skylogger
Posts: 76
Joined: Sun Dec 14, 2014 3:54 am

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sat Sep 08, 2018 8:06 pm

Did a really lengthy post about answering some of Electronpushers questions, but took too long and the form timed out and I lost it all.
So heres an abbreviated version

"Do we need to remove the black stuff in the dog house, or can we mount the new snubber caps on the riser (I know the rise is for SMD,
not sure if it is possible to retro fit through the hole onto it or not)."
My vertical riser PCBs were both damaged too much on the two OBCs that I've looked at so far. If your one looks re-usable, that would save you some time. I still managed to rework this without removing the main PCB from the box. I used a box cutter knife (did not have an exacto scalpel) to cut strips in the black pottiing stuff. Then I dug out with a tiny small screw driver. I also have some dental tools I bought from local chemist to do some finer cleaning. In my case, I desoldered and removed the vertical PCB and used the remaining pins to solder the two replacement through hold caps back to the main PCB, so I left the vertical PCB out altogether.

"Do we need to remove the board from the waffle plate, or can we do the diagnosis and repair with it attached to the waffle plate?"
You can test most of everything without removing the main board from the waffle or removing the main board from the box.
KIEV has done a really nice job of a schematic page with the connecting pins on the white stips on the main board that connect to the waffle.
You can use that page and an ohm meter set to DIODE testing to check all the diodes, bridges, and half the IGBT to see if most of it looks good.

"Can the board with the dog house etc be removed without desoldering?"
The vertical riser PCB inside the dog house cannot be removed without desoldering 8 pins (4 on front and 4 on back)
The doghouse is not a seperate board, but just an area on the main PCB that has a plastic boarder filled with the black potting stuff.
If you do want to remove the main PCB, you have to one by one LABEL and remove all the wires with blade connectors.
Then the four screws that mount the PCB to the box in the corner are removed.
Then all 5 standoffs need to be removed. The screw in the center of the Main PCB is removed, but the standoff that it screws into ALSO has to be removed. The four outer standoffs also need to be removed, because even though it looks like they do not tie down the PCB, They bolt the heatsink of the waffle to the box, and since the waffle is still soldered to the main PCB, its still fixed to the box until all five of these are removed.

coulomb
Posts: 170
Joined: Sun Jun 10, 2018 8:32 pm
Location: Brisbane, Australia

Re: Pre-charge relay the root cause?

Sat Sep 08, 2018 11:56 pm

I meant to mention earlier re the concept of the pre-charge relay possibly being the root cause of the problems. Since the pre-charge resistors are only 9.4 Ω, the highest current the relay contacts have to briefly pass is about 240 x √2 / 9.4 ~= 36 A. This is a fair bit more than the 16 A that the contacts are rated for. This could explain the micro-pitting seen in Skylogger#2's relay contacts. Though a colleague of mine said the contacts looked fine to him, and might be suffering from too little current, not "wetting" or cleaning them enough. I can see both points of view: it gets too much current for a fraction of a second, then has no action for probably 24 hours So maybe that's too little average current, and too much peak current. Either or both of these might contribute to the relay contacts going high resistance.

When in high resistance, it might exhibit what's seen in some of the poll results, where the charrger charges at very low current for a few minutes, then shuts off, and often dies shortly after that. The very low charge current could be due to the pre-charge resistors dropping a hundred or so volts, making it impossible to maintain ~400 VDC on the PFC output capacitors. The charger would struggle to get 360 V or so (after the transformer) to push current into the battery pack.

kiev
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Location: The Heart o' Dixie
Contact: Website

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sun Sep 09, 2018 5:34 am

i hope i didn't cause your relay problem with an error in the schematic drawing for the AC input. i just used a generic relay in Kicad and didn't put all the pins. Here is the datasheet picture from the Fujitsu pdf, and i think the concept is the same--a single pole N.O. contact that closes when the coil is energized.

