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Nicolas asked

SmartShunt + Lifepo4 setup (wrong SOC)

SmartShunt setup - wrong SOC


Hello guys, thank you for the great help on this forum.


I just ran out of power after 3 days of almost no solar charge, but I am confused because:

- the Smartshunt indicates 82% state of charge while the batteries are 9.7V. I doubled check with a multimeter and yes the batteries are 9.7v.

- I have 2x150ah=300ah lifepo4, and the Smartshunt indicates a deepest discharge of 118ah, which matches my recent consumption: laptop 5 hours/day 5x3x5ah=75wh, smartphone 5ah x3= 45ah, total: 120ah


My installation:

2x150ah lifepo4 ECOWORTHY batteries in //, with 3x150w solar panels in //, through Victron MPPT SmartSolar 100/50, monitored with the Victron Smart Shunt, and converter / charger Victron Multiplus 12/800.


My questions are:


-Does the SmartShunt not supposed to show 0% as batteries are fully discharged? I previously set the capacities and types of the batteries in the Smartshunt, I synchronized at 100% when batteries fully charged, I calibrated with zero current... what else should be setup?


-The batteries have 300ah, considering a max discharge at 20% I should have been able to get 240ah at minimum. Could my batteries out of services or low quality? What should I do?


Thank you!


when blackout:

screenshot-2022-11-16-184110.jpg


screenshot-2022-11-16-185507.jpg


after full shore recharge:

screenshot-2022-11-17-071133.jpg

only 118ah deepest discharge with 300ah lifepo4 batteries Ecoworthy

screenshot-2022-11-17-071136.jpg

what is strange is that about 3 weeks ago, I went deeper into discharge SOC +/-70%, but the voltage stayed higher. With equal settings.

screenshot-2022-11-17-074628.jpg

The settings:

screenshot-2022-11-16-213044.jpg


Thank you again

SmartShunt
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2 Answers
klim8skeptic avatar image
klim8skeptic answered ·

It appears that your smart shunt has not been set up correctly for lithium batteries.

Please view the BMV Youtube tutorial. and adjust your "charged voltage", "Peukert Exponent", "Charge Efficiency factor", and perhaps "tail Current" accordingly.

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Nicolas avatar image Nicolas commented ·

Thank you @klim8skeptic

If I understood weel, is this setup correct:


"charged voltage" 14.4V

Peukert Exponent" 1.05 (was 1.25)

"Charge Efficiency factor" 99% (was 95%)

"tail Current" 4% (was ok)

"Charge efficiency" 99% (was 95%)

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klim8skeptic avatar image klim8skeptic ♦ Nicolas commented ·

"charged voltage" 14.4V

Charged voltage should be a little bit below your mppt's bulk/absorb voltage. Probably 0.1v-0.2v below mppt bulk/absorb setting.


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klim8skeptic avatar image
klim8skeptic answered ·

Another common problem if for loads or chargers to be wired directly to the battery. This current bypasses the shunt and causes inaccurate SOC readings.

Please refer to the Quick install guide for the Smart Shunt.

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Nicolas avatar image Nicolas commented ·

Thanks, this point was ok

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