Main HV- contactor not engaging

[alucas]

Hello
I have just finished rewiring my zombieverter into my project car. I had a test setup prior to installing in the car. The setup was a Nissan leaf stack with the leaf batteries. I have experimented with using just the ISA shunt and the leaf BMS and both options worked. I decided to not try and wire the leaf BMS between my split packs and am just using the ISA shunt. When I split the pack I added two contactors to the rear pack that are connected to pin 31 of the VCU, one on the HV- one on HV+. Then I have another HV- contactor on pin 31 in the front pack. I looked up the transistor doing the pull down for this and I seem to remember that it can pull 2 amps which I should be fine. I have not looked up how much current the contactors pull. I did put a 7.5 amp fuse on the power supply for the contractors and it has not blown.

I know that the contactors can work as I tested by grounding the wire connected to pin 31 and they engage. I also know my pre-charge contractor. When I hit start the system triggers the pre-charge relay, then fails as I don't have power to the HV. I also didn't expect to have the precharge turn of if the main HV- contactor was not engaged.

I would like to know if I can tell if the car is in the "ON" state(pin 15 high) and is it trying to pull the HV low. I looked through the web interface spot values and didn't find anything indicating what should be happening. Can anyone point me to something to look at?

[tom91]

You can possibly have blown up your negative contactor output on pin 31.

The zombie closes Negative and Precharge when precharging so if you only have one output triggering the other one could be broken or wrongly configured.

Post your settings to check there are no issues there.

[alucas]

Thanks Tom
I have been experimenting and listening to the clicking of contactors. Here is what I have figured out. When I connect all 3 contactors to ground I pull about 0.5 amp. I opened the system and ON is correct to pin 15, and start is correct pin 52. I then decided to test what would happen if I only had 1 of the 3 contactors connected. I ground/engaged the two in the rear box. This made things work. From the clicking I figured out that when I hit start the HV- and pre-charge engage. I then fail pre-charge because I don't have the disconnect engaged. Then HV- stay's engaged until I turn the power off(pin 15).
My assumption is that the transistors can't source 0.5 amp which seems odd as I thought I looked them up and considered this ok. I think I have a couple options.
1. manually engage the rear box contactors ( I don't like this as why have them)
2. figure out how to replace the circuit on the zombie(I don't want to do this) too much risk and work
3. Add another relay that uses very little power that will drive the rear box's or all the HV- contactors.

If anyone has thoughts on this please share.

Thanks
Aaron

[tom91]

The peak current is ALOT higher then 0.5A

Use a relay to "amplify" the power from the one driver pin