[Spiny]

The 13A fuse is peculiar to the UK plug sometimes called a type G, it is not found in the European schuko plug. It cause problems when the plug is in continious high power use as it heats up and the fuse contacts can also heatup.
The EU plug is also rated at 16Amps which is higher than the UK one (13A intermittent and 10 amps continuous)

You appear to be measuring to earth. Please measure across the two thin wires in the mains lead - these will be attached to the thermistor(s). You can also measure Earth (green/yellow) to each thin wire in turn. The image seems to be red to earth. This all depends how the thermistors are wired internally.

 

[Nuno]

The 13A fuse is peculiar to the UK plug sometimes called a type G, it is not found in the European schuko plug. It cause problems when the plug is in continious high power use as it heats up and the fuse contacts can also heatup.
The EU plug is also rated at 16Amps which is higher than the UK one (13A intermittent and 10 amps continuous)

You appear to be measuring to earth. Please measure across the two thin wires in the mains lead - these will be attached to the thermistor(s). You can also measure Earth (green/yellow) to each thin wire in turn. The image seems to be red to earth. This all depends how the thermistors are wired internally.

I've measured now between the three small cables (with plug connected to 220V) and resistance is 12kOhm between the two cables (black/grey and black/pink) and 24kOhm between black cable and the two remaining ones.
Measuring ground to all three small cables is around 290kOhms.

 

[HandyAndy]

@Nuno , here's a pic of the thermistors disected out of a UK plug.

The wires look to be the same as yours, and assuming I chose the correct replacement thermistor, I'd expect to see 10 kOhms at 25C.

In yr post you said "I've measured the resistance and in all 3 wires value is close to 284kohm with plug connected to 220v and 0.0 ohm when disconnected. " Please do NOT go poking around inside while plugged into 220V ! Risking all sorts of problems, if you slip with the meter it's easy to short-circuit something and it all goes bang.

You do NOT want 220V around, and we do not need it, while we're checking out the thermistors & cabling to the mains plug!

the 12k Ohms you measured from black wire to the other 2 this wires is fine, so your thermistors are not the problem. Feel free to warm up the plug using a hairdryer, the resistance of the Viskay 10k thermistor I believe to be close to the actual part will change from 10 kOhm at 25C and drop to 3.6 kOhma st 50C. I'm expecting to see a drop in resistance of that sort of amount.

The resistance to Earth from these wires (290 kOhms) is totally irrelevant, and unknown. Some EVSEs wire one end of the thermistors to the Earth pin inside the plug, clearly this one does not.

You say the resistance of the thick mains cables all over the place is fine. In this case, I agree with Spiny that it's likely to be a failuire of the low voltage supply somewhere.

 

[Spiny]

Plugged into 220V - eeek!
Please no no no or we might have a 👻

 

[Nuno]

@Nuno , here's a pic of the thermistors disected out of a UK plug.
View attachment 171502

The wires look to be the same as yours, and assuming I chose the correct replacement thermistor, I'd expect to see 10 kOhms at 25C.

In yr post you said "I've measured the resistance and in all 3 wires value is close to 284kohm with plug connected to 220v and 0.0 ohm when disconnected. " Please do NOT go poking around inside while plugged into 220V ! Risking all sorts of problems, if you slip with the meter it's easy to short-circuit something and it all goes bang.

You do NOT want 220V around, and we do not need it, while we're checking out the thermistors & cabling to the mains plug!

the 12k Ohms you measured from black wire to the other 2 this wires is fine, so your thermistors are not the problem. Feel free to warm up the plug using a hairdryer, the resistance of the Viskay 10k thermistor I believe to be close to the actual part will change from 10 kOhm at 25C and drop to 3.6 kOhma st 50C. I'm expecting to see a drop in resistance of that sort of amount.

The resistance to Earth from these wires (290 kOhms) is totally irrelevant, and unknown. Some EVSEs wire one end of the thermistors to the Earth pin inside the plug, clearly this one does not.

You say the resistance of the thick mains cables all over the place is fine. In this case, I agree with Spiny that it's likely to be a failuire of the low voltage supply somewhere.

Understand Andy, clear, no 220V on during measurements.

Just did the test you suggested with the air dryer and yes both resistance values were already going to 4.7 and 4.9kOhm after a while heating up.

