how do Electrical Vechicle Solar charging stations work?

rollandelliott
rollandelliott Solar Expert Posts: 834 ✭✭
in General Solar Power Topics #1
I was reading that electric vehicles can get a quick 480V DC charge for ten minutes to give them an extra range boost.

I've also seen solar powered car ports with charging stations.

There are many grid tie inverters that work around 480V DC as well.

So I'm just curious how does all of this technology work?

I'm guessing these charging stations take normal 240V AC grid electricity and convert it it 480V DC for charging? Kind of ineffcient, but it provides a 24/7 solution.

Though it would be cool just to plug your solar array directly to your EV for a quick boost. Though DC arcing and safety considerations would have to be worked out and obviously would only work during peak sun hours.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: how do Electrical Vechicle Solar charging stations work?

    Actually, there is a good chance these are 480 volt three phase charging stations...

    Assuming the Nissan Leaf has a 24 kWH battery bank, could get a quick charge to 50% in ten minutes:
    • 24,000 WH * 50% * 1/480 volts * 60 min/10 min charging * 1/sqrt(3) = 87 amps @ 480 volts 3 phase power
    If you have several charging stations (stores, service station, etc.)--You will need a hefty service to support that.

    The other issue is reservation charges... In California, about 1/2 the bill for commercial power is the cost of 15 minutes of maximum power used from the grid in a 1 year period... Installing a quick charger that is rarely used will result in horrendously high power bills.

    Figuring out charges is not easy... But it appears just for the meter, the utility could charge $14-$40 per day for these sorts of power levels (72kW per charging station).

    It is not obvious how people and "power stations" can let people do a quick charge economically, on demand, on summer afternoons in California with only a direct grid connection (use a natural gas genset on site?).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #3
    Re: how do Electrical Vechicle Solar charging stations work?

    From what I have seen they are just grid tie Solar with a charging station on the meter. That is all we are doing.

    Nissan discourages Level three charging as like any battery overheating it is damaging. Also the Leaf dose not have thermal management of the battery. The volt does have thermal management but Limits the charge rate to 3.3 kw.
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  • DarkStar
    DarkStar Registered Users Posts: 12 ✭✭
    #4
    Re: how do Electrical Vechicle Solar charging stations work?
    rollandelliott wrote: »
    I was reading that electric vehicles can get a quick 480V DC charge for ten minutes to give them an extra range boost.

    I've also seen solar powered car ports with charging stations.

    There are many grid tie inverters that work around 480V DC as well.

    So I'm just curious how does all of this technology work?

    I'm guessing these charging stations take normal 240V AC grid electricity and convert it it 480V DC for charging? Kind of ineffcient, but it provides a 24/7 solution.

    Though it would be cool just to plug your solar array directly to your EV for a quick boost. Though DC arcing and safety considerations would have to be worked out and obviously would only work during peak sun hours.
    Hey rollandelliott,

    I wanted to reply to your post since I'm very familiar with these systems (and I'm also a Nissan LEAF owner).

    solar_dave is correct, what installers are doing is a grid-tied PV system, that happens to also have electric vehicle charging stations integrated with them.

    Typical electric vehicle charging is called "Level 1" (120 volts) and "Level 2" (240/208 volts). On the Nissan LEAF, it draws a maximum of 12 amps on Level 1 charging and 16 amps on Level 2 charging. It takes this electricity directly into the on-board charger in order to charge the battery.

    "DC Quick Charge" is the 3rd level of charging available on the Nissan LEAF (and Mitsubishi i MiEV). The charger is located external of the vehicle and supplied with three-phase electrical service (480 volts nominal). This off-board charger is able to supply the Nissan LEAF with 400 volt, 200 amps maximum, directly into the battery pack.

    "Level 3" charging is still being worked on by the Society of Automotive Engineers (SAE) and isn't defined yet, but it will be similar to DC Quick Charging.

    With DC Quick Charging, the Nissan LEAF can go from 0%-80% in 26 minutes and to 100% in an additional 20 minutes.

    The Nissan LEAF does incorporate thermal management in their battery pack. As the temperature increases, it tapers off the charging rate to minimize any potential damage (after all, they have an 8 year/100,000 mile warranty to protect). Also, Nissan no longer discourages DC Quick Charging as they stated in early 2010, they were able to improve their charging algorithms to better protect the battery.

    As BB. stated, if you are a commercial business and only have a single three-phase service to a DC Quick Charger, the "demand charge" fee by the power utility will be quite high, however it is expected that most DC Quick Chargers will be integrated into existing commercial buildings that already have a significant demand charge already in place.

    This is a pretty cool forum and will definitely check it out more going forward!
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #5
    Re: how do Electrical Vechicle Solar charging stations work?

    cool thanks for the education.
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