The Troubleshooting and Repair for On-board Charger (OBC) Thread
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No don't send me any personal messages about the ceramic resistors, there is a 20 message limit and my inbox is full--just post your questions for everyone to see. If i or anyone else can contribute something useful, then we will respond.
There are already plenty of discussions about these resistors in this thread, just do a search, or a google search for ceramic resistors on this thread to find them.
The 5V power supply was traced out but i don't recall if there is a schematic posted. It doesn't seem normal for it to be fluctuating and indeed it could cause the fused resistor to blow if it dropped too low and opened the relay. It might also blow the snubber caps on the output side--definitely don't want any uncontrolled interruption during charrging.
There are already plenty of discussions about these resistors in this thread, just do a search, or a google search for ceramic resistors on this thread to find them.
The 5V power supply was traced out but i don't recall if there is a schematic posted. It doesn't seem normal for it to be fluctuating and indeed it could cause the fused resistor to blow if it dropped too low and opened the relay. It might also blow the snubber caps on the output side--definitely don't want any uncontrolled interruption during charrging.
coulomb
Well-known member
Exactly. These are pre-charge resistors, If all goes well, they dissipate zero power after pre-charge because the relay is shorting them.Sandrosan said:
Sandrosan
Well-known member
kiev said:
Yes Kiev, I do not want to contact you privately, do not worry
. I prefer to show the argument in the forum so everybody can see and hope to be of help for someone in future.I have carried out 2 full charging sessions, and the voltage instability looks depending on the charge current (large currrent more instability). So I guess there is a component that is sufferring the heat. But as I said, the top board has been swapped and the voltage instability remains.
I used the hot air on the upper side of the middle board, but in vane.
You said that the 5v power supply was traced, Ok good thank you. I will review all the 67 pages once again hoping to see the schematic posted. I remeber the tracing but not the schematic.
Thanks in advance to you and all that can give me any advice.
Sandrosan
Well-known member
coulomb said:
Thanks Columb.
@Sandrosan, i found the discussion section about the low voltage power supplies on the control board,
http://myimiev.com/forum/viewtopic.php?f=23&t=4079&start=70#p36876
i have to review my notes to see if i hand-sketched the schematic, seems like i would.
Can you monitor your 12V output of the DCDC to the aux battery during a charge when the fluctuations are happening? If the 12V is unstable then it could affect the 5V supply.
http://myimiev.com/forum/viewtopic.php?f=23&t=4079&start=70#p36876
i have to review my notes to see if i hand-sketched the schematic, seems like i would.
Can you monitor your 12V output of the DCDC to the aux battery during a charge when the fluctuations are happening? If the 12V is unstable then it could affect the 5V supply.
Sandrosan
Well-known member
@Kiev Thanks very much for the low voltage power supply section.
The 12V output of the DCDC to the aux battery during a charge when the fluctuations are happening remains stable around 14.2 /14.3V.
Do you know where the AC coil relay 5V supply comes from? Which 5V regulator? Where is the transistor that drives the 5V for the coil? My eyes are not good anymore even if magnifier lents...
For your info, at the moment I put an external power supply at 5V that supplies the coil and it is driven by a transistor which base is driven by the original 5V for the coil. In this way I do not charge of the 70 mA necessary to the coil from the original circuit.
Monitoring the original 5V over time the fluctuations are much less in amplitude (the drop of voltage was down to 4.6V instead of 2.6V).
In the second charging session (on the way just while writing) such original 5V looks even more stable (not less than 5.06V).
Of course this is not a cool solution and generally I want to go to the origin of the problem.
But I want to avoid to remove the lower board (which would be great for deep checking specially where the IC702 and IC317 are located and relative components around them).
Also because the car has almost 120K km and the pack has many cells very weak, limiting the Range at 70 km only , in this season.
Another (not so cool, I agree ) solution that I already prepared (but not tested yet) was to I put an external power supply at 5V that supplies the coil and it is driven by a transistor which base is driven by an RC circuit with 2-3 seconds of delay. In this way the AC input relay closes its contacts (and keep them closed) when there is power via EVSE, apart 2-3 seconds at starting point necessary for the precharging the big 3 caps.
