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Solar panels and batteries for charging. Or a really long cable.

Discussion in 'EV (Electric Vehicle) Discussion' started by hkmb, Aug 25, 2022.

  1. hkmb

    hkmb Senior Member

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    My house is weird (but also nice). It was built in the 1920s, but then in the 1980s a small block of apartments was built on the tennis court and croquet lawn. Our house is part of the same complex as the apartments. (On the plus side, this means we have access to a pool but we don't have to maintain it ourselves. And it means when our idiot neighbour's greenhouse smashed through our roof last month, it was the apartments' responsibility to fix it. Hooray.)

    We have our own ground-level driveway and garage. The apartments have underground parking.

    If I'm getting an EV this raises a couple of issues if I want a 7kW or 11kW charger.

    First, there's the complexity of dealing with the building committee, a bunch of people who are dedicated to taking the longest time imaginable to make any decision about anything. We may have to get permission from them to put the electricity infrastructure in place if it goes through common areas (but not if it's within our walls).

    Second, our electricity meter is in the apartment block, a good 30-40 metres from our driveway. The Tesla guy said it can be difficult to install 7kW or 11kW chargers a long way from the electricity meter.

    So....

    First, is that true? Is it difficult to install a fast charger a long way from the electricity meter? Are there ways around this?

    Second, might it be easier to just install solar panels on the garage roof (something we were planning on doing anyway), and adding a home battery, and then using that to charge the car?

    Can you have a rapid (7 or 11kW) charger running off a home battery? Or would we be limited to 3kW, as we would with a normal electricity socket?

    Does anyone have any experience of this? I'd love to hear.
     
  2. hill

    hill High Fiber Member

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    7kw is not fast charging - it's more like medium charging considering if you're charging how some ev's will charge at only 1 KW - while others can charge at over 100 KW. Manny ev's only charge at 3.5KW - but 7 KW will certainly future-proof your situation. Now - as for the distance to your power source ... we just ran power for a hot tub that uses 7kw & the run was over 30 meters. No big deal.
     
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  3. bisco

    bisco cookie crumbler

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    the longer the run, the heavier the wire gauge. then there are all sorts of codes for burying cables.
    it is certainly worth getting an estimate from an electrician.

    do you folks have 240v standard, like europe?
     
    #3 bisco, Aug 26, 2022
    Last edited: Aug 26, 2022
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  4. Trollbait

    Trollbait It's a D&D thing

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    7kW is AC Level 2. Maybe Level 1 for DC.
    Don't know anything about Australia's electric utilities.

    In the US, the charger(EVSE) would come off the main panel between the meter and house. Unless you have an older service feed, you wouldn't need to mess with the meter. Considering the house's age, that might be the case. The EVSE you want for those charge rates is going to be 40 to 50 amps, so you want the main coming into the panel to be 200 amps.

    Our 1910 era house had only 60 amps service when we moved in. With the meter just being on the other side of an exterior wall, upgrading was easy. In your case, if the cable from the meter needs to be upgraded, it gets expensive. Hope things were upgraded when the apartment block was put in.

    Solar panels and a battery also sounds like a hassle/expensive. Maybe you avoid having to deal with the committee. Some home owners' associations here have rules against solar panels. I'm sure you can have a system that can handle the faster charging, but for higher cost. Going that route, look into a "slow" DC charger. Won't need an inverter, and will be more efficient. Likely not an option on the other hand.

    Depending on your drive cycle, you may not need that Level 2 EVSE, at least not right away. The Level 1 EVSE that plugs into a basic outlet here can supply around 4 miles of range per hour for most EVs; about 30 to 40 miles a night. With the BEVs you looking at having over 200 miles of range, you could still drive 10 to 20 miles more than that range charged overnight during the week, if you can let the car fully charge over the weekend.
     
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  5. hkmb

    hkmb Senior Member

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    Thanks everyone! This is all really useful.

