The Troubleshooting and Repair for On-board Charger (OBC) Thread

[kiev]

Is that a picture of a repair you made? Does it work or has it broken again?

 

[Bjossi]

Hello again
I did not attempt any repair. I noticed cracks in both of those resistor housings and they basically fell apart when I touched them. I cleaned up the white ceramic stuff and the outcome is on the picture.
There was no error codes and the car drove normally. Just did not charge.
Should I try to replace just those resistors?

 

[repairfrank]

Hello Bjossi,
if shipping to Germany is not too expensive. I can repair the OBC. I will send you my address by email. Here is my email address: [email protected] . I have already repaired over 50 of these OBCs. It is possible.
Greetings, Frank

 

[kiev]

... I cleaned up the white ceramic stuff and the outcome is on the picture.
There was no error codes and the car drove normally. Just did not charge.
Should I try to replace just those resistors?

Okay that now makes sense of what i was seeing.

Yes you could replace the resistors, and the little thermal fuse if desired--i assume the fuse has blown. Do you measure any resistance across the resistors or have they blown open?

The failure was due to lack of the AC relay becoming engaged into the circuit. The ceramic resistors are intended to only get used very briefly for a precharge function before the relay kicks in to carry the AC.

What is the age and condition of your 12V auxiliary battery? An old, weak or worn out aux battery can cause this failure to occur.

Need to determine what caused this failure if possible--is the relay defective or was the 12V battery degraded, etc. Otherwise just replacing the resistors might get a repeat performance. It might be wise to replace the relay also.

The screws holding the bottom power board can be removed along with the faston connections for the wires. Then just that board could be mailed off for repair if you decide not to do it yourself.

 

[ceskimiev]

Hello all, and thank you in advance for this fantastic forum filled with brilliant minds!

Like others, my 2012 I-Miev ES stopped charging with only 45k km. I'm a bit far from ChaDeMo chargers to see if it also charges on DC. It produces the normal sounds while charging for 5 seconds, then stops. I've found the two snubber capacitors beside the relay in the doghouse burnt and they were replaced. Fuse in inverter was also replaced. I've verified the two white resistors (they're good), the relay works (~10 Ohms when open, 0 Ohms closed) and the first AC to DC diodes in the waffle plate, all seems ok.

During those 5 seconds, the 12V battery goes to 14.7V (which tells me the DC/DC buck is ok and same when car is on), red plug light starts solid, then blinks, then the car with ! light turns on, then all go off. No error codes in HobDrive. 12V battery is good, tested at 79% health and was decently charged (12.7V when measured). If I keep on trying without resetting the charger, the cycle doesn't turn on any lights afterwards, but same if I unplug and replug the charger. Same if I use the climate remote to send charge commands.

All connections seem fine to both boards. It will be great if someone can provide hints of what shall I check next. The charger is the 9499C662 (has the filter on top of the charger).

I've been looking for a replacement and have found none.

Thanks,

 

[kiev]

Howdy ceski, sounds like you have been through it quite a bit, hopefully you can get to the bottom of this.

Do you have continuity on the AC wires from the charge port to the N and L terminals inside the OBC? i.e. that the fuses inside the EMI filter are okay. And continuity thru the upper board to the lower board and over to the N and L solder junctions on the waffle plate (measuring about 10 ohms thru the N for the ceramics).

If AC is getting to the box and thru the AC Input section (ceramic resistors + AC relay) to the Rectifier stage in the top left quad of the waffle plate, then the next section is the PFC Boost.

A problem may show up if you can check the diode drops in the waffle plate, there is a link section down on page 1 [posts #2 and 3] with the expected diode voltage drops plus links to schematics inside the plate. There is mostly high power semiconductors but also a few passive devices inside.

The 12V feeds to the OBC go to the upper control board, one has a fuse it might be worth checking. They create the low voltage supplies stored on the electrolytic caps, C701... worth checking if those voltages are present (requires careful setup and probing while plugged in).

