My car MELTED my 16A socket!

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#2432897 5-Mar-2020 08:16

A few notes:

- It is good the temperature safety shutoff of the EVSE worked!

- That circuit should really of had a 16A breaker to start with as a dedicated circuit with a socket designed for 16A. I've got effectively got the same setup - wired for 3-phase 32 A, but only have a single phase 16A socket currently connected and have a 16A breaker.

- No guarantee that the current measurement of the EVSE is accurate. I've found differences upto about ~12% compared to my Fluke.

- I believe the charger can increase current (upto max current as set by EVSE duty cycle) to reach 3.6 kVA. So a voltage drop could potentially increase current, although I think the EVSE also detects voltage drop so this should throw an error.

In any case, the EVSE likely has a fault here. Either the plug wasn't up to spec, or was allowing more current than it should. Technically could of also been a problem with the socket.

Bung

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#2432920 5-Mar-2020 08:44

I find it hard to believe that a quality socket designed for 16A nominal load would have such a low tolerance for overload. I don't have the 60309 standard but initial Googling suggests that the temperature rise test is at 24A and supposedly 20A shouldn't trouble a 16A plug and socket. You shouldn't get heat without resistance, where is that coming from? Was it poor cable termination?

Beccara

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#2432927 5-Mar-2020 08:56

Yes but standard do not always work in the real world. We have 15a wall outlet style plugs that routinely cook if you use them at close to 15a loads for prolonged periods. Given this plug/socket is fairly new tho I would suspect one or the other being out of tolerance

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k14

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#2432944 5-Mar-2020 09:30

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 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.

I've been using the 16A (120V) Japanese charger for over two years with no issues. It draws around 9-10A at 240V.

Bung

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#2432946 5-Mar-2020 09:36

Beccara:
Yes but standard do not always work in the real world. We have 15a wall outlet style plugs that routinely cook if you use them at close to 15a loads for prolonged periods. Given this plug/socket is fairly new tho I would suspect one or the other being out of tolerance

What brand? I have a collection of 10A sockets here that I pulled apart. The cheap ones have obviously lighter guage metal in the contact springs. TBH I haven't found any recent HPM or PDL to compare against their older versions.

Beccara

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#2432959 5-Mar-2020 09:57

Seen both HPM and PDL's cooking 15a 3pin plugs, Not sure which series but no older than 5-6 years. Not just using EVSE's either, UPS's and Welders too

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#2432962 5-Mar-2020 09:59

zenourn:

....

- That circuit should really of had a 16A breaker to start with as a dedicated circuit with a socket designed for 16A. I've got effectively got the same setup - wired for 3-phase 32 A, but only have a single phase 16A socket currently connected and have a 16A breaker.

....

Breaker exists to protect the wiring, not the sockets.

Circuits with 16A or 20A breakers fitted with 10A sockets are pritty much standard in any NZ house.

Beccara:

Yes but standard do not always work in the real world. We have 15a wall outlet style plugs that routinely cook if you use them at close to 15a loads for prolonged periods. Given this plug/socket is fairly new tho I would suspect one or the other being out of tolerance

Yeah, the 15A socket (Looks like a normal domestic socket with a slightly bigger earth pin) despite being rated for 15A continuous loading doesn't do well in that duty.

In the EV early adopter phase, it recommended charging socket for a little while, until people worked the above out. generally the blue 16A sockets have proved much more suitable.

Scott3

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#2432967 5-Mar-2020 10:07

k14:

I've been using the 16A (120V) Japanese charger for over two years with no issues. It draws around 9-10A at 240V.

Generally these are rated for 200v (so technically unsuitable at the 230v we use in NZ). They generally draw something in the range of 13A - 15A.

It is possible to spoof (open circuit?) the temperature sensor in them to reduce the current draw sounds like the latter has been done to yours.

tripper1000

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#2433169 5-Mar-2020 13:59

Bung: I find it hard to believe that a quality socket designed for 16A nominal load would have such a low tolerance for overload. I don't have the 60309 standard but initial Googling suggests that the temperature rise test is at 24A and supposedly 20A shouldn't trouble a 16A plug and socket. You shouldn't get heat without resistance, where is that coming from? Was it poor cable termination?

Well the electrician did stay that it wasn't a quality plug. Plus there could have been mistakes made during termination of the wire to the plug. Unless someone is doing maintenance on the pins and sockets they tarnish over time and naturally and progressively the contact resistance increases.