Do you or sameone else know if that AC input relay works just for the precharging circuit?
Thanks again!
Sandrosan
The 12V output of the DCDC to the aux battery during a charge when the fluctuations are happening remains stable around 14.2 /14.3V.
Do you know where the AC coil relay 5V supply comes from? Which 5V regulator? Where is the transistor that drives the 5V for the coil? My eyes are not good anymore even if magnifier lents...
For your info, at the moment I put an external power supply at 5V that supplies the coil and it is driven by a transistor which base is driven by the original 5V for the coil. In this way I do not charge of the 70 mA necessary to the coil from the original circuit.
Monitoring the original 5V over time the fluctuations are much less in amplitude (the drop of voltage was down to 4.6V instead of 2.6V).
In the second charging session (on the way just while writing) such original 5V looks even more stable (not less than 5.06V).
Of course this is not a cool solution and generally I want to go to the origin of the problem.
But I want to avoid to remove the lower board (which would be great for deep checking specially where the IC702 and IC317 are located and relative components around them).
Also because the car has almost 120K km and the pack has many cells very weak, limiting the Range at 70 km only , in this season.
Another (not so cool, I agree
) solution that I already prepared (but not tested yet) was to I put an external power supply at 5V that supplies the coil and it is driven by a transistor which base is driven by an RC circuit with 2-3 seconds of delay. In this way the AC input relay closes its contacts (and keep them closed) when there is power via EVSE, apart 2-3 seconds at starting point necessary for the precharging the big 3 caps.Do you or sameone else know if that AC input relay works just for the precharging circuit?
Thanks again!
Sandrosan
Sandrosan
Well-known member
Sandrosan said:
Sorry Coulomb, no Columb
That 5V relay is held closed constantly during a charging session; the ceramic resistors provide an inrush by-pass circuit to precharge the 3 caps, then when they meet the full condition, the controller commands the 5V to close the relay contacts.
The microcontroller chip, IC701, pin 38 drives the base/gate of transistor TR301, marked "CGRZ" possibly a 2SC5053, thru R302. This transistor pulls the coil return side on pin 25 of the flat ribbon cable to ground.
The 5V relay supply is on pins 26-29 of the flat ribbon cable and is created from the "switched" 12V supply to the OBC (versus the Hot All the Time 12V line). This 12V is supplied from the OBC relay onto the top board connector, CN101 pin 12, and is held up by C701 and C702. If these caps were leaky then the switched 12V might fluctuate.
Also the OBC relay is supplied thru fuse 11 in the fuse box, so the integrity of both the relay and the fuse should be checked. The EV-ECU controls the coil drive for the OBC relay.
The 5V buss that supplies the AC relay on the bottom board is held up by C703, C705, C706 and C840. There is a circuit on the lower side of the control board that measures this 5V thru a unity gain buffer and sends it to the IC701 microcontroller pin 80 for monitoring.
The 5V buss is created using a PWM DCDC converter chip, IC707, NJM2374A, transistor TR702 and diode D717, from the 12V Switched (and fused F701) supply on pin 12 of the CN101 connector. In addition this 5V is used to create the ~16V supply held on C704 and C707 and sent to the bottom board for the gate drive voltage of the waffle plate.
Since you swapped the board and are getting the same behavior, then it is likely some issue with the 12V supply circuit external to the OBC (EV-ECU, fuse, OBC relay, loose terminal in some connector?...)
The microcontroller chip, IC701, pin 38 drives the base/gate of transistor TR301, marked "CGRZ" possibly a 2SC5053, thru R302. This transistor pulls the coil return side on pin 25 of the flat ribbon cable to ground.
The 5V relay supply is on pins 26-29 of the flat ribbon cable and is created from the "switched" 12V supply to the OBC (versus the Hot All the Time 12V line). This 12V is supplied from the OBC relay onto the top board connector, CN101 pin 12, and is held up by C701 and C702. If these caps were leaky then the switched 12V might fluctuate.
Also the OBC relay is supplied thru fuse 11 in the fuse box, so the integrity of both the relay and the fuse should be checked. The EV-ECU controls the coil drive for the OBC relay.
