Thankyou to the OP for this thread as i've been banging my head against this problem for years now. About 4 years i've been running a powerwall with my rooftop solar with solaredge and it does everything right except it almost completely lacks the ability to charge off peak. If you're thinking of getting a PW for this then don't, there are other manufacturers out there - Powervault for eg - which will guarantee off peak charging by utilizing a "force charge" option based on time based controls. Tesla could easily implement this in their own app but over time i have come to realise that they couldn't give a damn what we think as Powerwall customers and continue to give us what they think is best.
Why do i say this? Well i contacted UK technical support years ago on many occasions about this asking that my ideas were fed back up the chain as it were, i was told, years ago, that this was the number 1 requested feature in the UK and yet still Tesla do not listen. Even now. I posted on the Tesla forum - a post i am unable to find today but ill keep looking - where others commented as well but noone from Tesla itself listens.
Unfortunately with a Powerwall, as many here already realise, we are limited to the ability to set off peak times only. It is then up to the algorithm (ie a piece of software) to decide whether it will charge up the battery during this off peak period. Everything in my house is electric (heat pump for heating and hot water, electric car, electric lawn mower ffs) so i really expected to receive a system that made the best usage of off peak. Unfortunately Powerwall does not do that and has been a huge letdown given the nonsense they spout on their info pages about using cheap electricty during peak times. I'm sorry but i have to call it out for what it is - lies, complete and utter lies giving you the false sense that you'll ve using cheap nighttime electricty during the day...which it regularly and persistently fails to do!!
Originally i was on an economy 7 plan so i relied on the powerwall charging up on cheap night rates during the winter as let's be honest, through mid spring through to early or mid autumn it's not really an issue as you get plenty of solar.
The problem would be that if i ever got any solar during the day, as little as say 4kwh, then i would be punished for this by waking up to a battery that had put zero, and i mean ZERO juice into itself overnight from the grib. This would continue for several days, you know, just in case the sun might come out for a tiny amount of time, let's not charge the battery up at all eh? Even though on a daily basis the most simple of maths would show how i was ripping loads of energy off the grid. Even on days where i'd get some solar and my usage was waaaaay over what was had generated the stupid battery still woulnd't even make up the balance!! The only way around this is to set the reserve power slider to a high or max level but as this forces the battery to start charging from the grid immediately you can only set this during your offpeak hours when ususally you're asleep!
So the two things that really frustrate me about my Powerwall system is that 1)tesla don't listen, or they listen but don't care and 2)the powerwall doesn't do what it says it should do on their website.
For a little while now i've been on the Octopus Tesla tariff which works pretty well, not perfect, but you know, ok. That's been binned now -so much for their virtual powerwall utopia- but my contract runs till the end of this year so i'll have to look for an alternative tariff at that time. It is for that reason i found this post and i read with interest that possibly our systems now look at weather forecasts and can predict when to charge more reliably? I mean here in the UK our weather changes rapidly and my powerwall can't even seem to do basic maths so i don't hold out much hope but maybe things have improved?
Next time i move i'm definitley not buying another powerwall for the new place, even if it means sacrificing some storage capacity as i'm fed up with Tesla and their inability to, as the forum title suggests, give us more control. The principle of solar plus battery is great, just be warned about the powerwall anyone who reads this. They're not all they're cracked up to be but too much of an investment to easily change once you've got one.
