just to add my 2pence.
I've removed the Vic Shunt in my BUS build,
which comprises of:
Roamer SB230Gen4
Vic Cerbo GX-S
Vic Orion XS
AMT12-2
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why did i remove the SHUNT?
to make a simpler install with less kit,
makes a cheaper install cost,
takes up less space,
less devices using parasitic power when idle,
the Gen4 plugs into the Cerbo GX and gives me all the data i need.
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View attachment 278776View attachment 278777
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why would you want to KEEP the shunt?
1- you will see the Shunt in Victron Connect APP. which is nice to look at, . . but not a deal breaker for me as the same data is on VRM, which i now use more.
no Cerbo - then fit a shunt
have Cerbo - shunt not needed.
View attachment 278778
2 - the shunt, if calibrated exactly can detect lower Amp draws,
most Lithium battery BMS will detect power above 0.5A (500mA)
where as the Vict shunt can detect power above 0.01A (10mA) - but in my testing its more like 0.1A (100mA).
this tiny amount of difference will mean, that after some time the SOC % reading of the SHUNT and Battery BMS will differ.
and this tiny amount of difference will have no impact unless the van is parked up for months on end, which will show as a difference in the readings.
again, no problems for me as all do is drive the van and the chargers will top up the battery and re-calibrate everything to 100% anyway.
3 - most battery BMS don't account for there own BMS internal self discharge, and having a SHUNT here wont help you either as the power is used internally and wont show on the shunt anyway. but a good battery BMS will have voltage trigger points in the firmware that will trigger changes in the SOC reading bases on cell voltages alone, even when no current use is detected. - this helps the battery BMS track internal self consumption.
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so unless you plan on leaving your van parked up for months on end and are worried about a few % difference in readings then fit a shunt.
if your not worried about a few % difference per month of a van in storage, - dont fit a shunt.
if you drive the van at least once a week to top up the battery - dont fit a shunt.
if you have solar that will top up the battery , - dont fit a shunt.
if you have access to EHU for top up - dont fit a shunt.
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Remeber all you need to do is charge the battery till its FULL, then everything resets back to 100% SOC anyway.
thats the battery BMS + any shunt you have fitted. - will all reset back to 100%
so any slight % difference is reset anyway.
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that's why i removed my Vic shunt. - for my BUS install.
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now for ballance. . .
my work VAN has a Fogstar 230sb, with no Cerbo intergration, but i have a CERBO GX and a Vic BMV712(shunt)
so i get battery data on the VRM, . . without the shunt i wouldnt see the battery SOC data on VRM,
i had to use the Fogstar APP to see battery data before.
View attachment 278779View attachment 278780
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if you want to have both and fit a shunt. . . we you will see slight differences in SOC readings.
if your OCD about the numbers it will drive you nutts trying to keep them in check with resyncs etc. - dont bother, just charge the battery full.
or just remove the shunt and stick one set of numbers.
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refernce:
vic smart shunt.
View attachment 278781
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Roamer SB230 G4 - BMS detection min not listed that i can see, ( but i believe its 500mA)
but the BMS internal power use is listed.
View attachment 278782
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