All the weldings seemed to look good, no braking welding or burned components...

From your experience what could I measure in order to try to identify what caused the problem?

Thanks for your input.

 

[Nuno]

Is there any detail picture from the circuits you would like to see in more detail that might help!!!...

 

[HandyAndy]

@Nuno, one of your photos suggests something's got rather old. Your big PCB is labelled HW 4.12.4 and I have a pic of another EVSE, same design, with HW 4.16.1 from a repair of October 2021. There are slight differences in the layout of the mains pins on the PCB, no idea what else got changed or why.

Another pic suggests a bit of overheating, or ageing anyway. See this cropped view where I've arriwed bits that look suspicious to me. The big mains solder-joints should be nice & smooth & shiny. If they're looking rough, pitted with tiny holes in, or damaged, then you may have fatigued joints which simply are not carrying power properly. These joints should all be resoldered & checked. You can do simple continuity checks on these big high-current pathways, expect to see abot 0.2 Ojms which will be the resistance of your meter's wires. Check the meter by measuring the resistance with the test-tips touching each other. 0.2 to 0.4 Ohms is ok, 1 or more ohms suggests bad leads. The resistance around the circuit boards on these high current pathways should be tiny, less than 0.01 Ohms.

 

[HandyAndy]

@Nuno, next thing is see if you have low-voltage power around.
The small PCB has a chip on it I can recognise, labelled STM32F 030C8T6
this is a microprocessor. Here's the datasheet for this chip.
https://4donline.ihs.com/images/Vip...terIC/IC/SGST/SGSTS49303/SGSTS49303-1.pdf?hkey=6D3A4C79FDBF58556ACFDE234799DDF0
It runs off 2.4 to 3.6V, so somewhere this voltage should exist on this small PCB. It's a 48 pin package.
The "dot" in one corner marks where pins 1 and 48 are. These 2 pins are both Vdd and should be 2.4 to 3.6V.
Vss is 0V and is on pins 47 and 23, and these should be connected to the Ground plane of the PCB.

With NO power applied, I suggest you trace the connectivity of these pins, and find a couple of places where you expect to see 3.6V and 0V somewhere on the PCB, well away from lots of other pins! Then, AT YOUR OWN RISK, I TAKE NO RESPONSIBILITY IF YOU KILL YOUSELF, carefully reassemble the whole lot back into the case, or somwhere where you can get at your 2 new test-points with your meter without getting antwhere near the 220V live stuff.

Ideally you should be wearing a pair of 1000V electric-insulating gloves with a pair of leather gauntlets over those.
If you are able to connect the meter using clips and not need to hold the probes yourself, then please do so, and stand back when you switch on.

You should then be able to plug the EVSE in, switch it on, and measure the voltage across the 2 test pins. If you do not see 2.4 to 3.6V, then your low voltage supply has broken. But I am now at the end of my advice, as I do not have one of these to play with, and I do not know anything about the low voltage generation in this EVSE.

 

[Nuno]

Existe alguma imagem detalhada dos circuitos que você gostaria de ver com mais detalhes que podem ajudar!!!

@Nuno, next thing is see if you have low-voltage power around.
The small PCB has a chip on it I can recognise, labelled STM32F 030C8T6
this is a microprocessor. Here's the datasheet for this chip.
https://4donline.ihs.com/images/Vip...terIC/IC/SGST/SGSTS49303/SGSTS49303-1.pdf?hkey=6D3A4C79FDBF58556ACFDE234799DDF0
It runs off 2.4 to 3.6V, so somewhere this voltage should exist on this small PCB. It's a 48 pin package.
The "dot" in one corner marks where pins 1 and 48 are. These 2 pins are both Vdd and should be 2.4 to 3.6V.
Vss is 0V and is on pins 47 and 23, and these should be connected to the Ground plane of the PCB.

With NO power applied, I suggest you trace the connectivity of these pins, and find a couple of places where you expect to see 3.6V and 0V somewhere on the PCB, well away from lots of other pins! Then, AT YOUR OWN RISK, I TAKE NO RESPONSIBILITY IF YOU KILL YOUSELF, carefully reassemble the whole lot back into the case, or somwhere where you can get at your 2 new test-points with your meter without getting antwhere near the 220V live stuff.