Image

copied from: https://www.fujitsu.com/downloads/MICRO ... r-k1kw.pdf
kiev = kenny's innovative electric vehicle

coulomb
Posts: 170
Joined: Sun Jun 10, 2018 8:32 pm
Location: Brisbane, Australia

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sun Sep 09, 2018 6:38 am

Um, but Kiev your photo of the underside of the charrger PCB shows 4 contact pins, plus 2 coil pins for 6 pins total.

I think Nichicon must use a version of this relay with the normally closed pins not present. Oh, maybe that's what the reference mark symbol ※ means; not present on some versions. [ Edit: That must be what they are saying with "form A", there is no "stationary arm", which must mean no normally closed contact. The arm is clearly present internally, at least in SkyLogger#2's case. ]

[ Edit: X with four dots -> reference mark ※ ]
Last edited by coulomb on Sun Sep 09, 2018 6:00 pm, edited 1 time in total.

kiev
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Location: The Heart o' Dixie
Contact: Website

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sun Sep 09, 2018 7:33 am

i think you are right, mine is marked K1AK005W, so it appears to be the single contact "1 Form A" contact configuration. Their note is incorrect, it is the stationary "pins" that are not brought out, but the stationary arm clearly is present.
kiev = kenny's innovative electric vehicle

electronpusher
Posts: 45
Joined: Sun Jun 25, 2017 3:11 am

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sun Sep 09, 2018 5:30 pm

skylogger wrote:Did a really lengthy post about answering some of Electronpushers questions, but took too long and the form timed out and I lost it all.
So heres an abbreviated version


Hi Skylogger,

I hate it when that happens half way through typing, very frustrating, however I very much appreciate your help and the abbreviated version anyway. We have take out the DC/DC Converter, but I have not begun disassembling it just yet, I will start that this week some time.

I think with the riser, I'll desolder the damaged caps, and take a look at how the pads held up before making a decision. If I can reuse the riser, it will make life easer.

Regarding removing the DC/DC Converter board with the dog house (not sure what we are calling that PCB board, do we have a name for it?), I know understand why last time we had trouble removing it, and that is because we still had the waffle house bolted down, and the PCB is soldered to the waffle house which I did not know at the time we last had it torn apart. I thought those white strips where the waffle house is soldered to the PCB were sockets or plugs initially, but now that makes sense, it is for heat transfer to the waffle house and hence the *hard* connection to the waffle house.

I'll need to do some reading back through Kiev's posts and study the schematic diagram he has produced.

kiev
Posts: 942
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Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sun Sep 09, 2018 5:43 pm

Check out post #2, it now has an index with links to the schematics and pictures that might be of help to you.
kiev = kenny's innovative electric vehicle

skylogger
Posts: 76
Joined: Sun Dec 14, 2014 3:54 am

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sun Sep 09, 2018 9:25 pm

Hi Electropusher:
If you look at Ohm out the riser vertical PCB, you will find as per KIEV's schematic, that the SMD Caps emulate the two original through hole caps, which connect to the main board by four holes. I thought these were in series with each other, but the track routing on the main board (and maybe on the riser vertical board also), actually make these two caps parallel each other. I think Coulomb pointed out that the vertical PCB was populated with a few SMDs, but there were unpopulated spaces for spare caps also. So if the pads are damaged where the original caps were blown, you might be able to use the spare locations. There is probably some layout consideration to prevent arcing, so Even though the caps are parallel, they are spread out a bit and not put too close to each other, so You might take that into consideration when you are mounting the through hole replacements.

ChristopheFR
Posts: 20
Joined: Sat Aug 11, 2018 1:08 am

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Mon Sep 10, 2018 11:12 am

Hello all,
My name is Christophe, and I am the proud owner of a C-zero in France since 2012
My Z totals 82,000 km, it is 2011. I use it every day.

my Czero's charger is dead. One more!

One morning in July, I realize that my “Z” is not ready . I make an appointment with Citroen for the following week and I go on vacation. On the return, serious problem : Citroen gave me a quote for the charger change: 2800 €

I think it died due to the heat this summer, over 35 °C in my garage while charging.

