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Hello everyone, i have 2020 kona (top trim, with 11 ac obc / i’m not from the uk, so top trims are different to the uk version. Also, pardon my potential bad grammar, english is not my native language).
A bit more background before i delve into the problem. I’ve had the car for 3 months and a solar array (10 kwp) plus a single phase fronius inverter for 2 months. I have also installed a webasto pure charging station which has been connected directly to the inverter (max 7.2 single phase). In the car settings i’ve selected the current to minimum so i used to get 4.2kw (this way i would charge mainly from what the pv array was producing). All was well for the last two months, until yesterday when, whilst charging, i heard a loud bang and the house was left without electricity.
I went and checked and saw three breakers had flipped: the main fuse outside (50A), the inverter breaker (40A) and the wallbox fuse (32A). I reset them and tried again, with the same result: a loud bang.
I called the company that installed the wallbox and they said it looked fine and said it must be the car. I wasnt convinced so i went to a public charger and tried charging on ac. The boom that followed made the public charger reset itself.

so i went to the hyundai service center who assured me they would fix it immediately. So they read the obd for fault codes, found a “low voltage while charging” error (they refused to print it out), said they reset/deleted it and sent me on my merry way, being convinced it was solved. I stopped at the first public charger and tried again and of course the result was the same, i had bricked another charger.

i tried at a different charger to dc fastcharge and that works flawlessly, but im guessing its the ac/dc inverter thats dead.

i will leave the car at hyundai on monday and they will start “ripping it open”.

Does anyone have the slightest clue what has happened ? I’ve yet to discover a similar problems on the “internets” that’s similar to mine.
Thank you in advance for your input.
 

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Does anyone have the slightest clue what has happened ?
Sounds like a serious short circuit inside. Most likely a semiconductor that has gone short I'd think.
Probably a 'bathtub' failure (components that pass tests at manufacture but aren't really OK and fail early in life).
 

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Discussion Starter #3
Hopefully they are able to fix it asap, i hate driving my petrol car. :)

p.s.: my Kona has 8500 km. So it’s quite unfortunate such a big failure occured so quickly. Im curious how the dealer handles it.
 

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No, it’s single phase from the inverter and the wallbox is set and wired for single phase. I only charged on 3-phase ac at a public charger for a few minutes (just to test if it indeed drew over 10 kw) just after i got the car. 90 % of the charging has been AC (dc only when roadtripping over long distances).
 

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Hopefully they are able to fix it asap, i hate driving my petrol car. :)

p.s.: my Kona has 8500 km. So it’s quite unfortunate such a big failure occured so quickly. Im curious how the dealer handles it.
They will almost certainly have to get a new module and/or wiring harness to fit, dependent on exactly where the fault is and if it's caused other damage. Those are not likely to be parts a dealer will have, and possibly not even the country agent.
So it could take some time I fear. :(
 

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Discussion Starter #7
That sounds just “lovely”. Im still hoping it’s a simpler fix, like a fuse or relay... but will find out for sure next week. Will keep you updated.
 

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Discussion Starter #11
CCS does work and i do have the car until monday, but somehow i’ve kinda lost faith in the reliability of the charging system (in my mind i’ve always thought the ac charging system to be almost “invincible”, i always thought if something were to go wrong with charging it would be the dc part, because of the high volts/amps).
Once the car does go in for servising, i am expecting a few weeks downtime aswell (as a minimum).
P.s. the loud bangs always came from the chargers, not the car (not that it matters :D)
 

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There is almost nothing to go wrong in the car for CCS-it's just a contactor that connects the battery to the connector pins, and some software. The rapid charger does all the work. The OBC is a lot more complex.
 

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Discussion Starter #14
I would assume a 35000 pound car with a 67 kwh “bomb” attached to it would have so many protections and fail safes / redundancies that a boom is extremely unlikely even whilst charging at the highest currents (like 77 kw and not a measly 4.2 kw). Thats why i initially assumed it must be the wallboxs fault. Or the circuit that feeds it.

let me rephrase, i did not, at any moment, feel that my well-being is in danger. Even if those bangs had come from the car.Which they didnt.
 

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i’ve kinda lost faith in the reliability of the charging system (in my mind i’ve always thought the ac charging system to be almost “invincible”,
They are electronic modules. There will be occasional failures in the population and it seems you were the unlucky one.

the loud bangs always came from the chargers, not the car
OK, then presumably breakers and contactors opening. Loud is subjective, but
three breakers had flipped: the main fuse outside (50A), the inverter breaker (40A) and the wallbox fuse (32A).
Even though there isn't a lot of discrimination between those devices, tripping them all instantly does suggest a substantial current flow - at least 150A and likely more. If that fault is inside the car charger it will almost certainly have vaporized some parts.
 

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Discussion Starter #16
Yes, my thinking exactly, for sure over 50A, but no idea by how much over.
Im still hoping it “just” fried some relays / fuses and not the OBC itself.
 

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Yes, my thinking exactly, for sure over 50A, but no idea by how much over.
Im still hoping it “just” fried some relays / fuses and not the OBC itself.
For the usual MCBs instantaneous trip (ie. less than about 10 seconds) requires 3x rated current. So to take the 50A one out is a minimum 150A.

If it had only fried fuses they should have opened and the fault then been isolated. The fact that you've tried a few times with the same instant trip implies there is a substantial, permanent fault.
It might be fixable, but car technicians don't usually have those skills or the equipment, so it's an exchange job. Hyundai might send it for repair, but more likely they'd just look to identify the fault for statistical/improvement purposes.
 

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Discussion Starter #18
Thanks for the info, but im extremely curious what the underlying “generator” of that huge amperage might have been. The hv battery ?
 

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Thanks for the info, but im extremely curious what the underlying “generator” of that huge amperage might have been. The hv battery ?
Is it was a backfeed from the battery then tripping the house breakers probably wouldn't have stopped the problem and the car either wouldn't work or be a molten heap ... Probably.

The generator is just the power stations at the far end of your house mains supply.

Your house and installation are of course unique, but in the UK the prospective short circuit current is of the order of a few thousand amperes for a standard domestic mains electrical installation. PSC is the value that the current will reach in a sustained short circuit, usually as measured at the main board. Each length of cable beyond will reduce it a bit, but that 150A is not huge at all - it may well have been 10 times that.
 

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2020 Kona EV, Red, 64kWh Premium SE (10.5kW OBC)
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I would assume a 35000 pound car with a 67 kwh “bomb” attached to it would have so many protections and fail safes...
That's very emotive language and not entirely accurate. By comparison, the average ICE vehicle with a 60 litre fuel tank has a 600kWh "bomb" attached to it, nearly ten times the energy held in a large EV's battery.
 
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