Ideally you should be wearing a pair of 1000V electric-insulating gloves with a pair of leather gauntlets over those.
If you are able to connect the meter using clips and not need to hold the probes yourself, then please do so, and stand back when you switch on.

You should then be able to plug the EVSE in, switch it on, and measure the voltage across the 2 test pins. If you do not see 2.4 to 3.6V, then your low voltage supply has broken. But I am now at the end of my advice, as I do not have one of these to play with, and I do not know anything about the low voltage generation in this EVSE.

Thanks for your inputs Andy. Test tips are inside 0.2-0.4Ohms so should be ok still. I could not measure this point you mean that should have 0.01 Ohms.

Weldings are not shiny but I check if it were lose, broken, and conductivity is good between the different points. I've sent more detail pictures on the weldings it self because you have more experience.

I noticed on the right side of the PCB a strange look similar to some glue residues or other. I passed the finger but it's not greasy, it's a dry residue.

The part you mentioned about the low voltage I think I will not check to avoid any potential issue when doing it...

 

[Peli]

An owner of one of these decided to swap the 13A plug for a Commando one, only to discover after cutting it off that there are 6 wires going into the plug! I acquired this, and have repaired it with a chunky new 13A Masterplug and have fitted the 2 thermistors inside where they belong. I'm posting what I've learned so as to help anyone else with a damaged/destroyed plug, or wanting to do the same kind of plug-swap, so they can buy they correct valued thermistors if required.

The original owner carefully disected away the plug, and rescued both thermistors & the fragments of wire, enough for me to be certain of the connections. Thank you!

In addition to the usual 3 wires, the cable from the EVSE has 3 more coloured Black, Purple/Grey, and Purple/Black.
One thermistor is connected between Black and Purple/Black.
One thermistor is connected between Black and Purple/Grey.
I believe the thermistors to be Vishay NTCLE100E3103 which are 10k Ohms at 25C. Colour code Brown-Black-Orange.

Type-2 plug EVSE (from a Bmw, probably i3) with new plug fitted:
View attachment 125434

Underside of EVSE:
View attachment 125436

Wire fragments:
View attachment 125435

13A Masterplug
View attachment 125437

A very small amount of trimming was needed inside the Masterplug to not trap the thermistor wires. In the Rhs view one thermistor has been tucked beside the Neutral wire, and the other thermistor sits above the fuse.

I checked the resistance of the 2 thermistors carefully, letting them cool slowly from 100C on my K-thermocouple-controlled Heated Base Plate. I believe the thermocuple temperature will have been at most 2 degrees C cooler than the thermocouple reported, and that reports in 1C intervals. So there's a fair bit of variation in the resistances I measured while the temp controller (an industrial Toho unit) was reporting a single temperature.
Here's a table of the max and min resistances (Ohms) I measured at a series of temps, and also the nominal resistance expected from a Vishay NTCLE100E3103 thermistor datasheet:

Temp Min Max NTCLE100E3103
100 707 759 677
95 800 847 786
90 908 957 915
85 1046 1099 1070
80 1224 1294 1256
70 1680 1768 1753
60 2380 2502 2490
50 3437 3556 3605
40 5044 5353 5330
30 7470 7800 8059
25 9187 9675 10000
24 9642 10110 (no data)

Given the variability in thermistors (the 2 I tested were usually about 30 Ohms apart, and must have been near-as-dammit identical temps) I consider this a pretty close match, certainly accurate enough for this Vishay thermistor to be used as an excellent replacement for a damaged original. My thanks to Farnell (& Cpc, part of the same group) for making the datasheets & parts available.

Hi i have same problem but i have diferent colors of cables orange, purple and white how i connect it?

 

[HandyAndy]

Hi i have same problem but i have diferent colors of cables orange, purple and white how i connect it?

Look at post 43 Delphi Granny Charger Repair IC-CPD Aptiv 240V 10A just above. One of the wires is the common Ground wire, the other 2 each have their own thermistor. So you need to measure the resistance between all the wires. When you find 10k Ohms between 2 wires, your have one thermistor & the Ground wire. When you find 20 kOhms you have the 2 thermistor wires, so the one you are not holding is the common Ground wire - Black in the picture above.
Then look inside the main unit to double-check this makes sense!

When you've managed this, please post the results here, colours of the wires, resistance values you got, and the ambient temperature when yo measured it all. This will surely help someone else in the future.

