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

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

Thu Aug 16, 2018 8:52 pm

I've run the repaired charger now for a few days, and it seems to be stable, so smoke has come out so far ;-)
Now that I have a working charger and a test bed, There are a few things I am interested in testing.

1) I've heard several people say that the charger will run even with a DC Voltage applied to the AC input. I think Coulomb
has mentioned that other chargers can be tested using a 52VDC as a input. I was wondering if anyone can confirm they have
tried running a I-MIEV Charger using DC input. Any ideas what the voltage range would be?
If A spare I-MIEV Battery pack fully charged sitting at 361VDC was connected to the AC input of this charger, would this DC Voltage
work, and would it not be to high to cause any damage?
I have a 48vdc (54v nom) supply on my solar house. It would be interesting to find out if this is too low to try charging directly from.

2) I am thinking of temporarily cutting one of the CANBUS lines to the charger to see if it would start charging without receiving any
communications from the EV-ECU, BMU or CMUs. This would be good to know if a charger is being tested on the bench without CANBUS
Communications.

3) I want to check the signal on the CHGP line that runs from the charger to the EV-ECU. Currently I don't know if this is just an on / off signal
or if it is a continual pulsed signal to prevent a timeout. When I get a chance I'll connect a scope to this and I'll let you know what I see.

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

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

Thu Aug 16, 2018 10:28 pm

skylogger wrote:I've run the repaired charger now for a few days, and it seems to be stable

Excellent!
, so smoke has come out so far ;-)

You do realise that little words like "no" are sometimes quite important ;)

1) I've heard several people say that the charger will run even with a DC Voltage applied to the AC input. I think Coulomb
has mentioned that other chargers can be tested using a 52VDC as a input. I was wondering if anyone can confirm they have
tried running a I-MIEV Charger using DC input. Any ideas what the voltage range would be?

Since the power supply doesn't run from the mains (it's different to the Elcon/TC chargers in that respect), you can probably go down to 24 V or even 12 V and still have useful, measurable things happen throughout the powertrain. But it's important to use a current limited power supply; if a MOSFET is shorted, then a 12 V car battery can blow up the leads and PCB tracks as effectively as the mains. You really want the situation where the worst that can happen is that an LED on the power supply lights up saying it's not current limited, and the volts go to zero with no drama.

If A spare I-MIEV Battery pack fully charged sitting at 361VDC was connected to the AC input of this charger, would this DC Voltage
work, and would it not be to high to cause any damage?

361 VDC corresponds to the peak of about 255 VAC, so it should not hurt the charger. The inrush current should be limited by the 4.7 Ω resistors, but only to about 361/9.4 = 38 A, which is still an unpleasant splat. I see no advantage in doing this.

I have a 48vdc (54v nom) supply on my solar house. It would be interesting to find out if this is too low to try charging directly from.

At least the energy in the capacitors is about 1/64th of what it would be with 400 V, but the energy in the batteries is massively more than that. So again, you really need the current limiting, as well as the voltage, to limit the energy available for damage. At least a 30 V (or less) current limited supply (limited to half an amp initially, so a transmitter power supply doesn't qualify) is fairly easy to obtain, perhaps even second hand. I'm at a colleague's place typing this, and he has two :-) (One was a freeby that only works 90% of the time, but it's still useful).

2) I am thinking of temporarily cutting one of the CANBUS lines to the charger to see if it would start charging without receiving any
communications from the EV-ECU, BMU or CMUs. This would be good to know if a charger is being tested on the bench without CANBUS
Communications.

That should be an easy test, but I think it's 99% certain that nothing will happen without CAN signals. Using some sort of CAN monitor to capture the appropriate CAN message would be great though.

3) I want to check the signal on the CHGP line that runs from the charger to the EV-ECU. Currently I don't know if this is just an on / off signal
or if it is a continual pulsed signal to prevent a timeout. When I get a chance I'll connect a scope to this and I'll let you know what I see.

Yes, that would also be great to know, thanks.

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

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

Thu Aug 23, 2018 3:03 pm

Hi Electronpusher:

<edit> just read your other thread

Are you able to determine if the 20 amp fuse is blown that is under the small cover on top of the motor controller box to the left of where the charger is? The fuse contains sand, so you can't just look at it, you have to use an ohm meter to check it.
If that fuse has blown, you may have good luck and it has saved the critical parts in the charger, which was the case in the charger that I was working on. You mentioned that you have the same blown up caps in the doghouse. This means you have already lifted up the top PCB to have a look. Can you take a photo of the lower PCB next to where the flex cable connects the top pcb to the bottom pcb?
It would be interested to see if we can visually spot any damaged components in that area.
Can you let us know the Mitsubishi part number on the label on top of the charger? I am interested to see if it is same version/revision
has the one I was working on. The one I was able to repair seems to be same as what KIEV has, but I also have one with a different part number that also came out of a 2010 I-MIEV that has totally different PCBs in it. Is your I-MIEV a 2010 or later model?

<edit> from the photo in the other thread, you have same version I have where the two caps in the dog house were replaced with a small vertical pcb. The way I did the repair of this, I used exacto knife to remove all the rebbery potting. I did not want to get involved with desoldering the heatsink/waffle so I did all the re-work from topside only. I desoldered the pins that connect the small vertical PCB, leaving
the pins sticking up from the bottom pcb. The Vertical PCB was used to emulate the original two through hole caps, so I purchased the original through hole caps (value listed earlier in this thread) and soldered them to the 4 pins that were sticking up from the bottom pcb that the vertical pcb was originally connected to.

