Charge On Solar Australia

[Vostok]

I think I found a work-around to prioritise PW2 charging when using CoS. Although you need to be a little bit vigilant with the App in the morning.

On Monday I used CoS to add 90km range to my car, but I waited until the PW2 was full before going to the garage and plugging my car in. Not super-convenient. I left the car plugged in overnight, knowing it would not grid charge with the CoS settings I have.

Yesterday was sunny again so I didn’t want to miss out on pumping up the Tesla with maximum solar. But I wanted the PW2 to fill up first.

So in the morning, once there was enough sun for CoS to start, and the App showed it had started, I swiped over to my car, and simply tapped “stop charging” in the charging panel. The car stopped charging, and all excess solar started filling the PW2 instead. CoS did not restart, because there was no longer enough excess solar.

Once the PW2 was full at midday, there was enough excess solar for CoS to restart, which it did automatically, without any intervention.

I did the same thing this morning once CoS started, and my PW2 has been filling all day. Although it’s been a bit cloudy so it won’t get to 100% and so CoS will not restart.

 

[JonDarian]

I think I found a work-around to prioritise PW2 charging when using CoS. Although you need to be a little bit vigilant with the App in the morning.
....

Great work, Vostok! I am trying that for the first time this morning and it seems to be working. It is a bit annoying to need this manual step to prioritise the PW2, but it is a good technique to know.

Edit: Nope, it just switched back to prioritising the car. Dang it.

 

[Vostok]

Edit: Nope, it just switched back to prioritising the car. Dang it.

Curious. That hasn’t happened to me. Both yesterday and the day before were cloudy and there wasn’t enough solar to fill my PW2 during the day (after stopping car charging in the morning when CoS started) and on neither day did the car charge after that, either from CoS or grid charging at the scheduled time.

I have iOS Tesla App 4.31.0, car is on 2024.2.7, CoS is set to charge from any source up to 30%, and CoS up to 80%. Car SoC is currently above 30%. Is your current SoC above or below your minimum CoS setting?

CoS started this morning once there was enough solar, but I stopped the car charging, and PW2 is now up to 60% with all excess solar going into the PW2, nothing to the grid or the car .

I’ll let you know if CoS restarts after the PW2 fills up - it’s supposed to be sunny all afternoon here.

 

[lazjen]

I hope they add something to prioritise the PW2 over the car. For my situation I think it's not too bad. I'm on 3 phase power with heaps of Solar, so I often have excess for everything to charge up no matter the order. It gets trickier though when the weather isn't great and the solar input is more variable, plus a lot of driving has been done.

A minor issue is their UI in the app showing the charging graphic needs a tweak. When the car is charging from the solar, the Home usage loses a digit, so if you're sub 1kW in usage at the time it'll show as 0.

 

[Vostok]

When the car is charging from the solar, the Home usage loses a digit, so if you're sub 1kW in usage at the time it'll show as 0.

Oooh I hadn’t noticed that.

Yeah CoS needs a bit of work but it’s not a terrible first attempt. Adding a toggle to prioritise PW2 charging (for those who want to do that) and fixing up the UI glitches (disappearing CoS controls - the 3 dots) and it would be awesome.

I was astonished how much charge my car got on the first sunny day with CoS. PW2 was filled and then CoS added 90 km. All from a piddling 5kW array. That was way better than my home-brewed python script has ever done.

 

[JonDarian]

I have iOS Tesla App 4.31.0, car is on 2024.2.7, CoS is set to charge from any source up to 30%, and CoS up to 80%. Car SoC is currently above 30%. Is your current SoC above or below your minimum CoS setting?

I am in the latest Android app, the car is 2024.2.7 like yours. CoS set to charge from any source to 30% and CoS to 100%. My SoC car was at 88%, PW2 at 10% when I started this morning. The car is charging via UMC.

I have a 20kW PV array and 15kW inverter, so have enough production on all but the wettest and darkest days. Today's weather has been very patchy (ideal for CoS to do its work!). It has prioritised the car and the battery only filled when there was surplus above the household and car requirements. I wonder if there is some other algorithm at work.

I agree with you that CoS is a good first attempt and does give me more confidence that I won't draw directly from the grid to charge the car. I just want to have control over whether the car scavenges from the battery charging and therefore leaves me to draw from the grid overnight.

 

[bcarp]

Edit: Nope, it just switched back to prioritising the car. Dang it.

I’ve been semi watching this today, using Vostok’s workaround above. I’ve had the system switch back to prioritising the car twice today. I think this has occurred when solar generation > house usage + 5kW. That is, when there’s too much power (> 5kW) to stuff into the Powerwall. To avoid it going to grid, it starts the car charging & reverts to its normal way of prioritising the car.

What I’ve been doing usually is using the Powerwall settings —> Vehicle Charging —> Wall Connector Schedule —> Allow charging overnight only. Then when Powerwall gets to about 80-90%, turn the schedule off and allow charge on solar. Since the system tries to have the car charging rate lower than actual solar production, there’s a small excess which runs into the Powerwall to finish the charging. My switchover time is vaguely based on gut feel whether there’s still enough sunlight remaining to top up the Powerwall with this run-off.

