lorenfb
Posts: 2489
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: wxmatt's OBC failure [blown PFC Boost section]

Thu Oct 08, 2020 11:28 am

nlspace wrote:
Thu Oct 08, 2020 7:22 am
Good catch to find that blown diode next to the capacitor. That gray material is an RTV staking compound to hold the cap to the board and reduce vibration.

The diode is inline on the HV(+) side to bypass the big PFC inductor coil (orange wires that attach to the board at the L201A and L201B faston tabs) and attach to the (+) of the big black 2700 uF capacitor that attaches to the Red and Black faston tabs.

The four 100k resistors in series comprise a bleed-down circuit for the big cap.

Does your big L201 inductor have continuity or might it be blown also?

Is the big 2700uF capacitor okay or might it be shorted?

Image
That diode is less likely to fail than the other diode, as it's just to reduce peak startup currents in the FET and sees less peak reverse voltage
than the other diode. If it opens, the FET drive signal may be designed to not occur. The coil has a lower chance of failure than the FET.
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F

wxmatt
Posts: 20
Joined: Sun Sep 27, 2020 3:34 pm
Delivery Date: 14 Nov 2014
Leaf Number: 023861

Re: wxmatt's OBC failure [blown PFC Boost section]

Fri Oct 09, 2020 11:32 am

nlspace wrote:
Thu Oct 08, 2020 10:39 am

Measure for continuity between the two orange wires leading to the inductor. It should read a very low, close to zero Ohms if okay.
Measured at zero ohms.

nlspace wrote:
Thu Oct 08, 2020 10:39 am

Measure the capacitor between the red and black wires. If it reads close to zero ohms then it is shorted. A shorted capacitor could cause the damage you have found so far. i would expect to see some evidence such as the vent plug would be blown out or bulging if it failed over time. For a sudden overvoltage punch-thru it might look normal externally, but would be shorted internally.
Resistance gradually builds to 19.7 mega ohms.

nlspace wrote:
Thu Oct 08, 2020 10:39 am
It seems that if the EVSE voltage was too high then i would expect something upstream would have been taken out. A lightning strike or sudden loss of power during charging could cause damage in the OBC, there are protection circuits but everything has limits.
I think it’s unlikely that lightning was an issue, because I’m a meteorologist and I don’t remember an instance of that, but we do have frequent power disruptions where we live.


nlspace wrote:
Thu Oct 08, 2020 10:39 am

There are 3 fuses on that board that need to be checked for continuity also. F101, 102, 103.
F101 - no continuity
F102 - zero ohms
F103 - zero ohms


nlspace wrote:
Thu Oct 08, 2020 10:39 am

Measure for resistance between the solder junctions labelled "8" and "7" on the seventh row down on the left hand side.
Zero ohms… Assuming that we are talking about two of the 72 pins that are soldered from the waffle plate to the bottom circuit board.

My wife and I were joking on our way back to work last night that I had “received my homework assignment”… and my 6 year old daughter is actually helping me to check this with a multimeter, so it has been an educational experience for both of us and I’m hoping that someone in the future uses what we are finding to diagnose their problem.
2012 LEAF (White) - Purchased in 11/14
2010 Rogue (Black)
1987 BMW 325i (Red)

nlspace
Posts: 321
Joined: Mon Jun 05, 2017 10:21 pm
Delivery Date: 06 Jun 2017

Re: wxmatt's OBC failure [blown PFC Boost section]

Fri Oct 09, 2020 3:45 pm

wxmatt wrote:
Fri Oct 09, 2020 11:32 am
...
F101 - no continuity
F102 - zero ohms
F103 - zero ohms
...

Zero ohms… Assuming that we are talking about two of the 72 pins that are soldered from the waffle plate to the bottom circuit board.

My wife and I were joking on our way back to work last night that I had “received my homework assignment”… and my 6 year old daughter is actually helping me to check this with a multimeter, so it has been an educational experience for both of us and I’m hoping that someone in the future uses what we are finding to diagnose their problem.
Haha that's funny, i'm glad she was learning how to use a voltmeter. Maybe we can find something else to measure and check, like re-check Fuse F101, and check for continuity on the those black nickel-sized lollypops next to the fuses in the black potted area. Also check continuity across that little glass tube (lightning arrestor) next to that.

So the inductor looks good, and the capacitor too. And yes those two labelled pins on the solder junctions to the waffle plate, so the sense resistor inside the plate looks okay. The output fuse 102 is okay, same for F103.

