Opel Ampera battery extender

[arber333]

I made my setup work again. This time it seems it wont throw a DTC when stopping shortly with both batteries still full.
https://wordpress.com/post/leafdriveblo ... s.com/1910

I am turning contactor ON with DCDC Enable signal.

Edit: Dang! Again i got DTC for "service HV system..." It seems HPCM2 module knows when a second battery is connected. From the fact that energy keeps flowing after main contactor is off. This annoys it and so it signals DTC.
I will try to connect SimpBMS and use it to delay contactor for 2s. Maybe when on start second battery will be off system will calm itself down.

[johu]

As this thread is rather important I will move it to the Opel section where it is easier found

[arber333]

If you would move the current sensor in the main battery to the wire between contactors and junction point of the batteries then current flowing between batteries won't be measured and won't cause any problem to the car.

Hm... i was thinking lately... if i would put the second HV+ cable from the rear battery through current sensor i would get complementary signal from both battery positive lines. Complete picture would remain the same.

But really what got me thinking was your comment on the delay between both contactors. Whatever the action i would need to take care of delaying positive contactor on the trunk battery. That way the OEM battery would be fully turned on. I think 2s should do it.

[Ejc1992]

for the IGBT can you outline the gate and m4 emitter connections? I see you have the main battery connected on the emitter and the VW cells to the collector (I assume for the passive diode in the IGBT). Are you using the transistor portion at all? it looks like there are connections.

[arber333]

for the IGBT can you outline the gate and m4 emitter connections? I see you have the main battery connected on the emitter and the VW cells to the collector (I assume for the passive diode in the IGBT). Are you using the transistor portion at all? it looks like there are connections.

NO, transistor GE pins are closed so transistor is open all the time.
IGBT diode is mounted on the positive line in reverse so that only main battery is allowed to see positive terminal of the additional battery.
Also you need to pick an IGBT larger than your max expected current and mouhnt it on some cooling thing. I noticed diode can get really hot.