 

[Peli]

Look at post 43 Delphi Granny Charger Repair IC-CPD Aptiv 240V 10A just above. One of the wires is the common Ground wire, the other 2 each have their own thermistor. So you need to measure the resistance between all the wires. When you find 10k Ohms between 2 wires, your have one thermistor & the Ground wire. When you find 20 kOhms you have the 2 thermistor wires, so the one you are not holding is the common Ground wire - Black in the picture above.
Then look inside the main unit to double-check this makes sense!

When you've managed this, please post the results here, colours of the wires, resistance values you got, and the ambient temperature when yo measured it all. This will surely help someone else in the future.

Done, charger working well here is colors of cabels.

 

[kjeldk]

I planned to do a CEE plug conversion from the Schuko plug. But to my surprise it has 5 wires.

Any tips would be appreciated. Maybe just hookup a NTCLE100E3103JB0 between them?
The CEE / Camping charger plug is helpful in the EU for 1 phase 16 amp charging in Germany and other places.

Greetings from the Netherlands

 

[HandyAndy]

Check the resistance between the red & white wires going into the plug you cut off. Maybe they reduced to 1 thermistor, not a lot of point in 2 inside such a small enclosure that doesn't have the 13A fuse assembly UK plugs have. I'd expect 12k Ohms, maybe 10k.

Also check the resistance beyween each of those 2 small wires to the Ground wire. Suppose you got 20 kOhms on the above reading above, and this test gives you 10 kOhms on each wire to Ground, this tells you they've done what other granny EVSEs have done, = common-up the return wires from 2 thermistors & connect to Ground, and use the 2 thin wires as the other ends of 2 thermistors. In which case you need 2 thermistors wired up between the 2 wires & Ground in yr new plug.

If it's a huge resistance (> 12k ohms, probably much greater) then there's just the 1 thermistor in there with its own dedicated 2 wires.

Your old plug is presumably scrap so yo can shave plastic/rubber off it carefully & recover the original thermistor(s) if you fancy!

 

[kjeldk]

Your old plug is presumably scrap so yo can shave plastic/rubber off it carefully & recover the original thermistor(s) if you fancy!

Tried to extract the probe from the plug. Totally destroyed it. It was some white stuff enclosed with the black rubber. The thermistor was enclosed in the white (porcelain?) stuff to make sure it picked up the heat of the entire plug. This blue thing is the only thing I could see of it.

Don't know where to go next. I tried 2 10ohm resistors like the following.

Did not work, fault blinking on charger. Thanks.

 

[HandyAndy]

Tried to extract the probe from the plug. Totally destroyed it...
Don't know where to go next. I tried 2 10ohm resistors like the following. Did not work, fault blinking on charger. Thanks.

Ok, remove those resistors totally.
What resistance did you measure across red to whte, red to Ground, white to Ground before taking the Shuko apart? You need to clone that.
Very high resistance between any 2 wires means probably thermistor is not wired across these two.

Maybe it wants a single 10k across Red & White wires. Perhaps they aren't using the Earth as a common.
If error, put those 2 in series across the red & white to make 20K. As thermistors heat up, the resistance falls, so a higher value measn it's colder,
less likely for the EVSE to signal "overheating".

 

[AlistairD]

An owner of one of these decided to swap the 13A plug for a Commando one, only to discover after cutting it off that there are 6 wires going into the plug! I acquired this, and have repaired it with a chunky new 13A Masterplug and have fitted the 2 thermistors inside where they belong. I'm posting what I've learned so as to help anyone else with a damaged/destroyed plug, or wanting to do the same kind of plug-swap, so they can buy they correct valued thermistors if required.

The original owner carefully disected away the plug, and rescued both thermistors & the fragments of wire, enough for me to be certain of the connections. Thank you!

In addition to the usual 3 wires, the cable from the EVSE has 3 more coloured Black, Purple/Grey, and Purple/Black.
One thermistor is connected between Black and Purple/Black.
One thermistor is connected between Black and Purple/Grey.
I believe the thermistors to be Vishay NTCLE100E3103 which are 10k Ohms at 25C. Colour code Brown-Black-Orange.

