Tesla to add the ability to Charge EV with excess solar

[miimura]

Our Model 3 finally got 2023.27.6 and I enabled Charge On Solar. When I plugged in after the Powerwalls were at 100% it worked perfectly. However, I manually stopped it at 2:57, just before the rate increase, so I don't know what it will do at that point. I would like to only charge on surplus solar that would otherwise be exported and I want to only charge during Off-Peak. As of yet, I'm not sure this feature will follow my desires.

I'm also dreaming that the Universal Wall Connector could provide the same functionality for my non-Tesla vehicle by modulating the pilot signal. However, there's no evidence of that yet.

 

[jjrandorin]

I havent even turned this feature on, because even though I like the idea of it, I dont like the idea of it waking the vehicle up hourly, and adding a strange powerwall key:

Tesla Charge on Solar keeps waking vehicle up

Tesla's new Charge on Solar keeps waking the vehicle up every hour, even though there is insufficient excess solar to support charging. Below is the current state of the Powerwall, at only 89% full. It has not yet begun to charge the vehicle today. But the vehicle has been waking up every...

teslamotorsclub.com

@power.saver (or anyone else who might know), have these issues been resolved? I dont want to even think about trying it until or unless those things are resolved, for myself.

 

[power.saver]

I havent even turned this feature on, because even though I like the idea of it, I dont like the idea of it waking the vehicle up hourly, and adding a strange powerwall key:

Tesla Charge on Solar keeps waking vehicle up

Tesla's new Charge on Solar keeps waking the vehicle up every hour, even though there is insufficient excess solar to support charging. Below is the current state of the Powerwall, at only 89% full. It has not yet begun to charge the vehicle today. But the vehicle has been waking up every...

teslamotorsclub.com

@power.saver (or anyone else who might know), have these issues been resolved? I dont want to even think about trying it until or unless those things are resolved, for myself.

The delay to start at top of the hour still exists, it happened to me again today. Powerwall was full at 1:35pm, vehicle didn't start charging until 2pm exactly. I haven't checked on the hourly wakeup, but that may have been fixed with one of the recent updates.

I can say in response to @miimura that COS will stop when it gets to your Peak time. I don't have partial peak (only Peak and Off-Peak) and it always stops at 4pm when Peak starts.

 

[h2ofun]

I havent even turned this feature on, because even though I like the idea of it, I dont like the idea of it waking the vehicle up hourly, and adding a strange powerwall key:

Tesla Charge on Solar keeps waking vehicle up

Tesla's new Charge on Solar keeps waking the vehicle up every hour, even though there is insufficient excess solar to support charging. Below is the current state of the Powerwall, at only 89% full. It has not yet begun to charge the vehicle today. But the vehicle has been waking up every...

teslamotorsclub.com

@power.saver (or anyone else who might know), have these issues been resolved? I dont want to even think about trying it until or unless those things are resolved, for myself.

Zero interest in it, not enough flexibility.

 

[swedge]

I havent even turned this feature on, because even though I like the idea of it, I dont like the idea of it waking the vehicle up hourly, and adding a strange powerwall key:

Re: strange Powerwall key, the car needs a key to communicate securely with the PW. To do CoS, the car needs information about the powerwall status, and also communicates the car's charging rate to PW which is then displayed in the PW page of the app. PowerWall protects it's communications, of course, because they all go over the internet, so they must be secure. Hence the "key".

I also finally got the CoS feature, and am still working to figure out how to get it to do what I want. One thing I did learn, though, is that the car charger needs to be connected so that it's power draw is included in what the PW sees coming from the grid. My charge is on the grid meter side of the gateway. As a result, when CoS is active, the charge rate is wrong, and the app displays incorrect home and car power draws. I believe PW could detect this situation and deal with it correctly, but it does not. I may get my wall charger rewired, but in the mean time I'm plugging the car into a dryer outlet which is on the home side of the gateway.

 

[jjrandorin]

Re: strange Powerwall key, the car needs a key to communicate securely with the PW. To do CoS, the car needs information about the powerwall status, and also communicates the car's charging rate to PW which is then displayed in the PW page of the app. PowerWall protects it's communications, of course, because they all go over the internet, so they must be secure. Hence the "key".

I also finally got the CoS feature, and am still working to figure out how to get it to do what I want. One thing I did learn, though, is that the car charger needs to be connected so that it's power draw is included in what the PW sees coming from the grid. My charge is on the grid meter side of the gateway. As a result, when CoS is active, the charge rate is wrong, and the app displays incorrect home and car power draws. I believe PW could detect this situation and deal with it correctly, but it does not. I may get my wall charger rewired, but in the mean time I'm plugging the car into a dryer outlet which is on the home side of the gateway.

