[Andy-Zoé-User]

I got the 22kw old zoe and taking some interior panel trims off the inside I didn't want to risk at all setting off the airbags so I killed the power of both the traction battery and the 12v battery so totally dead. Whilst I had the traction battery isolator (fuse?) out I see that the contacts are pretty badly scorched (only to be expected I suppose with 400v DC running through it as it sparks when disconnecting and reconnecting / arcing) So anyone got any ideas how to clean the contact pins up? - I was thinking of a little bit of wet and dry sandpaper just lightly removing the scorched bits of the terminals . Be too dangerous to spray some switch cleaner on it i think with that voltage around, seeing as switch/contact cleaner spray is flammable!
what do you think. - now I have seen them like that I dont think I could just pop it back in like that, not after seeing it like that . What has been seen cannot be unseen

 

[Tandy0]

I'd use one of these things. You might need to cut it in half to get it in there:

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[DBMandrake]

That's a bit concerning. When I took the safety link plug out on my Ion to drop the pack out the pins were in pristine condition, as you would expect.

If I had to guess I'd say there isn't enough contact tension. Hmm..

 

[Andy-Zoé-User]

it is a bit concerning - this has opened up my mind now, some people get a message on the Zoe Dash about 'electrical failure' or 'traction fault' or 'engine failure' or something like that and get concerned (quite rightly so) and it makes you wonder if any of it is caused because the terminals on the fuse is like this and not making proper contact.

I am no expert but i am thinking maybe you know when they take out this HV fuse at the garage whenever they are doing work under the bonnet (or change brake fluid) etc and have to de-energise the whole HV system if on insertion there is a big spark and pitting the terminals like this on reconnection. - much better system would be I think if it had some kind of electronics in the fuse itself or the car where you put the fuse back and there is no voltage there at the pins until maybe 20 seconds later so you wouldnt get a spark when putting it back in, surprised there is not something like that.

 

[Tandy0]

Presumably whatever it contacts with will have similar burning, won't it?

I think I might get some folded up wet & dry paper to clean the receptacle also.

 

[Andy-Zoé-User]

i would say left like this and not making full contact could throw up more than just a warning light on the dash - i would think in that situation trying to make proper contact and some arcing could cause the terminals to overheat and potentially cause a fire or am I overthinking. Thats why I would like to clean them terminals up before putting it back in

 

[Andy-Zoé-User]

Presumably whatever it contacts with will have similar burning, won't it?

I think I might get some folded up wet & dry paper to clean the receptacle also.

NO Dont! - please! - I wouldnt if I were you, in that receptible could be 400v DC don't touch it with your fingers or anything not insulated against 400v DC and more - you be electrocuting yourself please be safe!

 

[Eddie49]

The score marks on the fuse blades show that when fully inserted normal contact and pressure is fine. From the black pitting, it looks to me that on insertion something is drawing a short-duration surge of current. The main motor current will still be off, since the Contactors will be open, so this is perhaps the DC-DC converter that trickle-charges the auxiliary 12v battery. I think it is due to the charging of an input capacitor in that converter. Nothing to worry about.

I would clean the fuse blades with a fibreglass contact brush ( e.g. "Modelcraft 4mm Glass Fibre Pencil" ).

During normal use, there will be 100 or 200 Amps flowing through these contacts. If there was a "loose" contact, there would indeed be more than just a warning light on the dash!

 

[Andy-Zoé-User]

The score marks on the fuse blades show that when fully inserted normal contact and pressure is fine. From the black pitting, it looks to me that on insertion something is drawing a short-duration surge of current. The main motor current will still be off, since the Contactors will be open, so this is perhaps the DC-DC converter that trickle-charges the auxiliary 12v battery. I think it is due to the charging of an input capacitor in that converter. Nothing to worry about.

I would clean the fuse blades with a fibreglass contact brush ( e.g. "Modelcraft 4mm Glass Fibre Pencil" ).

During normal use, there will be 100 or 200 Amps flowing through these contacts. If there was a "loose" contact, there would indeed be more than just a warning light on the dash!

Thanks for that - good to know that it should be OK .
I am not sure of the correct procedure but I think I will replace in this order . Main traction battery first .. then followed by connect the negative post of the 12v battery next .

 

[DBMandrake]

The score marks on the fuse blades show that when fully inserted normal contact and pressure is fine. From the black pitting, it looks to me that on insertion something is drawing a short-duration surge of current. The main motor current will still be off, since the Contactors will be open, so this is perhaps the DC-DC converter that trickle-charges the auxiliary 12v battery. I think it is due to the charging of an input capacitor in that converter. Nothing to worry about.

Is the DC-DC converter on the Zoe permanently connected to the traction battery ? Unless it's physically mounted inside the battery enclosure with only 12v coming out it would be highly unusual to have live HV coming out of the pack for an external DC-DC converter even when the contactors are open as this would be a safety issue since you couldn't safely disconnect the battery. I can't think of any other EV's which do this.

