Powerwall algorithm is not good enough

Powerwall algorithm is not good enough


i own a powerwall in the UK as as we move into winter i am fed up with waking up in the morning to see that the powerwall has not charged overnight.

I have been through support with this already and am told that the algorithm needs to "learn my system". Well i'm sorry but this just doesn't cut it.

Why on earth can't i just tell my powerwall to charge up to a certain level every night on my cheap rate electricity because this is what i need to be able to do. And, frankly, this is what i thought i was getting.

There's no way on earth someone can write an algorithm that can predict my energy usage properly. Even if you tie the system into the local weather forecasts i live in a coastal region where the forecasts are frequently wrong and even if they were right, it's still not good enough.

I have an electrical heating system (air source heat pump) and i need to ensure that my battery is charged adequately, every night, so that the following day i maximise the usage of my low cost electricity.

And what happens if i'm away for a few days, or a holiday, does the algorithm learn that "hey, this guy's not using much power, let's not charge up at all!". Whereas the reality is that ifi had the ability to define when and by how much the powerwall charged up i could have the system ready and waiting for me upon my return. And vice versa, I can tell the system not to charge at night when i'm away up to the day before where it can charge from the mains electricity.

I ask that you give us, your customers, the ability to do this please. Give us the choice - if people are happy with the algorithm then fine, leave the box checked - call it "automatic learning" or something. But for goodness sake stop trying to be so clever because it just doesn't work for people like me, where i live.


Beeza | 09. lokakuu 2019

You’ve got my vote! I’ve also requested it!

gregbrew | 10. lokakuu 2019

Across the pond (USA), it's actually against the law to charge a Powerwall from the grid, except in weather emergencies via the Stormwatch function. PWs can only be charged from solar, during the day. The utilities don't want customers using the TOU tariff differential to make money by time-shifting. In Australia, for example, one *is* allowed to charge from the grid. You might want to check with your local laws to see if charging from the grid is even allowed in the UK.

Passion2Fly | 10. lokakuu 2019

Did you check your Tesla App?
Do you have an Option called Advanced Time Based Control?
In the US we can only charge the PowerWall from the Solar if using Time Based Control. The only way to charge from the grid is if in backup mode...

gregbrew | 10. lokakuu 2019

US utilities won't allow you to charge PWs from the grid...even in "Backup" mode. PWs can only be recharged from PV.

Beeza | 11. lokakuu 2019

There's no issue charging from the grid in the UK and we all have the Time based controls here, the issue is the Algorithm that controls the Time based controls which works by learning the historical usage and weather, it just doesn't work in a climate that has unpredictable weather where everyday is different. Some manual control is all we ask.

Passion2Fly | 11. lokakuu 2019

Tesla PW can be installed with or without solar. With solar, the PW only charges from the grid in emergency modes such as Storm Watch.

gregbrew | 11. lokakuu 2019

Passion2Fly, As I noted in my first post of October 10th.

Beeza, Time-based controls in the USA are set by the user. It's not a matter of the TEG learning behaviors and adjusting itself (like a NEST thermostat), but the user sets the behaviors of the PWs according to when TOU tariffs change. I hadn't heard that the TEG firmware allows for learning behaviors. Very interesting. I wonder if something like that will be rolled out in the States...

Passion2Fly | 11. lokakuu 2019

There is only one "smart behavior" which I'm aware of in Time based control. The system "makes room" for energy storage if the super off peak times fall during sunlight...
In San Diego, SDGE has weekends super off peak from 12AM-2PM. During the week is 12AM-6AM. Obviously, the super off peak are not during the maximum solar radiation. So, every Friday and Saturday, my time based algorithm empties the battery all the way down to "emergency reserves", so I can charge with solar on Saturday and Sunday... It doesn't do that Mon-Fri... It's cool, I like that. It's a smart use of what's called "shoulder rates" (between on peak and super off peak).

alanjenglish | 23. lokakuu 2019

I'm also in the UK and have recently experienced the same issues as cankfarm, with the battery starting the day at levels as low as 15% with little prospect of much solar due to rain and cloud. I don't think the algorithm uses any weather data, such us predicted number of hours of sunlight in your location, so being able to set a minimum level by the end of the off-peak rates would be very helpful. Having said that, I've had my Powerball 2 for just over a year and it has done a great job of managing the power, BUT I've noticed a big change over the last few weeks which has resulted in lower power levels in the battery and many periods when incoming PV has been sent to the grid rather than charging the battery. Today for example despite over 3kw coming from the roof and little power being used in the house (we were out) the battery sat at 58% for about two hours while all the power was sent to the grid. In the past all excess power was sent to the battery until it reached 100% then it would export to the grid. I think the algorithm has been 'updated'. When I phoned support they said the Tesla App shows incorrect data. If that's true then how can we know what's actually going on?

