Inside Look of 2018 On-Board Charger (OBC2) OBC Gen 2

[kriiise]

It's not clear to me exactly where this tiny spark was, but it's near a gate (left) lead. Perhaps it was a gate component arcing internally.

Yeah, i drew the arrow on my phone without zooming properly. The sparks came from the tiny bits and bobs to the left (in the image) of the gate lead(?) of the transistor. It may well have been from inproper cleaning after the last blow. All i did was spray a bunch of electric cleaner in the areas where i could see marks from the last blow.

replace the damaged transistors again, then test and as necessary repair every gate component before re-applying power.

Is there any way you can explain how to test the gate components for someone with a very basic knowledge of PCBs? Someone who calls the smaller parts for bits and bobs If you'd have to explain 6 months of college level engineering, then i get it if you can't be bothered :lol:

 

[coulomb]

Is there any way you can explain how to test the gate components for someone with a very basic knowledge of PCBs?

It's a matter of testing the components that drive the gate. Usually, that's resistors, diodes, driver transistors, and chips. The resistors can often be measured directly with a multimeter, but it helps if you understand how circuits work so that you won't be surprised when other circuit elements cause a resistor to read lower than its nominal value. Diodes can also be tested with a multimeter; they should read about 0.6 V in one direction (0.4 V for the larger ones) in the forward direction, and open circuit (on the diode range at least) in the reverse direction.

Chips and transistors usually have diodes in them, and for this sort of testing you can treat a bipolar transistor as two diodes in anti-series. Most chips and MOSFETs have diodes as well. Gates should read open circuit. The diode checking works well, because fault currents usually cause diodes to fail, usually short circuit, but occasionally open circuit or high leakage (medium resistance).

After these checks, I usually like to perform a powered test of the gate driver at DC. So with the circuit powered up and a multimeter measuring the gate to source or gate to emitter voltage, I'll short something to cause the gate voltage to change. Usually this requires the big transistors not to be soldered in place yet. In other words, you take out the old transistors, do the test, then solder in the replacements.

If this sounds complex, it gets much easier with time and familiarity. Not something you can really convey in a post, sorry.

 

[iOn_2017]

Hello

The discharge resistor R100 on the mains filter on the onboard charger has burned out.

I installed a used onboard charger. After charging it several times, the RCD switch tripped again. It made another bang. The resistor probably burned out again.

Does anyone know which resistor is installed here? What could be the cause?

I want to post a photo but I couldn't register.

Thanks.



Greetings from Thomas

 

[iOn_2017]

This are the pictures from the damaged board.

 

[iOn_2017]

I open the onboard charger i bought second hand. There exploded two power transistors. On the buttom on the board of the main filter the Resistor R100 is ok. It´s an 220 k Ohm resistor with 1W.

I have fear that there is a problem with the DC/DC converter that cause the problems on the onboard charger.

The problems happens in the cold season. The car stands outside. The temperature was below zero degrees.
The resistor was damaged, when I load with the Peugeot charging kable from the grid.
The power transistors damaged, when I load with the Peugeot charging kable from my inverter (Victron MultiPlus II) from the solar panels with battery storage.

I also use a wallbox with Simple EVSE. I load with 5,5 A.

 

[kiev]

Cold temperatures put a heavy load on the 12V lead acid battery, especially if it is old, weak or worn out.

Check the capacity of the 12V and verify it is good and strong, otherwise you are asking for problems such as this.

If the 12V glitches during charging then damage will occur in the OBC.

If the AC glitches during charging then you can also suffer damage in the OBC, e.g. massive overvoltage damage to R100 and FETs

Probably better to use clean mains AC for charging, and leave the inverter and other clever AC generators for loads that don't care about sinusoidal, stable AC supply.

 

[iOn_2017]

Thanks.

I will change the lead acid battery. The Battery is 7 years old. And I will only load with the power from the grid.

I change the resistor R100. The ODB works perfekt.

Is it possible to change the FETs? May other components also be defective or probably only the FETs?

 

[iOn_2017]

I will only charge the car in the cold season after driving.

I have a picture form the main switch under the seat. I'm wondering if the dark discoloration was caused by heat.

 

[kiev]

FETs can be changed, see coulomb's posting in this thread about checking the drivers for damage also.

There does appear to be thermal discoloration on the HV disconnect.

Was this car involved in an accident?

 

[iOn_2017]

I see the post from Coulomb after making my post with the FETs. I take a look at my damaged FETs. It look, they are destroyed between source and drain. When I habe problems with my ODB I try to repair the FETs. Then I would try to just cut off the transistor feet and solder on the new FETs without removing the board.

The iOn has not had an accident yet.