If the DC-DC converter is external to the pack and runs through the contactors as it does in most EV's then there should be nothing inside the pack to draw a large surge current when the link plug is inserted during maintenance.

It's highly unlikely there is a large capacitor connected across the pack inside the battery enclosure before the contactors - one obvious reason is that the current drawn to charge that capacitor would still be enough to electrocute you should you touch between the two pins in the safety plug. Not much of a safety plug in that case.

With no capacitor (or other load) just the series string of cells and open contactors (12v battery disconnected so no way to activate them) you could in theory touch across the pins of the link plug socket without issue, although I don't recommend it of course.

Normally any filter capacitor is external to the pack in the motor controller unit and is not charged until the contactors close. In fact there is a dedicated pre-charge contactor which switches a resistor in to charge the capacitor at a controlled rate before another contactor makes a direct connection. (This also lets the car detect shorts on the external HV bus before it "throws the switch" and fully connects the battery to the external circuit, avoiding spectacular fireworks if there was an external fault)

Since the filter capacitor is there to provide a low impedance at the high inverter switching frequencies there is no good reason for it to be in the pack instead of the MCU as it will not perform its function as well at the other end of the HV cables, and there is no reason I can think of to put any capacitor inside the pack due to the safety issue with the link plug.

So I'm highly sceptical that there is any way this charring has occurred when the plug has been removed or inserted (since there should be no current being drawn) unless someone pulled the plug while the car was fully switched on, against all good practice.

That's a pretty big "splat" to have occurred on just one occasion of the plug being pulled or inserted.

I'll qualify everything I've said as generalisations about how EV's are usually designed - I don't have any specific knowledge of the high voltage system in the Zoe but I have dismantled and worked on the traction battery in a Peugeot Ion and there is definitely no capacitor in the pack on that car, just the pre-charge resistor and the contactors. The filter capacitor is in the MCU.

 

[Andy-Zoé-User]

Is the DC-DC converter on the Zoe permanently connected to the traction battery ? Unless it's physically mounted inside the battery enclosure with only 12v coming out it would be highly unusual to have live HV coming out of the pack for an external DC-DC converter even when the contactors are open as this would be a safety issue since you couldn't safely disconnect the battery. I can't think of any other EV's which do this.

If the DC-DC converter is external to the pack and runs through the contactors as it does in most EV's then there should be nothing inside the pack to draw a large surge current when the link plug is inserted during maintenance.

It's highly unlikely there is a large capacitor connected across the pack inside the battery enclosure before the contactors - one obvious reason is that the current drawn to charge that capacitor would still be enough to electrocute you should you touch between the two pins in the safety plug. Not much of a safety plug in that case.

With no capacitor (or other load) just the series string of cells and open contactors (12v battery disconnected so no way to activate them) you could in theory touch across the pins of the link plug socket without issue, although I don't recommend it of course.

Normally any filter capacitor is external to the pack in the motor controller unit and is not charged until the contactors close. In fact there is a dedicated pre-charge contactor which switches a resistor in to charge the capacitor at a controlled rate before another contactor makes a direct connection. (This also lets the car detect shorts on the external HV bus before it "throws the switch" and fully connects the battery to the external circuit, avoiding spectacular fireworks if there was an external fault)

Since the filter capacitor is there to provide a low impedance at the high inverter switching frequencies there is no good reason for it to be in the pack instead of the MCU as it will not perform its function as well at the other end of the HV cables, and there is no reason I can think of to put any capacitor inside the pack due to the safety issue with the link plug.

So I'm highly sceptical that there is any way this charring has occurred when the plug has been removed or inserted (since there should be no current being drawn) unless someone pulled the plug while the car was fully switched on, against all good practice.

That's a pretty big "splat" to have occurred on just one occasion of the plug being pulled or inserted.

I'll qualify everything I've said as generalisations about how EV's are usually designed - I don't have any specific knowledge of the high voltage system in the Zoe but I have dismantled and worked on the traction battery in a Peugeot Ion and there is definitely no capacitor in the pack on that car, just the pre-charge resistor and the contactors. The filter capacitor is in the MCU.

Thanks Simon - interesting . So , really what your saying or sound of it is that to get that kind of arcing then possibly the fuse was / could have be pulled at some stage whilst the power was coming from the traction battery to power the 'engine' / motor .... could that be a possibility? ... or maybe pulled if the car was charging at some time - thats kind of what i am reading into it

 

[yoh-there]

The main contactor is in the battery itself. If the car is off, there is no voltage difference on these pins, and also implied feedback from the DCDC converter (nah) is impossible to flow through these contacts, as the circuit is literally open in the battery itself.

The mechanics have a specific long winding procedure to follow when pulling this plug, which ensures the battery is not and won't accidentily engage.