    I think different countries might use different terminology. Here we'd call 3kW (just plugging into a normal socket) "slow charging" or "trickle charging". 7kW or 11kW (from a wallbox) is called "fast charging". And DC charging at 50kW or more is called "rapid charging". It's odd: I'd have thought that "fast" implied being faster than "rapid", but here at least it isn't.

    Yes, 240v. So 7kW would require just under 30 amps, and 11kW would require just under 50 amps.

    Yes. We have an electrician coming in soon to do some repairs after our idiot neighbour's greenhouse crashed through our roof.

    But this is why I'm wondering whether a solar and battery system around the garage might actually turn out to be a cheaper (or at least not much more expensive) and easier option in comparison to burying a heavy-gauge cable over such a long distance on common property.

    Yes, I'll need to ask the electrician about this. I think the way to go is to find out what we need and then look at discussing it with the committee.

    Yes, I know it'll be a bit of a hassle, but it may be less of a hassle than dealing with the committee.

    I don't think we can have solar panels on the house roof, because of the damage they could do to the roof: given that the roof is the committee's responsibility, they're unlikely to be keen on that. But the garage roof is our responsibility, so they're OK with that. It's a decent-sized double garage and gets a lot of sun, so I'm thinking that if I were to install panels I'd be putting in enough to account for a lot of our home electricity usage as well as the car.

    In the longer term, I'd like to discuss the (less efficient) super-lightweight solar film with them for the house roof, because that might be something they're more comfortable with. But I'll leave that for now.

    I had never heard of these. I'll look into it. Thank you.

    This is a good point too. There's also a lot of free 22kW charging around local supermarkets and stuff.
     
  6. Trollbait

    Trollbait It's a D&D thing

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    Most people in the North America region use the old SAE levels. 1 is just using a standard outlet. 2 is AC charging faster than what that standard outlet can do. 3 is faster than what a home grid can support. Here it means DC, but Europe had some AC chargers early on.

    The kW numbers are generally used for the charger's rating here. The DC units are actually stand alone chargers, so it applies to them. When using AC, it is the car's onboard charger doing the work. Plug ins like the Prius Prime only have a 3.3kW onboard charger. The cord with the car, and the wallbox for your home are a EVSE. They are just a minicomputer that monitors the connection and charging for lower fire and electrocution risk.
    You can check the service level yourself at the panel. The circuit breakers should have their amp rating visible. The big main one you'd flip to shut off all electricity to the house is the max amperage that can be supplied to the house.
    Could be worth it without the car, or if you don't need them for the car.
    Neither have I:D
    Was thinking the PV panels and home battery are DC, why switch it to AC for the car to just switch it back to DC for its battery? If a slow 7 to 11 kW DC charger was available for home use, the cost is likely only worth it for an off grid house.
     
  7. bwilson4web

    bwilson4web BMW i3 and Model 3

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    In North America, we have split phase, a center tapped single phase transformer, or commercial three-phase. So typically we have
    • 110 VAC commercial - one phase of commercial three phase power. Typically circuit protected to 15-20 for 1.7-2.2 kW. However, usually limited to 80% of the peak current so as low as 80% * 15 A * 108 VAC = 1.3 kW
    • 120 VAC residential - one side of the center tapped power pole transformer. Typically circuit protected to 15-20 A for 1.8-2.4 kW. The same 80% rule applies.
    • Level 2 commercial, 208 VAC - two phases of commercial three phase power. Typically limited to 40 A after the 80% rule, 8.3 kW.
    • Level 2 residential, 240 VAC - both phases of split power transformer. Typically limited to 40 A after the 80% rule, 9.6 kW.
    • Fast DC charging - typically rated by kW maximum which I've seen as low as 50 kW for CHAdeMO up to 250 kW for Tesla V2 chargers. Electrify America and others claim 350 kW but I've never experienced those levels.
    What is maddening are the AC converters in the cars. Our 2017 Prius Prime was 15 A limited to ~3.3 kW; 2014 BMW i3-REx is 30 A limited, and; 2017 Tesla Model 3 at 31 A. To save a few bucks, our vehicle converters are hobbled to lower currents than the charging stations can provide.