But the Good News is that you have found another failed part, and that may actually have been the culprit to start this massive failure, namely the open fuse F101, which is the first fuse of the two in the AC Input voltage to the board. A sudden disconnect of the AC input is not good, it is the bad thing™.

If that fuse lets go in the middle of charging then all the magnetic field of the big coil will collapse and all that energy will induce a current in the coil, which, if it no longer has a return path, then as Miranda reads about not having an attorney, one will be created for you. That current will make a path thru whatever is in the way and wreak havoc all the way home.

WetEV
Posts: 4225
Joined: Fri May 04, 2012 8:25 am
Delivery Date: 16 Feb 2014
Location: Near Seattle, WA

Re: wxmatt's OBC failure [blown PFC Boost section]

Sat Oct 10, 2020 5:02 am

nlspace wrote:
Fri Oct 09, 2020 3:45 pm
But the Good News is that you have found another failed part, and that may actually have been the culprit to start this massive failure, namely the open fuse F101, which is the first fuse of the two in the AC Input voltage to the board. A sudden disconnect of the AC input is not good, it is the bad thing™.

If that fuse lets go in the middle of charging then all the magnetic field of the big coil will collapse and all that energy will induce a current in the coil, which, if it no longer has a return path, then as Miranda reads about not having an attorney, one will be created for you. That current will make a path thru whatever is in the way and wreak havoc all the way home.
Which came first, the chicken or the egg?

If parts fail, and the AC current increases enough, the fuse had better blow to prevent a fire or other damage.
WetEV
#49
Most everything around here is wet during the rainy season. And the rainy season is long.
2012 Leaf SL Red (Totaled)
2014 Leaf SL Red
2019 eTron Blue

nlspace
Posts: 321
Joined: Mon Jun 05, 2017 10:21 pm
Delivery Date: 06 Jun 2017

Re: Onboard charger capacitors failed

Sat Oct 10, 2020 12:13 pm

@matt: what is the age, voltage and condition of your 12V aux battery--has the car been sitting for an extended time during the covid shutdown, might the 12V aux have been weak or degraded?
Do you remember which EVVSE was being used when it failed? Maybe it was charging but never reached FULL?


Which came first?
F101 the first fuse in the path has a ceramic body and is blown. It is marked 250V 31.5A, and is directly followed by F103, with a glass body marked 250V T4A, a time-lag fuse that has pre-arcing time characteristic of 10msec at 100 A.

wxmatt
Posts: 20
Joined: Sun Sep 27, 2020 3:34 pm
Delivery Date: 14 Nov 2014
Leaf Number: 023861

Re: wxmatt's OBC failure [blown PFC Boost section]

Mon Oct 12, 2020 9:30 pm

nlspace wrote:
Fri Oct 09, 2020 3:45 pm
Maybe we can find something else to measure and check, like re-check Fuse F101, and check for continuity on the those black nickel-sized lollypops next to the fuses in the black potted area. Also check continuity across that little glass tube (lightning arrestor) next to that.
Finally got a few moments where my daughter and I could look things over.
1) Fuse F101 - No Continuity
2) Lightning Arrestor - No Continuity

Lollypops:
Since I don't have letter identifiers, I'll identify them by orientation, since two are aligned, and one is perpendicular.
1) The two that are side-by-side both showed no continuity
2) The perpendicular black lollypop showed 0.215 mega ohms
nlspace wrote:
Sat Oct 10, 2020 12:13 pm
@matt: what is the age, voltage and condition of your 12V aux battery--has the car been sitting for an extended time during the covid shutdown, might the 12V aux have been weak or degraded?
Do you remember which EVSE was being used when it failed? Maybe it was charging but never reached FULL?
The 12v that was in it at the time was about 2 years old. I have a trickle charger for the 12v that I would attach occasionally, though it had been a few months since I had topped it off. The LEAF is our workhorse, so we drove it pretty much daily, even through COVID. The car was parked for about a week (while we were on vacation) prior to the charging issue, though it was not plugged in during that time and stored in the garage, which is abnormal, because it is usually parked in the slab at the side of our driveway. When we returned from vacation, I plugged the car into the 240v EVSE that evening. I do not remember if it started charging or not. I believe it likely did because I drove it on a few errands the next 2 days and still had about 60% SOC when I first realized it wasn't charging any more a couple of days later. I then parked the car, knowing I needed to conserve battery power since I didn't know where/how I was going to fix it. When I went to drive it about 5-6 days later, the 12v had died (about 14-16 days after initially leaving on vacation). I attempted to recharge the 12v with the trickle charger, but it kept kicking out an error. I took the battery by Walmart, and they replaced it with a new one (under the 3 year warranty), and that's the battery in the car at the moment. Unfortunately, because the battery was flat dead when I took it to Walmart, I did not get a voltage reading on it (or more accurately, it was likely close to zero).

