AC Charging Issue & Main Contactor Weld

[Sapoty]

Hi I'm a newbie here. I've got a Minicab and I have a fault which seems to be related to the OBC. DC charging is not a problem, but AC charging sometimes works and sometimes not. It might be when the traction battery is fully charged that my attempts to get READY go wacky.

If I get hold of someone with an appropriate scanner they can clear the codes and then I get READY and everything works.

I'm thinking I just want to get an appropriate scanner so I can clear the codes and get on my way. So my primary question is can someone recommend a scanner that will do the job at minimal cost. I gather that cheap scanners are just readers and cannot clear codes.

I can't find how I can upload a photo... So I will transcribe...

ELECTRIC VEHICLE
P0AA1 main contactor P weld - Active DTC
P1A12. On board charge abnormal stop - Stored DTC

PN BOARD CHARGER
29| pilate signal fail -Stored DTC

Of course if anyone understands the fault and can spare the time, I would like to hear about it!

 

[kiev]

The Stored DTCs are "old" and will likely clear, but the Active code about the welded positive contactor is the big problem. This should be discussed in a thread all it's own, maybe the moderators can move it.

The car senses that there is still voltage on the HV lines even after the key is Off. This is a hazard if someone is working on the motor control unit or on-board charger back in the engine compartment, or the Air Conditioner or Heater up front.

The pack was designed to be serviced, but the factory service manuals don't instruct on how to do this, their solution is to replace the pack. But the pack cover is bolted on and sealed with a rubber gasket (not glued shut like a nissan laef). All the components and cells in the pack are screwed or bolted together (not welded buss bars like so many other EVs), So the main positive contactor could be removed and replaced.

The question would be what caused it to weld? It's possible a charging session was abruptly interrupted and the main contactor attempted to open while current was flowing thru the contacts, or maybe this happened while driving in READY mode, hard to know or say for sure, but either could do it.

i would guess that the HV fuse in the MCU has blown and the 12V battery is not being charged; if the car was operated and ran down the 12V battery to the point that it couldn't hold the main contactor coil closed, well that would be a possible way for the contactor to weld.

The fuse could be checked located under the little access cover on the MCU, but it connects to the HV positive line, which could be at 360V if the contactor is welded. So the service disconnect (under the left hand seat in the car) would need to be removed to reduce the hazard.

 

[Sapoty]

Thanks for your thoughts and warning Kiev.

If the main contactor is indeed welded, is that consistent with:
1. DC charging still works and does not generate a DTC.
2. AC charging works without generating a DTC about half the times, and generates a DTC the other times. Seems like an intermittent fault.
3. Clearing the code about the welded contactor allows AC charging, is that consistent with a real weld, or are there other failures that can generate the weld DTC?

When the problem first occurred I checked the 12V battery ... It was at 12.4V.
It was also tested for cranking current by an NRMA roadside assistant and he said the battery was in excellent condition.

I may have disconnected during charging:
1. I recall that my phone internet connection was having problems and I may not have disconnected via chargefox.
2. The disconnection lever on my type 2 cable was broken and I am now wondering whether that included a switch that signalled for disconnection?
3. Is the intermittency related to the sequence in which I am disconnecting my AC changing cables?

In summary I'm willing to admit that abrupt interruption of AC charging was probably the cause. Maybe it's the AC contactor is welded? Would that be consistent with the intermittency depending on how I disconnect the charging session?

 

[kiev]

i think you have found your initial culprit:

...
I may have disconnected during charging:
1. I recall that my phone internet connection was having problems and I may not have disconnected via chargefox.
2. The disconnection lever on my type 2 cable was broken and I am now wondering whether that included a switch that signalled for disconnection?
3. Is the intermittency related to the sequence in which I am disconnecting my AC changing cables?

In summary I'm willing to admit that abrupt interruption of AC charging was probably the cause. Maybe it's the AC contactor is welded? Would that be consistent with the intermittency depending on how I disconnect the charging session?

So Yes there is indeed a switch/signal sent by the release trigger. This is to tell the OBC to lower the charging current to zero before the handle is withdrawn to prevent damage to the main contactor precious metal contacts.

You have damaged the contacts and they may intermittently weld/ break the weld depending upon the extent of the damaged surface. Best to get the handle trigger repaired/replaced or use a different EVSE for charging to limit additional contact welding events.

The contactor may work okay for driving and charging, or it could suffer micro-welds upon activation. Carry a stick of lumber so you can try to smack the bottom of the pack in the middle (below the contactors) to maybe knock a welded contact loose if it hangs. Not very elegant but might work in a pinch.

 

[Dilbert100]

i think you have found your initial culprit:

...
I may have disconnected during charging:
1. I recall that my phone internet connection was having problems and I may not have disconnected via chargefox.
2. The disconnection lever on my type 2 cable was broken and I am now wondering whether that included a switch that signalled for disconnection?
3. Is the intermittency related to the sequence in which I am disconnecting my AC changing cables?

In summary I'm willing to admit that abrupt interruption of AC charging was probably the cause. Maybe it's the AC contactor is welded? Would that be consistent with the intermittency depending on how I disconnect the charging session?

So Yes there is indeed a switch/signal sent by the release trigger. This is to tell the OBC to lower the charging current to zero before the handle is withdrawn to prevent damage to the main contactor precious metal contacts.

You have damaged the contacts and they may intermittently weld/ break the weld depending upon the extent of the damaged surface. Best to get the handle trigger repaired/replaced or use a different EVSE for charging to limit additional contact welding events.

The contactor may work okay for driving and charging, or it could suffer micro-welds upon activation. Carry a stick of lumber so you can try to smack the bottom of the pack in the middle (below the contactors) to maybe knock a welded contact loose if it hangs. Not very elegant but might work in a pinch.

Hi Kiev

I think I have the same issue in my 2015 Outlander, I think your smacking the contactors method is exactly what I've been looking for and 100% worth a try. My issue is knowing where they are, can you give me any ideas or pointers as to what I'm looking for externally so I can target the blow! Thanks in advance.

 

[kiev]

Howdy Dilbert,
Unfortunately i don't know where the contactors are located in an Outlandr pack--do you have photos or links of the pack with the cover removed that might help? How do you think that your damage occurred--was the trigger on the charging handle defective?

If the contactors have been damaged/welded then they would likely need to be replaced. There are data list items that the MUT or a scan tool can read to indicate the state (position) of the contacts, and a DTC will be thrown to prevent READY if they happen to be closed when they should be open.

 

[MickeyS70]

Hi there check out below

Main contactor is shown @ time stamp 12:50

https://youtu.be/lB3kqipdtPQ

Good luck hitting it…

 

[kiev]

Great find on that video Mickey

Looks like the main and charging contactors are located along the centerline of the pack and towards each end--one set at the front and the other at the rear.

 

[Dilbert100]

Kiev & Mickey - Thanks Guys, really useful info. I am pretty sure I can't remedy this myself, I don't have the facilities, or quite frankly, the skills, hitting stuff is pretty much the full extent of my repertoire! At least I can actually see what's needed and will be involved with the fix it will help me in finding someone that can.

Anyone in the UK (Buckinghamshire / Bedfordshire area) that can, let me know!

 

[jray3]

This thread illustrates what I love about this forum! Advanced analytics that conclude with, "you might just have to whack it with a 2x4 now and then, but it should work". :mrgreen:
I shouldn't conclude that Kenny being from Alabama has anything to do with it, but this native of Mississippi certainly recognizes and appreciates the approach...