My car MELTED my 16A socket!

Forums › Transport (cars, bikes and boats) › My car MELTED my 16A socket!

duckInferno

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#268188 4-Mar-2020 12:59

You'll never guess what happened next! ... sorry.

I upgraded my garage's circuit to 40A (futureproofing) and installed a 16A caravan socket for my freshly arrived japanese import, and a 16A charger w/ caravan socket from OEMAudio.

It's been charging nicely over the last month. It goes up to 18.6A draw consistently, which I didn't really think anything of ("cool, faster charging!").

Turns out I should have thought a bit more about it because over the course of that month, those extra couple amps were melting the caravan plug and socket! One day I plugged it all in and noted a buzzing noise coming from it. Later in the day (I know, lack of thinking) I came back and the charger had stopped with a temperature error - it was at 74C. The plug was totally fused in the socket and I couldn't pull it out.

Sparky came the next day and got it out for me, he confirmed that the neutral pin on the charger's caravan plug had melted and fused with the socket. The circuit had a 40A fuse so the caravan socket effectively became the fuse in the circuit I guess :D

Now you might be wondering

"why did the charger rated for 16A supply more than 16A and melt itself?"
"aren't japanese leafs 16A max, I thought only UK leafs could be 32A, why is it accepting more than 16A?"

and those are good questions!

which I also have!

Supposedly there's a pilot signal that occurs between a charger and a car which negotiations what amperage to be used. According to this table it seems like both the car and the charger should be agreeing on 25% PWM to achieve a 15A continuous supply.

It's easy to point fingers at the charger here. After all, if you came along and plugged a 32A car in you wouldn't expect the charger to decide to self-immolate and try push 32A through.

But wouldn't the car also say "hey whoa there, stop at 15A buddy"? Which brings me to another question: how do I actually know what my car's onboard charger is? Supposedly only UK leafs have the 32A option (6.6kW charger) but this is a japanese import 916A / 3.3kW). It has two times on the dash but that doesn't seem very scientific.

Is there a piece of hardware on the car I can inspect or something?

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89 posts

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#2432377 4-Mar-2020 13:02

p.s. the sparky also replaced the 40A fuse with a 16A fuse. But I still can't charge my car if the fuse just pops every time.

tripper1000

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#2432465 4-Mar-2020 13:58

Something isn't as it seems here. I have dialled the charging current up to 20A on my charging lead in 1 amp increments and my JDM Leaf topped out at ~15 amps.

The charging modules in the Leaf have a model number on the side - try googling it. Maybe someone has fitted a UK charger to a JDM Leaf and it is capable of 32A? (free upgrade!).

Also your sparkies current meter could be out of calibration by 3 amps. He was possibly using a current clamp and the older/dropped ones are not too accurate at low currents (modern ones are more accurate but still go out of cal if you drop them). They're generally intended for measuring 100's of amps where a discrepancy of 3 amps is inconsequential.

Those 16 amp sockets are only good for 16 amps at 20 deg C for 8 hours, when in tip-top condition. All bets are off if the ambient temperature is significantly higher (eg in the sun-shine), or if you exceed 8 hours, or if there is poor contact engagement though being old/corroded/manufacturing defect. This is why the EV charging standards require temperature sensors when going to the max limit of the outlets.

I've seen those 16 amp outlets melt in the tropics when carrying 14amps continuously and I've seen them melt in boat marina's at just 5 amps due to the salt corrosion.

Beccara

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#2432479 4-Mar-2020 14:10

The red box has something wrong with it, i'd guess it's been programmed wrong and is allowed 32a but your car's charger is capping out at 18~amps. Talk to OEM audio about it?

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duckInferno

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#2432516 4-Mar-2020 14:40

tripper1000:

Something isn't as it seems here. I have dialled the charging current up to 20A on my charging lead in 1 amp increments and my JDM Leaf topped out at ~15 amps.

The charging modules in the Leaf have a model number on the side - try googling it. Maybe someone has fitted a UK charger to a JDM Leaf and it is capable of 32A? (free upgrade!).

I wish! Just checked and it's a standard 3.6kW charger.

It actually only goes above 18A when I get home from my commute and need to charge it up from 20-30%. When it's at 80% it seems to hover around 14.5A.

tripper1000:

Also your sparkies current meter could be out of calibration by 3 amps. He was possibly using a current clamp and the older/dropped ones are not too accurate at low currents (modern ones are more accurate but still go out of cal if you drop them). They're generally intended for measuring 100's of amps where a discrepancy of 3 amps is inconsequential.

The charger itself was reporting those numbers, I can't speak to their accuracy but it melted the pin. :c

wellygary

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#2432517 4-Mar-2020 14:40

Beccara:

The red box has something wrong with it, i'd guess it's been programmed wrong and is allowed 32a but your car's charger is capping out at 18~amps. Talk to OEM audio about it?

I'm guessing he has already had to talk to OEM to get a replacement EVSE, given that last one fused itself to the caravan socket..

It would be interesting to hear what they said....

Hopefully they asked for the unit to be returned to them so they could run some tests on why it is serving up more than 16A...

duckInferno

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#2432518 4-Mar-2020 14:44

Beccara:

The red box has something wrong with it, i'd guess it's been programmed wrong and is allowed 32a but your car's charger is capping out at 18~amps. Talk to OEM audio about it?

Getting a replacement sent through tomorrow so we'll see!

