OffGrid, the Batrium's SoC should not drift much day to day, especially not in one direction.
Not sure how you have your system wired but ALL loads, charging & other connections (incl the Batrium controller) should be to one side of the shunt & ONLY the battery packs (& cellmons) on the other.
There is a known problem where some inverters are electrically noisy & this causes shunt inaccuracy. There's a fix for this out from Batrium I think.
Heavy balancing operation may also make the SoC drift.
Since you don't take your packs to 100%, getting a completely accurate SoC doesn't sound like it's for you.
But since you like to operate your packs in the middle of the range, you could still do an "accurate enough" method eg
- enter the total "full to empty" Ahr capacity you understand your battery bank has (ie full range 4.2V to 3.5 or whatever low end V)
- manually setting the Batrium SoC value based on your existing knowledge of your bank at that time (ie take an at-rest V reading & decide the SoC from that).
- occasionally (weekly?) manually rechecking the voltage at-rest SoC & re-entering the SoC
You would see the SoC cycling say 85% down to 40% or whatever the range is for you.
Will this be perfect? No. But since you're operating in the middle of the range this should let you relax a bit & start using coulomb SoC from the Batrium system.
Hopefully the SoC corrections should only be small eg <5% or better maybe <2%
If you are getting big corrections at first, the values or pack connections might be wrong to start with.
If, later, you start getting increasing corrections being needed, this might indicate a developing pack problem.
Re DoD, this is basically the same as the low end of SoC.
Not sure how you have your system wired but ALL loads, charging & other connections (incl the Batrium controller) should be to one side of the shunt & ONLY the battery packs (& cellmons) on the other.
There is a known problem where some inverters are electrically noisy & this causes shunt inaccuracy. There's a fix for this out from Batrium I think.
Heavy balancing operation may also make the SoC drift.
Since you don't take your packs to 100%, getting a completely accurate SoC doesn't sound like it's for you.
But since you like to operate your packs in the middle of the range, you could still do an "accurate enough" method eg
- enter the total "full to empty" Ahr capacity you understand your battery bank has (ie full range 4.2V to 3.5 or whatever low end V)
- manually setting the Batrium SoC value based on your existing knowledge of your bank at that time (ie take an at-rest V reading & decide the SoC from that).
- occasionally (weekly?) manually rechecking the voltage at-rest SoC & re-entering the SoC
You would see the SoC cycling say 85% down to 40% or whatever the range is for you.
Will this be perfect? No. But since you're operating in the middle of the range this should let you relax a bit & start using coulomb SoC from the Batrium system.
Hopefully the SoC corrections should only be small eg <5% or better maybe <2%
If you are getting big corrections at first, the values or pack connections might be wrong to start with.
If, later, you start getting increasing corrections being needed, this might indicate a developing pack problem.
Re DoD, this is basically the same as the low end of SoC.