question

Michael.Samer avatar image

Cable from Shunt to BMV700

Hello community

I wonder what sort of protocol the little Shunt to the BMV700 is using. Simple analogue would make it an easy target for crosstalk and interference, while RS232/485/CAN needs a real uC (or better a DSP) at the shunt. As I have no logic analyzer or Osci available so hard to look into.

Background is the resilence to background EMC "noise" like parallel running big power cable (battery) or switching noise (Smartsolar, Multiplus).

Cheers

Michael

BMV Battery Monitorbattery
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3 Answers
Michael.Samer avatar image

Today I received the Cat7 cable and the RJ12 6P6C plugs.

I figured and measured the cable and pairing of my cable:

Pin1 = Vcc (+)

Pin2 = B2 connector (in my version not used)

Pin3 = to Battery GND

Pin4 = to Load

Pin5 = to Load

Pin6 = Vcc (+)

The shielding of the cable is on one side (GND) connected to the Battery - so the shield is working and no groundloops could form.

I tested the cable two times with my LAN meter, which even allowed a 100MBit connect (and complained about GND problems which is as it should be in my case.

The pair1 is P1+3; pair2 is 2+4; pair 3 is 5+6 (Correct me if I'm wrong; I was not willing to disassemble the cable for more than eye proof)

Maybe this helps someone.

I'm now happy to have a shielded cable, even when the measuring surely works quite well thanks to the low Rin of the battery (~40mOhm in my 24*OPzS), but UTP, screens and shielding is better than just UTP :-)

Cheers

Michael

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Michael.Samer avatar image

I wondered if anyone did every replace the UTP cable with a screened or even shielded one. I'm currently ordering a 10m CAT.7 cable (S/FTP) and RJ12 plug to build a "proper" cable for a ten meter connect in noisy enviroment like mine with big power cables running alongside with the Shunt/BMV cable.

Did anyone did such a thing before?

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Michael.Samer avatar image

Strange... my input from yesterday is gone somehow and the change in the subject as well...

Well the tech department answered about the protocol question (which I answered as well in the last reply):

Hello,

There is an analgue signal, so no protocol.


Best regards
Met vriendelijke groet

Johannes Boonstra
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