    Bob Wilson
     
  8. bisco

    bisco cookie crumbler

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    i would think pv and battery would still be much more expensive, but amortized over x years, perhaps not.
    any government incentives?

    how did a greenhouse get all the way up on to your roof? sounds like the wizard of oz
     
  9. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    I got a quote for solar two days ago for $50k but the places they would have to put the panels to get the efficiency they were citing was so asymmetrical and ugly that it was a non-starter. The places I assumed they would put them were much less efficient and it made no economic sense to install them there.

    So get the angles analyzed before you go down the solar path.
     
  10. Trollbait

    Trollbait It's a D&D thing

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    The SAE dropped the Level 1, 2, & 3 designations for AC Level 1 & 2 and DC Level 1 & 2.

    The AC Levels are pretty much the old Level 1 & 2 as far as most people are concerned. DC Level 1 is up to 80kW, which much higher than I guessed. The DC Level 2 is up to 400kW. I think Tesla has a few Level 1 Supercharger locations in major cities. They are intended for local use, as oppose to for long trips like the Supercharger network was intended for. https://en.wikipedia.org/wiki/SAE_J1772#Charging

    I was thinking a DC charger around the speeds of AC Level 2 might be worthwhile for a PV installation from a technical perspective. Very likely the economics make it a non-starter.
    For a PHEV of the PP's capabilities, a slower charger is fine. Between the smaller battery and its air cooling system, the effective charging time likely doesn't get much better. You always have the engine to fall back on.

    The manufacturers have realized faster charging time are better than saving a few bucks. The standard charger on the Leaf was once no faster than the Prime's. This is balanced by the fact that the public AC Level 2 EVSE's might have lower amp limits than the standard allows. That top limit is also more than an owner will need for home charging. For fast charging on the road, the makers are putting in DC charging connections. Is there a BEV available today that doesn't have DC charging standard?
     
  11. bwilson4web

    bwilson4web BMW i3 and Model 3

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    If the Bolt could DC charge at 100-150 kW, it would be a candidate to replace our 2014 BMW i3-REx. But a 50 kW limit I too slow.

    Bob Wilson
     
  12. Trollbait

    Trollbait It's a D&D thing

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    When the Bolt came out, CCS was only an option.
     
  13. hkmb

    hkmb Senior Member

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    Right. Thanks for the clarification.

    I'll have to have a look.

    I've had a search - it doesn't seem that any such thing is available here, which is a shame.

    But our neighbours three doors down are rock music promoters. The street's electricity feeder box is outside their house, so they've covered it in their AC/DC posters, which we were all very impressed by.
     
  14. hkmb

    hkmb Senior Member

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    This bit set me thinking.

    When I was in Britain in June, I hired an ID.3 with a 58kWh range. When I stayed at my parents' house, I plugged into a normal socket overnight. I was on holiday, so that was generally around 12 hours. That added 30-35kWh - a bit more than half a tank - which worked out to about 120-140 miles.

    So a fast wall charger might not be necessary.
     
  15. hkmb

    hkmb Senior Member

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    Gosh, that seems like a lot. Here, a 7kW package (no battery or anything - just panels and inverter, with installation and connection) costs around US$3000.
     
  16. hkmb

    hkmb Senior Member

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    Yes. We're not facing the sort of comedy energy prices my parents are facing in Britain, but still it could pay for itself pretty cheaply.

    It was the greenhouse effect.

    ------

    I said "greenhouse" because I don't know whether pergola is a word in America. Until one came through my roof I didn't know it was a word in Australia. It was a big thing - about 3 metres x 3 metres x 2 metres. Our idiot next-door-but-one neighbour had installed it illegally and hadn't fixed it to the ground properly. She'd already been fined by the council and had been ordered to take it down, but refused to do so.

