Voltage discrepancy query

[robstrom]

4 or 5 intertwined questions, so I'll just post the first for now.

Initial 3 year old build: 2 x 410w on trailer roof, EpEver BN 4215 (40A) w/ MT50 monitor, single SOK 206, Samlex 600/1000 inverter.
Ran great for my intended use, lived in it all last summer away from home, on short notice.
Having to fire up the gen for microwave/ coffee pot got old fast. Sooo,

Upgrade: Samlex 1500/3000 inverter, 2nd SOK 206,Victron LVD, assorted BOS changes.

SOKs are paralleled w dead even =/- to common busbar.
The MT50 and LVD show the same voltage.
The SOK bluetooth (only seeing the new battery) is consistently lower.
At the moment: 13.45 vs 13.15.
I can live w the displays being different. Not an exact science.
It's the why.
The app shows charge/discharge, the other systems don't match up then either.

The question:
Is the old battery carrying more load than the new one, in spite of my OCD cabling?

 

[sunshine_eggo]

The only time voltage measurements will be equal in all conditions is if they are open circuit voltage (OCV) measurements. These are typically direct with voltmeter, shunt or BMS. If OCV values are not in agreement, you are dealing with measurement error.

Chargers that report volage will report higher voltage than OCV.

Loads that report voltage will report lower voltage than OCV.

All voltages should be confirmed with a calibrated/trusted voltmeter. You can order voltage standards for calibrating/correlating your equipment.

 

[robstrom]

Standard useless input ( your norm).
Thanks no thanks.

 

[John Frum]

Initial 3 year old build: 2 x 410w on trailer roof, EpEver BN 4215 (40A) w/ MT50 monitor, single SOK 206, Samlex 600/1000 inverter.
Ran great for my intended use, lived in it all last summer away from home, on short notice.
Having to fire up the gen for microwave/ coffee pot got old fast. Sooo,

Upgrade: Samlex 1500/3000 inverter, 2nd SOK 206,Victron LVD, assorted BOS changes.

If that is a discrete high frequency Samlex inverter rated at 1500 continous watts it may not run your Microwave.
By Victron LVD do you mean Victron battery protect?

The question:
Is the old battery carrying more load than the new one, in spite of my OCD cabling?

Please describe your "OCD cabling".
A picture is usually helpful in this regard.
Is this a 12 volt system?

 

[robstrom]

Vicrton battery protect, yes.
It's the standard available Samlex unit.
12 volt system yes.
OCD = quality cables/ connectors etc.
That's not at issue. Yet.

 

[robstrom]

Combination of 4 gauge/ 2 gauge.
May have to to suck up n go bigger.
Can, but rather work it prior to that

 

[John Frum]

Depending on how your batteries are wired you may be able to determine how equitably they share current using a dc clamp meter.
I'm getting off here.