question

frankie-elcid88 avatar image
frankie-elcid88 asked

Victron BMV SOC does not increase at all

Recently upgraded to LiFePo from AGM. Using same BMV and MPPT in setup. All wiring to Shunt is correct. Nothing is on battery side, except battery - wire. I do have a known parasitic draw (~.5Ah) on the house battery given the design on my Airstream Interstate. I have Full Charge set to 14.2V per the battery manufacturer (300Ah). Did Sync to 100% SOC and let it sit overnight. What I see is a gradual decrease in the SOC overnight to 13.8V / 92% SOC. In the morning, the MPPT Solar charger kicks in just for a very short period of time (3x100watt panels) and brings the battery voltage back up to 14.2V....yet the SOC stays at 92%. I've repeated this process with a variety of settings...scenario stays the same. SOC never goes up...always down. In the chart below, you can see where I did the reset and then the voltage coming back up and each time the SOC decreases. I am stumped. The only thing I can think of is the manufacturer has documentation that the battery resting voltage @ 100% SOC at 13.6V. 100% SOC charging voltage is 14.4. Maybe I have my battery charged voltage set too high? The MPPT has absorption set at 14.4V and Float at 13.8. Plus, when the MPPT is in Float mode....there is zero current flowing into the battery.


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BMV Battery Monitor
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3 Answers
Trevor Bird avatar image
Trevor Bird answered ·

Can you please provide the settings of the MPPT and the BMV?

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oyfant avatar image
oyfant answered ·

Had some issues with my battery bank.

Did a capasity test and it turns out that my battery actually was 150Ah short of capacity

Typed in New capacity and now it reads fine and SOC follows battery Voltage almost perfectly


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frankie-elcid88 avatar image
frankie-elcid88 answered ·

Here are all my settings for everything:


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1663949640553.png (30.2 KiB)
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