Private CCS charging station

Discussion in 'Hyundai Kona Electric' started by Tomek, Jun 13, 2021.

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  1. Tomek

    Tomek Member

    For DIY enthusiasts - what if you had to build your own DC charger using a purchased 11kW factory inverter from Hyundai Kona and standard EVSE? Would it be possible?
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  3. marshall

    marshall Active Member

    I would think key safety features that prevent you from getting electrocuted would be missing if one did as you propose.

    Secondly, the cars already come with a charger. Why reinvent the wheel?
  4. I don't think so. The charger needs to communicate with the car. You're talking CCS protocol. It's not like an AC EVSE that actually doesn't do anything. Totally different story.
  5. I think Level 2 electricity supply for car charger at home is sufficient, takes only 4 hours to recharge my Kona from 50% to 100%.
    I use a Grizzl-E home charging station, works perfect.
  6. Assuming you are wanting 50 to 70KW fast charge here.

    Your expenses are going to range from $20K to 100K depending on whether your site already has 440V 3phase 200A service, how much your local permitting and inspection costs run, and whether you hire a qualified electrician to do it for you and of course the electrical panel and parts kits.

    Unless you understand the safety features of DC fast chargers you could harm yourself or your car. For instance, a 440V 3phase arc flash at that energy level will likely kill you
    Electrical Arc Flash Demonstration - YouTube

    Don't let the Magic Smoke out
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  8. GeorgeS

    GeorgeS Active Member

    If you note the DC fast chargers out in the public, they have transformers or cooling towers. This amount of power comes at a cost. In the US, it would require a business account to have the power company install a service large enough to make it worthwhile to do DC Fast charging. These do NOT have cheap power rates like residential rates. Sometime it is an average power consumption rate. This takes your high period and low period and charges you the average over the entire clock. Good for business but not for home. Lastly, the DC fast charging components can be purchased but could be upwards of $20K. These are needed because of the protocol needed to DC Fast charge. Simply put I wouldn't want to try it. Why would anyone unless you have lots of money to save a few minutes.
  9. hobbit

    hobbit Well-Known Member

    In theory you could build a 10 kW CCS charger for not much time benefit over your onboard AC one,
    but you would have to re-implement the undergrad CS thesis gone horribly wrong that is the CCS
    protocol to do it. The analog / duty-cycle level 2 protocol is just so much more ... accessible.

    On the other hand, outfits like Sparkcharge are angling toward the portable fast-charging market
    and will obviously have to support CCS to get people going again relatively quickly. Still, I don't expect
    units like that to be anywhere north of 50 kW at best.

    Wallbox is also evidently hoping to be a player in the V2<whatever> market, and is facing the same challenges.

  10. The closest DC charger for practical home use might be a 25kW unit from Delta, provided you have a 3-phase feed. Here's the spec.
    There are a few of these here in NZ either at supermarkets, remote locations and my local dealer. I like this size because it's not too hard on the battery.

    Last edited: Jun 13, 2021
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  11. What scope are you using? There are scopes I've used that have multiple databus protocol analyzers to see what's being communicated. The worst example I recall was some noob engineers in the lab who'd never heard of a bus analyzer that were manually converting scope captures to packets for aerospace ARINC 429 packets. Then we bought this bus analyzer and they were much happier

    It seems like a breakout box could easily be built that passes DCFC packets to the car, but hack the cars response packets by suppressing or substituting. Not sure if this gains anything other than ability to tell EA chargers you're at 74W to avoid the upcharge.

    I could see some inventive hackers eventually running a webserver from their car assuming CAN to open internet is what the charging stations are doing.
    Last edited: Jun 13, 2021
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  13. hobbit

    hobbit Well-Known Member

    My current scope is a GW Instek, and it has some rudimentary but useful bus decode modes, but
    it certainly has no concept of CCS or the underlying Homeplug PHY network layers. A really sharp
    protocol and hardware wonk could probably build something to cross-convert most of what's out
    there, such as a box that would look like a Tesla to a supercharger [probably needs an authorized
    VIN] and feed charge current out the other side as CCS. The high-current connections would be
    the simplest part of that... and it would need its own independent low-voltage supply to get
    anything started.

  14. Tomek

    Tomek Member

    I am considering the following assumption: There is a 230 / 400V home power supply with a power of 14kW (main fuse 32A). One can charge his car by AC EVSE, but that's not the point. Since the charger built into the car (converter) takes 230 / 400V 7.2kW (or 11kW, depending on the version), I can imagine that it could theoretically be built into the "charging station" outside the vehicle and charge it with DC via the CCS connector. The whole problem basically boils down to the extent to which the car's converter works independently of other electronic systems of the car (I am not talking about cooling, but about logic systems, let's call it "vehicle computer"). So, assuming that it would work independently outside the vehicle and it would be properly cooled, would it need any other electronic components for proper operation, apart from the electrical input (AC) and output (DC) connectors? I don't need to convince anyone about the daily benefits of DC 11kW versus AC 7.2kW? Similarly, I do not need to explain that "direct current is much more dangerous than alternating current and that if you are not an electrician, do not do it yourself at home, blah, blah" because it's quite obvious, and I mean only information, whether it is technically possible and how complicated it would be (Ghostbusters like it).
  15. mikeselectricstuff

    mikeselectricstuff Active Member

    Yes it's technically possible. You have two major things to do :
    1) Figure out how to get the OBC to play nice, by reversing its CAN messages - this should be pretty doable if you have a car available to do the CAN logging. Maybe a few weeks' work.
    2) Implement the CCS EVSE-side interface. This is highly nontrivial due to the terrible choice of the Greenphy PLC layer for the CCS standard. There are some modules available for this, for example , but you may find licensing the software difficult for a 1-off

    For bonus points, use two OBCs in parallel to get 22kW DC charging.
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  16. Tomek

    Tomek Member

    A very interesting and not even such an expensive solution (at least until the customs officers add VAT - in Europe has just ended the golden era of shopping on Alibaba without VAT and duty)

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