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How to get Powerwall 2 to charge fully overnight

njrobson_98511893njrobson_98511893
in Energy Products
I’m in the UK and have a pv system and Powerwall 2 . Also have economy 7 electric supply. I never export any excess generation as I have a mechanism that uses any spare to heat water for my UFH system. Obviously in winter I generate much smaller amounts. In order to efficiently “time shift” the cost of electricity I want the battery to be fully charged by 7am every morning. I can then use during day and be topped up at night. How do I get the battery to fully charge overnight?
Currently it charges to varying levels such as 25%, 30%, 70%_ all over the shop and no- one seems to know what the “algorithm “ looks at!
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Comments

  • gregbrew_98470014gregbrew_98470014
    I'm jealous. Here, across the pond, we're rarely allowed to charge from the grid.
  • bpbp
    Technically, it is possible to configure the Gateway to charge PowerWalls from the grid. For all installations, this should be possible if Storm Watch is enabled - and then triggered, quickly charging the PowerWalls to full in anticipation of a storm (hurricane) that could result in prolonged power outages.

    But, the Gateway is usually configured to charge only from the solar panels (except for Storm Watch) - which means that once the sun goes down, the PowerWalls won't charge - and depending upon the Gateway customization, they will provide at least some power to the house overnight.

    It is possible to configure the Gateway to allow charging from the grid. This isn't allowed in the US, if government incentives were used in purchasing the system - which prevents energy storage to be charged from the grid (except for Storm Watch).

    If there aren't government restrictions, then it should be possible to configure the Gateway to charge from grid - which could provide charging overnight.

    However, doing so will change the warranty on the PowerWalls. When operating in solar charging only mode, the warranty is for 70% capacity for 10 years, unlimited charging cycles. But when charging from non-solar sources (grid, generator), the warranty changes to 70% capacity for 10 years, with a limit of 37.8 MWh of throughput per PowerWall.

    This is 2800 full recharge cycles (going from 0% to 100%). Since 10 years has 3650 days, it's possible the warranty could expire sooner than 10 years when charging from non-grid sources.
  • bpbp
    I just looked up the European warranty - and the warranty is for 80% capacity in Austria, Belgium, France, Germany, Ireland, Luxembourg, Netherlands, Switzerland and UK, higher than the 70% in the rest of Europe and the US.
  • calvin940calvin940
    It's 80% for Canada as well.
  • rupert_98348807rupert_98348807
    I am UK powerwall 2 , third winter, I charge pw at night off peak rate 10p KW. Just set advanced time based, cost saving, peak and off peak.
    If there is two very sunny days the pw may fully charge
    Thinking off going to Tesla energy traiff.
  • njrobson_98511893njrobson_98511893
    I also have cost saving set as you say but still get varying charge levels
    Eg last 4 nights @ midnight charge level <10%- at 7am charge levels of 25%,35%,29%and 79%
    How to get consistent >79% is my problem!
  • barry.importpartners_98277589barry.importpartners_98277589
    I agree that for UK use the powerwall software is far from good , in fact its barely adequate in our climate. I doubt it would take the programmers more than an hour to add a simple minimum charge level feature that was user set for the already designated off peak hours , It would not take masses more to incorporate another feature where surplus solar is used to charge the car , the in car controls for charge amps could be utilised to keep the charge level down to match the surplus solar or at least close so the battery isnt drained. If it can be done manually through the touch screen then its software controlled so should be available for the app and car to do between them
  • njrobson_98511893njrobson_98511893
    Bizarrely last night it charged to 92%. Great
    How to get that every day!
  • JCUKJCUK
    My powerwall 2 was delivered on the 6th of June 2017, initially it did not have the app and could not charge from the grid; I was not informed of this until after it was delivered. On the 12th September 2017 I was informed that I would be able to program the powerwall to charge from the grid during off-peak. At the end of February 2018 I received the time of use app to enable charging from the grid during off-peak, but I only got this as I had agreed to take part in the trial. When I complained that I had no control over how much it charged from the grid, I was informed that it was not necessary as it used local weather forecasts to estimate solar generation.
    This statement was obviously wrong (though might have been intended). In my opinion it forecasts solar generation for each five minute time period by looking at the previous three days and taking the highest value, this is a very optimistic approach for the UK.
    I have observed that if I have a sunny day then for the next three days it will put up to 20% into the powerwall, just enough to get to the time when it expects the solar generation to be adequate; it is not unusual to be drawing peak energy from the grid at 10am.
    I have complained many times and have received a number of verbal promises but nothing has happened. They have now stopped replying to my complaints.
  • njrobson_98511893njrobson_98511893
    Can you tell me the email address to complain to. I have complained to the Tesla “help” desk but they cannot do much.
    In the UK we must surely represent a big enough group to warrant a software fix?
  • mike509mike509
    > @bp said:
    > It is possible to configure the Gateway to allow charging from the grid. This isn't allowed in the US, if government incentives were used in purchasing the system - which prevents energy storage to be charged from the grid (except for Storm Watch).
    >
    > If there aren't government restrictions, then it should be possible to configure the Gateway to charge from grid - which could provide charging overnight.
    >

    Can you tell me where this is marked? That would include everyone since we are all eligible for the federal incentive. My utility (PSEG) has a Time of Use with 40% nightly rate made specifically for "battery storage" or "EV". Moreover, the tesla website specifically advertises the use of Powerwall without PV to offset electricity costs by charging at off-peak hours.