Which, assuming you did not create this arcing when you were fiddling, only leaves arcing under load. While I hate to say it as a staunch ZOE fan, that would not be too good.

 

[Andy-Zoé-User]

you would hear a fair ol 'crack' to get arcing trace like that on removal to cause that blackness on the terminal wouldnt you ? .. accompanied with a smell of sparking surely? - i dont know the history of the car alas. Only bought it end of July . - was in garage for 3 weeks having aircon compressor replaced and leaky aircon pipe seal leak repaired (or replaced) - they would have had to de-energise the system then, but it was a renault main dealer that done that so they would have surely done that in the correct manner and would have known /heard a crack as it was disconnected (or reconnected Im pretty sure) ?

 

[Spike]

Renault Techs only pull this fuse whilst wearing full DC protection gear. You need to be REALLY careful when working with this item. The earlier suggestion of cleaning inside the contacts on the battery side of it is crazy.

Presumably this would arc if pulled before the 12v had been disconnected and the car systems shut down?

 

[HughF]

That bit of arcing is nothing to worry about. Don't go cleaning it or putting anything in there. Slam it back together, drive the car...

 

[yoh-there]

With the utmost respect: you are right that the LEVEL of arcing seems not so bad. What is worrying is that there is arcing at all. Either the dealership effed up or something is not quite right. Given the signs of fairly stiff contact pressure, I am inclined to think the former.

The EV equivalent of "oh, that will buff right out"

 

[Andy-Zoé-User]

Renault Techs only pull this fuse whilst wearing full DC protection gear. You need to be REALLY careful when working with this item. The earlier suggestion of cleaning inside the contacts on the battery side of it is crazy.

Presumably this would arc if pulled before the 12v had been disconnected and the car systems shut down?

Really! - full protection gear??? to pull that fuse? - sometimes health and safety in the workplace is too over the top these days me thinks..

I made a good point of reading up on where a isolation switch or fuse was in the Zoe before I picked it up from the garage whilst it was being prepared (valeted and all that lot) when buying it so i exactly knew where the isolation switch or fuse was should there be an emergency (say car on fire or malfunctioning) and I think it useful for everyone to know , just the same if your at home and something happens with the electrics and you know exactly where the mains switch is in the fusebox /consumer unit in your house.

i knew of course how to disconnect my cars 12v battery in previous ICE cars should I smell smouldering electrics , and i know it might sound silly but i used to keep a 10mm spanner in my boot as a backup with some other tools for that reason - or look up fusebox info in the under bonnet fusebox as to what main fuse to pull to kill for the 12v system. So naturally I wanted to look on the zoe what you would need to do to kill the 400v DC power from the traction batteries as well.

Ideally not in a fantastic suitable place in the drivers footwell and if water got in from a leak in the bulkhead or scuttle drains getting blocked and the water pooling up in the footwells but not a lot can be done about that.

 

[andrew*debbie]

I got the 22kw old zoe and taking some interior panel trims off the inside I didn't want to risk at all setting off the airbags so I killed the power of both the traction battery and the 12v battery so totally dead.

In most cars, Disconnecting the batteries does not safe the airbags. The system has back up capacitors so the air bags will work even if the batteries are disconnected, as might happen in a crash. I wouldn't count on Zoe airbags being safe by disconnecting batteries unless that is the proceedure in the service manual.

Every car is different, but there are usually special disconnects that short out the airbag wires when you pull the plug. I wouldn't go pulling random yellow plugs without a manual because you might end up setting off an airbag or trigger the airbag warning light.

 

[Andy-Zoé-User]

In most cars, Disconnecting the batteries does not safe the airbags. The system has back up capacitors so the air bags will work even if the batteries are disconnected, as might happen in a crash. I wouldn't count on Zoe airbags being safe by disconnecting batteries unless that is the proceedure in the service manual.

Every car is different, but there are usually special disconnects that short out the airbag wires when you pull the plug. I wouldn't go pulling random yellow plugs without a manual because you might end up setting off an airbag.

thanks never really thought of that aspect - I disconnected 12v battery, then the big DC fuse and left it all for about an hour whilst I had some lunch . Thought it may be enough to drain /de-energise the system but true, didnt take into account the capacitors holding charge like you indicate in the airbag ecu circuit. - at least if it wasnt a 100% satisfactory solution as least it might have gone some way to help stop the airbags deploying.

I wasnt touching around the steering wheel area , I was removing the console around the handbrake lever (with the cup holders in etc) to spray paint and i didnt know if there might have been a airbag sensor anywhere near that area so just as a precaution really.

 

[Mr_G]

If you have never worked (having been trained) with high AC/DC voltage and/or current, my advice would be don't.

At the very least you need a pair of perfect High Voltage gloves and eye protectors.

How about sending the photos to Renault UK and asking if it is normal and/or safe.

You can see a pit developing on the bottom pin which looks the worst.