Energy Products

How to get Powerwall 2 to charge fully overnight

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!

Comments

  • I'm jealous. Here, across the pond, we're rarely allowed to charge from the grid.
  • 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.
  • 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.
  • It's 80% for Canada as well.
  • 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.
  • 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!
  • 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
  • Bizarrely last night it charged to 92%. Great
    How to get that every day!
  • 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.
  • 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?
  • > @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.
  • > @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
  • 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??
  • 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!
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