    My yearly solar can only cover 50% of my home energy usage. I got the powerwalls thinking that I can take advantage of the off-peak rate (even if the powerwalls charge to 50% at night). To my surprise, Tesla does not allow me to charge at night and the investment becomes pointless.
  • calvin940calvin940
    > @mike509 said:
    > Can you tell me where this is marked? ...
    >
    > My yearly solar can only cover 50% of my home energy usage. I got the powerwalls thinking that I can take advantage of the off-peak rate (even if the powerwalls charge to 50% at night). To my surprise, Tesla does not allow me to charge at night and the investment becomes pointless.

    Isn't this the Advanced (Time based control) setting in the app for the Powerwall? I don't have/use that yet, but my local power company says I qualify so I just need to get it setup. I had understood that the Advanced selection is just for that reason
  • njrobson_98511893njrobson_98511893
    My system does charge from the grid- just to very inconsistent levels - see previous posts.
    Example - today we have first of 3 days storm “Christophe”
    So no solar production but from zero base charged overnight to 50%. Whereas a week ago normal conditions again from zero base charged to 90%.
    What weather pattern or forecast does it look at??
  • gregbrew_98470014gregbrew_98470014
    I am currently seeing the "Storm Watch" indicator at the top of the app main page, immediately below the location name. My PWs were fully charged from the grid this morning. First time I've ever seen this myself. Santa Ana winds are blowing pretty good in the area, but not as bad at the coast. The red flag warning is more widespread this time, and includes coastal areas (I'm in Huntington Beach, CA). Pretty cool!
  • PHB_CAM_UK_93505419PHB_CAM_UK_93505419
    edited January 23
    > @njrobson_98511893 said:
    > My system does charge from the grid- just to very inconsistent levels - see previous posts.
    > Example - today we have first of 3 days storm “Christophe”
    > So no solar production but from zero base charged overnight to 50%. Whereas a week ago normal conditions again from zero base charged to 90%.
    > What weather pattern or forecast does it look at??

    There was an exceptionally sunny day here in the East of England yesterday and the PW has decided not to charge fully overnight. It is very dull today and the PW is down to 30% by 11:00am, this is not useful. I would like an option to just charge fully during off peak regardless of weather or usage forecast.
  • JCUKJCUK
    Re njrobson, you are lucky, no offpeak charging on Saturday morning, and was using peak energy by 9:10am
  • JCUKJCUK
    As stated previously in my opinion it forecasts solar generation for each 5 minute time period by looking at the previous three days and taking the highest value. I have queried this with Tesla but as expected they have not replied. Does anyone have any information which contradicts this?
  • gregbrew_98470014gregbrew_98470014
    JCUK, Rather than looking for "information which contradicts this", you should be showing us why you believe the 5 minute interval prediction stuff to be true.

    Besides, any AI algorithm to do this kind of thing is probably proprietary to Tesla.
  • JCUKJCUK
    It is the three day time period which is critical and for the last 2 years (in winter) whenever I get a sunny day say 20kwh then it takes 3 days before it will put a significant charge into the powerwall in off-peak. I do not know if it is the same for anyone else and it might be because at this time of year I can generate up to 6Kw per hour. Friday was a sunny day and for Saturday and Sunday I was drawing from the grid before 9:30am and I expect something similar on Monday. My only proof is if others have made a similar observation.
  • rupert_98348807rupert_98348807
    Yes mine I think recharges as "JCUK"
  • gerald.riddler_98731107gerald.riddler_98731107
    Yes JCUK I'm getting the same issue with my charging . its all over the place some nights 100% next night as it was last night 58%. I have my two Powerwall's set to Advanced , Cost saving, off peak 23.30 -07.30 week and the same at the weekend so it chargers overnight. I also have an electric Aga that takes about 40kwh charge every night. its always fully charged but the Powerwall's no. so unless I get some sun today I'm going to be using peak power. and after forking out so much on 2 Powerwall's not what i signed up for.
    If any one else in the UK preferably has an answer to our regional issue I would like to hear
  • PHB_CAM_UK_93505419PHB_CAM_UK_93505419
    Exactly the same problem here and very irritating. I discussed the issue with Tesla support today on 01628 450630 and they have raised a ticket.
  • JCUKJCUK
    PHB_CAM_UK best of luck with Tesla support my experience is that they will wait until a significant charge is put into the powerwall in off-peak and then inform you that the problem is fixed.
  • JCUKJCUK
    Do those in the UK who have off-peak charging problems have above average power generation. I have 8Kw of solar panels, and the problem as I understand it is if your generation on a particular day is similar to or higher than your peak home usage, then in my opinion it will use that generation value as the forecast for the next 3 days. Therefore to maximise your savings the powerwall only needs to have sufficient energy stored to last to the time it expects generation to cover home usage

    I use cost saving mode, and it can help to reduce the hours for off-peak by making the start time later. This increases your peak usage as far as the powerwall is concerned. This can help on those days with sunny intervals.
  • rupert_98348807rupert_98348807
    Hi I have 4kw solar panels, I think powerwall just looks at the last few days and if that was ok do the same next nights charge.
    What I would like is a button on the side which means fill up top top no next over night change.
    But hey I am going over to Tesla lite so they can sort it out, 11p/KW 24/7.
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