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willow2022 avatar image
willow2022 asked

SOC shows 100% but not exactly

51ae181c-c02a-48a6-9e1c-253a328b1dc8.jpegI notice that my batteries never reach float or maximum absorption (unless I plug into shore power) because my SOC is already 100%. For example, if my SOC reads 50% and there’s enough sun, my SOC will get to 100% but my batteries don’t show full absorption. However, if my SOC has the same 50% reading and I plug into shore power, the batteries will eventually go to float after absorption, but when I unplug, they instantly drop to a reading of around half full despite the SOC still reading 100% It will maintain voltage and work fine, but I notice I will lose power and get a low battery warning when the SOC reads 30%-45%. There also is an exclamation point on the settings icon in the top right of my VE.Bus Smart HQ21083Y19T page, but when I go there, there is nothing that indicates an issue. Above are screenshots of that page before I unplug and directly after unplugging from shore power with charger on float and SOC reads 100%. What needs to be done? Thank you kindly and in advance for any ways to rectify this and get things synced up again.



SOCmultiplus ve.busvictron
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2 Answers
snoobler avatar image
snoobler answered ·

Are you strictly using the inverter's battery monitor, or do you have a separate battery monitor (BMV or smartshunt)?

If using the inverter's battery monitor, it can't see incoming charge from solar. It only sees what goes in and out of the battery through the inverter.

The battery being at 100% SoC will not prevent solar charging.

If your "half full" refers to the graphical image, ignore it.

An overview of your system's design/configuration would be helpful.

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willow2022 avatar image willow2022 commented ·

I have the BMV monitor so I can see what I’m taking in from the panels. However, I remember the graphical image always staying close to full when fully charged. I can ignore the graphical image, but what I can’t ignore is having a SOC of 45% and receiving a “low battery” warning and shortly losing power afterwards. I’ve attached a shot of my set-up and settings. This is being powered by 3 x 200 watt panels on the roof. 2b2a0f70-3814-4b99-996e-bef8057ae84a.jpeg



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willow2022 avatar image willow2022 commented ·

System Settings


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kevgermany avatar image kevgermany ♦♦ willow2022 commented ·
Which type of batteries are installed?
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kevgermany avatar image kevgermany ♦♦ willow2022 commented ·
Please add a screen shot of the charge settings of the solar controller
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snoobler avatar image
snoobler answered ·

The images you originally included were from the inverter.


You have the BMV incorrectly configured.

Charged voltage should be 0.2V below absorption voltage when charging with solar. If you don't do this, you will get false syncs to 100%.

BB should be charged to 14.4V, so BMV charged voltage should be set to 14.2V.

Tail current should be 6%. BB LFP batteries are fully charged at 0.05C (5%)

This is why your SoC jumps to 100% prematurely and you're getting low voltage warnings at 45% - you're not getting fully charged - likely due to insufficient solar and compounded by incorrect SoC.

Your batteries are not fully charged until they achieve 14.4V, and the current has dropped to below 15A@14.4V. This is the only time BMV should sync to 100%.


MPPT should be set to:

14.4V absorp

13.5V float

Fixed absorption period, 30 minutes

Tail current 15A


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