My Wall connectors are on the grid side of my install (they are the only thing that is, actually), but since there is a CT on the circuit, its included in my tesla app, my powerwalls see it, etc. I am reasonably confident that it would work for me, even though my wall connectors are on the grid side.

Have you looked into getting a CT installed so that your non backed up loads can still be served powerwall power?

 

[swedge]

Have you looked into getting a CT installed so that your non backed up loads can still be served powerwall power?

I agree that CoS it will probably work fine with your configuration.

I have not got a bid yet on adding or moving a CT or moving the connection point for the wall charger. I've been pretty happy so far with having my car data separate from my home data because the car is such a huge, intermittent, but mandatory draw. The PW does a nice job of time-shifting solar and home draw, and I'm not clear on how well PW's algorithms would cope with car charging. So I am playing with that now before deciding to re-configure or not. I do have the car's info, plus TeslaFi, plus a separated CT system monitoring the car charging, so I am capturing and using that data.

 

[miimura]

I agree that CoS it will probably work fine with your configuration.

I have not got a bid yet on adding or moving a CT or moving the connection point for the wall charger. I've been pretty happy so far with having my car data separate from my home data because the car is such a huge, intermittent, but mandatory draw. The PW does a nice job of time-shifting solar and home draw, and I'm not clear on how well PW's algorithms would cope with car charging. So I am playing with that now before deciding to re-configure or not. I do have the car's info, plus TeslaFi, plus a separated CT system monitoring the car charging, so I am capturing and using that data.

Shortly after my Powerwall installation, I had the Grid CTs moved from the Gateway switch to the conductors between the main breaker and the main panel bus. The Powerwall system does a great job dealing with Off Peak car charging with Time Based Control. My two car charging circuits and all my un-used high power circuits are not backed up in the main panel. I have circuits for an electric clothes dryer and two air conditioning compressors, which are all un-used and a 50A 240V circuit for a possible electric range which is currently gas. I wish I had also planned for possible heat pump water heater even though I really like the condensing high efficiency tankless gas water heater we have now.

 

[YRide]

I agree that CoS it will probably work fine with your configuration.

I have not got a bid yet on adding or moving a CT or moving the connection point for the wall charger. I've been pretty happy so far with having my car data separate from my home data because the car is such a huge, intermittent, but mandatory draw. The PW does a nice job of time-shifting solar and home draw, and I'm not clear on how well PW's algorithms would cope with car charging. So I am playing with that now before deciding to re-configure or not. I do have the car's info, plus TeslaFi, plus a separated CT system monitoring the car charging, so I am capturing and using that data.

I also have this setup, with 2x wall chargers on the main not backed up. Tesla guys easily wired up two CT’s on each charger circuit, and then spliced them together (didn’t know you could do that), so that there’s 240V being measured on both CT1 and CT2 inside the TEG. There remains one CT3 port left…which im planning to use for the 3rd wall charger. Was actually thinking of a 4th…if you are allowed to splice more then 240V onto a single CT port in the TEG…anyone know that?

Anyways, it’s cool to see the separation out of the car (red) and home (blue) consumption once you turn on CoS.

It’s a bit finicky I’ve noticed…sometimes the car (red) loads don’t show up for a while and then 5min later voila, they’re there. Also, with multiple EV’s it only makes the current primary CoS the “red”…the other secondary CoS shows up within home “blue” loads.

All in all…I’ve been happy with CoS. Still a little buggy, but for the most part works and seems to be ever-improving.

Now having 1) a PW+ inverter brick within 3mo, and 2) now one of my PW’s die due to a FW update a few weeks after that…hmmm.

 

[power.saver]

I also have this setup, with 2x wall chargers on the main not backed up. Tesla guys easily wired up two CT’s on each charger circuit, and then spliced them together (didn’t know you could do that), so that there’s 240V being measured on both CT1 and CT2 inside the TEG. There remains one CT3 port left…which im planning to use for the 3rd wall charger. Was actually thinking of a 4th…if you are allowed to splice more then 240V onto a single CT port in the TEG…anyone know that?

Anyways, it’s cool to see the separation out of the car (red) and home (blue) consumption once you turn on CoS.

It’s a bit finicky I’ve noticed…sometimes the car (red) loads don’t show up for a while and then 5min later voila, they’re there. Also, with multiple EV’s it only makes the current primary CoS the “red”…the other secondary CoS shows up within home “blue” loads.

All in all…I’ve been happy with CoS. Still a little buggy, but for the most part works and seems to be ever-improving.