The 5V buss that supplies the AC relay on the bottom board is held up by C703, C705, C706 and C840. There is a circuit on the lower side of the control board that measures this 5V thru a unity gain buffer and sends it to the IC701 microcontroller pin 80 for monitoring.
The 5V buss is created using a PWM DCDC converter chip, IC707, NJM2374A, transistor TR702 and diode D717, from the 12V Switched (and fused F701) supply on pin 12 of the CN101 connector. In addition this 5V is used to create the ~16V supply held on C704 and C707 and sent to the bottom board for the gate drive voltage of the waffle plate.
Since you swapped the board and are getting the same behavior, then it is likely some issue with the 12V supply circuit external to the OBC (EV-ECU, fuse, OBC relay, loose terminal in some connector?...)
Sandrosan
Well-known member
Thanks veeery much Kiev!!
Tomorrow I am going to check all the part of the circuit deeply, which you so gently describe.
But today charging session did not give any fluctuation, just to help me on the troubleshooting....
As I already have swapped the top board few days ago, and the voltage fluctuation remains, the fault should not in it, but we never know.
I will let you know
Tomorrow I am going to check all the part of the circuit deeply, which you so gently describe.
But today charging session did not give any fluctuation, just to help me on the troubleshooting....
As I already have swapped the top board few days ago, and the voltage fluctuation remains, the fault should not in it, but we never know.
I will let you know
coulomb
Well-known member
My guess is that it's the crystal for the processor on the other side of the board (IC701).Matheos said:
Sandrosan
Well-known member
@ Kiev,
thanks very much for the precious additional edit of your previous message that I just noted now.
This morning I removed the external power supply at 5 V and the transistor driver and fix back all in original condition.
Then I traced the circuit and make the draft in this link: https://we.tl/t-weFrPIjrum
Pls check if it correct.
Then I connected my PQA (logger) for monitoring the + 5V (on C705) that supplies the coil and the voltage on the collector of the TR301 together with the charging current.
Unfortunately the main battery was almost full (and there are some weak cells too) and then the charge current was reducing, a not good testing process! In fact the + 5V remanis stable and the voltage on the collector of TR301 too (close to 0 V apart the starting time). So I could not see any voltage fluctuation.
Now I have to discharge the main battery (using heating system it will take some 2 hrs I have noted, but I want to be there in case something goes wrong...).
On the other hand I fully agree on your sentence " Since you swapped the board and are getting the same behavior, then it is likely some issue with the 12V supply circuit external to the OBC (EV-ECU, fuse, OBC relay, loose terminal in some connector?...)".
But first I have to discharge the main battery, charge at full power (14A), hoping the voltage anomaly will appear again and ask the help of a friend of mine.
However I cannot do this today I hope in the next days.
Surely I will keep informed , hoping this will be of help for someone else.
Thanks
PS (Edit) I am wondering if the DC supply voltage circuits in the main board (IC317, IC702 etc and relative components) are involved on making the + 5V ? Or such part of DC supply voltage circuits are supplied by that +5V? Unfortunately such components are on the lower part of the main board that is not accessible without disassambling all the main board (action that I have never done till now and I am afraid of doing it).
thanks very much for the precious additional edit of your previous message that I just noted now.
This morning I removed the external power supply at 5 V and the transistor driver and fix back all in original condition.
Then I traced the circuit and make the draft in this link: https://we.tl/t-weFrPIjrum
Pls check if it correct.
Then I connected my PQA (logger) for monitoring the + 5V (on C705) that supplies the coil and the voltage on the collector of the TR301 together with the charging current.
Unfortunately the main battery was almost full (and there are some weak cells too) and then the charge current was reducing, a not good testing process! In fact the + 5V remanis stable and the voltage on the collector of TR301 too (close to 0 V apart the starting time). So I could not see any voltage fluctuation.
Now I have to discharge the main battery (using heating system it will take some 2 hrs I have noted, but I want to be there in case something goes wrong...).
