess you're aware of this?
-stew
Its clear that the current supplied by a Gen3, and probably a Gen2 as well, is dynamically controlled at least in part by the HPWC side. In the case of a singular HPWC, the Gen3 HPWC can detect its input lugs/circuit board overheating and either disable or reduce current. I suspect the Gen2 can do that as well, at least for handle temperature. Its much more clear that's done in the sharing case, where there's no way the two(or more!)sharing cars will by chatting about how much each should be allowed to take, and its dictated rather by the HPWCs that are configured for sharing.
@IvesSM
Absolutely. That's why I put in that bit, "What the car figures it can accept." The car can figure that based upon what the Battery Controllers say or what somebody puts into the car's GUI. Once again, the lowest value winning.
As a random example, suppose that one has the following:
- The HPWC set to 60/48A (i.e., 60A circuit, 48A max draw)
- The car set to 20A through the GUI
- One has a SR Tesla that has but two of those 16A modules, and can therefore draw no more than 32A, period.
The lowest of the 48A/32A/20A is the GUI setting.. But, there's more!
Say one is about to go on a long trip and has set the max charge to 100%. The car's battery controllers keep track: At some point, 20A is too much and the car will limit the max charge rate to an ever-decreasing value, bottoming out at 5A or something, or whatever the car's computer and the battery management firmware says the max charge rate is. Note that if the battery is too cold (it might be -5F outside?) the battery management software will limit the current for those reasons, too, or at least until the battery gets warmed up.
Going back to your comment, however: I've heard the occasional complaint, usually after a software update, that the car will lose the charge limit and/or localization (i.e., where that charge limit is enforced) from time to time. So, one might have set the limit to 24A; but, then after the next gee-whiz update, the car might lose that information. In which case, putting the limit into the HPWC settings is a bit more permanent since the HPWC is unlikely to lose that information.
No biggie.
Similar threads
