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czarofak avatar image
czarofak asked

Motorhome setting issues

Dear all,

i have the following system installed in my motorhome:

drawing.jpg

  • The BMS is the Stuart Pittaway's "diybms v4" connected via BMS-BUS, which is working very reliable!
  • the Battery Shunt is coupled with the diybms
  • there is a second shunt (victron smart shunt) configured to measure DC-power
  • ESS is off, DVCC is on.

I have got three issues which i was not able to solve yet:

  1. The System does not keep the battery on 100%, even with shore-power
  2. The System does not priorise the MPPTs over the Multiplus to charge the batteries
  3. The Multiplus (Compact 1600W) is showing "external control" at all times

Below a screenshot of my VRM:

1680761033241.png

MultiPlus Quattro Inverter ChargerSOCDVCCshorepowerdc meter
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2 Answers
derrick thomas avatar image
derrick thomas answered ·

#1 what source do you have selected for battery monitoring, and what are your settings for charging parameters?


#2 this is by design, it is doing what it is supposed to. If you want to only use mppt even when connected to shore power, you will need to setup an assistant in the multi to ignore ac input, or turn off charging on the charger tab. ESS is not for use in a mobile environment.


3# the multi shows external control because the bms is telling it what to do as far as charging is concerned.

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czarofak avatar image czarofak commented ·

#1, diybms shunt, which feeds its values through bms-can to the cerbo.

do you want the values from the multiplus or diybms?

#2, i thought so... i will have to check that back home.

#3, ok. It would be helpful, to show the "ext control" as a second label not instead of the true op mode.

i will try to leave the CCL, DCL and CVL empty in the bms (for normal operation) and control those values through the cerbo's dvcc.



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derrick thomas avatar image
derrick thomas answered ·

I have found that not all bms (talking about bms's we use in the diy world) are very accurate at calculating SOC. My Daly bms for example loses about 1% per day. My Daly bms is connected to the cerbo but my battery monitoring is selected to the 500 amp smart shunt because it is much more accurate. I have dvcc active and use a node red flow for dynamic voltage and current control. Much better than just letting the Daly try to do it's thing.

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Related Resources

DVCC chapter in GX manual  

Additional resources still need to be added for this topic