I own a BlueSolar 75/15 along with a V.E. Direct Bluetooth Dongle. My MPPT controller is consistently reading the battery voltage 0.2 volts too high. To use an example, measuring the voltage with a professional grade multimeter on the battery terminals as well as directly on the MPPT controller's battery connections reads 25.5 volt. The Victron app reads 25.7 volt.
The obvious problem with this is that my battery doesn't get fully charged. While the controller thinks we are full at 25.7 volt, the battery is only at 25.5 volt.
I went over the installation and all cables. I re-cut the battery connection cable ends and attached them well to the battery as well as the controller. Everything is snug, it's a simple installation. Still, the 75/15 is consistently reading 0.2 volts more than my multimeter.
I disabled the temperature compensation to temporarily let more volts into the battery to not discharge it too much. With temperature compensation disabled I get closer to full, but that is a hack at best and dangerous at worst.
Is this a hardware issue or something that can be calibrated by me? Are there any workarounds?