This is pretty all just for fun anyway. Our feed-in tariff is 7c & our overnight electricity rate is 8c (incl. GST) – not a large enough difference to bother chasing the sun really.

 

[Vostok]

I’ve been semi watching this today, using Vostok’s workaround above. I’ve had the system switch back to prioritising the car twice today. I think this has occurred when solar generation > house usage + 5kW. That is, when there’s too much power (> 5kW) to stuff into the Powerwall. To avoid it going to grid, it starts the car charging & reverts to its normal way of prioritising the car.

Ah, that would make sense as to why the car never gets reprioritised for me. I have a 5kW solar array, and so it’s not possible for me to have the situation where solar generation > house usage + 5kW. Once the PW2 starts to charge after stopping the car, there can never be any excess solar for me until the battery is full or very close to it.

Car has started to charge and I haven’t lost a digit on reported house consumption

 

[Vostok]

PS. Why does the Tesla App show the house in the dark with the lights on? No solar at nighttime!!

They should autoanimate daytime light conditions based on your location! More eye candy!

 

[power.saver]

Car has started to charge and I haven’t lost a digit on reported house consumption

The car will only report in whole kW (x.0 kW) so the fractional part is lost, and it's rounded down. If you're charging at 3.8kW actual, it will show 3.0kW, and then this affects the house kW display.

 

[dronus]

PS. Why does the Tesla App show the house in the dark with the lights on? No solar at nighttime!!

They should autoanimate daytime light conditions based on your location! More eye candy!

What does the graphic show if you have 2 cars charging?

 

[Jules22]

What does the graphic show if you have 2 cars charging?

It shows both cars, adds a second garage

 

[Vostok]

It shows both cars, adds a second garage

Pix or it didn’t happen!

Note you’d have to have 2 (or more) Teslas. Tesla can’t distinguish my LEAF from the oven, kettle or sandwich maker. If it is charging it is part of the household load bucket.

 

[dronus]

It shows both cars, adds a second garage

Ohh cool

 

[Jules22]

Pix or it didn’t happen!

Note you’d have to have 2 (or more) Teslas. Tesla can’t distinguish my LEAF from the oven, kettle or sandwich maker. If it is charging it is part of the household load bucket.

Ask and you shall receive (not my picture, I've seen it in a few videos etc and just found this with a google search)

 

[Nevyn72]

Ask and you shall receive (not my picture, I've seen it in a few videos etc and just found this with a google search)

View attachment 1033251

I look at that picture and wonder why, with 4 powerwalls @ 98%, it's drawing household load from the grid!

 

[JonDarian]

Pix or it didn’t happen!

Note you’d have to have 2 (or more) Teslas. Tesla can’t distinguish my LEAF from the oven, kettle or sandwich maker. If it is charging it is part of the household load bucket.

What kind of highway range do you get in the sandwich maker?

Btw, thanks for all of your informative posts in this and other threads. You do good work!

 

[bcarp]

I look at that picture and wonder why, with 4 powerwalls @ 98%, it's drawing household load from the grid!

Ours does that sometimes. Could be off peak right now and shoulder peak starts in an hour, so saving the battery for that period? You don’t know the times, costs or expected loads.

 

[dronus]

Ours does that sometimes. Could be off peak right now and shoulder peak starts in an hour, so saving the battery for that period? You don’t know the times, costs or expected loads.

Yeah they might have one of those 2 hour windows where they get free power from the grid or something.
Nothing is free in SA.

 

[IanOnSummit]

If I understand you correctly, your HPWC is on a separate circuit that does not have a CT clamp on it, so there is no visibility of that load to the PW2 gateway?

While CoS knows what the excess solar is and what charge rate on the car that could support, the problem might be there is no feedback loop, i.e. the algorithm probably works by saying “ramp up the vehicle charge current until excess solar is close to zero” and then adjusts it periodically to keep the excess near zero.

So if the car charging has no impact on the amount of excess solar reported by the gateway, the charge current will simply ramp to whatever you have set in the car as the charge current for that location.

Sorry about the delay in responding.
The Tesla Wall Connector is on the same (single phase) grid circuit as the house, solar and Powerwall, but is attached on the grid side of the Powerwall grid sensing CT, meaning the Wall Connector load cannot be seen by the Powerwall.
However, the Charge on Solar App is aware of both the solar excess and the grid infeed (via the Powerwall sensing), so even with the Wall Connector load being not directly visible, CoS only needs to adjust the rate of car charging until it equals the apparant 'grid infeed' - which has all come from the excess solar. This will be what the ChargeHQ App does when selecting the 'Consumption Excludes Charging' option, and it works nicely.

I am aware why CoS doesn't work with my switchboard configuration, and was observing that it would be useful to Tesla owners like myself if the Tesla App was further refined to include a similar option to accomodate such switchboard configuration - as is already offered by ChargeHQ.