 

[ceskimiev]

Thank you Mr. Kenny for your quick reply!

I measured continuity from the inlet all the way through the waffle plate solder points for L and N and it is all good. I've also measured AC to the bottom board (through the connectors) successfully. I also measured some 370VDC to the two rightmost connections on the inverter (right before these hit the inverter fuse). All during that short time.

The fuse on the top board is also good. I'll see about checking for that voltage. Onward to find C701 and the PFC section...

 

[kiev]

All the electrolytic can caps C701, 702,703, etc

 

[ceskimiev]

Found C701 and checked. Getting close to same voltage as the 12V battery (i.e. 14.7V while trying to charge, nothing while not), similar to pin 12 of CN101. I also checked the CN101 always on and it also has same as 12V batt.

I'm starting to wonder if the CAN bus is not good...

 

[kiev]

See this post for list of voltages to check, #86

 

[ceskimiev]

Thank you Sir! I will check in the morning.

 

[ceskimiev]

Good Morning, and thank you again! Voltages to capacitors are close to the values on post 86. TR310 has appropriate drops with the multimeter like a regular mosfet. F701 is good, so is the Schottky diode D715. There is continuity all the way through the ribbon cable from D715 and before (fuse) it to the switched 12V.

I did not venture to measure the voltage in the cap C841 because no easy access, the charger is still in the car. I'll remove the charger as last resource or if I find a decently priced replacement, car is old, this is Canada and they put salt on the road, prefer to leave as much untouched as possible to prevent further breakage.

 

[kiev]

That sounds like the control board is getting powered up and making the LV supplies, so likely an issue on the power board/waffle plate.

There is a drawing of the waffle plate solder connections and internal parts to check the diode drops on page 1.

Remove the faston connectors by sliding down on the tab and gently pulling up on the wire to release the blade lock. Label the tabs with wire color to help when reconnecting. Check the diode drops in the waffle plate, info is on page 1.

 

[ceskimiev]

Thank you Mr. Kenny, will do.

Checking on, reached post #109 where skylogger reinstalled the charger to the car and worked. I do not have a MUT-III, I wonder if all that needs to happen from here is simply to clear any codes only visible with the MUT-III and not a regular OBD (I've got the Veepeak WIFI using with HobDrive but no codes). Any other way to reset anything before I try the diodes?

 

[kiev]

If you have no codes and no MIL on the dash, then it seems there would be nothing to clear.

Checking the diodes is much safer than trying to probe the power board with HV present, with the OBC opened and control board sprawled across cardboard. Extra careful setup is needed when dealing with a powered-up OBC because there is pack HV on the Output plus the AC on the input and boosted HV on the waffle plate junctions, transformers, etc. Best to use clips or soldered fly wires to make connections for probes of the meter, then power up and make reading, then power off. Any mistake could be fatal and/or result in expensive damage.

Inspect the bottom surface of the control board for signs of metal splatter from the exploding snubber capacitors--tiny blobs of molten metal can burn thru traces or short out pins on tiny ICs.

 

[Piki]

Hi, what a great place to get information on repair of on-board charger and other related issues. Read about 10 pages and learned a lot but my problem was solved easier than re-soldering new capacitors or fixing a waffle plate. Thought to leave it here anyway in case someone experiences the same issues as I had since I haven't found any similar (or exactly the same) issue described. So here is my story.

Bought a car and was using quick chargers for a 400 km trip, an experience on its own! When got back home put it on 230V charger that came with the car. The charging started fine but stopped in about 1,5h. At reconnecting the charging was starting and then stopped in a minute. I asked the previous owner and he hasn't had that issue before (of course) but he says he only used slow type 2 public charging stations, not the 230 V charger. It turned out that after the car sat for a day it would again charger for about 1,5h and the story starts again. The strange thing was that 3 h was not enough, it had to rest for longer. Since the temperature outside was around 0 C, it was strange since if some component got overheated, 3 h would be more than enough to cool it down. I couldn't check any public charging station at that time because the car was not registered and could not be insured. Looking on the internet found this page but also people reporting having problems with the same/similar charger. The input cable is often tightened too much when it comes into the "box" which leads to one of the leads breaking after some time. Mine was fine on the input side but very suspicious on the output side. After disassembly and striping the wires no braking wires were found, put everything together but the problem persisted.

