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CANBUS cable

5689 Views 9 Replies 5 Participants Last post by  MemphisPapa, 
M
So I have been back and forth with a Chinese company (cough-BestGo-cough) about a charger that won't pick up the message to begin a charge cycle. My BMS is getting the CAN message and I can see the CAN message going to the charger. My BMS support has pointed out that not all CANBUS transceivers are created equal. I suspect that my cheap Chinese charger has a cheap transceiver and is unable to pick up the messages over my dirty cable. I have chopped the stubs to only 8" and have soldered all my wire connections. I have a BT scan tool that is working okay with Torque. All my communication with my BMS is over the CAN which works fine too. I can actually see the message from the charger that shows the communication failure. Does anyone have a special technique to build a solid CANBUS cable that might help resolve my cheap charger issue? Evidently, the charger won't work unless the CAN message is received by the cheap charger transceiver... lesson learnt, buy American.
Thanks.
dh
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M
I have 120 Ohm termination resistors at the physical ends of the cable. The cable is a shielded twisted pair of stranded 22. The connector at the charger doesn't have a signal ground, so only the high and low are connected. I tried leaving the shielding exposed to clamp in the back of the connector, but it didn't make a difference. I don't have an o-scope , but I suppose it is time to try and find one.
Does anybody have a technique to build the stubs off the main bus cable?
Thanks
dh
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M
I have an Orion BMS. All the messages on the bus are adjustable. I'll try reducing the messaging. The Torque scanner alone send out about eight though. Not exactly what I would call quality on the charger side for the CAN.


No change after I stopped all but the charger message. I'll find an o-scope, but I suspect a defective charger.
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I found an o-scope. Here are the images (High and Low). I physically cut my CAN cable, stripped the wires, and soldered them all together. I used electrical tape to keep them separate. I did my best to keep the twist going. I also ensured the electrical connection of the shielding. It has been a while since I used on o-scope, but I think this is the expected result.

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