I think these two caps and the fuse blew because the output voltage increased too high. If your problem is same as mine, you will still need to find the other fault that caused the output voltage to go too high. If you get a chance, please take a photo of the PCB next to where the flex cable connects the top pcb to the bottom.

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

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

Fri Aug 24, 2018 7:16 pm

Gday, we havnt checked the 20 amp fuse on the motor controller yet, but this weekend i will be going to my fathers shop where the car is at the moment, and ill get as many pics and as much info as i can.

Thanks again,

Rob.

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

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

Tue Aug 28, 2018 2:27 am

sorry for the late reply, here are some pics,

Image

Image

Image

hope these help.
also of note, our car is a 2010 model, yet the converter appears to be a 2015, so i am assuming that it is not the original converter. either way, it appears the failure mode is the same as others.

these are older photos of when we first pulled the converter apart some months ago. ill get some others as requested as soon as i can. this weekend hopefully. unfortunately the car is not stored at my house at the moment.

thanks again for all your efforts in the reverse engineering and working through a repair.

rob.

kiev
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Location: The Heart o' Dixie
Contact: Website

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

Tue Aug 28, 2018 4:51 am

It does look like a fresh new charger since you can actually see the colors of the fat wires within the clear tubing--they are not showing signs of heat discoloration yet. But the tubing covering the tops of the large caps is already starting to recede. They added a second fuse to the AC input line and put an EMI ferrite on the AC line. Removed the external EMI filter box that was bolted to the lid, since it doesn't make sense or help to have the surge suppressor after that filter.

So this is another case where the snubber caps have blown. Something has caused an over-voltage at the output of the boost stage and before the final output filter. Inspect the bottom board with a magnifying glass looking for missing or cracked solder joints on all the tiny resistors and caps.
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, DC-DC Converter

Tue Aug 28, 2018 5:06 am

electronpusher wrote:sorry for the late reply, here are some pics, ...

Interesting. I note some differences, for example two fuses versus one on the top board (middle photo).

And: the two fuses appear to be in series.

Huh?? How does that work?

kiev
Posts: 942
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

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

Tue Aug 28, 2018 6:52 am

The new lower fuse is in line between the Live (Line) input terminal and the Black wire (L00) feeding AC to the bottom board. There was no fuse on the Line side before except in the external EMI filter bolted to the lid. So all Live/Line traces downstream of the AC input terminals are protected by this new fuse.

The top fuse (F103 previously and likely now) is only in line with the lower ZNR varistor that connects between Line and Neutral, so the circuit is: Line-fuse-ZNR-Neutral. So this is now protected by the new fuse also.

It appears that they made some changes to eliminate the external EMI filter box and retain some of its functions.
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, DC-DC Converter

Wed Aug 29, 2018 7:09 pm

Electropusher: The charger label on your charger has the same Mitsubishi part number 9481A092 as the charger that I just repaired.
Both are in 2010 I-MIEVs here in Australia that were built in Japan.
You also have the vertical PCB with blown caps in the dog house, VS the older style that had the through hole caps that the vertical PCB emulates. The fault on the one I repaired ended up being a poor solder connection of a 39K 0603 resistor close to where the flex cable connects the top PCB to the bottom PCB of the charger boards. I noticed that when I tried resoldering the 39K resistor, it would not re-solder properly and I found the end caps of the 0603 resistor did not have all of the plating on them. It would be interesting if your charger and my charger happened to be made in the same batch, of the same reel of SMD resistors (with faulty end cap plating), and you also had a bad solder connection in the same area that I had. I think there are actually 2 of these 39k value resistors in this circuit. My charger probably worked for a while until vibration caused the poor cold solder joint to the resistor to open. The lack of solder plating on the ends caps of the resistor is probably why during the manufacturing process, when the PCB was going through the oven, its mounting twisted a bit because the solder past only barely connected and held one end down and it floated a bit.

I think you will find when you dig out the rubbery potting around the vertical PCB in the doghouse, the only damage is the SMD Caps on the vertical pcb. The two spots that look like something else is burnt in front and to the right of the vertical PCB is where the shrapnel from the caps of the vertical PCB Caps has landed, and melted back into the potting. If you dig there, you will find no actual components under that area on
the main PCB. KIEV found the cap values on the other thread and the Murata info is:
DEHR33F102Kppp 3150Vdc 1000pF±10% 13.0mm max. 7.5 6.0mm max. A3B B3B N3A
I used 2 of these through hole caps and soldered to the four pins that connected the vertical PCB to the main board by removing the vertical PCB and soldering the caps to the remaining pins sticking up. I replaced with Altronics equivalents.

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

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

Wed Aug 29, 2018 8:15 pm

If you find badly soldered 39k resistor(s), I have some here and can drop them in the post for free. Just PM me your address.

It would be so sad if a bad batch of sub-one-cent components is what is crippling these $4000 chargers.

However, the SMD HF filter capacitors just seem to be a terrible design decision. Hopefully it was only done in response to some acute through-hole parts shortage.

[ Edit: "SMD Y capacitors" -> "SMD HF filter capacitors" ]
Last edited by coulomb on Thu Aug 30, 2018 1:03 am, edited 1 time in total.

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