I had an original 12 V PSA battery and I read at several places that when it goes old the voltage is too low for activating the relay and starting charging. I measured the battery voltage and it had 14.3 V at the terminals when the charging was ongoing and a bit lower when the charging stopped, probably around 13 V. So that didn't seem to be a problem. Also, even though the car is from 2011 I think the battery was changed already at one of the yearly services. There is a sticker saying that it "expires" at the end of 2022. It is hard to believe the producer would trust the battery will be good for 11 years.

When the car was registered I drove it first to a yearly control and then tried to charge at the nearby type 2 station. It didn't want to start charging at all. Left it at home for a day and planned to go to another station the next day. Then I tried again at the same station the next day. The station is just 300 m from where I live. Sure enough, it started charging, but, sure enough, it also stopped in 45 min.

I read about that sometimes relays (two of them I think) cause charging problems. So what I did is to remove all the relays, cleaned the contacts (some minor corrosion on some of them but nothing too bad) and swapped them around so that no single relay ended up at the same place. To remove the relays the 12 V battery needs to be disconnected first to avoid any shorts. The realys are hard/impossible to pull by hand. I ended up bending some thin wire to make something that looks like a keycap puller (google it) and then pulling it up with plies. The 12 V battery terminals looked corroded, one terminal worse than the other but nothing that I would think of as a heavy corrosion. Also, it is a strange selection of batter/leads they used, hard to justify why they select a battery with so thin terminals but cables with a bigger diameter of clamps so that a lead "spacer ring" needs to be used. That is an extra connection point to corrode. Anyway, after everything was cleaned the main battery charged like a charm without any stops. If it wouldn't I would test to connect my other car's battery with jump wires and charge the main battery like that to make sure it is not the 12V that is causing the issues.

Even though I cannot be 100% sure I think the problem was with an aging 12V battery and corroded terminals. When I measured the voltage I did it at the terminals but probably the voltage at the car was lower. I think when the car sat for a while the battery went a bit lower on charge, when the charger was connected the voltage was enough to close the relay and activate the charging. Probably charging of the 12 V battery was activated immediately also so the OBC got stable 14 V during the period the 12 V battery was charged up slowly. When the charging of the 12 V stopped probably the voltage at the OBC dropped and it shut off the charging of the main battery. When it was reconnected again there was almost no need for charging the 12 V battery so it shut off much faster. That would also explain why I couldn't start charging directly after driving - the 12 V battery was charged during driving.

I will of course change the battery now but wanted to leave it here and contribute to someone experiencing the same issue

OK, so the old battery was not the issue. How do I modify the old post, cannot find that function on the forum?

After successful charging all the way to 100% for 2-3 times at 8 A I tried charging at 14 A and it stopped after 30 min and the same problem started again. After few 30 min charges it finally charged from 50% to 100% during 3 h at 8A. So the problem was intermittent, sometimes it charges, sometimes it stops. I checked the battery and it was 12,6 V after leaving overnight. After turning on the lights for about 1 min and waiting for another 2 min the voltage was 12,3 V, so quite ok. I didn't measure the battery capacity (have no battery tester) but I finally spotted another label on the battery which indicated that the battery was installed in dec 2021. So the marking of nov 2022 was probably the end of warranty period, not when it was recommended to change the battery. With only 2 years old battery it is unlikely that the battery is the issue. So I decided to open the OBC. The 2.2 mF capacitor next to the ceramic resistors is definitely blown. It is hard to see from the photo (a better photo is coming when the board is removed) but it is swollen on the side next to the resistors and puked on one of the resistors. I am in the process of removing the lower board now. I saw a similar issues in this thread and will review those but some quick questions here before I go to bed:
1. Would the blown capacitor result in the issues I experienced (intermittent charging that stops after some time)?
2. Is it likely that the capacitor failure was caused by another issue which also needs to be solved?
3. Does the Waffle plate need to be desoldered for soldering a new capacitor? Can the old one be just ripped apart to reveal the contacts and solder to those?
4. Which capacitor to buy? The marking says 310 V, which is kind of strange, with 230 VAC in Europe the peak voltage is 324V, shouldn't the capacitor be rated to that/higher voltage? Is it ok to buy a capacitor rated for a higher voltage? It should be ok with a higher capacitance, right? Any brand/type recommended?