Type-2 plug EVSE (from a Bmw, probably i3) with new plug fitted:
View attachment 125434

Underside of EVSE:
View attachment 125436

Wire fragments:
View attachment 125435

13A Masterplug
View attachment 125437

A very small amount of trimming was needed inside the Masterplug to not trap the thermistor wires. In the Rhs view one thermistor has been tucked beside the Neutral wire, and the other thermistor sits above the fuse.

I checked the resistance of the 2 thermistors carefully, letting them cool slowly from 100C on my K-thermocouple-controlled Heated Base Plate. I believe the thermocuple temperature will have been at most 2 degrees C cooler than the thermocouple reported, and that reports in 1C intervals. So there's a fair bit of variation in the resistances I measured while the temp controller (an industrial Toho unit) was reporting a single temperature.
Here's a table of the max and min resistances (Ohms) I measured at a series of temps, and also the nominal resistance expected from a Vishay NTCLE100E3103 thermistor datasheet:

Temp Min Max NTCLE100E3103
100 707 759 677
95 800 847 786
90 908 957 915
85 1046 1099 1070
80 1224 1294 1256
70 1680 1768 1753
60 2380 2502 2490
50 3437 3556 3605
40 5044 5353 5330
30 7470 7800 8059
25 9187 9675 10000
24 9642 10110 (no data)

Given the variability in thermistors (the 2 I tested were usually about 30 Ohms apart, and must have been near-as-dammit identical temps) I consider this a pretty close match, certainly accurate enough for this Vishay thermistor to be used as an excellent replacement for a damaged original. My thanks to Farnell (& Cpc, part of the same group) for making the datasheets & parts available.

Hi HandyAndy,

Thank you so much for posting this. I have exactly the same problem with a badly overheating plug which I am in the process of replacing.

Quick question - You mentioned the Vishay NTCLE100E3103 thermistor from Farnell. When I checked their website there would 14 different variants available. Could you check which one you ordered and let us know?

Many thanks,
Al

 

[HandyAndy]

Hi HandyAndy,

Thank you so much for posting this. I have exactly the same problem with a badly overheating plug which I am in the process of replacing.

Quick question - You mentioned the Vishay NTCLE100E3103 thermistor from Farnell. When I checked their website there would 14 different variants available. Could you check which one you ordered and let us know?

Many thanks,
Al

Of the 14 "variants" there, 3 have an extra delivery charge £15.95 added probably sourced from EU or USA. So avoid those!
Looking at the associated datasheet there, the J/H/G letter denotes tolerance, 5%, 3%, 2%. You're not making a sophisticated temperature sensor here, just looking for a largeish temp-change to be detected.
The B0/T1/T2 denotes packing, bulk (loose), or a couple of tape-variants. Irrelevant to you.
Some have a date-code printed - again irelevant.
So go for the cheapest. They're all the same item as far as this job's concerned.

But if you can keep the existing thermistor, do so. I can't guarantee they used a Vishay one, this is my best-estimate fit for a replacement.

 

[AlistairD]

Of the 14 "variants" there, 3 have an extra delivery charge £15.95 added probably sourced from EU or USA. So avoid those!
Looking at the associated datasheet there, the J/H/G letter denotes tolerance, 5%, 3%, 2%. You're not making a sophisticated temperature sensor here, just looking for a largeish temp-change to be detected.
The B0/T1/T2 denotes packing, bulk (loose), or a couple of tape-variants. Irrelevant to you.
Some have a date-code printed - again irelevant.
So go for the cheapest. They're all the same item as far as this job's concerned.

But if you can keep the existing thermistor, do so. I can't guarantee they used a Vishay one, this is my best-estimate fit for a replacement.

That's great. Thank you!

Al

 

[ShaunDW]

I’m another who had a “snip - Doh!” moment with a BMW/Mini home charge cable (similar to shown in post #35).

After carefully trimming the plug away from the wires, I ended up with this additional wiring contained within the plug. The two white blocks were situated on the Live & Neutral pins. After re-wiring these onto the cable I was able to hardwire the cable into a fused spur box, doing away with the plug altogether (and securing the cable in my open car port). I realise that this arrangement will probably not detect any overheating, being in a box rather than tightly enclosed in a plug, but it is working.

Any comments about whether this is a dubious arrangement gratefully received, but please provide an explanation.

Oh, and thanks to all for their input to this thread that helped immensely.