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How much do you charge from solar in Australia?

Discussion in 'Australia & New Zealand' started by Blue heaven, Jan 16, 2019.

?

What percentage of your car battery is charged with work/home solar?

  1. More than 75%

    15 vote(s)
    41.7%
  2. 51% to 75%

    3 vote(s)
    8.3%
  3. 26% to 50%

    3 vote(s)
    8.3%
  4. Nil to 25%

    15 vote(s)
    41.7%
  1. Blue heaven

    Blue heaven Fair Dinkum Tesla

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    Location:
    South West Australia
    Keep in mind this for Australia only.
    Please respond even if you never or rarely charge from solar.
    Base your choice on the expected or known average percentage over a full year.
    Work or home solar refers to charging directly from a solar source or via a solar charged storage battery, it does not include renewable energy electricity deals provided from the grid.
     
    • Like x 1
  2. paulp

    paulp Active Member

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    Location:
    Adelaide, Australia
    You havn’t provided a 100% option
     
    • Like x 1
  3. Blue heaven

    Blue heaven Fair Dinkum Tesla

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    South West Australia
    My though process was that it's extremly difficult to 100% charge from solar for a full year unless the charging is from solar off-grid or the car owner is extremely vigilant, there's probably only a handful of those owners around so I made the first category above 75%.
     
  4. aegidius

    aegidius Member

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    Location:
    Brisbane
    Car uses maybe 10-15kWh/day, my panels generate about that in summer, 7-8kWh in winter. So I said 75%. But I'm charging at night, so the grid is involved, as it would be for most people (unless they are home during the day and have a dedicated solar array or no useful FIT)
     
  5. paulp

    paulp Active Member

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    Very easy to be 100% (other than the odd supercharger use for 10 minutes to grab a coffee) when parked at home most days, and only plugged in on days that the meter says there is significant exporting. I don’t have a storage battery, and I never charge at night.
    In fairness I have a 30kw solar array, and although its looks after two tesla, we don’t drive massive distances each day. Generally charge at about 30% of the maximum amps as that avoids importing, and I never charge both at the same time. Works all year round for me.
     
  6. Jays200

    Jays200 Member

    Joined:
    Apr 1, 2016
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    459
    Location:
    Perth, Western Australia
    Our 6.5kW solar system generates about 43kWh this time of the year and "clips" to 5kW from about 10:30-14:30.

    I hate, with a passion, giving Synergy any of my "juice" for about a quarter of what they charge me to buy it back, 7cents vs 28cents :(

    To this end, when the car is home during the day, fortunately more often than not, I can dial down to 5A 3P charge rate which is about 3.5kW. This lets me run our house, including two split systems air-cons from solar and hang around the 5kW inverter cap. We'd rather pay for a little extra power than give it away. We use the washing machine and dishwasher from about 08:00-09:30 and then put the car on. This equates to about 15kms/hr of added range for 70-90kms per day. If my wife takes the car to her work they have 32A 3P EV charging run from solar too.

    Our last 60 day power bill was $105 to run a family of four household INCLUDING running a Tesla Model X :)

    Here's a usage graph for our house last Monday. At our feed in tariff you need 4x the green area under the curve to offset the grey area above the green curve.

    upload_2019-1-18_7-57-10.png

    BTW, Synergy offers an EV tariff which is a 30% discount between 23:00-04:00hrs which I never use to charge the car. When we finally ever get our Powerwall 2 I might use that off peak discount juice to top up the battery in winter. As you can see from the excess green in the above graph, I have heaps of spare juice to put into a 13.5kWh Powerwall 2.

    IMHO, Synergy should be offering a much cheaper nightly EV tariff. Here is a link to the daily half hour MWh price. Click on 2019 and download the spreadsheet and then scroll to the current period. For example, for 01:00-05:30, the MWh price is $27/MW 1/2 hour.

    Market Data


    upload_2019-1-18_8-5-23.png
     
    • Like x 2
  7. MangroveMike

    MangroveMike Member

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    Apr 22, 2014
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    351
    Location:
    Newcastle, Australia
    I've only charged from solar for the last month. Slightly more effort in timing and added a wall charger in at work - but I love the concept.
     
  8. MangroveMike

    MangroveMike Member

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    Apr 22, 2014
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    351
    Location:
    Newcastle, Australia
    Nice!

    What App is tracking your use and generation?
     
  9. Jays200

    Jays200 Member

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    Apr 1, 2016
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    Location:
    Perth, Western Australia
    Solar energy monitor - Smappee

    but I hope when the Powerwall gets here it will be more integrated. I just want to be able to set an export/import limit and forget about it.
     
