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Tesla to add the ability to Charge EV with excess solar
- Thread starter holeydonut
- Start date
CrazyRabbit
Active Member
I’m qualified, I slept in a holiday inn express last night!
There is one setting in there that can’t be changed once set (other then support), which I think might have been solar export limits.
Cool so there’s a strong chance the Tesla software (assuming this is ever enabled) will simply communicate with your car and instruct it to charge at whatever amps will soak up
Edit, ok so I mis-read your picture. Hypothetically if your solar system were generating more than what your home was using, then ideally the software would instruct your vehicle to soak up the excess. In your posted picture, presumably the car wouldn't be charging at all.
The ChargeHQ software (which also interacted with the Tesla API) refreshed once per minute. So cloudy skies or home loads that were intermittent would result in the home + EVcharging using more energy than was produced by the solar array.
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I use Home Assistant and have both the official bundled Tesla integration and the custom HACS integration installed. I use the bundled integration to manage my Powerwalls and the other for my vehicles.
My workflow for the automation, simplified, is something like this: IF Powerwall charging status goes from on to off WHEN the Powerwall SOC > 99% AND the time of day < 15:00:00, start a script which starts charging whichever vehicle is plugged in, calculates excess/backfeed solar, and adjusts charging amperage on the vehicle to match that excess. It re-evaluates every 5 minutes or until either the car is finished charging or the time is 15:00:00, when it will stop charging my vehicle. If the vehicle finishes charging prior to 15:00:00, I get a push notification alerting me that I'm backfeeding off-peak, which means I can plug the other vehicle in, or run whatever energy hungry thing I would like to run at that time.
Hope this makes sense.
Yeah I just took that screenshot as the sun is going down. I just wanted to show the energy flow. I understand with a power wall there would be a bit more going on at that screen. Mine is just panels.
You basically described what ChargeHQ was doing... except they refreshed once a minute. So I assume Tesla is just going to do the same thing with the same data... except make it part of their app.
I am interested how this is going to work if there are two Teslas in the household (and two EVSEs). If it will charge them in series or in parallel - or allow the user to choose.
But first things first, they gotta implement the feature
. So many people claim the grid is "dirty" as an attack on EVs. Having this type of feature seems like a slam dunk to dispel the issue of where the energy is coming from.
I just changed mine to once a minute. Honestly doubt it matters much since at the time of day this is happening, things don't change that quickly.. but it costs nothing to look more often.
That does make sense! Well done. It matches what I was imagining, and I hope Tesla launceseit follows the same logic, and that it works on my system.
I wonder where the operating code will be run. I'm not clear on exactly how the current EV Charging settings do what they do, but it seems to imply that there can be communication between the PW and the car. So, perhaps this new feature will be something the PW monitors and manages. In the Home Assistant model, the HA host does this. Having to leave my Mac running or get a Pi gave me pause about saving pennies per day. If the PW gateway can do it, cool!
We'll see... Thanks.
Based on data returned by the API, the current EV charging setting seems to do the charging control using frequency shifting. Obviously this can only happen when the grid is down, so they'll have to come up with a new way of communicating for this feature.
The frequency shift is clever, since any Tesla presumably will respond to it, even if it's on a different account.
reference (/api/operation):
JavaScript:
{
"real_mode": "autonomous",
"backup_reserve_percent": 33.5,
"freq_shift_load_shed_soe": 90,
"freq_shift_load_shed_delta_f": -0.32
}I've been hoping for this integration to happen. And it has taken a long time if it really is coming. I'd like to see the app be able to lock in the current state of charge of my powerwalls so I'm not charging the car from my powerwalls. Right now I have to do this manually. And I'd like to have charging start after for example my powerwalls reach a certain level and there is excess solar, then stop charging when solar goes away. Each user is going to have different amounts of excess solar and charging needs. I have a lot of excess production which I installed just so I can charge a car. I have been successful in charging both the car from about 40% to full and my 2 powerwalls in a single sunny day.
Imagine if @h2ofun ever finds a BEV that isn't "too small" for him and he fills his garage with 5 BEVs connected to 5 EVSEs. He'll have to add more solar panels to keep up with the demand.
CrazyRabbit
Active Member
I hope this api would include some logic for when off grid that if powerwalls are full that the car will charge from powerwalls so that solar can resume, state of charge <97%.
But in any case user should be given preference for what to charge first, car(s) or powerwalls.
I produce 18kw now, probably 20kw come summer, and car only uses a small fraction of that. So I will probably give preference to fill car first..
But in any case user should be given preference for what to charge first, car(s) or powerwalls.
I produce 18kw now, probably 20kw come summer, and car only uses a small fraction of that. So I will probably give preference to fill car first..
This will make for a nice optimization to save some NBC charges for the times when one or both of the BEVs are home during the day AND they didn't already charge to their limit the night before. Typically I charge at night so if a car is still sitting at home the next day (i.e. didn't go into the office or it's a weekend) it's already going to be at the charge limit. I wonder if the app will allow one charge limit setting for the scheduled charge time and a different limit to be used for excess solar charging. I could then lower my nightly limit (say instead of 80, set it to 60) and allow excess solar to do top-offs to 80.
CrazyRabbit
Active Member
I do it manually, plug in when I got good solar. Today charging MY, doing laundary with hot water, running dishwasher, and got heat set at 70 degrees inside. I got a 250kwh surplus this billing period, so I got heat set at 70!
Jeremy3292
Active Member
It's a lot more than just someone finding strings in the app:
Tesla app update introduces 'Drive on Sunshine' and other new features
Tesla has updated its phone app to version 4.19, bringing new features like "Drive on Sunshine" to Tesla owners.
www.teslarati.com
Jeremy3292
Active Member
That article and all others you find are solely based on the fact that there are new strings in the latest app version now…It's a lot more than just someone finding strings in the app:
Tesla app update introduces 'Drive on Sunshine' and other new features
Tesla has updated its phone app to version 4.19, bringing new features like "Drive on Sunshine" to Tesla owners.
It's a lot more than just someone finding strings in the app:
Tesla app update introduces 'Drive on Sunshine' and other new features
Tesla has updated its phone app to version 4.19, bringing new features like "Drive on Sunshine" to Tesla owners.
If you click the article you linked to (the teslarati article) they have a statement in there that says "allows you to drive on sunshine" and those words are a link. If you click THAT link, it goes to another one of their articles that.... points back to the same "someone finding strings" stuff that is mentioned by @Jeremy3292 .
So, At this point at least, its just someone finding strings in the app, even according to the article you linked to.
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