Power cable shielding

[arber333]

I opened this topic so we can share experience on power cable EMI and how to shield sensor cables from them.
In my EV i identified three problems.

1. my EVdisplay gets swamped on acceleration and while it is working good its signal is translated from sensing unit by a LAN cable. I think i need to shield either my LAN cable or my phase cables so EMI doesnt distort the signal too much.

2. My speedo works quite good while i have wheels in the air. On the road however it starts to throw needle wildly. This meens signal is also swamped inside EMI. I will also shield the signal cable from speedo sensor which is a magnetic hall sensor.

3. While accelerating i get ticks from the axle/motor that i feel on my steering wheel. That means
a) a bearing or brake has something to tell me or
b) hall sensors cant keep up with magnet rotation and phase jumps the magnet and gets a momentary bump.
I also see this as a product of EMI

I am battling this EMI in some ways that i know of:
1. I will put every phase cable in braiding mesh and then close it in orange wrapping. Similar what Leaf motor had in original
I will connect all meshes together and finalize connection with one piece of mesh going to car chassis

2. I will use a smaller wrapping for my sensor cables and also ground them to car chassis.

3. I am not sure what to do with DC cables. They are some 4m long! I dont have such a long mesh tube. Do you think i could just use s 1 or 2m length DC cable wrap and terminate it at inverter end towards chassis?

I found a reliable way of getting a phase cable size of shield mesh. I bought/got a 18p or 24p marked signal cable with shielding and i used numbered signal wires for inverter interface harness. I cut off the cable in desired lengths and carefully took off the shield. Then i bunched both ends together to expand the shield. I put it over phase cable and fixed in one end. Then i pulled on the other end so it naturally closes around the cable. I fixed both ends and in between with plastic zipties.
I expect you could get special Liycy cables with shielding for signal cable, but i need LAN cable and it is a bit awkward format. So i will get a special shielding and will install it over my UTP cable. https://www.tme.eu/en/details/hegemipv0 ... 173-60600/
P.S. i cant use shielded FTP cable since EVdisplay needs to be isolated from chassy because of voltage measurement. GND connection is one the same plane with - DC cable. So shield needs to be separate.

What do you think of shielding termination and what are your experiences. Do i need to fit one side termination or double one on each side? Do you have an argument pro/contra?
Do you have an alternative way maybe, something i havent considered yet? You are welcomed to suggest...

I must admit i used a one sided termination up to now and it worked in Mazda. But that is a simple car with hardly any complex electronics.

[joromy]

Signal wiring.

If you look at the new EV's there is no long analog/signal wires. Everything is CAN bus.
Cast "heavy" aluminium enclosures. They don't save on weight there?

In old EV's like the Ford Ranger 1999, there is no shielded wires.
Where there is long analog/signal wires, it's twisted, 12V and "high" current.
Cast "very heavy" aluminium enclosures.

In many DIY project, there are low volt and low current on many of the analog circuits.
Plastic enclosures!!

Some options:

1. Shield all signal wires and AC HV, best practice is to ground at both ends. I use copper tape, when I don't want to change wire/connector or use braided sleeve.

2. Go all can bus, Isabellenhütte is a good option. (don't know for encoder, but there is probably some CAN)

3. 12V and higher current, check max volt and current for sensors/endoder and add some low termination resistor.

BTW. if you need to shield your DC HV, then there is something very wrong. (check filtering, charger or inverter)

[arber333]

Well yes, like i said i will shield phase cables primarily.
Just in case i will also shield my sensor wires for speedo, because i added the sensor additionally.


Also for EVdisplay i found one FTP cable and cut the shield before connector. I pulled some of it out of the insulation and fixed a wire with eye connector on it. Reason is that i want to pull the shield to GND level not to BATT-. Well see how it goes when i assemble the battery box back.

Also i affixed motor and connector with the same braids so they are grounded to one another and to GND level.

[arber333]

I have success! I used Liycy cable for speedo signal and i now get steady dial response from speedo.

My EVdisplay wouldnt work with heavy load, which lets me to believe that signal cable in paralell with DC cables are not a good idea. I used another LAN cable which i routed through a side window in the cabin and connected display that way. It works good!

Since i shielded my phase cables what remains is to shield DC cables. It will be tougher, but i think it is worth it because i can then use the exhaust channel to rout other cables too.

Hm... i may use those light steel tubes to route DC cables and then finish off with braided wrap.

[johu]

I had mixed up signal and DC cables in exhaust tunnel and CAN was very disturbed. That said only part of the DC cable is shielded and of course the contactors aren't shielded. Is the Pugs underside covered with plastic? Might be worthwhile taking it off, could reveal some wiring opportunities.