Now having 1) a PW+ inverter brick within 3mo, and 2) now one of my PW’s die due to a FW update a few weeks after that…hmmm.

CTs are spliced in parallel, so the current adds not the voltage. You can do more than two, but you could also run multiple conductors through the CT to get the same effect.

 

[miimura]

If you have multiple circuits in the same panel that need to be measured and summed, the easiest way is to run multiple wires through each CT. You just have to make sure that in each CT you have running all the wires with current running the same direction and the same phase. This is how my 3 solar circuits are measured - three wires through each CT.

 

[BlueMoon1224]

Finally got all the required firmware updates last week to run Charge on Solar. I’ve checked it several times to find that some of my generation is still going to the grid when I think it shouldn’t be. For example right now I’m generating 6.7 kW. The house is using 1.4 kW, the PowerWall is at 100%. My M3 is getting 2.6 kW and 2.7 kW is going to the grid. The car still has 17% to go to the set charge max. Why is power still going to the grid?

 

[ItsErik]

Our Powerwalls finally updated today so I can set this up now \o/

 

[swedge]

Having CoS enabled while charging from a connection outside of PW's CT really messed up the displays in the app, so I turned CoS off. But the vehicle still showed up in the PW app and munged the data. Worse, CoS itself disappeared from the car app so there was no obvious way to fix it.

Eventually I tried signing out of the app (not quitting, but signing out) and then signing back in, and after a few minutes, this did restore CoS to the car app. Reconnecting CoS and then disconnecting from the PW did restore the PW app to normal display with no car charging displayed.

Others have reported that the downloaded data from the app is bad: PowerWall and Grid power show zero when they are actually negative. The monthly downloads do show grid exports separately, but those number are wrong and differ from the same data in the daily and monthly graphic displays. While others have done so already, I am sending a bug report to [email protected]. Squeaky wheel...

I will also request an option to prioritize PW charging over vehicle. With Export Everything and Grid Charging enabled, it did appear to do a decent job of getting itself to 100% before 3pm when the rate goes up. (PG&E EV2-A). At least on the last couple of days with marginally adequate solar. Still, I'd prefer to be able to select wether to charge the car or the PW first: If I plan to be out in the afternoon, I'd prefer the car first and let the PW charge when the car is out.

 

[YRide]

It’s a bit finicky but usually eventually corrects itself. That said, I haven’t pulled any of the raw data.

Btw, losing access to CoS in the app, try 1) going into the schedule tab, and at the bottom there is text to edit CoS.

Also, if that goes away (I’ve had it happen) you can go into the car itself at the CoS destination and toggle it.

 

[Gwgan]

First full sunny day in weeks. Expecting the car and the PW to charge after solar feeds the house but that’s not what happened. This is during Peak rate time. No change with PW set from time-based to self-powered. Turned off CoS to get car to charge.

 

[rando]

During peak, ordinarily the system would export all solar and run the house from the grid to maximize credits. Since your powerwalls are at 20% (assume that might be your reserve), solar is powering the house and only surplus is exported. We would need to see the whole day and know your settings and rate profile to understand what happened during off peak.

 

[Gwgan]

But why was Vehicle not being treated like House and taking some solar after House and before Export? That’s what happened once I turned off CoS.

I was really expecting the car and the PW to charge on this sunny day. The PW can’t charge from the grid and it wasn’t charging from solar either.

Does it think exporting during peak is more valuable than storing solar when available?

This was not the usual behavior but did come after cloudy or rainy days since Oct 3. Perhaps the AI was confused.

 

[rando]

Mine always export all solar during peak but I haven't ever had them down to the reserve to see how/if that changes behavior. In my area, peak is 4-9pm so only the last few hours of solar production. When there is excess solar during the day (most of the year), the system seems to charge the Powerwalls and the cars in intervals up until one or the other is full or there isn't an excess.

With your TOU rates, it looks like CoS will charge your car and Powerwalls on weekends. During weekdays, I assume your Powerwalls will also only charge up to their reserve with solar. In the evenings, your car will charge to the lower setting. With all day peak rates, there isn't a cost advantage in storing solar.

 

[metalblaze]

New to CoS: we have a newly installed 14.5 kWh + 2PW system with 1:1 net metering. We are still waiting for PTO. So, just experimenting with CoS.

1. This morning when I plugged in our M3, the car had approx. 68% battery left.

2. First both our PWs were topped off at 100% - this is expected behavior.

3. But later in the afternoon (some clouds, 51F outside temp), the M3 stopped charging completely, and energy was exported to the grid - this is not expected behavior.

Can someone please explain what might be happening? Again….still trying to understand how the system should operate.