Onboard charger capacitors failed

[nlspace]

The B2840 points to the OBC more than the P3173. i posted this in another thread but can't find it rn, it may be in the technical or engineering section. i have a 2012 OBC dismantled on my workbench and have many of the circuits traced out if you decide to repair yours.



There is a Waffle Plate™ located underneath this bottom board with the HV diodes and switching transistors, but it rarely has ever had an internal failure. Typically it is the AC input filter caps and you will easily see when they spill the beans.



The Waffle Plate™

[wxmatt]

The B2840 points to the OBC more than the P3173. i posted this in another thread but can't find it rn, it may be in the technical or engineering section. i have a 2012 OBC dismantled on my workbench and have many of the circuits traced out if you decide to repair yours.

Thank you for your response. Unfortunately, after reading through everything that I have, though I have limited experience with this, I agree... the B2840 is not a good sign.

I would like to at least attempt to fix the charger. If I can’t, I would like to replace it myself and save all that $$$ on labor.

My biggest question(s) revolve around the safety protocols on how you get the charger out of the vehicle. I know it’s the point of the document, but the dismantling guide scares the $#@& out of me. Yet, it seems to me that if you perform the discharge procedure for the capacitor and 12 V properly, with a high-quality set of high-voltage rubber gloves you should be good. I have watched the EV Enhanced YouTube video numerous times, and I feel that compared to some of the major repairs I’ve done on ICE cars, this is straightforward.... other than the undeniable threat of electrocution.

Is my fear overblown? Or, as long as there’s not physical damage to the harness/battery/etc, is it really relatively straightforward? Again, thank you for your response and help.

[nlspace]

It's a straightforward task. As long as the car is not ON there is no HV external to the pack--the main contactors must be energized to put HV outside the pack. Disconnect and remove the 12V aux battery and the contactor coils will have no possible power source.

But always check with a voltmeter to be sure--if there were some strange situation such as a wrecked car in which the contactors welded shut then that could be a fault which could leave the cables hot. Not very likely at all, but until you feel comfortable it's better to measure first before you touch.

The dismantling guide is intended to scare you, but you won't be handling any hot HV wires.
Trust, but verify with your meter.

[wxmatt]

I decided to work on the charger myself. Getting it out took a bit, and I disconnected more than probably necessary underneath the car, just to be safe, but it is out and on the bench.

When I opened up the onboard charger, shards of black components were rattling around on the back (below the bottom circuit board).



Upon closer inspection… This is about the most useful piece that fell out.

Typically it is the AC input filter caps and you will easily see when they spill the beans.

I’m going to guess that this is not the same thing you were referencing and instead is coming from the high-voltage side on the underside of the bottom circuit board.

For the life of me, I don’t know how to get that bottom circuit board out so that I can check on the bottom side. I’ve taken out all of the screws, but it seems to be held in by something… The brass pins maybe?



This is probably something straightforward to an electrical engineer, but I appreciate any guidance you are willing to give. If I’m fortunate enough to be able to accurately diagnose what needs to be replaced, I do have access to a few folks who regularly work on circuit boards that I could probably have help me do a more professional soldering job.

Thank you so much for help so far!!

[goldbrick]

Your nose can be a good tool when trying to find where a PCBA went bad. The smell of burnt electronics is pretty strong and quite noticeable.

That said, that part doesn't look burnt. It's odd to see it separate like that without any sign of damage. It could still be a swolen capacitor that caused the problem by contacting adjacent parts and causing them to pop out of place.

[LeftieBiker]

It may be an artifact of the flash, but looking at the rectangular black component labeled "Okaya X2" (?) there seems to be a crumbled section of black plastic on its left side...

[Nubo]

For the life of me, I don’t know how to get that bottom circuit board out so that I can check on the bottom side. I’ve taken out all of the screws, but it seems to be held in by something… The brass pins maybe?

I'm curious about the "2" in a circle, with the arrow next to it. Also there's an item "frame 2" nearby with something mounted there. Can't tell what it is but maybe a fastener of some kind? From other picture I found there is also a "1" in a circle further up that side of the board with a similar silver thing mounted. There's also something with a hex nut near the middle of the board.

[wxmatt]

Upon further review, my piece looks exactly like a part of this "Waffle Plate."

The Waffle Plate™

I'm guessing it's pretty likely that I'll be buying a new onboard charger. I talked to an engineer I work with, and when I showed him a picture of the piece of the component and the waffle plate side-by-side, he didn't seem too encouraged about me fixing it.

In a related twist, I posted my pics above on Twitter (@matt_laubhan) so that I had a place where they would be hosted semi-permanently. After tagging them in a reply, Nissan reached out about getting my car towed to the nearest LEAF dealership, which is about 80 miles away. While tempting, my car is already dismantled, and I doubt that they'll spring for the cost of the charger, being that the car is a 2012. I'm leaning toward ordering a new charger, installing it, refilling the coolant, and hoping for the best.

[coulomb]

Edit: crossed post.

When I opened up the onboard charger, shards of black components were rattling around on the back (below the bottom circuit board).

Oh oh.

Upon closer inspection… This is about the most useful piece that fell out.

That's from the Waffleplate™. The Mitsubishi iMiEV has a similar (not identical) OBC, also made by Nichicon, and it also uses a Waffleplate™:



Unfortunately, it's a custom component. People have had to X-ray it to figure out what's inside:



So unfortunately, this OBC is very likely not serviceable unless you have another OBC with a spare Waffleplate™. Or maybe you're really lucky and it's only one diode, so you could find a replacement and mount it on its own heatsink. For what it's worth, failures of the Waffleplate™ are rare (in the iMiEV OBC), so you should feel special

For the life of me, I don’t know how to get that bottom circuit board out so that I can check on the bottom side. I’ve taken out all of the screws, but it seems to be held in by something… The brass pins maybe?

Yes. You need to desolder every one of those pins. This is only practical with a proper vacuum desoldering station (a cheap on will likely do), and even then some care and/or experience is required. A lot of the time, common repairs can be performed leaving the Waffleplate™ in place. Sadly, it seems that yours may not be one of those cases.

The arrows in the below are for a different purpose, but you can see all the brass pins de-soldered:



Perhaps you can take the WafflePlate™ out of the charrger (some of the screws are sneaky, follow the numbering guide), with the PCB still attached, and post a photo of the presumably damaged Waffleplate™ from one or two sides. This should give an indication of whether this OBC can be repaired.

Edit: many of the photos and ideas for the above come from this post: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter.

[coulomb]

I'm curious about the "2" in a circle, with the arrow next to it.

It's part of a daisy chain of screws to undo; note it's near a screw. The arrow points you in the direction of the next screw to undo. A nice touch, in the era of "no user serviceable parts inside".

Also there's an item "frame 2" nearby with something mounted there. Can't tell what it is but maybe a fastener of some kind?

I think it's a place where EMI capacitors need to connect to chassis ("frame").