We almost exclusively charge at home on the 240v Juicebox EVSE, and it would likely have been the one that was utilized when the failure occurred. Unfortunately, because the kids are ALWAYS a distraction, I'm not sure which time it failed (as mentioned above), so it's possible/likely that failure occurred without it reaching a full charge at some point in the 2-3 days after we returned from vacation.

I apologize for the glut of details, but I figured it was better to lay everything out so I didn't miss a critical detail.
2012 LEAF (White) - Purchased in 11/14
2010 Rogue (Black)
1987 BMW 325i (Red)

nlspace
Posts: 321
Joined: Mon Jun 05, 2017 10:21 pm
Delivery Date: 06 Jun 2017

Re: Onboard charger capacitors failed

Tue Oct 13, 2020 5:56 am

No that's the kind of detail needed to troubleshoot this sort of thing. I was expecting that there might be some issues associated with the 12V aux and you have confirmed that there were.

One thing we know is that the 12V charging of the laef is insufficient to prevent sulfation of the cells; with 2 years of sulfation that battery was in a weak and worn out state. One theory is that left to its own daily discharge over vacation it was too weak to support HV charging with the EVSE, either to the LV supplies for the OBC and VCU, or for the Main Contactors and relays used during HV charging.

Another is that the fuse failed due to mechanical fatigue over time.

What is amazing to me is that the output stage and filter section with fuse survived without damage, but that's a good thing.

wxmatt
Posts: 20
Joined: Sun Sep 27, 2020 3:34 pm
Delivery Date: 14 Nov 2014
Leaf Number: 023861

Re: Onboard charger capacitors failed

Wed Oct 14, 2020 10:42 am

nlspace wrote:
Tue Oct 13, 2020 5:56 am
I was expecting that there might be some issues associated with the 12V aux and you have confirmed that there were.

One thing we know is that the 12V charging of the laef is insufficient to prevent sulfation of the cells; with 2 years of sulfation that battery was in a weak and worn out state. One theory is that left to its own daily discharge over vacation it was too weak to support HV charging with the EVSE, either to the LV supplies for the OBC and VCU, or for the Main Contactors and relays used during HV charging.

Another is that the fuse failed due to mechanical fatigue over time.

What is amazing to me is that the output stage and filter section with fuse survived without damage, but that's a good thing.
So… In a fortunate and surprising turn of events… My onboard charger is going to get here early… Probably today. Considering that I have a new 12V battery, and based upon what we know so far, is there any reason to believe, that the car will likely cause a failure in the new (used) charger?
2012 LEAF (White) - Purchased in 11/14
2010 Rogue (Black)
1987 BMW 325i (Red)

nlspace
Posts: 321
Joined: Mon Jun 05, 2017 10:21 pm
Delivery Date: 06 Jun 2017

Re: Onboard charger capacitors failed

Wed Oct 14, 2020 11:04 am

wxmatt wrote:
Wed Oct 14, 2020 10:42 am
...
So… In a fortunate and surprising turn of events… My onboard charger is going to get here early… Probably today. Considering that I have a new 12V battery, and based upon what we know so far, is there any reason to believe, that the car will likely cause a failure in the new (used) charger?
i think you should be good to go. It was driving okay before you removed the OBC, right?

If you want to donate the circuit boards to support OBC troubleshooting i will pay the shipping costs.

wxmatt
Posts: 20
Joined: Sun Sep 27, 2020 3:34 pm
Delivery Date: 14 Nov 2014
Leaf Number: 023861

Re: Onboard charger capacitors failed

Thu Oct 15, 2020 12:25 am

nlspace wrote:
Wed Oct 14, 2020 11:04 am
i think you should be good to go. It was driving okay before you removed the OBC, right?

If you want to donate the circuit boards to support OBC troubleshooting i will pay the shipping costs.
I got the replacement charger installed in the car tonight. It is presently charging using my 240v EVSE. I refilled the coolant, but I noticed that the replacement on board charger was rather warm. I imagine that’s to be expected, but I measured somewhere in the neighborhood of around 90 to 100°F. Checking Leafspy Pro, I am code-free!

I would be willing to donate the circuit boards. Considering all you have helped me with on this project, it’s the least I can do. I really appreciate all of yours responses and help over the last few weeks!
2012 LEAF (White) - Purchased in 11/14
2010 Rogue (Black)
1987 BMW 325i (Red)

Return to “Problems / Troubleshooting”