    We had a big winter storm in early July. The pergola took off, bounced across our next-door-neighbours' roof, smashing some of their tiles, spun round, and then smashed through our roof. Three legs went through the roof; the other stopped about 10cm short of my daughter's bedroom window. It then got lodged there: it took the fire brigade and the State Emergency Service five hours to get it down.

    As it happened during a storm and at the start of two weeks of heavy rain, it did a lot of internal damage. We're still dealing with insurance, and then once that's sorted we have to sue her for the things that aren't covered. She's denying responsibility, which, given the fine and the council order, is not going to stand up in court.

    Fortunately she's the only neighbour on the street who we don't know and like, so it's not caused unnecessary unpleasantness with people we like or anything.

    IMG-20220703-WA0008.jpg IMG-20220703-WA0009.jpg IMG-20220703-WA0011.jpg IMG-20220703-WA0018.jpg
     
  17. hkmb

    hkmb Senior Member

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    All wizards in this country are wizards of Oz.
     
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  18. bisco

    bisco cookie crumbler

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  19. Trollbait

    Trollbait It's a D&D thing

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    Yeah, your grid gives you an advantage when using 'Level 1'. The 4 miles an hour is with 12amp 120V going into the car.
    I'd say it's a gazebo, but an odd one. You put those up for a shaded spot, but this thing has a 'glass' roof.

    Which reminds me of something unrelated that has been passed around in certain circles for decades.

    The Tale of Eric and the Dread Gazebo
    In the early seventies, Ed Whitchurch ran "his game", and one of the participants was Eric Sorenson. Eric plays something like a computer. When he games, he methodically considers each possibility before choosing his preferred option. If given time, he will invariably pick the optimal solution. It has been known to take weeks. He is otherwise, in all respects, a superior gamer. Eric was playing a Neutral Paladin in Ed's game. He was on some lord's lands when the following exchange occurred:

    ED: You see a well groomed garden. In the middle, on a small hill, you see a gazebo.
    ERIC: A gazebo? What color is it?
    ED: [pause] It's white, Eric.
    ERIC: How far away is it?
    ED: About 50 yards.
    ERIC: How big is it?
    ED: [pause] It's about 30 ft across, 15 ft high, with a pointed top.
    ERIC: I use my sword to detect good on it.
    ED: It's not good, Eric. It's a gazebo.
    ERIC: [pause] I call out to it.
    ED: It won't answer. It's a gazebo.
    ERIC: [pause] I sheathe my sword and draw my bow and arrows. Does it respond in any way?
    ED: No, Eric, it's a gazebo!
    ERIC: I shoot it with my bow. [roll to hit] What happened?
    ED: There is now a gazebo with an arrow sticking out of it.
    ERIC: [pause] Wasn't it wounded?
    ED: OF COURSE NOT, ERIC! IT'S A GAZEBO!
    ERIC: [whimper] But that was a +3 arrow!
    ED: It's a gazebo, Eric, a GAZEBO! If you really want to try to destroy it, you could try to chop it with an axe, I suppose, or you could try to burn it, but I don't know why anybody would even try. It's a @#$%!! gazebo!
    ERIC: [long pause. He has no axe or fire spells.] I run away.
    ED: [thoroughly frustrated] It's too late. You've awakened the gazebo. It catches you and eats you.
    ERIC: [reaching for his dice] Maybe I'll roll up a fire-using mage so I can avenge my Paladin.

    At this point, the increasingly amused fellow party members restored a modicum of order by explaining to Eric what a gazebo is. Thus ends the tale of Eric and the Dread Gazebo. It could have been worse; at least the gazebo wasn't on a grassy gnoll. Thus ends the tale of Eric and the Dread Gazebo. A little vocabulary is a dangerous thing.
    Eric and the dread gazebo — Experience Point
     
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