On the other hand I fully agree on your sentence " Since you swapped the board and are getting the same behavior, then it is likely some issue with the 12V supply circuit external to the OBC (EV-ECU, fuse, OBC relay, loose terminal in some connector?...)".
But first I have to discharge the main battery, charge at full power (14A), hoping the voltage anomaly will appear again and ask the help of a friend of mine.
However I cannot do this today I hope in the next days.
Surely I will keep informed , hoping this will be of help for someone else.
Thanks
PS (Edit) I am wondering if the DC supply voltage circuits in the main board (IC317, IC702 etc and relative components) are involved on making the + 5V ? Or such part of DC supply voltage circuits are supplied by that +5V? Unfortunately such components are on the lower part of the main board that is not accessible without disassambling all the main board (action that I have never done till now and I am afraid of doing it).
Sandrosan
Well-known member
Matheos,
I have learned that many dealers do not know too much, or almost nothing about EV car.... So I would not take too much into consideration such sentence.
I have learned that many dealers do not know too much, or almost nothing about EV car.... So I would not take too much into consideration such sentence.
Sandrosan
Well-known member
Hello to all,
This morning I have discharded the main battery and started the charging process with the max current, so 14A at 230V. Monitoring over time the 12V on pin 12 of CN101 connector , the 5V on C703 and the VCE of the Tr301.
The 12V is 14.2 V while charging.
The 5 V is 5.13V
The VCE is 0.065V approx. (so it is correctely saturated)
All of above voltages without any particular variation / fluctation! Even during the 20 mins pause at zero current (for balacing the celles I guess).
I have not touched anything in paricular from this test and the previous tests when the fluctuation occurs, so the problem is not showing anymore, very unfortunately.
While charging, I tried to move connectors, cables, flat cable, fuse box and 12V batt clips, but no fluctuation anymore....
Now there are 3 bars left to full battery, and no fluctuation.
To find out the problem when there is not the problem is hard
I need more tests and time.
If anyone has any extra advise, they will be welcome. Tks.
This morning I have discharded the main battery and started the charging process with the max current, so 14A at 230V. Monitoring over time the 12V on pin 12 of CN101 connector , the 5V on C703 and the VCE of the Tr301.
The 12V is 14.2 V while charging.
The 5 V is 5.13V
The VCE is 0.065V approx. (so it is correctely saturated)
All of above voltages without any particular variation / fluctation! Even during the 20 mins pause at zero current (for balacing the celles I guess).
I have not touched anything in paricular from this test and the previous tests when the fluctuation occurs, so the problem is not showing anymore, very unfortunately.
While charging, I tried to move connectors, cables, flat cable, fuse box and 12V batt clips, but no fluctuation anymore....
Now there are 3 bars left to full battery, and no fluctuation.
To find out the problem when there is not the problem is hard
I need more tests and time.
If anyone has any extra advise, they will be welcome. Tks.
The link did not show me the schematic, so i could not review it. Maybe you can post it as an image?
It sounds like your test was good but the problem did not occur. Was there anything different--temperature, charge or change the 12V aux battery, etc? An intermittent problem is the most difficult to solve.
It sounds like your test was good but the problem did not occur. Was there anything different--temperature, charge or change the 12V aux battery, etc? An intermittent problem is the most difficult to solve.
If the big ceramic resistors have failed open, then no charging will occur and this will throw a DT Code. The code is stored in the EV-ECU, and it can only be retrieved by individuals and owners using aftermarket CAN buss tools such as an OBDII scantool or with a bluetooth or wifi dongle with one of the android/iOS applications.
The Mitsubishi i-MiEV, Citroen C-Zero and Peugeot iOn service departments all have different software packages and hardware to connect thru the OBCII port and communicate over the CAN buss with much more detail than the aftermarket solutions. Very few owners have been able to obtain these special tools but obviously they are highly desired and many fakes exist, so buyer beware.
The Mitsubishi i-MiEV, Citroen C-Zero and Peugeot iOn service departments all have different software packages and hardware to connect thru the OBCII port and communicate over the CAN buss with much more detail than the aftermarket solutions. Very few owners have been able to obtain these special tools but obviously they are highly desired and many fakes exist, so buyer beware.