While waiting to change the charger or to repair it, I recharge my "Z" on the Chademo socket at Ikea.

The apparent diagnosis: when I plug my charging cable, the green charging light on the cable box comes on for several seconds, I hear a few clicks to the cable and to the car, the car's blower starts a few seconds, then everything stops, no blower, no green light on the cable, and no fault on the cable or on the dashboard.

With the ignition key closed, when I take the voltage across the auxiliary battery, I get 12.4 volts
With the ignition key open, I get 14.5 volts.

(At the December 2015 maintenance, Citroen told me that the accessory battery was low, so I changed it preventively).

Do I have to believe that the 360/12 VDC converter works?

I'm going to autopsy the charger next Saturday, and take pictures.

Anyway, the problem is that I can not do without my "Z", how to do if the repair is worse than the load on the Chademo terminal?

Can I remove the PCB from the charger for repair and continue charging with the Chademo plug?

And does the accessory battery continue to charge?

Congratulations to all for this excellent topic. Christophe

skylogger
Posts: 76
Joined: Sun Dec 14, 2014 3:54 am

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Mon Sep 10, 2018 3:31 pm

Hi Christophe:


The fault with your charger might be a bit different to the ones I am working on. It sounds like DC-DC is still working which means the 20 amp fuse has not been blown. It also seems to detect when AC is connected.

"The apparent diagnosis: when I plug my charging cable, the green charging light on the cable box comes on for several seconds, I hear a
few clicks to the cable and to the car, the car's blower starts a few seconds, then everything stops, no blower, no green light on the cable,
and no fault on the cable or on the dashboard."
With the ignition key closed, when I take the voltage across the auxiliary battery, I get 12.4 volts
With the ignition key open, I get 14.5 volts."

The input to your on board charrger is working as the AC is being detected, since you hear the contactors and blower come on for a bit.
It sounds like the DC-DC Converter section is also working as you see the voltage on the 12v aux go from 12.4 to 14.5, but not sure when you say "key open" and "key closed" seems to be opposite. When the car is "READY" you should see the higher voltage of 14+ volts which means the DC-DC Converter is charging the battery. When the car is OFF, The 12V Aux battery voltage should drop down to the 12v range.

"Do I have to believe that the 360/12 VDC converter works?"
Based on the above, it does look like the DC-DC 360/12 part of the box is working

"Anyway, the problem is that I can not do without my "Z", how to do if the repair is worse than the load on the Chademo terminal?
Just confirming, you earlier said you can still use the Chademo charger at IKEA with no problems? If so, that goes through a seperate relay and contactors and fuse, so that should be mostly separate to faults with the on board charger.

If you remove the Charrger/dc-dc converter out of the car, you would need to do a few things to be able to use the car while working on the charrger:
1) The liquid coolant runs in series from tank to pump to MCU (motor control unit) To Charrger, and back to pump.
with the charrger removed, you would need to put a bit of pipe between the hose that is the charrger coolant IN to the charrger coolant OUT of the charrger, so that a bypass is made and the full loop is present. If this is not done, the coolant will not flow and cool the MCU.
2) With the charrger out of the car, The 12v aux battery will not get charged and will continue to drain. you could connect an external 12v battery charrger to the battery every night, so you could do a few small drives during the day, and then put back on the external 12v charrger again every night.

3) You could still charge the car at IKEA CHADEMO to maintain power in the 360v traction battery.

"Can I remove the PCB from the charrger for repair and continue charging with the Chademo plug?"
And does the accessory battery continue to charge?

The connection of the traction battery goes through the charrger pcb, then goes down to the lower pcb that is the DC-DC Converter.
There is also some communications lines that go from top section down to bottom DC-DC section.
It might be possible to do some kind of bypass connections but its not really easy.
It's probably easier to use an external 12v charrger every night as long as your not using the car for long trips, and use the CHADEMO at IKEA to keep charge on the traction battery while you have the whole box out of the car. You would still need to bypass the coolant hoses so the MCU still has coolant circulated ok.

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