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DMOC 445 Contactor Not Closing

2484 Views 5 Replies 3 Participants Last post by  rclugnut
I know this is covered in other threads, but not to the level that it helps me with my problem. I've been having this issue for several months now and I'm just not smart enough to figure it out on my own...

Here's the backstory:
I bought a brand new DMOC 445 and AC24LS directly from Azure just a few months before they went under (when Azure and Electro Auto had the discount). I have the high-voltage setup; 100GBS batts in series (currently showing as 340V at the HV terminals). I ran the motor several times with no issues.
Then it just quit working. No contactor click, no ccShell interface. I sent it to Gary Snyder and it worked fine for him. He sent it back to me and it worked again for a couple of months (maybe used 4 or 5 times).

Now it's just the SOS. No contactor click, no interface.
Last weekend, I tried rigging up a new 35-pin connector with just the basic connections as detailed in the Troubleshooting portion of the DMOC guide, but even that didn't work.

Any thoughts or suggestions would be greatly appreciated!

1 - 2 of 6 Posts
What are you using for a +12v supply for the DMOC? I have not had a chance to look at a DMOC, but I've repaired many UMOCs that needed the contactor dismantled and cleaned.

You need to make sure you 12v supply is solid, if its too low the DMOC wont show an interface, or close the contactor.

The contactor also wont close if the batteries are under the Low Voltage setting of the DMOC.
I'm using a typical 12V car battery. I think it has about 650 Cranking Amps. I'll check the voltage again (it has been cold lately), but it used to be right at 12V.
One possible issue may be that it's wired through a switch that also controls the BMS... I'll rig up a direct connection to see if this helps.

Thanks for the comment!
12v for a car battery is pretty low, it should be around 12.6-12.8v after a full charge.
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