  10. smithy

    smithy Member

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    Location:
    Sydney
    I have 10kW of solar and a PW2. Typically drive to work only 2 days per week, so for the others I remotely start charging the car once the PW2 is fully charged. I've set a limit of 5kW for charging so the solar output exceeds the charge. With the PW2 I can still charge from effectively 100% solar if a cloud comes across as it then draws from the battery to charge until the cloud passes the sun. I typically do a couple of days for 2 hours per day, which enough to see me through with my average weekly driving. I'll give it a bit more if I'm driving more or I'll go to the supercharger if I'm going for a weekend drive. So certainly from Sept-April I fully power my house from solar and charge the car for 75% of the kms I do. Doing some renos later this year so plan to add more solar and another PW2...I want to be 100% sufficient for house and car 365 days per year.
     
    • Like x 1
  11. paulp

    paulp Active Member

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    Nice data Jays200. Our SA power rates (after discounts) is 33c import 16.3c export. Hence I need to generate double my nightly needs during the day, which I do most days other than june july aug. My figures suggest that if I had a powerwall or two, I would only have a power bill in July.....which actually isnt very feasible. Adding more solar would be significantly cheaper.
    It’s been cloudy and a heat wave the past 3 days so the cars are getting down around 60%. Tomorrow is sunny so they’ll get their solar juice all day. My last 60 days was a credit of $197, which with two tesla’s, family of 4, pool heater, massive aircon system, I’m very happy with. It’s clawed back power costs from september last year.
     
  12. Jays200

    Jays200 Member

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    Location:
    Perth, Western Australia
    Ta.

    If Synergy gave us a 50% feed in of 14c then I'd probably get a credit too. However, I think the Synergy accountant gets a nasty rash whenever they have to sign a cheque to credit a customer ;)
     
  13. dogphlap

    dogphlap Member

    Joined:
    Jan 24, 2015
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    Location:
    Australia
    I mostly charge at night in the small hours of the morning, before sun up because that is the coolest part of the day (it gets warm in Queensland). However if I have less than 50% charge I will top that up to 55% during the day. My solar panels generate 4.6kW max, my wall connector is set to charge single phase 240V at 40A so they could not supply the full 10kW or so by themselves anyway. However I generate a lot more energy than I use and my electrical utility sends a cheque each year for about $3000 for the difference, I never have to pay them. As an early adopter I get paid $0.54/kWh for PV energy I send to the grid but they only charge me $0.28kWh for grid energy I use so it actually makes financial sense to charge my EV in the dark.
     
  14. paulp

    paulp Active Member

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    I have another smaller system on another property that has had 3 quarters of credits. AGL are so determined to not pay that they are trying to justify why they should be allowed to make up their own meter readings and ignore the real ones. They’ve now issued me seven differnet invoices for the last quarter, none of which reflect the actual meter reading.
     
    • Informative x 1
    • Funny x 1
  15. ICUDoc

    ICUDoc Member

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    Location:
    Sydney NSW
    I generate about 35kWh/ day in summer
    Have a Powerwall 2
    Charge the car at night mostly, so it drains the Powerwall completely most nights in winter
    I am unhappy with the losses of battery-to-battery, but that’s how it is.
    when I am home in daylight I always charge off the wall, so it draws well under the panel outputs.
    So, to answer the question, I don’t know how much I really charge off solar.
    But after 12 months of solar:
    The Tesla app says the household drew 60% from panels and battery, so I guess on average I charge 60% or so from solar, sometimes via the Powerwall battery.
    PS OT, but after a year, the Powerwall looks like it loses about 10% of the charge the panels stick in it...
     
  16. EcoCloudIT

    EcoCloudIT Member

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    Melbourne, VIC
    @ICUDoc I assume you have a 5-6KW in total system?
     
  17. ICUDoc

    ICUDoc Member

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    Hi, EcoCloudIT.
    Look, I’m not sure what the rating is. 17x345W panels, so yes, in that ballpark.
    I am a little light for solar, especially in winter, but the geography and anatomy of the root are suboptimal. Looking for a new house that’s better!
     
  18. paulp

    paulp Active Member

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    “Anatomy of the root are suboptimal”?

    Anyway it amazes me that house rooves are still not designed to maximise solar.
     
  19. Jjdsyd

    Jjdsyd Member

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    Location:
    Sydney
    Very interesting. But, why does your system clip and why do you have a 5kw inverter cap if you have 3p?

    Tks
     
  20. ICUDoc

    ICUDoc Member

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    Location:
    Sydney NSW
    D’oh! That would be roof, of course!
    And yes, my 1940s house rooF is pretty crap for solar
     

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