Sarah avatar image
Sarah asked

Lynx Shunt VE.CAN SOC Percentage Anomaly

fdd8bc76-ee50-4ff9-ab9d-99905d48f9e3.jpeg9c634882-215e-497f-b346-1b1c6fbd7fbb.jpegHi all, this maybe a config error, firmware bug or complete misunderstanding on my part. I have a Lynx Shunt VE.CAN and Cerbo GX (both have up to date firmware). I also have four AGM 12 V 280 Ah batteries in parallel (1120 Ah in total). The state of charge currently reads 85% whereas the consumed amp hours reads 298 amp hours. Given the consumed amp hours and the battery capacity I would have expected the SOC to read 73% and not 85% (my assumption has been that SOC is calculated directly from consumed amp hours). The battery bank capacity has been set to 1120 Ah. Thanks for you input.

lynx shunt
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1 Answer
Paul B avatar image
Paul B answered ·

The SOC is not calculated from the A/H used and added info as far as I am aware.

the SOC is the net of the used amps and the charge amps (adjusted for the Peukert’s Law calculation) and if its been a long time since its been reset to 100% you will get a error or a comparison error.

yes they should in theory be the same but I think they are two different fields and thus they can drift apart

ie the amp ours used graph maybe at 0 A/Hs used as the direct maths says so - but the SOC maybe at 80% because it has not meat its requirements to reset itsself to 100% and has droped out of sync over a period.

These figures are all a little bit variable and every battery is different - and then the Peukert's figures % change over time as the battery ages as well.

I myself only used those figures a guild and always compare to voltage to them as well. Voltage Based on NO load draw and NO charge for min of 30 min


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Sarah avatar image Sarah commented ·

Thanks for the answer - I forget how inconsistent these results can be. It has probably been at least a ten days since the batteries were 100%. Will do a synchronise when I know the batts are charged and see how they track.

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kevgermany avatar image kevgermany ♦♦ Sarah commented ·
It should synch automatically. But look at your charging and detection settings.
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Sarah avatar image Sarah kevgermany ♦♦ commented ·

Thanks @kevgermany. It is interesting because the last time the consumed amp hours and SOC were reset to 0 and 100% was only five days ago. I am surprised that the drift was so substantial in such a short period of time. One possibility is that We only drop below 90% SOC occasionally so perhaps this doesn’t count as a full synchronisation. I will monitor more over time. Please ignore the battery charged voltage in the image this is normally higher (.2 volts below float voltage).

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