charlesj | 23. lokakuu 2019

@Passion2Fly, what if there is no solar power on Sat and Sun and batter ran itself down?

charlesj | 23. lokakuu 2019

@alanjenglish : that is a lousy excuse from Tesla How does he know it is incorrect, does he have the correct data? Have him update your data in the battery then ;)

cankfarm | 13. marraskuu 2019

ok folks so i've not replied in a while as I feel that other than guaging whether other people are getting the same problem (or if there's a magical solution) then the people that matter within Tesla just don't give a damn/notice what people are reporting on the forums. Happy to stand corrected but there you go.
I will impart additional information that i have found out but my current barrier is first line support. Don't get me wrong, they're very helpful and understand the issue but the most i can do is get them to send a "feature request" to Tesla. I have no idea if this request is being considered but apparently this is the most requested feature from UK users. I am currently trying to get additional information out of my supplier and the Tesla footprint in the UK generally and will report back if anything useful comes up.

So firstly it's importatnt to point out to people in general and especially our friends in the US that this is specifically a UK issue because, as was previously pointed out by gregbrew, you can't charge from the grid - it's solar only. In the UK we can set the "time based control" to reflect our off peak electricity hours and as the much vaunted Tesla literature states, we can then power our homes from cheap electricity during the day. That is a lie because this stupid algorithm seemingly ignores our actual energy usage. Now i understand if it works well for you but my house is run entirely from electricity - cooking, heating (air source heat pump), water, the lot. So i need that battery charging up fully at night, or at least 80% or something.
The problem is that most of the time it does not and it definitely will not if you happen to get some solar on a partiicular day. I've had this confirmed by support - if you get solar on one day, and irrespective of your power usage on that day, the powerwall will charge little or nothing during off peak because, and get this, it assumes that you'll get solar the next day. WHAT? How utterly stupid is this for a climate (in winter now) that is very unpredicatable. I get punished if i happen to get some solar on a particular day. Why is it assumed that the algorithm can predict my requirements better than me?
I know that once you set the time based control then it has to "learn" your system to react accordingly but it's very poor at doing that. VERY poor. I don't understand the apparent reluctance to allow us to explicitly define by how much the powerwall charges at night. It's my battery isn't it? I can predict my usage can't I? I can guess what the weather's going to be like can't I?
I'm not saying turn off the algorithm, I'm just saying allow us to switch to manual control and hey, if i get it wrong and end up exporting electricity because i've charged up the PW too much overnight then that's my problem. And it's a preferable problem than not having enough juice in the PW in the first place.
And don't get me started on the the PW discharging during my off-peak hours......geez. PW charing during off-peak then discharging during off-peak how stupid is that given the lossed incurred in charge and discharge. Dischage during off-peak should be a big no-no and yet it does.

All this can be avoided by giving us a manual option. I was going to buy a second battery to help me in winter but i'm not going to now as the problem will be the same.It's pointless.

I can't even see an excuse with respect to the app - they've already developed the sort of interface we'd need to use with the sliders etc so just give us a "charge up to" slider for off peak hours for goodness sake.

But then again they're never going to read this are they.....all i can say is keep on putting those "feature requests" in through support and see if they'll listen. Or consider getting a battery system from another supplier. If i new this would be the case I woudl have thought a bit harder prior to my original purchase.

Tesla, please let ME manage my energy storage and use rather than trying out this rubbish little AI on us.


cankfarm | 13. marraskuu 2019


Yep i get exactly the same sort of issue - wake up with mid-teens power stored in the PW when i'm getting a day of crap weather and no/little solar predicted. I once went to bed with 3% and woke up with 3%!!!???
With respect to the app not displaying correctly although that is a crap excuse i have seen that quite a bit. On balance the app is correct most of the time but it certainly can be wrong. I've had it showing max drain on the battery when it thinks it's still supplying my heat pump when in fact my heat pump was off at the time after haivng run for a while. However, the stored power in the powerwall wasn't going down by the same extent if you know what i mean. So it was reporting the power drain, but the power drain wasn't actually happening.

That make sense? I'm happy to forgive a lot of this to be honest but i just wish they'd allow us manual setting of the PW during off peak. It would make an almost great system, bloody great.