If you look into the standard you can see it isn't overly stringent. At a fault current of 22A the pin temperature is allowed to rise 50 deg C in 1 hour. This will be at ambient of 20 or 25 deg C, so the pin is allowed to get to 70 deg C - that's too hot to touch. If ambient is higher the pin will get hotter. If the fault exists longer than 1 hour, the pin will get hotter. EV's charge for many hours on end it the maximum limits of the plug so will inevitable find any weak links. This is way plug temperature sensor are mandatory for EVSE when going to the max rating of plug. This is also why you're not supposed to use extension leads - the EVSE is unable to monitor the temperature of the plug at the far end of the lead so failures can go undetected and turn into fires.

duckInferno

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#2433231 5-Mar-2020 15:21

tripper1000:

Well the electrician did stay that it wasn't a quality plug. Plus there could have been mistakes made during termination of the wire to the plug. Unless someone is doing maintenance on the pins and sockets they tarnish over time and naturally and progressively the contact resistance increases.

It's worth noting that the EVSE was plugged in at all times. I only actually unplugged it once when I first got it just to demonstrate it. We've been using it for about a month so it didn't really have any chance for fatigue or whatever.

duckInferno

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#2433232 5-Mar-2020 15:25

An update-

A replacement EVSE arrived today so I tested it out.

At 63% charge the EVSE reported 15.2A max
At 16% charge the EVSE reported 14.1A max (we'd hypothesised that it reached higher amps at lower charges)

The socket/plug makes no buzzing sounds (for now).

So from this limited testing it seems like the old EVSE was faulty. I've sent it back to OEMAudio so we'll see what they find out.

Kudos to Paul from OEMAudio for their co-operation through all this though, I think this would have been really easy for either 'side' to start blaming each other's gear and throw it over the fence but this didn't happen, Paul sent the replacement (technically a more expensive variant actually) before knowing what was really at fault with a packing slip to send back the old one.

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#2433334 5-Mar-2020 18:22

duckInferno: An update-

The socket/plug makes no buzzing sounds (for now).

I was about reply saying I think there was an issue with either the plug or socket.

This is a massive red flag to me. I would never accept it as being safe/normal for buzzing sounds to occur. It indicates to me there was arcing going on inside the plug/socket this will cause the contacts to burn, increase their resistance, thus creating heat.

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duckInferno

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#2433343 5-Mar-2020 19:04

Technofreak:
duckInferno: An update-

The socket/plug makes no buzzing sounds (for now).

I was about reply saying I think there was an issue with either the plug or socket.

This is a massive red flag to me. I would never accept it as being safe/normal for buzzing sounds to occur. It indicates to me there was arcing going on inside the plug/socket this will cause the contacts to burn, increase their resistance, thus creating heat.

I agree with th buzzing assessment but I believe at this point it was because of a month of sustained 18A charging sessions melting the pin to the point where it started arcing.

k14

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#2433344 5-Mar-2020 19:16

Scott3:

k14:

I've been using the 16A (120V) Japanese charger for over two years with no issues. It draws around 9-10A at 240V.

Generally these are rated for 200v (so technically unsuitable at the 230v we use in NZ). They generally draw something in the range of 13A - 15A.

It is possible to spoof (open circuit?) the temperature sensor in them to reduce the current draw sounds like the latter has been done to yours.

Still has the original temp sensor in tact (precision job cutting the plug apart without damaging the sensor). Thought it was 9-10A because it was plugged into a 16A socket with a 10A HRC fuse and didn't blow it. Also when doing the charge time calcs I came up with about 9a for the time it took to charge the battery.

Technofreak

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#2433369 5-Mar-2020 20:42

duckInferno:
Technofreak:

I was about reply saying I think there was an issue with either the plug or socket.

This is a massive red flag to me. I would never accept it as being safe/normal for buzzing sounds to occur. It indicates to me there was arcing going on inside the plug/socket this will cause the contacts to burn, increase their resistance, thus creating heat.

I agree with th buzzing assessment but I believe at this point it was because of a month of sustained 18A charging sessions melting the pin to the point where it started arcing.

Somethings not adding up to me here, though I must admit I'm not an expert on charging EV batteries. Why was there sustained 18A charging session previously when you haven't seen these figures since you replaced the plug/socket? Having had a quick read about EV battery charging characteristics there was nothing there that indicated charging rates would vary upwards at higher battery levels.

2 amps above the rated 16 amp limit isn't likely to be your problem, providing the plug and socket is in good condition. I'm highly suspicious of the numbers you are seeing.

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