Also, I spotted some corrosion probably due to moisture coming through a plastic plug. Some residue ended up on the lower board. Is it common? I plan to clean it and silicone the plug in place

 

[coulomb]

1. Would the blown capacitor result in the issues I experienced (intermittent charging that stops after some time)?

It's hard to say. That capacitor is across the mains input, so it seems unlikely to me that it would cause stops. The stops sound like an overheating issue to me. It seemed seemed to charge longer at lower power.

2. Is it likely that the capacitor failure was caused by another issue which also needs to be solved?

I don't believe so. Those capacitors seem to have a hard life.

3. Does the Waffle plate need to be desoldered for soldering a new capacitor? Can the old one be just ripped apart to reveal the contacts and solder to those?

Others have done just that, so yes it is possible. Desoldering the Waffle Plate™ is best done with a desoldering station, and it's a lot of work even then. So it's worth avoiding if you can.

4. Which capacitor to buy? The marking says 310 V, which is kind of strange, with 230 VAC...

Capacitor insulation seems to respond to RMS voltage more than peak voltage. So 310V will be an AC rating. Sometimes capacitors have a DC rating, and if they have both, the DC rating is always much higher than the AC rating. This needs to be a safety capacitor, at least X2 rating; X1 is a higher rating. Make sure that the replacement will fit and has the right lead spacing. A higher voltage rating is OK, but much higher is unlikely to fit. A slightly higher capacitance is also OK, but again, the replacement is less likely to fit.

Also, I spotted some corrosion probably due to moisture coming through a plastic plug. Some residue ended up on the lower board. Is it common? I plan to clean it and silicone the plug in place

That plastic thing probably has ir had some sort of filter in it. Siliconing it would seal it, I don't know the consequences of that. But moisture coming through is probably worse.

 

[Piki]

It's hard to say. That capacitor is across the mains input, so it seems unlikely to me that it would cause stops. The stops sound like an overheating issue to me. It seemed seemed to charge longer at lower power.

I don't believe so. Those capacitors seem to have a hard life.

That plastic thing probably has ir had some sort of filter in it. Siliconing it would seal it, I don't know the consequences of that. But moisture coming through is probably

Thanks for the fast reply! I read some more in this thread and found another conversation about two of the input capacitors blown up and an instruction how to open the external box with the input filter. And the capacitor there was also blown up! I found identical capacitors to be sold online, will order 5 of them (min order) and resolder. Any clues to what could potentially be also blown up/damaged? Is it worth to resolder those and give it a try or anything else should be changed/checked while I am on it?

Bought a 12V battery tester and it showed 84% battery health

 

[coulomb]

How do I modify the old post, cannot find that function on the forum?

The edit link is now down the bottom of your own posts, just after "Report". There is now a limit of 30 days (was only minutes originally) then the edit option goes away:

 

[coulomb]

anything else should be changed/checked while I am on it?

Definitely check the resistors. The ½Ω measurement is if you turn on the relay with a 4.5 V battery or 5 V power supply.


To activate the relay, see small red and black circles:



Negative on black, positive on red, obviously. The ribbon cable needs to be in place.