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Dugimodo

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#2432522 4-Mar-2020 14:49

I think I read somewhere that the 32A charger has 4 of the heavy orange cables under the bonnet and the 16A only has 2. Or something like that, just google how to tell the difference.

I have a 20A breaker on my caravan socket and I'm using the Japanese 16A charger (yeah I know it's not rated for 220-240V) but I have no way to measure the actual current draw. Been using it like that for 8 months now, nothing even gets warm.

I also got a 3 pin 8A charger to carry around for emergencies.

AlanWilden

1 post

Wannabe Geek

#2432560 4-Mar-2020 16:14

Hi, What Year and spec is your leaf? Is it a 2016 or 2017 G spec? Is it a 24 or 30KWh?

There is a possibility that it could have had the 6.6Kwh onboard charger upgrade ticked by the original owner.

If it did however, this still doesn't explain why a 15A EVSE would allow higher charging. Please keep us informed on this. It's very interesting

Thanks

Alan

tripper1000

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#2432564 4-Mar-2020 16:17

duckInferno: The charger itself was reporting those numbers, I can't speak to their accuracy but it melted the pin. :c

TBH I wouldn't trust a Chinese chargers accuracy too much either. I'd expect that it is more likely to be an indication error than the car to be truly drawing 18 amps. The pin can melt because the wires were not terminated correctly inside the plug. There has been a race to the bottom with those 16 amps plugs - many don't even have screw terminals for the wires any more, relying on spring terminals and Insulation Displacement terminals - telephone style. This would have been unacceptable in the 80's & 90's and I can see some types getting banned in the future.

wellygary: ....Hopefully they asked for the unit to be returned to them so they could run some tests on why it is serving up more than 16A...

That isn't quite how the J-1772 standard works - the EVSE can't "serve up" too much current - "offer up" would be a better description as they can't force feed the car more current than the car wants.

The EVSE advertises the maximum current that the car may draw, and the car draws what ever it wants up until it reaches either the limit advertised by the EVSE or the cars on board chargers limit - which ever is lower. In the case of the JDM Leaf the cars on board charger limit is ~16 amps and it would/could/should never exceed that.

An example is that there are plenty of public EVSE's around that offer/serve up to 32 amps but a JDM Leaf will only ever draw 16 amps when using them. A UK Leaf on the same charger will take the full 32 amps on offer.

RunningMan

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#2432565 4-Mar-2020 16:18

Just because there is some confusing terminology being used here - the charger is built into the car itself, check the model number on the charger to determine what its capacity is. The OEM audio cable is not a charger, it's the EVSE (Electric Vehicle Supply Equipment). It should be sending the correct PWM signal to the charger in the car to advertise the maximum current available. It's possibly not sending the correct PWM signal and the charger is then drawing more than it should. Would be interested to know the charger model in the LEAF.

duckInferno

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#2432572 4-Mar-2020 16:30

The car is a 2014 24X.

Dugimodo:

I think I read somewhere that the 32A charger has 4 of the heavy orange cables under the bonnet and the 16A only has 2. Or something like that, just google how to tell the difference.

I've got 3, what do I win? :D

RunningMan:

Just because there is some confusing terminology being used here - the charger is built into the car itself, check the model number on the charger to determine what its capacity is. The OEM audio cable is not a charger, it's the EVSE (Electric Vehicle Supply Equipment). It should be sending the correct PWM signal to the charger in the car to advertise the maximum current available. It's possibly not sending the correct PWM signal and the charger is then drawing more than it should. Would be interested to know the charger model in the LEAF.

Sorry yeah EVSE! I posted a pic of the label on the charger (I think) above, is that enough info to tell? The model is expressed in japanese. It's really hard to get an angle on it. According to the label I've got the 3.6kW charger.

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duckInferno

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#2432573 4-Mar-2020 16:30

tripper1000:

TBH I wouldn't trust a Chinese chargers accuracy too much either. I'd expect that it is more likely to be an indication error than the car to be truly drawing 18 amps. The pin can melt because the wires were not terminated correctly inside the plug. There has been a race to the bottom with those 16 amps plugs - many don't even have screw terminals for the wires any more, relying on spring terminals and Insulation Displacement terminals - telephone style. This would have been unacceptable in the 80's & 90's and I can see some types getting banned in the future.

My sparky did say it was a cheap plug.

Scott3

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#2432606 4-Mar-2020 17:01

Kinda only 3 options:

EVSE was sending the wrong pilot to the car.
Car was drawing too much power for the pilot it was given.
There is some kind of measurement error with the charge current.

It seems worrying that an EVSE with temperature monitoring on the pins let the pins get hot enough to melt stuff. Typically such monitoring would slow things down when the pins are getting quite warm.

RunningMan

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#2432608 4-Mar-2020 17:06

duckInferno:

@RUKI might be able to ID that perhaps?

Assuming it is 3.6kVA @ 230V, I wonder if there is a neutral or similar fault at the charging location that is lowering the voltage so the charger draws more current up to the same kVA load? Of course, this would have also had to have had an effect on the EVSE and what it advertises. Could be a faulty on-board charger just drawing too much, but I think the standard says the EVSE should disconnect under those conditions (check, as I am not 100% sure).

gzt

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#2432862 4-Mar-2020 23:31

A local fault seems likely. Also, that is a KVA rating, and KVA rating implies a power factor may be involved.

Inductive clamp cannot measure/adjust for power factor.

Edit: not true, some do.

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